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While the past decade has witnessed unprecedented progress for patients with chronic lymphocytic leukemia (CLL), outcomes for patients with Richter transformation (RT) remain dismal. Multiagent chemoimmunotherapy regimens, such as rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone, are commonly used, although outcomes are far poorer than observed with the same regimens used in de novo diffuse large B-cell lymphoma. The revolutionary targeted therapies approved for CLL, such as inhibitors of Bruton tyrosine kinase and B-cell leukemia/lymphoma-2, have limited activity in RT as monotherapy, and initial promising activity of checkpoint blockade antibodies was also eventually found to be ineffective as monotherapy for most patients. Over the past few years, as outcomes for patients with CLL improved, there has been a growing focus of the research community on improving our biological understanding of the underlying pathophysiology of RT and on translating these new insights into rational combination strategies that are poised to improve therapeutic outcomes. Here, we present a brief overview of the biology and diagnosis of RT, as well as prognostic considerations, before providing a summary of the data supporting various therapies that have been recently studied in RT. We then turn our attention to the horizon and describe several of the promising novel approaches under investigation to treat this challenging disease.

Purpose Venetoclax is an orally bioavailable B-cell lymphoma 2 inhibitor. US Food and Drug Administration and European Medicines Agency approval for patients with 17p deleted relapsed/refractory chronic lymphocytic leukemia [del(17p) CLL] was based on results from 107 patients. An additional 51 patients were enrolled in a safety expansion cohort. Extended analysis of all enrolled patients, including the effect of minimal residual disease (MRD) negativity on outcome, is now reported. Patients and Methods Overall, 158 patients with relapsed/refractory or previously untreated (n = 5) del(17p) CLL received venetoclax 400 mg per day after an initial dose ramp up. Responses were based on 2008 International Workshop on Chronic Lymphocytic Leukemia criteria, with monthly physical exams and blood counts. Computed tomography scan was mandatory at week 36, after which assessment made was by clinical evaluation. Marrow biopsy was performed when complete remission was suspected. MRD was assessed by flow cytometry. Results Patients had a median of two prior therapies (range, zero to 10 therapies), 71% had TP53 mutation, and 48% had nodes that were ≥ 5 cm. Median time on venetoclax was 23.1 months (range, 0 to 44.2 months) and median time on study was 26.6 months (range, 0 to 44.2 months). For all patients, investigator-assessed objective response rate was 77% (122 of 158 patients; 20% complete remission) and estimated progression-free survival at 24 months was 54% (95% CI, 45% to 62%). For 16 patients who received prior kinase inhibitors, objective response rate was 63% (10 of 16 patients) and 24-month progression-free survival estimate was 50% (95% CI, 25% to 71%). By intent-to-treat analysis, 48 (30%) of 158 patients achieved MRD below the cutoff of 10−4 in blood. Common grade 3 and 4 adverse events were hematologic and managed with supportive care and/or dose adjustments. Conclusion Venetoclax achieves durable responses and was well tolerated in patients with del(17p) CLL. A high rate of blood MRD < 10−4 was achieved in this high-risk population.

Purpose Double-hit lymphomas (DHLs) and double-expressor lymphomas (DELs) are subtypes of diffuse large B-cell lymphoma (DLBCL) associated with poor outcomes after standard chemoimmunotherapy. Data are limited regarding outcomes of patients with relapsed or refractory (rel/ref) DEL or DHL who undergo autologous stem-cell transplantation (ASCT). We retrospectively studied the prognostic impact of DEL and DHL status on ASCT outcomes in patients with rel/ref DLBCL. Methods Patients with chemotherapy-sensitive rel/ref DLBCL who underwent ASCT at two institutions and in whom archival tumor material was available were enrolled. Immunohistochemistry for MYC, BCL2, and BCL6 and fluorescence in situ hybridization (FISH) for MYC were performed. In cases with MYC rearrangement or copy gain, FISH for BCL2 and BCL6 was also performed. Results A total of 117 patients were included; 44% had DEL and 10% had DHL. DEL and DHL were associated with inferior progression-free survival (PFS), and DHL was associated with poorer overall survival (OS). The 4-year PFS in patients with DEL compared with those with non-DEL was 48% versus 59% ( P = .049), and the 4-year OS was 56% versus 67% ( P = .10); 4-year PFS in patients with DHL compared with those with non-DHL was 28% versus 57% ( P = .013), and 4-year OS was 25% versus 61% ( P = .002). The few patients with concurrent DEL and DHL had a poor outcome (4-year PFS, 0%). In multivariable models, DEL and DHL were independently associated with inferior PFS, whereas DHL and partial response ( v complete response) at transplant were associated with inferior OS. Conclusion DEL and DHL are both associated with inferior outcomes after ASCT in patients with rel/ref DLBCL. Although ASCT remains a potentially curative approach, these patients, particularly those with DHL, are a high-risk subset who should be targeted for investigational strategies other than standard ASCT.

7502 Background: The BCL-2i venetoclax is active in certain HMs but can increase the risk of tumor lysis syndrome (TLS), requiring a 5-week dose ramp-up for CLL patients. Cases of severe neutropenia with venetoclax treatment have also been reported. Lisaftoclax is a novel, potent, selective BCL-2i that is active against HMs and is under clinical development. Methods: This first-in-human global phase I dose study assessed the safety, PK, PD, efficacy, and MTD/RP2D of lisaftoclax in patients with R/R CLL and other HMs. Lisaftoclax was orally administered daily in a 28-day cycle. Patients with CLL or intermediate-high TLS risk were initiated on a daily ramp-up schedule until the assigned dose before the study cycles. Results: On January 7, 2021, 35 pts had been enrolled and treated with lisaftoclax at doses ranging from 20 to 1,200 mg, with a median (range) of 2 (1-13) prior lines of treatment, and had diagnoses of R/R CLL or SLL (n = 15), MM (n = 6), FL (n = 5), WM (n = 4), and either AML, MCL, DLBCL, MDS, or HCL (n = 1 each). No DLT has been observed, even though 1,200 mg was considered as the highest dose treated. The MTD has not been reached, and no laboratory or clinical TLS has been reported. Any grade TRAEs in > 10% of pts included neutropenia (22.9%) and anemia (17.1%; hematologic), and fatigue (28.6%), diarrhea (17.1%), and nausea (11.4%; nonhematologic). Grade >3 TRAEs were neutropenia (14.3%) and thrombocytopenia, leukopenia, lymphopenia, fatigue, and nausea (2.9% of pts each). In CLL/SLL pts, grade 3-4 TRAEs included neutropenia (13.3%) and thrombocytopenia (6.7%), which did not cause treatment-related discontinuation. In all, 12 of 35 pts (34.3%) had non-treatment-related SAEs, and only two pts experienced > 1 SAE. With a median (range) treatment of 7 (3-20) cycles, 12 of 14 evaluable R/R CLL/SLL pts achieved PR, for an ORR of 85.7% and a median (range) time to response of 3 (2-7) cycles. Absolute lymphocyte counts (ALCs) were reduced at lisaftoclax doses as low as 20 mg/day. The preliminary PK profile showed that exposures increased with lisaftoclax doses from 20 to 1,200 mg (average half-life: 4-5 hours). On BH3 profiling, lisaftoclax rapidly triggered changes in BCL-2 complex in CLL/SLL pt samples, which were consistent with rapid clinical reductions in ALCs. Conclusions: Lisaftoclax was well tolerated up to 1,200 mg/day. No TLS was observed, even with the daily ramp-up schedule. There were no significant new or unmanageable safety findings, and the ORR in R/R CLL/SLL pts was 85.7%. Grade 3-4 TRAEs were infrequent, even at dose levels of 800 mg and above. BCL-2i lisaftoclax offers a treatment alternative for patients with R/R CLL/SLL and other HMs, with a daily ramp-up schedule that may be more pt “user friendly” and a favorable preliminary safety profile. Internal study identifier APG2575-001. Clinical trial information: NCT03537482.

8004 Background: While therapeutic options for CLL have improved, patients (pts) who develop Richter’s Syndrome (RS) still have a poor prognosis. Chemoimmunotherapy regimens such as R-EPOCH lead to CR in about 20% of RS pts, but PFS/OS is typically < 6 mo. The oral Bcl-2 inhibitor venetoclax (ven) had a 43% single agent response rate in RS. Here, we report the results of a phase 2 study of VR-EPOCH in RS. Methods: This is a single-arm, phase 2, IST of VR-EPOCH for RS (NCT03054896) at 3 US sites. CLL pts with biopsy-confirmed DLBCL were treated with R-EPOCH for 1 cycle, then after count recovery underwent accelerated inpatient ven daily ramp-up (20/50/100/200/400 mg), then ven + R-EPOCH for up to 5 more 21d cycles (ven 400 mg qd, d1-10 each cycle). Responders went to alloHCT or to continuous daily ven 400 mg maintenance. Response evaluation by Lugano criteria with PET/CT. Results: As of the data cut on 2/3/2020, the study is fully enrolled with 27 pts. Median age: 63 yrs (range 49-77). CLL features: 26% del(17p); 44% complex karyotype; 48% IGHV unmutated; 41% TP53 and 15% NOTCH1 mutation. Median prior CLL treatments: 2 (range 0-5, prior ibrutinib [n = 8], ven [n = 2], and PI3Ki [n = 2]) with 6 untreated CLL pts. Median # ven + R-EPOCH cycles: 4 (range 0-6). 5 pts had dose de-escalation of R-EPOCH, 1 pt had dose escalation. ≥Gr 3 heme tox: neutropenia (58%), anemia (50%), thrombocytopenia (50%). ≥Gr 3 non-heme tox in > 15% of pts: febrile neutropenia (38%) and hypophosphatemia (23% each). No pts had TLS with daily ven ramp-up. Infections: pneumonia (n = 4), sepsis during C1 of R-EPOCH prior to starting ven (n = 3), enterocolitis (n = 3), sinusitis (n = 2), and 1 pt each with influenza A and norovirus. 10 pts have died, including 7 due to disease progression (2 during C1 before ven), and 1 each due to sepsis, sudden death, and GVHD post-alloHCT. In ITT analysis, 16 responded (ORR 59%); 13/27 (48%) had CR as best response, all with undetectable bone marrow MRD for CLL. Six pts were not evaluable for efficacy of the combo (5 had toxicity in C1 and never started ven, 1 withdrew after C1). In the 21 pts who started combo therapy, the ORR was 76%, CR rate 62%. Only 1 pt with CR has progressed. The pt on longest ven maintenance is in CR 2 years post chemo. 8 pts went to alloHCT, with pts still in CR now up to 2.5 yrs post-alloHCT. With a median follow-up of 9.3 mo (range 0.6-30), median PFS and OS are both 16.3 mo. Conclusions: VR-EPOCH is active for RS. Expected toxicities from intensive chemoimmunotherapy and ven were seen, but daily ven ramp-up was feasible. The 48% CR rate and median PFS of 16.3 mo are favorable in the context of historical results. Clinical trial information: NCT03054896 .

7523 Background: Duvelisib (DUV), a first-in-class oral dual PI3K-δ,γ inhibitor, is approved for treatment (tx) of R/R CLL/SLL after ≥ 2 prior therapies. In the phase 3 DUO trial, DUV 25 mg BID significantly improved efficacy vs ofatumumab (OFA; mPFS, 13.3 vs 9.9 mo; HR, 0.52 [ P < .0001]; ORR, 74% vs 45% [ P < .0001]) in pts with R/R CLL/SLL. Tx-emergent AEs (TEAEs) of special interest (AESIs) such as infections, diarrhea, colitis, neutropenia, rash, ALT/AST elevation, and pneumonitis, were moderate and manageable with early intervention and dose modification. We examined dose-modification patterns and their impact on response to DUV in the DUO trial. Methods: Dose interruptions (DI) or reductions (DR) to 15, 10, or 5 mg BID were permitted per study protocol to manage TEAEs. Responses were assessed by IRC. Results: Among 158 DUV-treated pts, median duration of DUV exposure was 11.6 mo (vs 5.3 mo, OFA). DI and DR occurred in 80% (126/158) and 27% (43/158) of pts, respectively. The most common cause of DI was diarrhea (23%), followed by neutropenia (12%) and pneumonia or colitis (11% each). Among responders (n = 118), median time to first response on DUV was 1.9 mo and estimated median duration of response was 11.1 mo. Median time to first DI was 3.9 mo and median duration of DI was 15 d (range, 1-133 d). Response to DUV was improved or maintained in most pts evaluated for response who had ≥ 1 DI for > 1 wk (84% [42/50]) or > 2 wk (82% [31/38]) followed by ≥ 3 wk on DUV. In a landmark analysis, median PFS was similar in pts with DI and those without DI for > 1 wk (17.8 vs 16.3 mo) or > 2 wk (17.8 vs 16.3 mo) within the first 3 mo. The median time to DR after CR/PR was 5.6 mo (n = 25) and median duration was 3.4 mo. Median time to onset across AESIs after starting DUV ranged from 2.2 to 4.3 mo; median time to resolution was within 4 wk across AESIs. Proportions of pts experiencing AESIs were stable or decreased over time after 3-6 mo: 0-3 mo, 64% (101/158); > 3-6 mo, 63% (86/137); > 6-9 mo, 47% (54/114); > 9-12 mo, 52% (52/100), and seldom led to discontinuation of DUV (≤ 10%). Conclusions: DI/DR can contribute to the effective management of TEAEs with DUV. These findings suggest that DI of > 1-2 weeks or more do not appear to significantly impact response to DUV or PFS. Clinical trial information: NCT02004522.

The B-cell lymphoma/leukemia 2 (BCL-2) family of proteins has attracted the attention of cancer biologists since the cloning of BCL-2 more than 25 years ago. In the intervening decades, the way the BCL-2 family controls commitment to programmed cell death has been greatly elucidated. Several drugs directed at inhibiting BCL-2 and related antiapoptotic proteins have been tested clinically, with some showing considerable promise, particularly in lymphoid malignancies. A better understanding of the BCL-2 family has also provided insight into how conventional chemotherapy selectively kills cancer cells and why some cancers are more chemosensitive than others. Further exploitation of our understanding of the BCL-2 family promises to offer improved predictive biomarkers for oncologists and improved therapies for patients with cancer.

7512Background: Therapies are urgently needed for patients (pts) with CLL relapsed/refractory (R/R) to BCRi. We report outcomes for the full trial population from an ongoing phase 2 trial with VEN ...

7533Background: Duvelisib, an oral dual inhibitor of PI3K-δ,γ, is being developed for the treatment of hematologic malignancies, including relapsed/refractory (RR) CLL/SLL. In the Phase 3 DUO study...

7526Background: VEN can cause rapid tumor debulking in patients (pts) with relapsed/refractory CLL. Current VEN dosing schedule with TLS prophylaxis/monitoring averts overt TLS, but further data on...

e18786Background: With expanding treatment options for chronic lymphocytic leukemia (CLL), shared decision-making (SDM) is essential for high-quality care. In a quality improvement program, we eval...

12048Background: Duvelisib (IPI-145) (DUV) is an oral dual inhibitor of phosphoinositide 3-kinase (PI3K)-δ and PI3K-γ being developed to treat B-cell malignancies. PI3K-δ inhibition directly target...

7532Background: The CLL literature focuses largely on the objective aspects of diagnosis (dx), active observation (AO), prognosis and management. While health care providers (HCPs) try to effective...

7505 Background: Novel agents (NA) targeting B cell receptor kinases and Bcl-2 have substantially improved outcomes in CLL; however, the development of RS in CLL patients (pts) on NAs has been observed, and has not been systematically evaluated. Methods: We retrospectively reviewed pts at 9 academic centers diagnosed with pathologically-confirmed RS from 2011-16. Informed consent was provided through IRB-approved protocols. Descriptive statistics were utilized and overall survival (OS) was calculated from RS diagnosis (dx) to death or last follow-up by Kaplan-Meier. Results: 71 pts who developed RS on NAs for CLL were identified. Median age at CLL dx was 55 yrs (range 21-82), median of 3 therapies (range 0-12) prior to the NA. 68% pts were fludarabine-refractory, and 5 pts (7%) had relapsed post alloHCT. Median time from CLL dx to initiation of NA was 68.5 mo. (range 1.1-246.2). FISH at NA initiation: del(17p) 30/61 (49%), del(11q) 15/61 (25%), trisomy 12 15/61 (25%). Complex karyotype was present in 40/53 (75%). 46/52 (88%) were IGHV unmutated, VH1-69 10/43 (23%), VH4-39 4/43 (9%). 59 (83%) pts were on a BTK inhibitor, 6 (8%) PI3K inhibitor, 6 (8%) venetoclax. RS histology: DLBCL (87%), plasmablastic (6%), Hodgkin (4%), 3% other. RS Ki-67%: >90 (23%), 75-90 (25%), 50-75% (25%)

e19041 Background: VEN is a selective orally bioavailable BCL-2 inhibitor. The dose-escalation Phase 1 study of VEN in 106 patients (pts) with relapsed/refractory NHL reported an ORR of 44%. Most pts had diffuse large B-cell/follicular lymphoma; we report on updated results in pts with less common NHL subtypes. Methods: VEN was administered and continued until progressive disease (PD)/unacceptable toxicity, in dose cohorts ranging from 300–1200 mg. Adverse events (AEs) were assessed by NCI-CTCAE v4.0 and response by 2007 Cheson IWG response criteria, utilizing CT scans beginning at wk 6. Results: 35 of 106 pts had mantle cell lymphoma (MCL, n=28), marginal zone lymphoma (MZL, n=3) or Waldenström macroglobulinemia (WM, n=4). Most common all grade treatment emergent AEs were nausea (51%), diarrhea (49%) and fatigue (34%); grade 3/4 AEs in >10% of pts were neutropenia and anemia (17% each). Laboratory TLS was reported in a single pt (bulky MCL). MCL pts (median age: 72 years) had received a median of 3 (1–7) prior treatments (tx). Median time from start of prior tx to start of VEN was 13 mo (2–148) and time on VEN was 11 mo (0.2–42). ORR was 75%, 6 pts (21%) achieved CR and remain on study (DORs: 25–40 mo). One pt with a PR proceeded to elective allogeneic stem cell transplant and remained disease free at last protocol defined follow-up (24 mo after coming off study). Median PFS was 11 mo and DOR was 15 mo. MZL pts (median age: 63 years) had received a median of 4 (2–6) prior tx. Time from start of prior tx to start of VEN was 8, 14, 73 mo and time on VEN was 5, 1, 35 mo. One pt (6 prior tx) received VEN for

7519Background: Patients (pts) with chronic lymphocytic leukemia (CLL) who relapse after or become refractory (R/R) to BCR pathway inhibitors have poor outcomes. Venetoclax (VEN) is a selective, or...

7527Background: Venetoclax (VEN) is an orally bioavailable BCL2 selective inhibitor. Patients (pts) with relapsed or refractory CLL or small lymphocytic lymphoma were treated in a phase 1 trial (M1...

7528Background: Venetoclax is a potent, selective, oral BCL-2 inhibitor that has activity in patients (pts) with relapsed/refractory (R/R) CLL, with an objective response rate of > 70%. Here we rep...

e18049Background: Lack of access to specialized oncology care is increasing. The underprivileged and underserved are at a great disadvantage, as time and financial expenses can create barriers to r...

7082 Background: Lenalidomide is an immunomodulator with activity in CLL. Bendamustine-rituximab (BR) is a widely used upfront regimen. We conducted a phase I trial combining lenalidomide (len) wit...

7013 Background: ABT-199 is a selective, orally bioavailable Bcl-2 antagonist that induces rapid apoptosis of CLL cells and > 80% response rate as monotherapy in pts with R/R CLL. R synergizes with...

7015 Background: Overexpression of Bcl-2 in relapsed CLL/SLL is associated with dysregulated apoptosis and chemoresistance. ABT-199 is an orally bioavailable, selective Bcl-2 inhibitor that trigger...

TPS7121 Background: Evasion of apoptosis is a hallmark of cancer. Overexpression of the anti-apoptotic Bcl-2 protein is associated with tumorigenesis and resistance to chemotherapy. ABT-199 is a se...

8522 Background: The anti-apoptotic protein Bcl-2 is a highly expressed in NHL and contributes to chemotherapy resistance. ABT-199 is a selective, orally bioavailable, small molecule Bcl-2 inhibitor that is a promising agent for the treatment of patients (pts) with NHL. Methods: Objectives of this Phase I, dose-escalation study include evaluations of safety, pharmacokinetics (PK), and preliminary efficacy in pts with R/R NHL. ABT-199 was given on Week 1 Day -7 (W1D-7), followed by continuous, once-daily dosing from W1D1 until progressive disease or unacceptable toxicity. A 2 to 3 week lead-in period with stepwise dose titration was implemented. Final cohort doses of 200 - 900 mg have been evaluated. Results: As of December 4, 2013, 44 pts have been enrolled, 15 (35%) with mantle cell lymphoma (MCL), 11 (26%) with FL, 10 (23%) with DLBCL, 4 (9%) with Waldenstrom macroglobulinemia (WM), 2 (5%) with marginal zone (MZL), 1 (2%) with primary mediastinal B-cell lymphoma (PMBCL), and 1 (2%) with multiple myeloma...

TPS7122 Background: Phosphoinositide 3-kinase (PI3K)-δ,γ isoforms are preferentially expressed in leukocytes and are central to the growth and survival of certain B and T cell malignancies. Inhibit...

7018 Background: Targeting BCL-2 is a promising strategy for treating CLL, including disease refractory to fludarabine (F), or with (del(17p). ABT-199 is a selective BCL-2 inhibitor with >500-fold higher affinity for BCL-2 (KiL (Ki=48 nM). Methods: Objectives of this Ph I dose-escalation study include evaluations of safety, pharmacokinetics and preliminary efficacy of ABT-199 in patients (pts) with R/R CLL. A single oral dose was given followed by 6 days off drug, before continuous once daily dosing. After cohort 1, the initial dose was reduced and daily dosing modified to include a 2 or 3 step dose-escalation to the target dose for each cohort. Results: As of January 11, 2013, 56 pts have been enrolled; median age 67 y (range 36-86); 41 males; median 3.5 prior therapies (range 1-10). 16 (29%) had del(17p) and 18 (32%) F-refractory CLL. Median follow up is 6.3 months (range 0.03-16.5); 7 pts have been on study for more than 1 yr. 13 pts discontinued; 7 due to PD, 6 for other reasons: tumor lysis syndrome (TLS; 2), other illness (2), thromboembolic event (1), consent withdrawal (1). The most common non-hematological AEs (>15% pts) were nausea (36%), diarrhea (30%), fatigue (25%), upper respiratory tract infection (23%), and cough (16%). Grade 3/4 AEs occurring in > 5 pts were neutropenia 21(38%), thrombocytopenia 6 (11%) and TLS 5 (9%). TLS occurred in 3/3 pts in cohort 1 and 2/53 pts with the modified stepped dosing schedule (DLTs). Additionally, 1 fatal AE occurred within 48 hrs of dose-escalation to 1200 mg in a pt with laboratory evidence of TLS (DLT). 46 of 54 pts (85%) evaluable for efficacy achieved a response to ABT-199; 7 (13%) a CR or CR with incomplete count recovery and 39 (72%) a PR (30 confirmed by consecutive scans). 14/16 (88%) and 12/16 (75%) of pts with del(17p) and F-refractory CLL, respectively, achieved at least a PR. Conclusions: ABT-199 is highly active achieving a 85% overall response rate in R/R CLL, independent of high risk markers such as del(17p) and F-refractory disease. Additional dosing and scheduling modifications are currently being explored to minimize the risk of TLS. Clinical trial information: NCT01328626.

8520 Background: BCL-2 is highly expressed in NHL, including mantle cell lymphoma (MCL), and is a promising therapeutic target as it is involved in NHL pathogenesis and mediates resistance to many cytotoxics. ABT-199 is a second generation inhibitor with 500-fold higher affinity for BCL-2 (KiL (Ki=48 nM). Methods: Objectives of this Ph 1 dose-escalation study include evaluations of safety, pharmacokinetics and preliminary efficacy in patients (pts) with relapsed or refractory (R/R) NHL. A single oral dose (50-400 mg) was administered followed by 6 days off drug prior to the initiation of continuous once daily dosing. Due to concerns of potential tumor lysis syndrome (TLS), a 2 to 3 wk lead-in period with step-wise escalation to the target cohort dose was implemented. Dose cohorts up to 900 mg have been evaluated to date. Results: As of January 2013, 31 pts have been enrolled (median age 68 y (range 35-85); 20 males; median prior therapies 3 (range 1-7). 13 (42%) and 4 (13%) had bulky adenopathy (>5 and >10 cm, respectively). The most common AEs (≥15% of patients) were nausea (36%), diarrhea (26%), dyspepsia, vomiting, fatigue, pyrexia and cough (16% each). Gr 3/4 AEs occurring in >1 patient were anemia, neutropenia (4 pts each), and febrile neutropenia (2 pts). Two of 14 pts in cohort 5 experienced DLTs at the target dose of 600 mg: Gr 3 febrile neutropenia and Gr 4 neutropenia. Although Gr 3/4 thrombocytopenia was observed in 3 pts, it was not dose dependent. Gr 3 TLS was seen after the initial dose in 1 pt with very bulky MCL (>10 cm). With a median follow-up of 5 months (range 0.5-15), 17 have discontinued: 13 due to PD, 2 due to AEs and 2 who received a BMT. Of the 29 pts evaluable for efficacy, the overall best response rate was 55% with 1 DLBCL pt achieving a CR and 15 (52%) a PR (8/8 MCL, 3/3 Waldenstrom macroglobulinemia, 2/7 follicular lymphoma and 2/7 DLBCL pts). Conclusions: ABT-199 is highly active in R/R NHL, particularly in MCL. Additional dosing and scheduling modifications are currently being explored to optimize the efficacy/safety profile of this active new agent. ABT-199 warrants further single-agent and combination trials in NHL. Clinical trial information: NCT01328626.

22002 Background: Approximately 10% of Ashkenazi Jewish (AJ) women with breast cancer (BC) carry one of three mutations in BRCA1 or BRCA2 (BRCA1 185delAG or 5382insC, BRCA2 6174delT). There is an association between BRCA1 mutations and ‘triple negative’ (TripNeg) phenotype (estrogen receptor (ER) and progesterone receptor (PR) negative, HER2 non- overexpressing). TripNeg is not over-represented in BRCA2-BC. We sought to determine the predictive value of the TripNeg phenotype for the presence of any BRCA mutation in a cohort of Jewish women ascertained without respect to family history (FH). Methods: DNA samples were collected between 8/2000 and 6/2004 from 495 Jewish women with BC(median age at diagnosis 57 years) treated at a single institution. Medical records were reviewed and samples annotated with limited clinical information. Patients were considered to be ER or PR negative if fewer than 10% of cells stained by IHC, and HER2 negative if they were 0–1+ by IHC or 2+ with FISH < 2.0. Samples were genot...