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Primary CNS lymphoma (PCNSL) in immunocompetent patients is a disease of older adults who are often unsuitable for the high dose therapy or experience substantial morbidity from whole brain radiotherapy. As therapeutic studies in older patients are limited, there is a need for real world data to guide patient care. Here we report a series of 38 consecutive immunocompetent patients with PCNSL treated with curative intent using R-MPV/Ara-C with omission of consolidative radiotherapy in older patients. Outcomes for patients aged60 years and60 years were similar with overall response rates of 100% vs 85%, (

LEOPARD was a single arm, phase II study of lenalidomide (LEN) and alternate day prednisolone maintenance in patients with newly diagnosed multiple myeloma (MM) following autologous stem cell transplantation (ASCT). Sixty patients were enrolled. Estimated median potential follow-up was 44 m, median PFS was 38.3 m, median OS was not reached (landmark 36 m OS: 71.4%). Correlative immunohistochemistry performed on pre-ASCT trephines demonstrated high MM tumor cereblon (total/cytoplasmic) was associated with superior OS (p = .045, p = .031, respectively), whereas high c-Myc was associated with inferior PFS (p = .04). Patients with high cereblon (total/nuclear) were more likely to improve depth of response, whereas patients with high c-Myc were less likely, suggesting alternative/more effective post-ASCT strategies for patients with high c-Myc need identification. Peripheral blood immune profiling (mass cytometry) informed a more sustained response to LEN maintenance, demonstrating enrichment of activated/cytotoxic NK cells and cytotoxic T cells in patients with durable responses, contrasting with enrichment of B-regs in early relapsers.

The title "great imitator" refers to conditions which can cause varied manifestations and mimic many diseases. Lymphoma is worthy of this title. We describe three cases of lymphoma in which lymphoma mimicked other diseases causing neurological dysfunction, specifically sarcoidosis, vasculitis and infection respectively. Case 1 was a 66-year-old man with subacute progressive diplopia and gait disturbance and investigations revealing a supratentorial para-falcine soft tissue lesion, mid-thoracic cord enhancement and right axillary mass and an elevated serum ACE. Right axillary mass core biopsy was diagnostic of Burkitt lymphoma. Case 2 was a 50-year-old man with several weeks of constitutional symptoms and development of lower limb weakness and numbness, urinary retention and confusion while in hospital. MRI brain demonstrated multi-territory cerebral infarcts. Intravascular lymphoma was diagnosed on random skin biopsy. Case 3 was a 65-year-old man with several weeks of headache and diplopia on a background of previously treated Burkitt lymphoma. CSF analysis showed a lymphocytic pleocytosis and markedly low glucose with cytologic analysis negative for malignancy. Investigations for an infective cause were negative. FDG-PET demonstrated marked, disseminated spinal and cranial leptomeningeal disease and a multi-focal, intra-dural relapse of Burkitt lymphoma was diagnosed. The varied manifestations in our cases demonstrate the ability for lymphoma to mimic infective, inflammatory, granulomatous (including sarcoidosis) and neoplastic aetiologies. An elevated serum ACE appears insufficiently diagnostic to confirm sarcoidosis and tissue for histological examination should be sought whenever possible. When the diagnosis is uncertain, the possibility of this great imitator should be considered, especially for multi-focal disease.

PURPOSE Oral melphalan and dexamethasone (MDex) were considered a standard of care in light-chain (AL) amyloidosis. In the past decade, bortezomib has been increasingly used in combination with alkylating agents and dexamethasone. We prospectively compared the efficacy and safety of MDex and MDex with the addition of bortezomib (BMDex). METHODS This was a phase III, multicenter, randomized, open-label trial. Patients were stratified according to cardiac stage. Patients with advanced cardiac stage (stage IIIb) amyloidosis were not eligible. The primary end point was hematologic response rate at 3 months. This trial is registered with ClinicalTrials.gov identifier NCT01277016 . RESULTS A total of 109 patients, 53 in the BMDex and 56 in the MDex group, received ≥ 1 dose of therapy (from January 2011 to February 2016). Hematologic response rate at 3 months was higher in the BMDex arm (79% v 52%; P = .002). Higher rates of very good partial or complete response rates (64% v 39%; hazard ratio [HR], 2.47; 95% CI, 1.30 to 4.71) and improved overall survival, with a 2-fold decrease in mortality rate (HR, 0.50; 95% CI, 0.27 to 0.90), were observed in the BMDex arm. Grade 3 and 4 adverse events (the most common being cytopenia, peripheral neuropathy, and heart failure) were more common in the BMDex arm, occurring in 20% versus 10% of cycles performed. CONCLUSION BMDex improved hematologic response rate and overall survival. To our knowledge, this is the first time a controlled study has demonstrated a survival advantage in AL amyloidosis. BMDex should be considered a new standard of care for AL amyloidosis.

Introduction Patients (pts) with relapsed/refractory (R/R) higher-risk myelodysplastic syndromes (MDS) have a dismal median overall survival (OS) of 4.3 - 5.6 months (mos) and a 1-year survival probability of 28% after failure of the 2 approved hypomethylating agents (HMAs) azacitidine (Aza), and decitabine (Dec). There is no existing standard of care for pts after failure of HMA therapy; hence, there is a critical need for effective therapeutic strategies. Venetoclax (Ven) is a selective, potent, oral BCL-2 inhibitor that in combination with Aza improved clinical outcomes as frontline therapy in pts with higher-risk MDS in an early phase clinical trial. We present an updated analysis of the safety and efficacy of Ven+Aza for the treatment of pts with R/R MDS. Methods This ongoing, phase 1b, open-label, multicenter study (NCT02966782) evaluated the safety and efficacy of either Ven monotherapy or Ven+Aza combination. Pts enrolled and treated with Ven+Aza were ≥18 yrs with R/R MDS and Eastern Cooperative Oncology Group performance status ≤2. Pts were considered R/R if they received a prior therapy with no response or had a response but subsequently relapsed after receiving at least 4 cycles of Aza or Dec within the last 5 yrs. Pts were excluded if they had myelodysplastic/myeloproliferative overlap neoplasms, had prior therapy with a BH3 mimetic, or underwent allogeneic hematopoietic stem cell or solid organ transplantation. For the Ven+Aza combination, pts were treated with escalating oral doses of Ven: 100, 200, or 400 mg daily for 14 days (d) every 28-d cycle. Aza was administered at 75 mg/m 2/d on 1─7 d every cycle. Responses were assessed per modified International Working Group 2006 criteria. Results Due to limited efficacy with Ven monotherapy, this analysis focuses on outcomes in pts treated with Ven+Aza combination only. As of April 30, 2021, 44 pts were treated with Ven+Aza (male 86%, median age 74 yrs [range 44-91]). Prior to enrollment, pts received a median of 1 HMA regimen and 65% of pts received >6 cycles of HMAs. The median follow-up was 21.2 mos, range 0.4 ─ 37.5. Pts received a median of 4 cycles (range 1 ─ 32) of Ven treatment. Forty-two pts (96%) reported ≥3 grade treatment-emergent adverse events (AEs). The most common ≥3 grade hematological AEs were febrile neutropenia (34%), thrombocytopenia (32%), neutropenia (27%), and anemia (18%). Pneumonia (23%) was the most common ≥3 grade infection. Serious AEs were reported in 61%. There were 29 (66%) deaths, of which 1 (2%) occurred ≤30 d after the first Ven dose, and 3 (7%) occurred within ≤60 d of first dose. Nine (21%) deaths occurred due to disease progression, and 4 (9%) were due to AEs (gastrointestinal hemorrhage [n=1], and infections [n=3]). Twenty-one (48%) pts required Ven dose interruptions due to an AE, most frequently due to febrile neutropenia (n=7; 15%) and neutropenia (n=4; 9%). Five (11%) pts required dose duration reductions, and 9 (21%) pts required Ven discontinuation. Fifteen (34%) pts were alive at the time of data cutoff. The objective response rate (mORR, defined as complete remission [CR] + marrow CR [mCR] + partial remission [PR]) rate was 38.6%, observed in 17 pts (CR 3, mCR 14, PR 0). Median time to first response of CR or mCR was 1.2 mos (range 0.7 ─ 6.3), and the duration of response for mORR was 8.6 mos (95% CI 6.0 ─ 13.3) (Fig A). Overall median progression-free survival was 8.6 mos (95% CI 5.4 ─ 14.3) and median OS was 12.6 mos (95% CI 9.1 ─ 17.2); mOS for pts with mORR was 14.8 mos (95% CI 11.3 ─ not estimable) (Fig B). Six pts with mCR also achieved hematological improvement. Post-baseline RBC and platelet transfusion independence (TI) was achieved by 16 (36%) pts overall with a median first duration of 4.0 mos (range 1.9 ─ 8.3). Nine pts (20.5%) moved to post-study transplant. Nine pts (20.5%) progressed to acute myeloid leukemia (AML). The median time to AML progression was 4.97 mos (range 0.03 ─ 19.84), and the median time to subsequent therapy was 5.7 mos (95% CI 4.8 ─ 8.8). Conclusion With longer follow-up, the tolerability and efficacy of the Ven+Aza combination in pts with R/R MDS were consistent with what was previously reported. In a very difficult-to-treat pt population, an ORR of 39%, RBC and platelet TI rate of 36%, and a median OS of 12.6 mos all suggest that Ven+Aza treatment leads to meaningful clinical benefits. Additional analyses, including associations of genetic mutations with clinical outcomes and patient-reported outcomes, will be presented. Figure 1 Figure 1. Disclosures Zeidan: Daiichi Sankyo: Consultancy; BeyondSpring: Consultancy; Kura: Consultancy, Other: Clinical Trial Committees; ADC Therapeutics: Research Funding; Amgen: Consultancy, Research Funding; Aprea: Consultancy, Research Funding; AbbVie: Consultancy, Other: Clinical Trial Committees, Research Funding; Geron: Other: Clinical Trial Committees; Agios: Consultancy; BioCryst: Other: Clinical Trial Committees; Genentech: Consultancy; Boehringer Ingelheim: Consultancy, Research Funding; Astellas: Consultancy; Astex: Research Funding; Pfizer: Other: Travel support, Research Funding; Jazz: Consultancy; Jasper: Consultancy; Ionis: Consultancy; Epizyme: Consultancy; AstraZeneca: Consultancy; Janssen: Consultancy; Gilead: Consultancy, Other: Clinical Trial Committees; Incyte: Consultancy, Research Funding; Novartis: Consultancy, Other: Clinical Trial Committees, Travel support, Research Funding; Loxo Oncology: Consultancy, Other: Clinical Trial Committees; Cardiff Oncology: Consultancy, Other: Travel support, Research Funding; Acceleron: Consultancy, Research Funding; BMS: Consultancy, Other: Clinical Trial Committees, Research Funding. Borate: Genentech: Membership on an entity's Board of Directors or advisory committees, Other: Advisory Board; Jazz Pharma: Research Funding; Daiichi-Sankyo: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees; Blueprint Medicine: Membership on an entity's Board of Directors or advisory committees; Astellas: Membership on an entity's Board of Directors or advisory committees; incyte: Membership on an entity's Board of Directors or advisory committees, Research Funding; Rampal: Membership on an entity's Board of Directors or advisory committees; Galecto, Inc.: Consultancy; Promedior: Consultancy. Pollyea: Jazz: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: advisory board; Bristol Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees; Kiadis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Syndax: Honoraria, Membership on an entity's Board of Directors or advisory committees; Syros: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other; Teva: Research Funding; Curis, Servier: Other; Pfizer: Research Funding; Agios: Other, Research Funding; Karyopharm: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Gilead: Consultancy, Honoraria, Other: advisory board; Astellas: Honoraria, Membership on an entity's Board of Directors or advisory committees; Foghorn: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Honoraria, Other: advisory board; Aprea: Honoraria, Membership on an entity's Board of Directors or advisory committees; Genentech: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Brunner: Celgene, Forty Seven Inc, Jazz: Other: Advisory Board; Novartis, Celgene, Takeda, AstraZeneca: Research Funding. Roncolato: AbbVie: Other: Investigator in AbbVie funded Clinical Trials. Garcia: AstraZeneca: Research Funding; Pfizer: Research Funding; Prelude: Research Funding; Genentech: Research Funding; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees; Astellas: Consultancy, Membership on an entity's Board of Directors or advisory committees; AbbVie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Odenike: Celgene, Incyte, AstraZeneca, Astex, NS Pharma, AbbVie, Gilead, Janssen, Oncotherapy, Agios, CTI/Baxalta, Aprea: Research Funding; AbbVie, Celgene, Impact Biomedicines, Novartis, Taiho Oncology, Takeda: Consultancy. Watson: Astellas Pharma, Inc.: Consultancy; Roche, Amgen: Other: Travel support. Krishnadasan: AbbVie: Other: Investigator in AbbVie funded Clinical Trials. Bajel: Amgen: Speakers Bureau; Abbvie, Amgen, Novartis, Pfizer: Honoraria. Naqvi: Genentech/Roche: Current Employment, Current holder of stock options in a privately-held company. Zha: AbbVie: Current Employment, Current holder of stock options in a privately-held company. Hogdal: AbbVie: Current Employment, Current holder of stock options in a privately-held company. Zhou: AbbVie: Current Employment, Current holder of stock options in a privately-held company. Hoffman: AbbVie: Current Employment, Current holder of stock options in a privately-held company. Kye: AbbVie: Current Employment, Other: May hold equity. OffLabel Disclosure: Venetoclax is a BCL-2 inhibitor that is FDA approved for multiple indications. Venetoclax is not currently approved for the treatment of myelodysplastic syndrome. Azacitidine is FDA approved for continued treatment of adult patients with acute myeloid leukemia who achieved first complete remission or complete remission with incomplete blood count recovery following intensive induction chemotherapy and are not able to complete intensive curative therapy.

Introduction R-mini-CHOP is an established standard of care in elderly patients with DLBCL, with a 2yr OS of 59% and PFS of 47% (Peyrade et al, Lancet Oncol 2011). The addition of ibrutinib to full dose R-CHOP in younger pts with DLBCL has efficacy, but significant toxicity limits the ability to complete therapy in pts ≥60 yrs (Younes et al, JCO 2019). We previously demonstrated the deliverability of ibrutinib with R-mini-CHOP in 80 pts ≥75yrs with DLBCL with a median average relative total dose of 97%; 77% of pts received 6 cycles of R-mini-CHOP despite SAEs in 62% (Verner et al, Haematol Oncol 2019). Here we present the primary efficacy endpoint and key secondary and exploratory endpoints. Methods This was a prospective, multicenter, single-arm, phase 2 study of patients aged ≥75yrs with newly diagnosed DLBCL. Pts received six 21-day cycles of ibrutinib 560mg/d and R-mini-CHOP (Rituximab 375mg/m 2, cyclophosphamide 400mg/m 2, doxorubicin 25mg/m 2, vincristine 1mg on day 1 & prednisone 40mg/m 2 or 100mg/d x 5) followed by an additional two 21-day cycles of rituximab + ibrutinib (or high dose methotrexate for CNS prophylaxis). The efficacy primary endpoint was 2yr OS. Sample size calculations were made using a one-sample two-sided approach to detect a 15% improvement on the fixed reference OS (59%) and PFS (47%) rates (Peyrade et al, Lancet Oncol 2011). Results Eighty pts were recruited from Nov 2015 to Dec 2018. One died prior to receiving treatment and is not included in the analysis. Median age was 82yrs (75-95); 51% female, 81% stage III/IV and 63% IPI 3-5: 47% had a CIRS-G score of ≥6 (range 0-17). On centralized immunohistochemistry (IHC), 57% (45/79) were non-Germinal Centre B cell-like (GCB) subtype; 43% (34/79) were GCB. At a data cut-off of 6June 21, median follow-up was 29.5 months (m) (0.2 to 66.3). Two-year OS was 68% (95% CI 55-77%), not differing significantly from the null hypothesis of 59% (p=0.10), (Figure 1A). Median OS was not reached (NR) (95% CI 34m to NR), and was longer in those with lower IPI (IPI 1-3: NR, IPI 4: 35m, IPI 5: 19m). Two-year PFS was 60% (95% CI 47-70%), significantly different from the reference 47% (p At least one adverse event (AE) occurred in 99% pts (78/79): 30% (24/79) grade 1-2, 64% (49/79) grade 3-4, and 6% (5/79) grade 5. Most common grade ≥3 AEs were lung infection (13%), other infections (11%), anemia (11%), febrile neutropenia (9%), thrombocytopenia (9%), and atrial fibrillation (8%). Serious AEs occurred in 67%: most commonly lung infection (11%), atrial fibrillation (9%), fever (9%), and other infection (9%). 12/14 pts with atrial fibrillation/flutter were new onset. Ibrutinib was temporarily ceased in 62% of patients, and permanently ceased in 25%, mostly due to adverse events. As previously reported, the overall response rate on an intention to treat basis was 57/80 (71%) (Verner et al, ASH 2019). Response rates did not differ by cell of origin (COO) (ORR: non-GCB 76%, GCB 68% p=0.44). When recorded, pt's EORTC-QLQ-C30 global health status significantly improved between screening [n=78; mean (SD) 58(25)], end of treatment [n=57; 63(23)] and 18mo post-treatment [n=29; 74(19)] p=0.007. Significant reductions in fatigue, nausea and vomiting, pain, insomnia, appetite loss, constipation and diarrhea were also observed in respondents. There was no impact of CIRS-G score on disease response rate or risk of death. Conclusion The addition of ibrutinib to R-mini-CHOP was deliverable and improved 2-yr PFS compared to R-mini-CHOP alone. However, while there was a trend towards improvement in 2-yr OS, a target 15% increase was not achieved in this small sample size. Despite considerable and not unexpected toxicity in this elderly cohort, the QOL and functional improvements in survivors are also promising. These data support further study of the addition of ibrutinib to R-mini-CHOP in elderly patients with DLBCL. Figure 1 Figure 1. Disclosures Verner: Janssen-Cilag Pty Ltd: Research Funding. Hawkes: Merck KgA: Research Funding; Bristol Myers Squib/Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Specialised Therapeutics: Consultancy; Antigene: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Janssen: Speakers Bureau; Gilead: Membership on an entity's Board of Directors or advisory committees; Regeneron: Speakers Bureau; Merck Sharpe Dohme: Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees, Other: Travel and accommodation expenses, Research Funding, Speakers Bureau; Astra Zeneca: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Lee: Roche: Honoraria; BeiGene: Membership on an entity's Board of Directors or advisory committees. Cheah: BMS: Consultancy, Research Funding; Abbvie: Research Funding; Janssen: Consultancy, Honoraria; MSD: Consultancy, Honoraria; Gilead: Consultancy, Honoraria; Ascentage Pharma: Consultancy, Honoraria; AstraZeneca: Consultancy, Honoraria; Lilly: Consultancy, Honoraria; TG therapeutics: Consultancy, Honoraria; Beigene: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Roche: Consultancy, Honoraria, Other: travel, Research Funding. Purtill: Novartis: Honoraria; Gilead: Honoraria; BMS Celgene: Honoraria. Enjeti: Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Roche: Speakers Bureau; AbbVie: Honoraria; Sanofi: Honoraria; Astra Zeneca: Honoraria. Curnow: Bayer: Consultancy, Research Funding; Pfizer/BMS: Consultancy, Honoraria; Mylan: Consultancy; Norgine: Consultancy, Honoraria. Butcher: WriteSource: Current Employment, Other: Medical writing for Pharma companies. Not pertinent to this abstract for which author is study Statisticiam. Trotman: JANSSEN: Research Funding; TAKEDA: Research Funding; BMS: Research Funding; PCYC: Research Funding; roche: Research Funding; beigene: Research Funding. OffLabel Disclosure: Ibrutinib is not approved for use in DLBCL

The molecular profile of clonal hematopoiesis in patients (pts) with idiopathic aplastic anaemia (iAA) has been shown to predict response to immunosuppressive therapy (IST). Moreover, clonal evolution is associated with transformation of iAA to aggressive myeloid malignancies such as myelodysplastic syndrome (MDS) and acute myeloid leukaemia (AML). Detection of somatic mutations may help identify pts more likely to respond to IST and also those at increased risk of transformation however the predictive value of detecting mutations at a single timepoint is limited. Longitudinal detection of changes in mutation profile over time may improve prediction of transformation risk, however due to bone marrow hypocellularity DNA quality and quantity from pts with iAA is frequently suboptimal. Serial mutation analysis of cell-free DNA (cfDNA) is one approach that may overcome this problem as the majority of cfDNA originates from hematopoietic cells and mutations detected in this compartment have been shown to closely resemble those detected from peripheral blood (PB) / bone marrow (BM) analysis in other haematological malignancies. We aimed to characterise longitudinal genomic changes in pts with iAA and contrast mutation detection in the cellular compartment with those detected in cfDNA. Fifteen pts (10 female and 5 male) with a diagnosis of iAA were included (median age 35 years (range 17 - 78)); eleven were newly diagnosed (within six months of diagnosis) and four were two or more years post diagnosis. Cellular DNA (PB or BM aspirate) and cfDNA were collected upon study enrolment and cfDNA samples were collected longitudinally for each pt. Somatic mutations in cellular samples were assessed using custom targeted next generation sequencing panels with an analytical sensitivity of ~1%. cfDNA samples were assessed using a custom anchored multiplex PCR panel with molecular barcodes with an analytical sensitivity of ~0.5%. Twenty-nine genes were assessed in both cellular and cfDNA. Somatic mutations were detected in 13 of 15 (87%) pts at the first sampled timepoint, with two or more mutations detected in seven pts. Overall 27 mutations were detected in seven genes including PIGA (n=12), DNMT3A (n=5), ASXL1 (n=5), BCOR (n=2), BCORL1, NPM1 and RUNX1 (n=1 each) with a higher proportion detected in cfDNA (25 of 27) compared to cellular DNA (22 of 27). Mutations unique to cfDNA were in PIGA (n=3), ASXL1 (n=1) and DNMT3A (n=1) and those unique to cellular DNA were in NPM1 (n=1) and PIGA (n=1). The variant allele frequency (VAF) was We next assessed the mutation dynamics in cfDNA over time by analysing a median of 3 (range 2 - 4) sequential samples per pt (median follow-up interval 670 days, range 249 - 923). 20 of 25 cfDNA mutations were detected in longitudinal cfDNA at similar VAF, including PIGA (n=9), BCOR (n=2), DNMT3A (n=5), ASXL1 (n=3) and RUNX1 (n=1). Five mutations in PIGA (n=2), ASXL1 (n=2) and BCORL1 (n=1) became undetectable over time. Importantly, acquisition of new mutations during follow-up was observed in four pts (total of 13 new cfDNA mutations detected). Three out of these four pts experienced disease transformation to hematological malignancy (MDS n=2, AML n=1), with acquired mutations in SETBP1, NPM1, NRAS, KRAS, WT1 and KIT. Importantly, these mutations often went from undetectable to relatively high VAF within a short interval (5 - 13 months) which is important to consider when designing molecular screening schedules to potentially pre-empt transformation. In summary, our data shows that cfDNA mutation profiling in pts with iAA is technically feasible and is able to detect additional mutations not detectable in the cellular compartment. Importantly, we demonstrate the limitations of analysis of both compartments in the context of low VAF mutations, suggesting that concurrent testing of both cellular and cfDNA may increase the sensitivity for detecting low frequency events. Our data also suggests that longitudinal changes in mutation profile may improve identification of pts at high risk of transformation to hematological malignancy. The optimal frequency of monitoring and the magnitude of increased risk requires validation in prospective trials. GLR and LCF contributed equally to this work Disclosures Szer: Alexion Pharmaceuticals Inc.: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Apellis: Consultancy; Pfizer: Honoraria, Speakers Bureau; Takeda: Honoraria, Speakers Bureau; Novartis: Consultancy, Honoraria, Speakers Bureau; Prevail Therapeutics: Honoraria, Membership on an entity's Board of Directors or advisory committees. Bajel:Astellas: Honoraria; Novartis: Honoraria; Amgen: Honoraria, Speakers Bureau; Pfizer: Honoraria; Abbvie: Honoraria. Blombery:Novartis: Consultancy; Invivoscribe: Honoraria; Amgen: Consultancy; Janssen: Honoraria.

The management of CML in pregnancy is challenging with the need to balance disease control against potential teratogenic effects of TKI therapy. In this multi-center case-cohort study of 16 women in chronic phase, CML ceased TKI treatment pre- or post-conception during their first pregnancy. Thirteen patients were on imatinib; 9 ceased their TKI prior to conception and 7 ceased at pregnancy confirmation. Twelve patients had achieved either MMR or better at time of TKI cessation. Eleven women lost MMR during pregnancy and two patients lost CHR. Fourteen women reestablished MMR on TKI recommenced. The depth molecular response prior to conception appeared to correlate well with restoration of disease control on TKI recommencement though duration of MMR did not appear to be as important. While interruption of TKI treatment for pregnancy usually leads to loss of molecular response, loss of hematological response is uncommon and disease control is reestablished with resumption of therapy in the majority of women. Refereed/Peer-reviewed

In the treatment of diffuse large B-cell lymphoma, a persistently positive [18F]fluorodeoxyglucose positron emission tomography (PET) scan typically carries a poor prognosis. In this prospective multi-center phase II study, we sought to establish whether treatment intensification with R-ICE (rituximab, ifosfamide, carboplatin, and etoposide) chemotherapy followed by 90Y-ibritumomab tiuxetan–BEAM (BCNU, etoposide, cytarabine, and melphalan) for high-risk diffuse large B-cell lymphoma patients who are positive on interim PET scan after 4 cycles of R-CHOP-14 (rituximab, cyclophosphamide, doxorubicin, and prednisone) can improve 2-year progression-free survival from a historically unfavorable rate of 40% to a rate of 65%. Patients received 4 cycles of R-CHOP-14, followed by a centrally-reviewed PET performed at day 17–20 of cycle 4 and assessed according to International Harmonisation Project criteria. Median age of the 151 evaluable patients was 57 years, with 79% stages 3–4, 54% bulk, and 54% International Prognostic Index 3–5. Among the 143 patients undergoing interim PET, 101 (71%) were PET-negative (96 of whom completed R-CHOP), 42 (29%) were PET-positive (32 of whom completed R-ICE and 90Y-ibritumomab tiuxetan-BEAM). At a median follow up of 35 months, the 2-year progression-free survival for PET-positive patients was 67%, a rate similar to that for PET-negative patients treated with R-CHOP-14 (74%, P=0.11); overall survival was 78% and 88% (P=0.11), respectively. In an exploratory analysis, progression-free and overall survival were markedly superior for PET-positive Deauville score 4 versus score 5 (P=0.0002 and P=0.001, respectively). Therefore, diffuse large B-cell lymphoma patients who are PET-positive after 4 cycles of R-CHOP-14 and who switched to R-ICE and 90Y-ibritumomab tiuxetan-BEAM achieved favorable survival outcomes similar to those for PET-negative R-CHOP-14-treated patients. Further studies are warranted to confirm these promising results. (Registered at: ACTRN12609001077257).

Following the achievement of deep molecular response on tyrosine kinase inhibitors (TKIs), approximately half of patients with chronic myeloid leukemia (CML) can discontinue TKI and remain in treatment-free remission (TFR). The ALLGCML8 study enrolled 40 imatinib-treated patients with undetectable BCR-ABL1 mRNA (approximately MR4.5). Molecular relapse was defined as detectable BCR-ABL1 on two consecutive tests or any single value >0.1%. With a median follow-up of 8.6 years (range 5.7–11.2 years), 18 patients remain in continuous TFR (45.0%; 95% confidence interval 31.9−63.4%).The latest relapse detected was 27 months after stopping imatinib. No patient progressed to advanced phase. Twenty-two patients met criteria for imatinib re-treatment and all regained undetectable molecular response. Nine patients in long-term TFR were monitored by highly sensitive individualized BCR-ABL1 DNA PCR in a sufficient number of samples to enablemore precise quantification of residual leukemia. BCR-ABL1 DNA decreased from a median of MR5.0 in the first year of TFR to MR6.1 in the sixth year of TFR. Our results support the long-term safety and remarkable stability of response after imatinib discontinuation in appropriately selected CML patients. Serial high sensitivity testing provides a new and unexpected findingof gradually reducing CML cells in patients in long-term TFR. Refereed/Peer-reviewed

Despite its efficacy in prospective trials, full dose fludarabine, cyclophosphamide and rituximab (FCR) may be too toxic for elderly patients with chronic lymphocytic leukemia (CLL) in clinical practice. We retrospectively reviewed the impact of dose reductions in FCR therapy on the outcomes of 42 consecutive patients aged 65-87 (median 72) years. Despite a median cumulative fludarabine dose reduction of 50% from full dose, the objective response and complete response rates were 86% and 38% respectively (frontline 94%/59%; previously treated 80%/24%). Dose reductions of 25-75% were not significantly associated with inferior progression free survival compared to minimal reductions (≤25%) (p=0.49), and did not preclude deep responses, including six cases (14%) of minimal residual disease negativity. Although hematological and infectious toxicities were common, treatment limiting adverse effects were infrequent. Dose attenuated FCR appears to have preserved efficacy and may be a viable therapeutic option for elderly patients with CLL.

IntroductionThe label ‘great imitator’ refers to conditions which can cause varied manifestations and mimic diseases. Lymphoma is worthy of this title. We present three cases.Cases1: 66-year-old-man with progressive vertical diplopia and unsteady gait over four weeks. MRI brain and spine demonstrated a supratentorial para-falcine soft tissue lesion, mid-thoracic cord enhancement and right axillary mass. Serum ACE was elevated. Serum HIV serology was positive. Right axillary mass core biopsy diagnosed Burkitt lymphoma.2: 50-year-old man with a 4-week history of constitutional symptoms on a background of ITP and splenomegaly. During admission he developed urinary retention, bilateral lower limb weakness and numbness and confusion. Infectious and vasculitic screens were unremarkable. CT chest, abdomen and pelvis demonstrated splenomegaly. CSF and bone marrow analyses were non-diagnostic. A random skin biopsy diagnosed intravascular lymphoma.3: 65-year-old man with two weeks of headache and diplopia on a background of previously treated Burkitt lymphoma. CSF analysis showed 45×106/L white cells and glucose < 0.6 mmol/L. Cytologic analysis was negative for malignancy. Bacterial culture and Cryptococcal antigen were negative. FDG-PET dramatically showed disseminated spinal and cranial leptomeningeal disease. MRI brain showed thin dural thickening correlating to area of increased uptake on PET. He was diagnosed with Burkitt lymphoma relapse and treated with chemotherapy and autologous stem cell transplant.ConclusionThe varied manifestations in our cases demonstrate the ability for lymphoma to mimic infective, inflammatory, granulomatous (including sarcoidosis) and neoplastic aetiologies. When the diagnosis is uncertain, the possibility of this great imitator should be considered.

Background Although Australian consensus guidelines support the use of ambulatory care strategies for management of adult patients with low-risk neutropenic fever (NF), few centres have successfully implemented viable programmes. Aims To study the feasibility of an early discharge programme for adult patients with low-risk NF and assess organisational factors likely to influence successful implementation across participating Victorian hospitals. Methods Four hospitals participated in an organisational readiness assessment preceding selection of a pilot site for programme implementation. Prospective baseline auditing of current practice (i.e. inpatient care until resolution of NF) across three hospitals preceded programme implementation and evaluation. Results Barriers and facilitators to successful implementation were identified. One hundred and seventeen NF episodes were evaluated during audit phases. The frequency of low-risk NF presentations eligible for early discharge was low (less than two episodes per week). The programme reduced median (interquartile range) duration of parenteral antibiotics and length of stay for eligible patients (n = 11) from 4 (4, 5) days at baseline to 1 (1, 2) day during pilot (P = 0.02) and 4.5 (4, 5) days (baseline) to 2 (1, 3) days (pilot) (P = 0.02) respectively. The proportion of ineligible patients stepped down to oral antibiotics was improved from 38% (baseline) to 67% (pilot). No patients failed ambulatory care requiring readmission into hospital. Conclusion The ambulatory care strategy for management of NF proposed by Australian consensus guidelines has been successfully piloted at a single Victorian centre. Organisational readiness tools can be used to identify potential barriers to the implementation of evidence based practices in patients with NF.

Single agent azacitidine or immunomodulatory drugs are effective in myelodysplastic syndrome (MDS), with differing target mechanisms and toxicities. Objectives of this ALLG MDS3 study in clinically advanced MDS, AMML and low blast AML were to establish safety, response and quality of life of azacitidine and thalidomide. Patients received azacitidine (75mg/m2/d sc 7days every 28 days), and oral thalidomide up to 100mg/d for maximum 12months. Eighty patients registered; median age 68 years (range 42-82), 49% IPSS int2-high. With 36.5 months follow up, patients received median 9 cycles azacitidine, 6.1mths thalidomide. Nonhematologic toxicity grade 3+ in 85%, commonly infections. Overall response rate was 63%; 26% CR were unaffected by IPSS. Median response duration 26.3months; overall survival was 28.1months. This combination azacitidine and thalidomide in clinically advanced MDS, CMML and low-blast AML was tolerable without unexpected toxicity and encouraging responses support further investigation of combination approaches with hypomethylating agent and immunomodulatory drug.

Background Carfilzomib (K), a second generation proteasome inhibitor that is approved for patients (pts) with relapsed refractory multiple myeloma (RRMM) is associated with increased cardiovascular (CV) adverse effects (AE), in particular hypertension (HTN), dyspnea and cardiac failure (CCF), based on the ENDEAVOR (Dimopoulos, MA. et al. Lancet 2016) and ASPIRE studies (Stewart, K.et al. NEJM 2015). The clinical characteristic and underlying mechanism of K induced CVAE have been poorly elucidated, and the limited published data on the utility of cardiac enzymes as biomarkers have not been revealing. We conducted a retrospective single centre review of K-treated pts who have undergone systemic serial cardiovascular and cardiac enzyme assessment, to profile the nature of CVAE and patterns in cardiac enzymes that might have predictive utility in K-induced CVAE. Method: Between January 2016 to June 2018, all pts who were treated with K (D1,2,8,9,15,16 in a 28 day cycle)-based regimen for RRMM at St.Vincent's Hospital Melbourne underwent systematic cardiovascular assessment including documentation of baseline cardiac risk factors (RF) and transthoracic echo (TTE). Serial troponin, creatinine kinase (CK) and B-type Natriuretic Peptide (BNP) were performed at baseline (C1D1 or 2), mid cycle (D8 or 9) and end of treatment (D16) of every cycle. Repeat TTE was done at physicians' discretion. Systematic documentations of CVAEs (graded according to CTCAEv5) were retrieved from medical records. The incidence and severity of CVAE was collated and correlated with serial cardiac enzyme levels, the association of which was tested using Student's t-test. Results 76 pts (67% male; median age 66(46-86) years) with RRMM who received a median of 6 cycles (1-26) of K-based treatment were included in this analysis. At baseline, 16 pts (21%) had at least 1 CVRF including HTN, history of ischaemic heart disease, hyperlipidaemia, diabetes or smoking. The incidence of HTN prior to treatment was 39%. On treatment, the incidence of HTN was 85% (28% grade≥3). 17% of pts required the addition of antihypertensive medications and 11% had K dose reduction due to HTN. K-related dyspnea occurred in 53% of pts (28% grade≥3), 52% of who required K dose reduction/interruption. CCF occurred in 14.5% (grade≥3, 13%) that all necessitated K interruption/dose reduction. 69 pts had baseline TTE that showed a median RVSP (right ventricular systolic pressure) of 32mmHg (range 20-48). On treatment, 38 pts had repeat TTE, mainly driven by dyspnea with a median RVSP of 41(20-93mmHg). Of the 18 pts with grade≥3 dyspnea who had repeat TTE, 83% had RSVP ≥39mmHg and 33% had RVSP≥50mmHg, compared to 70% with RSVP ≥39mmHg and 10% RVSP≥50mmHg in the group with grade 1-2 dyspnea. Troponin_I and CK level did not change significantly throughout K-treatment. However BNP level rose and fell within each cycle, typically with peaks at mid cycle (D9 and D16) and troughs at the beginning of a new cycle (D1 or 2). 87.1% of pts had at least one elevated BNP (>100ng/L) with a median maximal level of 300ng/L (range 114-2320ng/L). There was a significant difference in the incidence of grade ≥3 CVAEs (mainly HTN) in pts whose mid cycle BNPs (D9 or 16) were elevated in ≥50% of measurements during the first 4 cycles of K compared to the rest (65.5% vs. 25.0%, p=0.0084). In pts with dyspnea, persistent rise in mid cycle BNPs that does not normalise prior to next treatment cycle trended towards an increased incidence of raised RVSP of ≥39mmHg (21.7% vs. 7.9%, p=0.0543). Conclusion. The incidence of CVAEs in pts treated with K is higher in the real-world setting compared to that reported in the Endeavor and ASPIRE studies. Dyspnea is frequent, the degree of which correlates with the degree of raised RVSP, thus indicating pulmonary hypertension as a contributor to dyspnea in the setting of K treatment. BNP level typically peaks during mid cycle and troughs at the beginning of next cycle, indicating a temporal relationship to K infusions. In pts with dyspnea, the association of persistent rise in mid-cycle BNP (rather than troponin or CK) with raised RVSP and HTN perhaps indicate transient endothelial dysfunction as the mechanism for K-induced CVAE rather than myocyte injury. Disclosures Quach: Amgen: Consultancy, Research Funding; Sanofi Genzyme: Research Funding; Janssen Cilag: Consultancy; Celgene: Consultancy, Research Funding. Tam:Roche: Honoraria; AbbVie: Honoraria, Research Funding; Pharmacyclics: Honoraria, Travel funding; Beigene: Honoraria, Other: Travel funding; Pharmacyclics: Honoraria; Gilead: Honoraria; Janssen: Honoraria, Research Funding; AbbVie: Honoraria, Research Funding; Beigene: Honoraria, Other: Travel funding; Gilead: Honoraria; Roche: Honoraria.

Around 40-50% of patients with chronic myeloid leukemia (CML) who achieve a stable complete molecular response (CMR; undetectable breakpoint cluster region-Abelson leukemia gene human homolog 1 (BCR-ABL1) mRNA) on imatinib can stop therapy and remain in CMR, at least for several years. This raises the possibility that imatinib therapy may not need to be continued indefinitely in some CML patients. Two possible explanations for this observation are (1) CML has been eradicated or (2) residual leukemic cells fail to proliferate despite the absence of ongoing kinase inhibition. We used a highly sensitive patient-specific nested quantitative PCR to look for evidence of genomic BCR-ABL1 DNA in patients who sustained CMR after stopping imatinib therapy. Seven of eight patients who sustained CMR off therapy had BCR-ABL1 DNA detected at least once after stopping imatinib, but none has relapsed (follow-up 12-41 months). BCR-ABL1 DNA levels increased in all of the 10 patients who lost CMR soon after imatinib cessation, whereas serial testing of patients in sustained CMR showed a stable level of BCR-ABL1 DNA. This more sensitive assay for BCR-ABL1 provides evidence that even patients who maintain a CMR after stopping imatinib may harbor residual leukemia. A search for intrinsic or extrinsic (for example, immunological) causes for this drug-free leukemic suppression is now indicated.

We conducted a trial in 103 patients with newly diagnosed chronic phase chronic myeloid leukemia (CP-CML) using imatinib 600 mg/day, with dose escalation to 800 mg/day for suboptimal response. The estimated cumulative incidences of complete cytogenetic response (CCR) by 12 and 24 months were 88% and 90%, and major molecular responses (MMRs) were 47% and 73%. In patients who maintained a daily average of 600 mg of imatinib for the first 6 months (n = 60), MMR rates by 12 and 24 months were 55% and 77% compared with 32% and 53% in patients averaging less than 600 mg (P = .037 and .016, respectively). Dose escalation was indicated for 17 patients before 12 months for failure to achieve, or maintain, major cytogenetic response at 6 months or CCR at 9 months but was only possible in 8 patients (47%). Dose escalation was indicated for 73 patients after 12 months because their BCR-ABL level remained more than 0.01% (international scale) and was possible in 45 of 73 (62%). Superior responses achieved in patients able to tolerate imatinib at 600 mg suggests that early dose intensity may be critical to optimize response in CP-CML. The trial was registered at www.ANZCTR.org.au as #ACTRN12607000614493.

Purpose Intrinsic sensitivity to imatinib, based on measurement of inhibitory concentration 50% for imatinib, is variable in untreated patients with chronic myeloid leukemia (CML). This suggests that patient-tailored dosing may be more rational than a fixed dose for all. Dose optimization potentially could be based on accurate measurement of the level of BCR-ABL kinase inhibition achieved in vivo. Patients and Methods In vivo kinase inhibition was measured by calculating the reduction in protein (p) -Crkl level in mononuclear blood cells taken from 49 CML patients at weekly intervals after imatinib therapy was commenced. Results Greater than 50% inhibition (> 50% reduction in p-Crkl from baseline) was achieved by 21% of patients by days 7 to 14 (and maintained in all patients on days 21 to 28) and an additional 24% of patients achieved more than 50% inhibition by days 21 to 28. Thus, overall 45% of patients achieved more than 50% inhibition. All of these patients achieved major molecular responses by 24 months compared with 56% of the patients who failed to achieve 50% kinase inhibition (P < .001). Patients with less than 50% kinase inhibition were also more likely to have suboptimal responses. Conclusion In vivo BCR-ABL kinase inhibition can be assessed in the first month of imatinib therapy and may provide a valuable guide to optimization of dosage. The extent of BCR-ABL kinase inhibition is an excellent predictor of cytogenetic and molecular response. These observations suggest that dose adjustment based on in vivo measurements of drug-induced target inhibition could be applied in settings beyond imatinib and may be a more effective approach than using one dose for all patients in targeted anticancer therapy.

Summary Background Initial treatment of acute promyelocytic leukaemia traditionally involves tretinoin (all-trans retinoic acid) combined with anthracycline-based risk-adapted chemotherapy, with arsenic trioxide being the treatment of choice at relapse. To try to reduce the relapse rate, we combined arsenic trioxide with tretinoin and idarubicin in induction therapy, and used arsenic trioxide with tretinoin as consolidation therapy. Methods Patients with previously untreated genetically confirmed acute promyelocytic leukaemia were eligible for this study. Eligibilty also required Eastern Cooperative Oncology Group performance status 0–3, age older than 1 year, normal left ventricular ejection fraction, Q-Tc interval less than 500 ms, absence of serious comorbidity, and written informed consent. Patients with genetic variants of acute promyelocytic leukaemia (fusion of genes other than PML with RARA ) were ineligible. Induction comprised 45 mg/m 2 oral tretinoin in four divided doses daily on days 1–36, 6–12 mg/m 2 intravenous idarubicin on days 2, 4, 6, and 8, adjusted for age, and 0·15 mg/kg intravenous arsenic trioxide once daily on days 9–36. Supportive therapy included blood products for protocol-specified haemostatic targets, and 1 mg/kg prednisone daily as prophylaxis against differentiation syndrome. Two consolidation cycles with tretinoin and arsenic trioxide were followed by maintenance therapy with oral tretinoin, 6-mercaptopurine, and methotrexate for 2 years. The primary endpoints of the study were freedom from relapse and early death (within 36 days of treatment start) and we assessed improvement compared with the 2 year interim results. To assess durability of remission we compared the primary endpoints and disease-free and overall survival at 5 years in APML4 with the 2 year interim APML4 data and the APML3 treatment protocol that excluded arsenic trioxide. This study is registered with the Australian New Zealand Clinical Trials Registry, number ACTRN12605000070639. Findings 124 patients were enrolled between Nov 10, 2004, and Sept 23, 2009, with data cutoff of March 15, 2012. Four (3%) patients died early. After a median follow-up of 4·2 years (IQR, 3·2–5·2), the 5 year freedom from relapse was 95% (95% CI 89–98), disease-free survival was 95% (89–98), event-free survival was 90% (83–94), and overall survival was 94% (89–97). The comparison with APML3 data showed that hazard ratios were 0·23 (95% CI 0·08–0·64, p=0·002) for freedom from relapse, 0·21 (0·07–0·59, p=0·001) for disease-free survival, 0·34 (0·16–0·69, p=0·002) for event-free survival, and 0·35 (0·14–0·91, p=0·02) for overall survival. Interpretation Incorporation of arsenic trioxide in initial therapy induction and consolidation for acute promyelocytic leukaemia reduced the risk of relapse when compared with historical controls. This improvement, together with a non-significant reduction in early deaths and absence of deaths in remission, translated into better event-free and overall survival. Funding Phebra.

Imatinib is generally well tolerated, but gastric antral vascular ectasia (GAVE) remains a rare but significant complication of imatinib therapy. Whilst this complication has been described in other disease settings, only one other case of GAVE has been reported in a chronic myeloid leukaemia (CML) patient receiving imatinib. Herein, we present three CML patients with GAVE complicating imatinib therapy. In all cases, GAVE resolved only with cessation of imatinib. This confirms a causal relationship between GAVE and imatinib. GAVE should be considered as a possible cause of anaemia and upper gastrointestinal bleeding in patients receiving imatinib therapy.

The therapeutic intensification in De Novo Leukaemia (TIDEL)-II study enrolled 210 patients with chronic phase chronic myeloid leukemia (CML) in two equal, sequential cohorts. All started treatment with imatinib 600 mg/day. Imatinib plasma trough level was performed at day 22 and if 10% BCR-ABL1 at 3 months. Confirmed major molecular response was achieved in 64% at 12 months and 73% at 24 months. MR4.5 (BCR-ABL1 ≤0.0032%) at 24 months was 34%. Overall survival was 96% and transformation-free survival was 95% at 3 years. This trial supports the feasibility and efficacy of an imatinib-based approach with selective, early switching to nilotinib. This trial was registered atwww.anzctr.org.au as#12607000325404. Refereed/Peer-reviewed

The characteristics of severe neutropenia with a delayed onset following administration of rituximab have been evaluated in 53 consecutively treated patients. All but one patient received rituximab for the treatment of non-Hodgkin's lymphoma. Eight episodes of grade 4 neutropenia were detected between 1 and 5 months after rituximab, when administered alone on five occasions, and on three occasions in combination with chemotherapy, where neutrophil counts had recovered prior to the development of neutropenia. In three episodes, the patients presented with sepsis. Development of neutropenia did not correlate with either the presence of detectable disease or the administration of further treatment. Neutropenia was associated with selective depletion of neutrophil precursors in all but one episode, where it was associated with generalized bone marrow hypoplasia. All episodes developed after a period of either normal or mildly depressed neutrophil counts following treatment with rituximab, and persisted for between several days and several months, before undergoing spontaneous recovery in four instances, and after administration of filgrastim in the remainder. Episodes of neutropenia were associated with disordered immune status manifested by lymphopenia and hypogammaglobulinaemia, raising the possibility that either disturbance of the balance of lymphocyte subsets or an immune dyscrasia induced by rituximab resulted in the development of this type of neutropenia.

We describe the case of a 35-year-old man presenting with thrombotic microangiopathy (TMA) and renal impairment following, as he later disclosed, intravenous injection of oral formulation tamper-resistant extended-release oxycodone hydrochloride (Oxycontin). Recurrent misuse of this agent was associated with relapsing TMA despite treatment with terminal complement inhibitor eculizumab. Cases of TMA have been reported in the USA in association with intravenous misuse of extended-release oxymorphone (Opana ER) after the introduction of a new non-crushable formulation in 2012. There are two reported accounts of TMA associated with tamper-resistant Oxycontin, which became available in Australia in 2014. This is the first documented case in which eculizumab was used. This case illustrates the practical diagnostic challenges in identifying TMA disorders, and the importance of a detailed drug history. It also highlights the need to clarify what role, if any, eculizumab therapy has in cases of drug-associated TMA.

The BTK (Bruton's tyrosine kinase) inhibitor ibrutinib is associated with an increased risk of bleeding. A previous study reported defects in collagen- and adenosine diphosphate (ADP)-dependent platelet responses when ibrutinib was added ex vivo to patient samples. Whereas the collagen defect is expected given the central role of BTK in glycoprotein VI signaling, the ADP defect lacks a mechanistic explanation. In order to determine the real-life consequences of BTK platelet blockade, we performed light transmission aggregometry in 23 patients receiving ibrutinib treatment. All patients had reductions in collagen-mediated platelet aggregation, with a significant association between the degree of inhibition and the occurrence of clinical bleeding or bruising (P=0.044). This collagen defect was reversible on drug cessation. In contrast to the previous ex vivo report, we found no in vivo ADP defects in subjects receiving standard doses of ibrutinib. These results establish platelet light transmission aggregometry as a method for gauging, at least qualitatively, the severity of platelet impairment in patients receiving ibrutinib treatment.

We report long-term results in 40 patients with Philadlephia chromosome-positive (Ph+) acute leukemia who received an imatinib monotherapy window to evaluate in vivo effects on BCR-ABL signaling prior to induction chemotherapy. The first 25 patients (cohort 1) received the LALA-94 protocol without further imatinib (newly diagnosed Ph+ acute lymphoblastic leukemia [ALL]) or induction chemotherapy followed by single-agent imatinib. Subsequent patients (cohort 2) continued imatinib concurrently with either LALA-94 (newly diagnosed Ph + ALL) or other intensive chemotherapy regimens. Cohort 2 had a complete response (CR) rate of 93% and 5-year survival of 69%. For newly diagnosed Ph+ ALL, survival was superior in cohort 2 compared with cohort 1. Toxicity was similar to that expected for chemotherapy alone. Among 10 evaluable patients, rapid loss of phospho-CRKL occurred during the imatinib window in seven patients (all achieved CR) and incomplete inhibition in three patients (none with CR). In summary, a pharmacodynamic window design permitted biomarker assessment of BCR-ABL targeting without compromising clinical outcomes.

The TIDEL-II trial used imatinib (IM) upfront in patients (pts) newly diagnosed with chronic myeloid leukaemia in chronic phase (CML-CP), and switched selected pts to nilotinib (NIL) on the basis of IM intolerance or failure to achieve time-dependent molecular response. We previously reported major molecular response (MMR; BCR-ABL ≤0.1% IS) at 12 months (mths) and transformation-free survival (TFS) at 3 years. This abstract reports the final analysis with minimum follow-up of 60 months. Patients were enrolled across 27 Australasian sites in 2 equal and sequential cohorts. All started treatment with IM 600mg OD and dose escalated to IM 800mg OD if IM trough levels were The study enrolled 210 pts with a median age of 49.7 years (range 16-81); 42% were female. Baseline demographics and outcomes were similar across 2 cohorts. Forty pts had day 22 IM trough At 60 mths, 75 (36%) pts had withdrawn from study, and 14 were lost to follow up (including 12 with outstanding data queries). Of the 121 pts (58%) who remained on TIDEL-II until 60 mths, 33 were on NIL (30 in MMR), 77 on IM (76 in MMR); treatment was unknown for 11 (10 in MMR). The median dose of IM was 600mg OD. Of the 51 pts who dose escalated to IM 800mg OD (31 for low IM trough level and 20 for failing to achieve molecular targets), only 9 remained on this dose until mth 60 (5 and 4 pts form the respective groups). Eight pts transformed to accelerated or blastic phase; 5 within the 1st year, 2 in the 3rd and 1 in the 5th year; 2/8 occurred after study withdrawal. There were 14 deaths, mostly due to cardiac events (n=5) or progressive leukaemia (n=6). In all, 13/210 pts (6%) had cardiac, cerebral or peripheral vascular disease, 9 while on NIL and 4 having only had IM. Pts failing to meet molecular targets (analysed according to the 1st target failed) at 3, 6 and 12 mths numbered 25 (12%), 23 (11%) and 30 (14%) respectively with 19, 16 and 20 switching to NIL (subsequent molecular outcomes, Table 2). Pts failing to achieve EMR had poor achievement of MMR and MR4.5 (44% and 8% respectively by 60 mths). Of the 11 EMR failure pts who achieved MMR, only 4 remained in MMR at 60 mths. Pts failing to achieve BCR-ABL≤ 1% at 6 mths had similarly poor outcomes, with MMR and MR4.5 being 52% and 13% respectively. In pts failing to achieve MMR by 12 months, MMR and MR4.5 by 60 mths were 93% and 33% respectively. Twenty pts switched to NIL for IM intolerance prior to 24 mths: 9/20 already in MMR, and 3/20 already in MR4.5 at time of switching. For the remaining pts, MMR and MR4.5 were achieved by 100% and 88% after switching. The TIDEL-II strategy of combining IM and NIL compares favourably with other upfront treatment strategies, with MR4.5 of 59% by 60 mths. IM dose escalation to 800mg OD for target failure was not well tolerated: only 18% of pts who dose escalated maintained this dose at 60 mths. However, this did not appear to be detrimental to overall outcomes, which were similar in the 2 cohorts. Pts switching to NIL for IM intolerance, and for failing to achieve MMR by 12 months after meeting prior goals, had high rates of MMR, superior to those who failed their 3 and 6 mth targets. Early identification of pts at high risk of EMR failure who might benefit from more intensive or experimental therapies may be necessary to further improve outcomes. Disclosures Yeung: Novartis Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Ariad: Research Funding. White:Novartis Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol-Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Ariad: Consultancy, Honoraria, Research Funding. Branford:Novartis: Honoraria, Research Funding, Speakers Bureau; Qiagen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Otsuka: Research Funding; Ariad: Research Funding; Bristol Myers-Squibb: Honoraria; Cepheid: Consultancy. Butcher:Janssen: Consultancy; Roche: Consultancy; Novartis: Consultancy. Gottlieb:Abbvie: Membership on an entity's Board of Directors or advisory committees; Celgene: Research Funding; Indee: Membership on an entity's Board of Directors or advisory committees. Arthur:Novartis: Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees. Ross:Novartis Pharmaceuticals: Honoraria, Research Funding; BMS: Honoraria. Tam:Novartis: Honoraria. Mills:Novartis: Membership on an entity's Board of Directors or advisory committees, Other: Meeting attendance sponsorship. Hughes:Novartis Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Australasian Leukaemia and Lymphoma Group (ALLG): Other: Chair of the CML/MPN Disease Group; Ariad: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol-Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding.

Background Despite improved outcomes achieved with high dose melphalan conditioned ASCT for MM patients, relapse is inevitable. Consolidation/maintenance therapy with novel agents following ASCT can prolong progression free (PFS) and overall survival (OS) as well as further improve depth of response, the latter being associated with superior survival. More sensitive techniques are now available to monitor minimal residual disease (MRD). Aim To document disease response changes in MM patients receiving maintenance lenalidomide and alternate-day prednisolone (RAP) after a single ASCT. To sequentially quantify MRD in those patients achieving an immunofixation negative (IF-) complete response (CR) utilizing freeLite chain (FLC), hevyLite chain (HLC, in patients with intact IgG or IgA immunoglobulin) and multiparameter flow cytometry (MFC). To assess PFS/OS and safety/tolerability. Methods Phase II, open label, single arm, multi-center study. Newly diagnosed patients with MM were commenced on RAP (lenalidomide 10mg/continuous daily increasing to 15mg after 8 weeks and alternate day prednisolone 50mg) 6-8 weeks after a single MEL200 ASCT as part of first-line therapy. RAP was continued until unacceptable toxicity or relapse/progression. Serum for FLC/HLC was collected every 2 months. Patients achieving an IF- CR had serial BMATs for MFC. This is an interim analysis of the first 30 of a total of 60 patients recruited to the study. Results This analysis included 30 patients (M 17, F 13), median age 61 years (range 46-71), ISS stage I: 11, II/III: 19. 27 patients had diagnostic cytogenetics +/- FISH performed - 10 had poor risk features (t(4;14), t(14;16), del17p, del13 and/or +1q). After a median 549 days (range 385-768), 16 patients remain on therapy. Median PFS was 470 days (range 64-768), median OS was 514 days (range 247-768). Discontinuation was due to relapse/progressive disease in 8, AEs in 5 and poor compliance in 1. 4 patients have died; 3 due to MM and 1 due to therapy related AML [tAML]. The best achieved overall response rate (ORR) was 100%, with 19 IF- CR (63%) (13 stringent CR [sCR]), 10 VGPR (33%) and 1 PR (3%). 16 patients demonstrated an enhanced response while on RAP, including conversion to CR (n=3) or sCR (n=10) (6/10 were MFC negative [MFC-]). Median time to achieving best response was 111 days (range 28-287). 18 patients who achieved IF- CR had MFC studies and 11 were MFC-: of these 11, 5 had normal (FLC-) and 6 abnormal (FLC+) FLC ratios. Five of the 18 were MFC+, 4 of whom were FLC- and have not relapsed. Two of the 18 fluctuated between MFC+ and MFC-. Seven IF- CR patients had HLC analysis; 5/7 patients were MFC- in all samples, 3 of which also had normal HLC ratios (HLC-) and were FLC-. 2/7 patients were MFC+/HLC-. 10 patients relapsed/progressed after a median of 229 days (64-621), 5 from IF- CR (3 sCR). 5/8 with diagnostic cytogenetics had poor risk features, all with +1q in addition to other abnormalities. 3/19 remaining patients with cytogenetics who did not progress have +1q, suggesting a trend (p=0.07) to worse PFS in those with 1q+. In those who relapsed from IF- CR: 2 converted from MFC- to MFC+ prior to relapse/HLC-, 1 was FLC+ and 1 converted to FLC+ at relapse; 2 were MFC-/FLC- converting to FLC+ at relapse; 1 was MFC+/FLC+). All grade haematologic AEs comprised thrombocytopenia 7/30 (23%) (grade 3/4: 4), neutropenia 2/30 (grade 3: 1) and anaemia 3/30(grade 3: 1). All grade non-haematologic adverse events regardless of relatedness to study treatment (>10%) were: infections (URTI: 53%, LRTI: 23%, VZV reactivation: 23%, UTI: 13%), diarrhoea (37%), fatigue (27%), muscle cramps (23%), insomnia (23%), mouth ulcers (13%), peripheral oedema (13%). There was 1 second primary malignancy (SPM) - tAML. This occurred 461 days after commencing RAP. AEs leading to discontinuation were thrombocytopenia (3 patients), central retinal vein thrombosis and tAML. 11 patients tolerated lenalidomide dosing as per protocol, 6 were not increased from 10 to 15mg, 8 required dose modification for AEs (6 to 10mg; 2 to 5mg) and 5 were discontinued due to AEs. Conclusion RAP maintenance improved depth of response post-ASCT with some achieving best response > 8 months after initiation. ORR was 100%, with high rates of CR (20%) and sCR (43%). Correlation between MFC and serological testing appears poor. Many patients who relapsed had poor-risk cytogenetics (+1q), suggesting that these patients may benefit less from RAP maintenance. Disclosures: Off Label Use: Lenalidomide not approved for maintenance therapy post ASCT in Australia. Spencer: Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees.

Thrombotic microangiopathy (TMA) is a serious medical condition that results from microvascular thrombotic occlusion, leading to red cell fragmentation (microangiopathic hemolytic anemia) and profo...

Most patients with chronic myeloid leukemia (CML) treated with imatinib will relapse if treatment is withdrawn. We conducted a prospective clinical trial of imatinib withdrawal in 40 chronic-phase CML patients who had sustained undetectable minimal residual disease (UMRD) by conventional quantitative polymerase chain reaction (PCR) on imatinib for at least 2 years. Patients stopped imatinib and were monitored frequently for molecular relapse. At 24 months, the actuarial estimate of stable treatment-free remission was 47.1%. Most relapses occurred within 4 months of stopping imatinib, and no relapses beyond 27 months were seen. In the 21 patients treated with interferon before imatinib, a shorter duration of interferon treatment before imatinib was significantly associated with relapse risk, as was slower achievement of UMRD after switching to imatinib. Highly sensitive patient-specific BCR-ABL DNA PCR showed persistence of the original CML clone in all patients with stable UMRD, even several years after imatinib withdrawal. No patients with molecular relapse after discontinuation have progressed or developed BCR-ABL mutations (median follow-up, 42 months). All patients who relapsed remained sensitive to imatinib re-treatment. These results confirm the safety and efficacy of a trial of imatinib withdrawal in stable UMRD with frequent, sensitive molecular monitoring and early rescue of molecular relapse.

The treatment of acute promyelocytic leukemia has improved considerably after recognition of the effectiveness of all-trans-retinoic acid (ATRA), anthracycline-based chemotherapy, and arsenic trioxide (ATO). Here we report the use of all 3 agents in combination in an APML4 phase 2 protocol. For induction, ATO was superimposed on an ATRA and idarubicin backbone, with scheduling designed to exploit antileukemic synergy while minimizing cardiotoxicity and the severity of differentiation syndrome. Consolidation comprised 2 cycles of ATRA and ATO without chemotherapy, followed by 2 years of maintenance with ATRA, oral methotrexate, and 6-mercaptopurine. Of 124 evaluable patients, there were 4 (3.2%) early deaths, 118 (95%) hematologic complete remissions, and all 112 patients who commenced consolidation attained molecular complete remission. The 2-year rate for freedom from relapse is 97.5%, failure-free survival 88.1%, and overall survival 93.2%. These outcomes were not influenced by FLT3 mutation status, whereas failure-free survival was correlated with Sanz risk stratification (P[trend] = .03). Compared with our previously reported ATRA/idarubicin-based protocol (APML3), APML4 patients had statistically significantly improved freedom from relapse (P = .006) and failure-free survival (P = .01). In conclusion, the use of ATO in both induction and consolidation achieved excellent outcomes despite a substantial reduction in anthracycline exposure. This trial was registered at the Australian New Zealand Clinical Trials Registry (www.anzctr.org.au) as ACTRN12605000070639.

Introduction: Early ASCT improves progression-free survival (PFS) but not overall survival (OS) in poor prognosis DLBCL treated with R-CHOP immuno-chemotherapy (Stiff P et al., NEJM 2013). Furthermore, indiscriminate ASCT exposes those poor-risk patients destined to remain in CR with R-CHOP alone to unnecessary toxicity. Here, the role of interim PET/CT to risk-stratify is controversial. One confounding factor is that interim PET/CT is typically performed after 2 (or 3) cycles of chemotherapy when FDG-avidity likely reflects a mix of residual cancer cells and inflammation; in contrast, interim PET/CT after cycle 4 may be more representative of resistant lymphoma. We hypothesized that: 1. assessment of DLBCL patients by interim PET/CT after 4 cycles (iPET4) of R-CHOP-14 allows greater specificity of FDG-avidity; and, 2. for patients with iPET4-positivity, early treatment intensification with R-ICE chemotherapy followed by Zevalin-BEAM conditioning and ASCT results in 2-yr PFS that is equivalent to interim-PET/CT-negative patients treated with R-CHOP alone. Methods: We conducted a prospective multicenter phase 2 study which enrolled DLBCL patients ≤ 70 yrs with either IPI=2-5, or IPI =0-1 with tumor bulk (≥ 7.5 cm), and who were considered fit for ASCT. All patients underwent a diagnostic PET/CT at study entry and were planned to receive 4 cycles of R-CHOP-14 and supported with Pegfilgrastim. Cycle 5 of R-CHOP-14 was delayed 7 days, and an interim PET/CT scan was undertaken at d17-d20 post-4th R-CHOP-14, the delay intended to reduce the impact of rebound inflammation after R-CHOP. All interim PET/CT scans were assessed centrally by a core group of imaging specialists using International Harmonization Project (IHP) criteria with mediastinal blood pool as the reference. Biopsy to confirm residual tumor was not mandated. iPET4-positive patients received 3 cycles of R-ICE followed by ASCT with Zevalin-BEAM conditioning; those who were iPET4-negative received a further 2 cycles of R-CHOP-14 plus 2 doses of Rituximab. Results: A total of 162 patients were enrolled from 20 Australian centers; 11 patients were excluded because of failure to meet inclusion criteria. Baseline characteristics of the 151 evaluable patients included: median age 57 yrs (range, 21 to 69), 40% aged > 60 yrs, 62% males, 79% stages 3 or 4, 13% ECOG PS > 1, 78% elevated LDH, 48% extranodal sites > 1, 54% bulky disease ≥ 7.5 cm, 20% IPI=0-1, 27% IPI=2, 31% IPI=3, and 23% IPI=4-5. No interim PET/CT scan was performed in 8 patients due to progressive disease (PD) (1), bowel perforation (2), toxicity (3), and dose delays ≥ 2 weeks (2). Interim PET/CT scans were undertaken at d17-d20 in 62% and d14-d16 in another 23%. Of the 143 patients with interim PET/CT, 101 (71%) were deemed iPET4-negative and 42 (29%) were iPET4-positive. Interestingly, the baseline characteristics were comparable between iPET4-negative and iPET4-positive patients. Of the 101 iPET4-negative patients, 5 failed to complete therapy due to PD (3), toxicity (1), or infection (1). Of the 42 iPET4-positive patients, 10 failed to complete intensification therapy due to PD (6), 2nd malignancy (1), or consent withdrawal (3). Among iPET4-positive patients undergoing ASCT, there was 1 treatment-related death due to viral infection. At a median follow-up of 35 months, the Kaplan-Meier (KM) estimate of 2-yr PFS and OS for the entire eligible cohort of 151 pts was 72% and 85%, respectively. For the 101 iPET4-negative and 42 iPET4-positive patients, 2-yr PFS was 74% and 67% (P =0.32) (Figure 1), and 2-yr OS was 88% and 78% (P=0.11) (Figure 2), respectively. Among iPET4-negative and iPET4-positive patients with IPI=3-5, 2-yr PFS was 65% and 69% (P=0.74), and 2-yr OS was 81% and 83% (P =0.85), respectively. Conclusions: Patients with poor risk DLBCL who are interim PET/CT-positive after 4 cycles of R-CHOP-14 and switched to intensification with R-ICE followed by ASCT with Zevalin-BEAM have favorable rates of PFS and OS that are equivalent to that seen for patients who are interim PET/CT-negative. This study supports further investigation of treatment intensification in patients with poor risk DLBCL who are interim PET/CT-positive after 4 cycles of immuno-chemotherapy. The study was supported in part by Roche Products Pty. Ltd, Amgen Australia Pty. Ltd, and Bayer Australia Ltd. Figure 1. Progression Free Survival by Interim PET/CT Figure 1. Progression Free Survival by Interim PET/CT Figure 2. Overall survival by Interim PET/CT Figure 2. Overall survival by Interim PET/CT Disclosures Hertzberg: Janssen-Cilag: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; AbbVie: Honoraria, Membership on an entity's Board of Directors or advisory committees; BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda Oncology: Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees; Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees. Gill:AbbVie: Honoraria; Roche: Research Funding; Sanofi Aventis: Research Funding; Roche: Honoraria. Ho:Celgene: Other: Travel. Cull:Janssen-Cilag: Membership on an entity's Board of Directors or advisory committees; Amgen: Other: Travel. Grigg:Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees; Merck: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees. Lewis:Amgen: Other: Travel; Roche: Honoraria, Other: Travel. Renwick:Amgen: Other: Travel; Bayer: Speakers Bureau. Seymour:Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel support, Speakers Bureau; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; Genentech, Inc.: Membership on an entity's Board of Directors or advisory committees; Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees; Incyte: Honoraria, Membership on an entity's Board of Directors or advisory committees; Infinity: Honoraria, Membership on an entity's Board of Directors or advisory committees; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel support, Research Funding, Speakers Bureau; Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel support, Research Funding; Phebra: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees.

The risk of infection with Pneumocystis jirovecii pneumonia (PCP) in patients undergoing chemotherapy is closely related to the intensity of corticosteroid exposure. PCP is uncommon with classical (3-weekly) R-CHOP, but the risk may be higher with biweekly R-CHOP (R-CHOP-14) due to the increased frequency of prednisolone pulses. Among 47 consecutive patients treated with R-CHOP-14 at our institution, five (11%) developed microbiologically proven PCP, with a further two (4%) having classical clinical and radiological features of PCP, but without microbiological confirmation. None of these patients were HIV-positive or had additional risk factors for PCP. Our experience suggests that PCP prophylaxis should be considered in institutions using R-CHOP-14 for the treatment of patients with aggressive lymphomas.

BACKGROUND. Interferon-alpha (IFN-α) confers a survival advantage for the minority of patients with chronic myeloid leukemia (CML) who achieve a complete cytogenetic response. The question of whether IFN-α-responsive patients can experience further improvements with imatinib has not been answered. Imatinib offers clear quality of life advantages. Furthermore, patients who achieve a major molecular response (MMR) while receiving imatinib are likely to remain progression free. METHODS. A total of 23 patients treated for a median of 4.5 years with IFN-α (range, 1.6–14.3 years) who had achieved a complete (Philadelphia chromosome [Ph] negative, n = 15 patients) or near-complete (1–10% Ph, n = 8 patients) cytogenetic response were studied. The primary objective was to determine whether ceasing therapy with IFN-α and switching to 12 months of imatinib treatment at a dose of 400 mg/day could improve the molecular response as assessed by real-time quantitative polymerase chain reaction of BCR-ABL transcript levels. Safety was also assessed. RESULTS. Every patient who had not achieved an MMR while receiving IFN-α (n = 16 patients) achieved an MMR after a median of 3 months of imatinib treatment. Significant BCR-ABL reductions (median, 63-fold; range, 18–425-fold) occurred in 15 of these patients. Every patient who had already achieved an MMR while receiving IFN-α (n = 7 patients) maintained an MMR while receiving imatinib. No patients discontinued imatinib due to toxicity, but 1 patient withdrew consent. CONCLUSIONS. These data suggest that switching IFN-α-responsive patients to imatinib leads to a rapid improvement in achieving an MMR, a response with established prognostic value, and is well tolerated. The study should help patients and their physicians make evidence-based decisions regarding the potential benefits and risks of switching to imatinib. Cancer 2007. © 2007 American Cancer Society.

BP-015 Immunohistochemical (IHC) biomarkers associated with response and survival following lenalidomide and prednisolone maintenance postASCT in patients with MM: an exploratory, hypothesis generating sub-study of the LEOPARD trial A. Kalff, N. Kennedy, P. Walker, T. Khong, A. Schwarer, A.W. Roberts, P. Campbell, R. Filshie, J. Reynolds, A. Thakurta, M. Wang, S. Cuoto, Y. Ren, A. Spencer Alfred Hospital, Monash University, Melbourne, Vic, Australia; Box Hill Hospital, Box Hill, Vic, Australia; Royal Melbourne Hospital, Vic, Australia; Geelong Hospital, Vic, Australia; St Vincents Hospital, Melbourne, Vic, Australia; Celgene Corporation

Background Despite improved outcomes achieved with high dose melphalan conditioned ASCT for Myeloma (MM) patients, relapse is inevitable. Maintenance therapy following ASCT improves the depth of response achieved by induction therapy and prolongs both progression free (PFS) and overall survival (OS). Achievement of stringent (s) complete response (CR) is predictive of improved outcome, as is minimal residual disease (MRD) negativity (-neg) assessed by sensitive techniques such as multiparameter flow cytometry (MFC) of bone marrow (BM). Aim To document disease response changes, PFS/OS in MM patients receiving maintenance lenalidomide and alternate-day prednisolone (RAP) after ASCT. To sequentially quantify MRD in patients achieving a complete response (CR) utilising freeLite chain (FLC) and MFC. To assess safety and tolerability. Methods Phase II, open label, single arm, multi-centre study. Newly diagnosed patients with MM commenced RAP maintenance (lenalidomide 10mg/continuous daily increasing to 15mg after 8/52 and alternate day prednisolone 50mg) 6-8 weeks after a single MEL200 ASCT as part of first-line therapy. RAP continued until toxicity or relapse/progression. Serum for FLC was collected every 2/12, patients achieving CR had serial BM MFC. Statistical analysis: Prism v5.0a. Results 60 patients (M=37, F=23), with a median age of 61 years (range 41-71) commenced RAP maintenance. ISS stage at diagnosis: I: 20, II/III: 37 (3 unknown). 51/60 patients had diagnostic cytogenetics ± FISH performed – 15 had poor risk features (t(4;14), t(14;16), del17p, del13, +1q21), 11/15 had +1q21. After a median 23 months (range 12-36) following initiation of RAP, 33 patients remain on therapy. One patient has been lost to follow-up. Discontinuation was due to relapse/progressive disease (10), AEs (13), physician choice (2), poor compliance (1) and death (1). 15 patients have relapsed/progressed, 11 patients have died; 7 due to MM, 2 due to therapy related AML (tAML) and 2 other. Both the median PFS and OS have not been reached. When looking at the association between survival and poor risk cytogenetics ± FISH, those with +1q21 had both inferior PFS and OS: median PFS was 646 days vs not reached (NR) for those without +1q21 (P=0.04), median OS was 701 days vs NR for those without +1q21(P=0.013). 34 patients improved their post ASCT response on RAP. Best response was CR in 36 (60% - 25 sCR), 21 VGPR (35%) and 2 PR (3%), achieved in a median of 77 days (range, 0-447). 30 of 36 patients in CR went on to have sequential MRD studies: 21/30 were multiply MRD-neg and 9/30 were multiply MRD-pos. There was no difference in PFS between MRD-pos and MRD-neg patients (p=0.3). Of the MRD-neg patients, 16/21 had predominantly normal FLC ratios (sCR), 4/21 MRD-neg patients relapsed, 3 had normal FLC ratios. Of the MRD-pos patients, 6/9 had normal FLC ratios (sCR), 3/9 MRD-pos relapsed. Correlation between MRD neg and sCR was poor (r2=0.05) and there was no difference in relapse rate between patients achieving MRD-neg versus those who achieved sCR. All grade haematologic AEs comprised thrombocytopenia 15/60 (25%)(grade 3/4: 6 [10%]), neutropenia 10/60 (grade 3: 5), and anaemia 5/60 (%)(grade 3: 1). All grade non-haematologic AEs regardless of relatedness to study treatment (>10%) were: infections (URTI: 35%, LRTI: 25%, VZV reactivation: 13%), diarrhoea (38%), insomnia (32%), fatigue (26%), peripheral neuropathy (20%), cramps (18%), hyperglycemia (12%). There have been six second primary malignancies (SPMs) – 2 tAML (onset post C1D1: 15m, 21m), 1 adenocarcinoma of bowel (onset post C1D1: 30m) and 3 skin cancers (SCCs). AEs leading to discontinuation were myelosuppression (9), SPM (2), retinal vein thrombosis (1) and fatigue (1). 24 patients (40%) tolerated lenalidomide dosing as per protocol, 13 were not increased from 10mg/d to 15mg day, and 23 required dose modifications for AEs. Conclusion RAP maintenance improved depth of response post-ASCT (including conversion to deeper response categories > 14months), with high rates of CR/sCR (60%). Neither MFC or FLC demonstrated superiority over the other for prediction of outcome and correlation between the two was poor. Recapitulating earlier findings of an interim analysis, patients with +1q21 had inferior PFS/OS, suggesting that this group may benefit less from RAP maintenance. Only 21% of patients discontinued RAP due to toxicity, comparable to IFM 2005-02 and CALGB 100104 studies. Disclosures Off Label Use: Lenalidomide used as maintenance post-ASCT. Spencer:Takeda: Consultancy, Honoraria; janssen-Cilag: Consultancy, Honoraria, Research Funding; novartis: Consultancy, Honoraria, Research Funding; celgene: Consultancy, Honoraria, Research Funding.

Hemophilia B is an X-linked genetic disorder that typically results from chronic circulating deficiency of blood coagulation factor IX (FIX) (1). While the occurrence of hemophilia B is significantly less frequent than hemophilia A (factor VIII, deficiency) it has received special attention as a model for gene therapy. This is because hemophilia B is one of the least complicated genetic diseases from the point of view of demonstrating the proof of principle of a gene therapy protocol. Specifically, hemophilia B is a single gene recessive disorder and a wide range of tissues can be targeted for FIX gene delivery and strict regulation of FIX expression is not required. In addition, the 2.8 kb FIX cDNA is much smaller than the 9 kb FVIII cDNA, and FIX expression in transfected mammalian cells has been less problematic than FVIII expression (2). Since clinical severity of bleeding episodes closely corresponds to a patient's FIX activity, achieving even partial restoration of normal FIX levels in the bloodstream can alleviate internal bleeding. Individuals with FIX levels less than 1% of normal experience severe symptomatic episodes but providing roughly 5% of normal levels (i.e., 250 ng/mL plasma) can significantly reduce the frequency and severity of bleeding episodes and reduce long term complications (3). Treatment of hemophilia B primarily relies on intravenous injections of FIX protein purified from pooled human plasma, or very recently, on newly developed recombinant FIX. Treatment is applied typically only when bleeding episodes have occurred or are expected, for example, in case of a trauma or surgery. Although the risk of viral transmission of HIV and hepatitis viruses has been largely eliminated the absolute safety of any product derived from blood cannot be guaranteed. Furthermore, supplies of factor concentrates are limited and costs (especially if prophylactic treatment is being considered) are high. Thus, the application of gene therapy to hemophilia, whereby long-term correction of factor IX deficiency might be achieved, would be extremely useful.

Delayed rejection of pig kidney xenografts by primates is associated with vascular injury that may be accompanied by a form of consumptive coagulopathy in recipients. Using a life-supporting pig-to-baboon renal xenotransplantation model, we have tested the hypothesis that treatment with recombinant human antithrombin III would prevent or at least delay the onset of rejection and coagulopathy. Non-immunosuppressed baboons were transplanted with transgenic pig kidneys expressing the human complement regulators CD55 and CD59. Recipients were treated with an intravenous infusion of antithrombin III eight hourly (250 units per kg body weight), with or without low molecular weight heparin. Antithrombin-treated recipients had preservation of normal renal function for 4-5 days, which was twice as long as untreated animals, and developed neither thrombocytopenia nor significant coagulopathy during this period. Thus, recombinant antithrombin III may be a useful therapeutic agent to ameliorate both early graft damage and the development of systemic coagulation disorders in pig-to-human xenotransplantation.

Bortezomib, a proteosome inhibitor used for the treatment of multiple myeloma, was first approved by the US FDA on 13 May 2003. At that stage, one case of respiratory failure associated with the dr...

Abstract 3771 Background: We have previously reported promising results from the TIDEL-II trial, using imatinib (IM) treatment upfront in patients (pts) newly diagnosed with Philadelphia chromosome positive Chronic Myeloid Leukaemia in Chronic Phase (CML-CP), and switching selected pts to nilotinib (NIL) on the basis of failure to achieve time-dependent molecular response (MR). This strategy showed excellent rates of major molecular response (MMR; BCR-ABL ≤0.1% IS) at 12 months (mos) and transformation free survival. Aim: To optimise molecular outcome and survival in treatment naïve CML-CP pts by selective dose escalation of IM for pts with low trough levels and early switching to NIL for pts with poor MR. Methods: TIDEL-II enrolled 210 CML-CP pts across 23 Australasian centres in 2 equal and sequential cohorts. All pts started treatment with IM 600mg/d and dose escalated to IM 800mg/d if IM trough levels were Results: Median follow up (f/u) for C1 and C2 pts were 42 & 24 mos respectively, and 31 mos for all pts (15–56 mos) – see table 1. The primary end-point, confirmed MMR at 12 mos, was achieved by 64%, with no difference between C1 and C2. This climbed to 75% at 24 mos. At 12 & 24 mos, the proportion of pts with confirmed MR4.5 (BCR-ABL ≤ 0.0032% IS) was 18% and 29% respectively. Six pts progressed to blast crisis (BC) : 4 in their 1st year of treatment, and 1 each in the 2nd and 3rd yrs, resulting in 2 deaths. Four other deaths were recorded, caused by stroke (1), pneumonia (1) and cardiac disease (2); 2 pts had NIL treatment before death. Eighteen mutations had been identified in 11 pts, including 4 pts with the highly resistant mutations T315I or E255K either singly or in combination with others. These were identified in the context of BC (3), loss of MMR (2), lack of MMR by 12 mos (4), and lack of CCR by 6 mos (2). One other pt lost MMR in the absence of a mutation and regained MMR with switching to NIL. Thirty-one pts in C1 switched to NIL: 19 for intolerance and 12 for failure to achieve targets after a trial of IM 800mg/d. Of the latter, with median f/u of 26 mos on NIL, 5/12 reached MMR subsequently. In C2, 44 patients switched to NIL, 12 for intolerance and 32 for failing targets: of the latter, 9 reached MMR with median f/u of 14 mos. In contrast, in the 31 (C1+C2) pts switching for IM-intolerance, all but 2 reached MMR (including 12 patients already in MMR at time of switch). Of the 25 pts with BCR-ABL ≥ 10% at 3mos, 3 pts progressed to BC (1 at 3.5mos), 6 more withdrew from study. Of the remainder, four pts achieved MMR, 9 more achieved BCR-ABL Conclusion: Overall, the TIDEL-II strategy compares well with other upfront studies of CML-CP pts with regard to MR, as well as risk of death and progression to BC. A small proportion of pts experience further falls in BCR-ABL when switching from IM to NIL for failure to achieve deep MR. In the 12% of pts who fail to achieve BCR-ABL ≤10% at 3 mos, there is greater risk of BC and so far no deep MR are seen, despite intensification in kinase inhibition instituted at as early as 3 mos. Alternative approaches are needed both to identify these pts early and protect them from disease transformation. Disclosures: Yeung: Novartis Pharmaceuticals: Honoraria, Research Funding; Bristol-Myers Squibb: Honoraria, Research Funding. White:Novartis Pharmaceuticals: Research Funding; BMS: Research Funding. Branford:Novartis : Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol-Myers Squibb: Honoraria, Research Funding; Ariad : Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Cepheid : Consultancy. Slader:Novartis Pharmaceuticals: Employment. Hiwase:CSL Ltd: Research Funding. Schwarer:Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees. Ross:Novartis: Honoraria, Research Funding; Bristol-Myers Squibb: Honoraria. Grigg:Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding. Hughes:Novartis Oncology: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Ariad: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding.

Abstract 451FN2 Background: While nilotinib and dasatinib produce faster responses than imatinib as first-line therapy in de novo Chronic Phase Chronic Myeloid Leukemia (CP-CML), an equally effective strategy may be to selectively use these more potent tyrosine kinase inhibitors (TKIs) only in patients who fail to achieve stringent early molecular targets or are intolerant. Aim: To update the molecular outcome and survival of patients in the TIDEL-II study. Method: TIDEL-II is a multicentre, single arm prospective ALLG trial for de novo CP-CML adult patients with two sequential cohorts each of 105 patients. All patients started on imatinib (IM) 600mg OD. Patients with IM trough levels Disclosures: Yeung: Novartis Pharmaceuticals: Research Funding; BMS Oncology: Research Funding. Osborn:Novartis Pharmaceuticals: Research Funding; BMS Oncology: Research Funding. White:Novartis Pharmaceuticals: Research Funding. Branford:Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Honoraria, Research Funding; Ariad: Research Funding. Slader:Novartis Pharmaceuticals: Employment, Equity Ownership. Hiwase:CSL: Research Funding. Schwarer:Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen-Cilag: Honoraria; Hospira: Membership on an entity's Board of Directors or advisory committees. Arthur:Novartis Pharmaceuticals: Honoraria; BMS Oncology: Honoraria. Ross:Novartis: Honoraria, Research Funding. Mills:Novartis Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Sponsorship to professional meetings; BMS Oncology: Sponsorship to professional meetings. Hughes:Novartis Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS Oncology: Research Funding.

Abstract 209 Background: Although the majority of chronic phase (CP) Philadelphia positive (Ph+) chronic myelogenous leukemia (CML) patients (pts) achieve good disease control with imatinib, some pts demonstrate suboptimal responses. Early dose escalation or switching to nilotinib, a more potent BCR-ABL kinase inhibitor, as soon as suboptimal molecular response is recognised may improve response and disease outcome. Aim: To optimise clinical and molecular outcomes in Ph+ CML using imatinib (IM) as frontline therapy with selective IM dose escalation based on pharmacokinetic (PK) results and switching to nilotinib (NIL) in case of suboptimal response, or IM-intolerance. Method: TIDEL-II is a multicentre, single arm prospective ALLG trial in de novo CP-CML pts with 2 separate sequential cohorts. In Cohort I, pts are treated with IM 600mg/d up-front, aiming for BCR-ABL RQ-PCR target values of ≤ 10%, 1%, and 0.1% IS (major molecular response, MMR) at 3, 6, and 12 months respectively. Pts who do not reach these treatment targets are classified as suboptimal responders. Dose escalation to 800mg/d or maximal tolerated dose occurs if trough IM level is Results: 105 pts were assessed with median follow up of 18.9 months (range: 9–33) in cohort I. For pts with a minimum of 12 months follow up (n=80), complete cytogenetic response (CCR), MMR and complete molecular response (CMR)# rates at 12 months were 92%, 66% and 11% respectively. BCR-ABL levels at 3 months were predictive of MMR at 12 months, but not for CMR due to small pt numbers (Table 1). For pts who failed to achieve BCR-ABL of ≤10% at 3 months, the 12 month MMR rate was 25% (vs 5% in TIDEL-I where pts were also started on IM 600mg/d and suboptimal responders were dose escalated to IM 800mg/d). Of the 105 pts, 16 pts dose escalated IM due to a day 22 IM blood level 1.0% at 3 months. In contrast, no resistant mutations were detected or transformations occurred in the 49 pts with BCR-ABL values ≤1.0% at 3 months. Conclusion: A strategy of selective intensification of BCR-ABL inhibitor therapy based on molecular response and PK values resulted in a 66% MMR rate by 12 months. Despite a minority of pts (20%) requiring a switch to NIL, this has enhanced the rate of MMR by 12 months when compared to IM intensification alone as seen in TIDEL-I where the rate of MMR and CMR by 12 months was 47% and 9% respectively. The IM intolerant pts demonstrated excellent response rates after switching to NIL. To date, the results from TIDEL-II compare favourably with other frontline strategies with regards to response and transformation rates. Disclosures: Yeung: Novartis Pharmaceuticals: Research Funding; Bristol Myers Squibb: Research Funding. Osborn:Novartis Pharmaceuticals: Research Funding; Bristol Myers Squibb: Research Funding. White:Novartis Pharmaceuticals: Research Funding; Bristol Myers Squibb: Research Funding. Branford:Novartis Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Research Funding. Slader:Novartis Pharmaceuticals: Employment, Equity Ownership. Ross:Novartis Pharmaceuticals: Honoraria, Research Funding. Mills:Novartis Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees. Hughes:Novartis: Honoraria, Research Funding, Speakers Bureau; Bristol-Meyers Squibb: Honoraria, Research Funding; Ariad: Honoraria.

Abstract 1125 Poster Board I-147 The Australasian Leukaemia and Lymphoma Group conducted a trial (TIDEL I) in 103 patients with newly diagnosed chronic phase CML, using imatinib 600 mg/day with dose escalation to 800 mg/day for suboptimal response. This was defined as failure to achieve (1) complete haematological response (CHR) at 3 months, (2) major cytogenetic response (MCR) at 6 months, (3) complete cytogenetic response (CCR) or molecular equivalent at 9 months, or (4) less than 0.01% (IS) BCR-ABL by RQ-PCR at 12 months. Here we report the outcomes with all surviving patients having been treated for at least 60 months. We aimed to determine whether the patient outcome at 60 months was predicted by the molecular response within the first 18 months of imatinib therapy. The outcomes for patients maintaining a dose of imatinib of ≥600 mg/day in the first 12 months was compared to those who were on a reduced dose for at least part of this time. Event-free survival (EFS) was defined as death from any cause, accelerated phase/blast crisis (AP/BC), and loss of CHR, MCR or CCR. The 103 patients included 66 males and 37 females with a median (±SD) age of 49 (±14) years. All patients had an ECOG performance status of 0-2 at enrolment. The 5-year EFS was 71%, transformation (AP/BC) free survival (TFS) was 95%, and overall survival was 87%. Of the 14 patients who died, 3 died in blast crisis, 2 from transplant-related complications, 8 from CML-unrelated causes, and the cause of death of 1 patient was unavailable. The annual rates of progression to AP/BC over 5 years were 3%, 1%, 0%, 1%, and 0%, while annual event rates were 13%, 8%, 8%, 1%, and 4%. CCR was achieved by 89% of patients by 60 months, while 72% achieved a major molecular response (MMR) by this time. In the first 12 months of treatment, 55% of patients maintained an imatinib dose of ≥600 mg/day (mean ±SD dose = 604 ±10 mg/day), while 45% were on The outcome was also determined for all patients dependent on the BCR-ABL levels at various assessment timepoints. Patients with a BCR-ABL level of 10% (IS) (n=8) had an event (P1% (IS) (P In conclusion, our data suggest that patients maintaining a dose of ≥600mg in the first 12 months of imatinib therapy are more likely to achieve CCR and MMR, and superior EFS compared to those with a lower dose. This study also confirms that achieving an MMR by 18 months is associated with improved EFS. This emphasises the value of achieving a molecular response early in the treatment course, as well as adding weight to the evidence supporting the role of molecular monitoring in CML. Disclosures Branford: Novartis Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol-Myers Squibb: Honoraria, Research Funding. White:Novartis and Britol-Myers Squibb: Research Funding. Seymour:Bayer Schering: Consultancy, Membership on an entity's Board of Directors or advisory committees, Travel grants; Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Travel Grants. Catalano:Roche: Honoraria, Research Funding, Travel grants. Mills:Celgene Pty Ltd: Honoraria, Membership on an entity's Board of Directors or advisory committees. Hughes:Bristol-Myers Squibb: Advisor, Honoraria, Research Funding; Novartis: Advisor, Honoraria, Research Funding.

Abstract 1749 Poster Board I-775 Introduction Both thalidomide (Thal) and 5-azacitidine (Vidaza; AZA) have single-agent activity in patients (pts) with myelodysplastic syndromes (MDS), but there is limited experience with the combination. The addition of Thal to AZA may improve efficacy, but tolerability of the combination may be limited by side-effects. Patients and Methods This analysis included all evaluable pts on the Ph I/II Australasian Leukaemia and Lymphoma group (ALLG) MDS3 study of Thal and AZA. Pts were eligible if they had any FAB subtype of MDS; those with RA and RARS also required clinically significant cytopenias. Pts were excluded if they had previously received Thal or its derivatives or any demethylating agent. All pts were treated with Thal 50mg/d for the first 28d increasing to 100mg/d for a max of 12 Mo treatment and AZA 75mg/m2/d x7d every 28d until progression or prohibitive toxicity. The protocol specified dose delays or reductions for treatment-related toxicities. Results A total of 80 pts have been enrolled, with 41 treated between 7/08 – 7/09 currently evaluable. Median age is 68.5y (42-81) with 66% male. FAB MDS category was RA 15%, RARS 10%, RAEB 46%, RAEB-t 10% and CMML 17% with IPSS low 12%, intermed-1 37%, intermed-2 34% and high 12%. Median baseline Hb 88g/L (71-127), ANC 1.91×10 9/L (0.06-87.65) and platelets 75 ×10 9/L (10-399). Median time post diagnosis was 9 Mo. Seventeen pts (41%) remain on treatment with AZA alone (n=3) or both agents (n=14) with a median follow-up of 208d (60-297d). For those still on Thal and AZA median exposure to Thal is 209d (60-297d), with a median 7 cycles of AZA (2-9). For those 27 ceased Thal median exposure was 49d (17-220d) and of 24 ceasing AZA, median number cycles was 2 (1-8). Of 27 pts ceasing one (n=3) or both (n=24) agents; 7 withdrew consent, 3 at investigator decision, 4 for toxicity, 6 progressive disease, 1 lack of efficacy, 2 death (1 respiratory failure in setting of PD and WCC>300, 1 sepsis) and 4 unknown. There were 3 additional deaths within 28d of ceasing study therapy (all with PD); 2 due to sepsis and 1 intracranial haemorrhage. No pt experienced peripheral neuropathy Gr3 or worse. During cycle 1 of the first 40 consecutive patients on treatment, there were 18 episodes of Gr3+ non-haematologic toxicity in 13 patients; this was more likely in those with ECOG 2 (67% v 26%, p=0.053), age>65y (39% v 19%, p=0.175) and baseline ANC'0.5 (75% v 21%, p=0.008). Most of these events were infection related (a recognised risk of underlying MDS and of AZA alone); others occurred on only one occasion each (syncope, postop hemorrhage, respiratory disorder, renal failure, abdominal pain, pain, thrombosis and hypokalemia). Conclusions The combination of Thal 50-100mg/d and standard dose AZA is feasible without unexpected toxicity. Infections are common in the first cycle, particularly in pts with baseline neutropenia or impaired performance status. An updated toxicity analysis will be presented. Disclosures Kenealy: Celgene Pty Ltd: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Seymour:Celgene Pty Ltd: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Mills:Celgene Pty Ltd: Honoraria, Membership on an entity's Board of Directors or advisory committees. Szer:Celgene Pty Ltd: Honoraria, Speakers Bureau.

After 5 years of imatinib treatment 40–50% of chronic myeloid leukaemia (CML) patients will have stable undetectable BCR-ABL by real-time quantitative RT-PCR (RQ-PCR) using strict sensitivity criteria (‘complete molecular response’, CMR). Many patients who stop imatinib in CMR will relapse, but small numbers have been reported with sustained CMR after imatinib withdrawal. We designed a non-randomised prospective Phase 2 study of imatinib withdrawal in adult chronic phase CML patients in CMR for ≥2 years (ACTRN012606000118505). Patients were treated in multiple centres around Australia, and RQ-PCR for BCR-ABL was performed centrally: monthly for the first year after imatinib withdrawal, and 2-monthly in the second year. Molecular relapse was defined as a single PCR result above the level of major molecular response (MMR) or any two consecutive positive results. Molecular relapse was treated with imatinib and patients were monitored monthly for 12 months to assess response to retreatment. Patients were enrolled in two cohorts: imatinib de novo (IM only, n=5) and imatinib after prior interferon therapy (IFN-IM, n=13). The median duration of prior IFN was 39 months. Both cohorts continue to accrue. For all 18 patients the median age at study entry was 58 years; 44% were male. The median duration of imatinib treatment was 60 months (R40-89). The Kaplan-Meier estimate of the rate of sustained CMR after 12 months off treatment was 67% (95% confidence interval 40–85%, see Figure). Ten of 13 IFN-IM patients (77%) remain in CMR, and 7 of these have been in CMR for at least 12 months without treatment (maximum 23 months). The median follow-up in the IM only patients is currently only 7 months (R1-15), and 3/5 remain in CMR. All molecular relapses in both groups have occurred within 5 months of stopping imatinib. The median duration of prior imatinib treatment was not different in the 5 patients with loss of CMR (76 months) versus those in stable CMR (60 months; p=0.59). Among the 5 patients with loss of CMR the median time to molecular relapse was 3 months (range 2–5 months). Two relapsing patients lost MMR, and 3 had detectable BCR-ABL mRNA below this level. No patient has experienced haematological relapse or developed a kinase domain mutation. At last follow-up all 5 relapsing patients had regained CMR after a median of 5 months of re-treatment with imatinib. Patient-specific DNA Q-PCR assays were developed to test whether minimal residual disease (MRD) was detectable in genomic DNA in patients in CMR defined by RQ-PCR for BCR-ABL mRNA. Results are available for 6 patients, 3 of whom have relapsed. One relapsing patient had BCR-ABL DNA detected prior to imatinib withdrawal. In the remaining 2 relapsing patients BCR-ABL DNA was detected after imatinib withdrawal, but 2–3 months prior to the detection of BCR-ABL mRNA by RQ-PCR. BCR-ABL DNA increased by at least 1-log between the time of the first positive result and the detection of molecular relapse by RQ-PCR. The 3 patients in stable CMR had no detectable BCR-ABL DNA. In conclusion, with close molecular monitoring imatinib withdrawal in stable CMR appears to be safe: currently all patients are either in stable CMR off treatment or back in CMR after re-treatment. Withdrawal of effective treatment outside the setting of a clinical trial is not recommended. Monitoring of MRD by genomic DNA Q-PCR was able to detect molecular relapse prior to mRNA RQ-PCR, and shows promise for the prospective identification of patients at high risk of relapse. There is an apparent dichotomy of response between early molecular relapse and durable CMR, at least in patients treated with imatinib after IFN. It is too early to identify clinical or laboratory factors (such as prior IFN treatment) that may influence the probability of sustained CMR without treatment. Figure Figure

IFN confers a survival advantage for the minority of patients with CML who achieve a complete cytogenetic response. The 10-year survival rate was reported as 72%. In the IRIS trial only 3% of patients remained on IFN after randomization and 65% crossed-over to imatinib. Imatinib offered superior compliance and toxicity profiles and clear quality of life advantages. Furthermore, patients on first line imatinib with a major molecular response (MMR) by 12 months had a 100% progression free survival to advanced phase. An important clinical question of whether IFN-responsive patients can experience further improvements with imatinib has not been answered. We studied 23 chronic phase patients treated with IFN for a median of 4.5 years (r1.6–14.3) who had achieved a complete (n=15) or near-complete (n=8) cytogenetic response. IFN was ceased and 400mg imatinib commenced in a clinical trial with the primary objective of determining if switching to imatinib in IFN-responsive patients improves response when assessed at the molecular level. Molecular assessment was undertaken for the first 12 months of imatinib therapy by measurement of peripheral blood BCR-ABL levels by quantitative PCR at 3 month intervals. A subset of 10 patients had follow-up molecular assessment for 3.8 to 4.5 years after commencing imatinib. Prior to IFN cessation all patients had detectable BCR-ABL and 16 of 23 had not achieved a MMR, which is a 3 log reduction of BCR-ABL from a standardized baseline value for untreated patients. At a median of 3 months of imatinib (r3–12) these 16 patients achieved MMR. A significant reduction of BCR-ABL over the 12 month assessment was considered >50% and this occurred in 15 of these 16 patients (median 98.4% reduction, r94.4–99.8). In the sole patient without a significant reduction, BCR-ABL returned to the pre imatinib level after repeated dose interruptions of 93 days and decrease to 200mg imatinib due to thrombocytopenia. Of the 7 patients with a MMR prior to IFN cessation, all 7 maintained this level of response after switching to imatinib. Therefore, over the 12 month assessment all patients either achieved MMR (n=16) or maintained MMR (n=7). One patient withdrew consent after 83 days. The 10 patients with longer molecular follow-up of up to 4.5 years of imatinib all maintained MMR. The typical molecular response is illustrated in the figure, which plots the log reduction of BCR-ABL from the standardized baseline for 3 patients assessed at regular time-points before and after switching to imatinib. In conclusion, the data suggest that switching to imatinib leads to rapid and significant improvement in IFN-responsive patients in terms of achieving MMR, a response with established prognostic value with imatinib therapy. The study should help patients and their physicians make evidence-based decisions about the potential benefits and risks of switching to imatinib with prior response to IFN. Figure Figure