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PURPOSE There are significant disparities in care and outcomes for patients with leukemias and multiple myeloma (MM). To evaluate the extent to which clinical trials (CTs) match the demographic and geographic diversity of populations affected by leukemias and MM. METHODS CTs leading to drug approval were identified from the US Food and Drug Administration databases. Demographic and geographic data were collected from ClinicalTrials.gov and primary manuscripts. Standard descriptive statistics were used to summarize the data in frequencies and proportions, including 95% CIs, by race, ethnicity, sex, and malignancy subtypes. RESULTS A total of 41 (67.2%) trials leading to drug approval reported data on race and 20 (48.8%) on ethnicity. These trials included 13,731 patients, of whom 11,209 (81.6%) were White. Among minorities, Asian-Pacific Islanders and Blacks had the highest representation in chronic myeloid leukemia, 147 (12.7%) and 61 (5.3%), and lowest in chronic lymphocytic leukemia, 55 (3%) and 20 (1.1%), respectively. Proportions for Blacks, Native Americans, and Hispanics were significantly low, reflecting under-representation in trials compared with the proportion in the general population. Females were also under-represented in acute myeloid leukemia (44.7% v 60.5%, P < .0001), and males in MM (55.3% v 60.2%, P < .0001) and chronic myeloid leukemia (55.2% v 62.9%, P < .0001). The geographic distribution of trials showed inadequate regional and state participation compared with mortality for all malignancies except MM. CONCLUSION There are significant demographic and geographic under-representation and imbalances in pivotal CTs leading to drug approvals for leukemias and MM compared with the population affected. These disparities need to be addressed to make results applicable to all relevant populations.

PURPOSE Colony-stimulating factor-3 receptor ( CSF3R)-T618I is a recurrent activating mutation in chronic neutrophilic leukemia (CNL) and to a lesser extent in atypical chronic myeloid leukemia (aCML) resulting in constitutive JAK-STAT signaling. We sought to evaluate safety and efficacy of the JAK1/2 inhibitor ruxolitinib in patients with CNL and aCML, irrespective of CSF3R mutation status. METHODS We conducted a phase II study of ruxolitinib in 44 patients (21 CNL and 23 aCML). The primary end point was overall hematologic response rate (ORR) by the end of 6 continuous 28-day cycles for the first 25 patients enrolled. We considered a response as either partial (PR) or complete response (CR). We expanded accrual to 44 patients to increase our ability to evaluate secondary end points, including grade ≥ 3 adverse events, spleen volume, symptom assessment, genetic correlates of response, and 2-year survival. RESULTS ORR was 32% for the first 25 enrolled patients (8 PR [7 CNL and 1 aCML]). In the larger cohort of 44 patients, 35% had a response (11 PR [9 CNL and 2 aCML] and 4 CR [CNL]), and 50% had oncogenic CSF3R mutations. The mean absolute allele burden reduction of CSF3R-T618I after 6 cycles was greatest in the CR group, compared with the PR and no response groups. The most common cause of death is due to disease progression. Grade ≥ 3 anemia and thrombocytopenia were observed in 34% and 14% of patients, respectively. No serious adverse events attributed to ruxolitinib were observed. CONCLUSION Ruxolitinib was well tolerated and demonstrated an estimated response rate of 32%. Patients with a diagnosis of CNL and/or harboring CSF3R-T618I were most likely to respond.

7004 Background: Asciminib is the first BCR::ABL1 inhibitor to specifically target the ABL Myristoyl Pocket (STAMP). In the ASCEMBL primary analysis, asciminib had superior efficacy and better safety/tolerability than BOS in pts with CML-CP after ≥2 prior TKIs. After a median follow-up of 2.3 years (16.5 months’ additional follow-up since primary analysis), we report efficacy and safety results (cutoff: October 6, 2021). Methods: Eligible pts were adults with CML-CP after ≥2 prior TKIs, with intolerance or lack of efficacy per 2013 European LeukemiaNet. Pts were randomized 2:1 to asciminib 40 mg twice daily or BOS 500 mg once daily, stratified by major cytogenetic response (MCyR) status (Ph+ metaphases ≤35%) at baseline. The key secondary endpoint was major molecular response (MMR) rate at wk 96. Results: 233 pts were randomized to asciminib (n=157) or BOS (n=76). At cutoff, treatment was ongoing in 84 (53.5%) and 15 (19.7%) pts, respectively; the most common reason for discontinuation was lack of efficacy in 38 (24.2%) and 27 (35.5%) pts, respectively. MMR rate at wk 96 (per ITT) was higher on asciminib (37.6%) than BOS (15.8%). The difference, adjusting for baseline MCyR, was 21.7% (95% CI, 10.5%-33.0%; 2-sided P=.001). More pts on asciminib than BOS, respectively, had BCR::ABL1IS ≤1% (45.1% vs 19.4%) at wk 96. The probability of maintaining MMR and BCR::ABL1IS ≤1% for ≥72 wk was 96.7% (95% CI, 87.4%-99.2%) and 94.6% (95% CI, 86.2%-97.9%), respectively, on asciminib and 92.9% (95% CI, 59.1%-99.0%) and 95.0% (95% CI, 69.5%-99.3%), respectively, on BOS. Median duration of exposure was 103.1 (range, 0.1-201.1) wk on asciminib and 30.5 (range, 1.0-188.3) wk on BOS. Despite the longer duration of asciminib exposure, safety/tolerability of asciminib continued to be better than that of BOS (Table). No new on-treatment deaths were reported since the primary analysis. Most frequent (>10%) grade ≥3 adverse events (AEs) on asciminib vs BOS were thrombocytopenia (22.4%, 9.2%), neutropenia (18.6%, 14.5%), diarrhea (0%, 10.5%), and increased alanine aminotransferase (0.6%, 14.5%). Conclusions: After >2 years of follow-up, asciminib continued to show superior efficacy and better safety/tolerability vs BOS. Responses were durable, with more pts on asciminib in MMR. Additionally, more pts on asciminib had BCR::ABL1IS ≤1%, a milestone response in later lines associated with improved survival. These results continue to support the use of asciminib as a new CML therapy, with the potential to transform standard of care. Clinical trial information: NCT03106779. [Table: see text]

e19061 Background: The rapid spread of SARS-CoV-2 has elicited an equally rapid development of effective vaccines, leading to a reduction of COVID-19 severity and deaths. There is limited data on COVID-19-related immunity in chronic myeloid leukemia (CML) patients. Methods: SPARTA (SARS2 SeroPrevalence And Respiratory Tract Assessment) is an ongoing observational study for participants age ≥18 years to investigate immunity to SARS-CoV-2 after infection and/or vaccination. We included patients with CML and compared them with a non-cancer group. We collected saliva and peripheral blood to measure antigen levels by RT-PCR and antibodies (secretory IgG antibodies and neutralizing antibodies). Results: From October 1, 2021, to February 4, 2022, we prospectively enrolled 49 participants (23 CML, 26 non-cancer). Most were male (56.5%) in the CML group and female in the control group (61.5%), mean age 56.39 y vs. 51.96 y, respectively, and self-identified as white (87% vs. 76.9%). In the CML group, 11 (47.8%) had ≥1 comorbidities, vs 13 (50%) in the control group. Twenty-one (91.3%) CML patients were receiving tyrosine-kinase inhibitors; 4 (18.2%) non-cancer subjects reported taking any medication. Most participants in both groups had received at least one dose of COVID-19 vaccine (73.9% vs. 73.1%); 100% of CML patients received two doses vs. 84.2% of controls; the CML group had a higher percentage of subjects fully vaccinated (66.7% vs. 25%). The CML group had a lower percentage of patients previously diagnosed with COVID-19 (8.8% vs. 57.7%). However, there was no difference in the detection of SARS-CoV-2 antigen at the time of enrollment (0% vs. 4%). SARS-CoV-2 IgG antibodies were detected in most of the participants regardless of cancer status (78.3% in the CML cohort and 88% in the non-cancer cohort), and neutralizing antibodies were detected in 82.6% and 95.6%, respectively. The two groups had comparable IgG (mean 146.3 Ru/ml vs. 148.9 Ru/ml) and neutralizing (mean 1329.1 ng/ml vs. 1112 ng/ml) antibody levels. Conclusions: Our preliminary data comparing concomitant cohorts with similar socio-demographic characteristics and medical history indicate that a diagnosis of CML did not impact the development of antibodies against SARS-CoV-2. We are conducting continuous analysis of antibodies levels over time to assess the evolution of antibody immunity and functional studies including cellular immunity assessments.[Table: see text]

7049 Background: Efficacy and safety of BOS vs imatinib (IMA) in patients (pts) with newly diagnosed chronic phase CML was assessed in the phase 3 BFORE trial. Here we characterize the safety profile of BOS after 5 yrs follow-up, with a focus on GI, liver, effusion and renal treatment-emergent adverse events (TEAEs). Methods: Pts who received ≥1 dose of BOS (n=268) or IMA (n=265) 400 mg/d in BFORE were included. Adverse events (AEs) of special interest were analyzed by selecting prespecified MedDRA terms to generate TEAE clusters. Final database lock: June 12, 2020. Results: Median duration of treatment (Tx) was 55 mo for pts receiving BOS or IMA; respective median (range) dose intensity was 393.6 (39–583) vs 400.0 (189–765) mg/d. Any grade TEAEs occurred in 98.9% and 98.9% of BOS- vs IMA-treated pts. Most common newly occurring TEAEs (any grade) after 12 mos were increased lipase (9.0%) with BOS, and diarrhea (8.3%) with IMA. In BOS- vs IMA-treated pts, 25.4% vs 14.3% had AEs leading to permanent Tx discontinuation; the majority discontinued in yr 1 (14.2% vs 10.6%). Most frequent AEs leading to discontinuation were increased ALT (overall, 4.9%; yr 1, 4.5%) with BOS vs thrombocytopenia (overall, 1.5%; yr 1, 1.5%) with IMA. GI, liver, effusion and renal TEAEs, respectively, occurred in 79.9%, 44.0%, 6.0% and 10.4% (maximum grade 3/4 [G3/4]: 9.0%, 26.9%, 1.1% and 2.2%) of BOS- vs 61.5%, 15.5%, 2.3% and 9.8% (G3/4: 1.1%, 4.2%, 0.4% and 0.8%) IMA-treated pts. One grade 5 renal TEAE occurred in the BOS arm and was not considered related to Tx. Cumulative rates per Tx yr are shown in the Table. Most common GI TEAEs were diarrhea (BOS vs IMA: 75.0% vs 40.4% [G3/4: 9.0% vs 1.1%]) with BOS, and nausea (37.3% vs 42.3% [G3/4: 0% vs 0%]) with IMA. In both arms, the most common liver, effusion and renal TEAEs, respectively, were increased ALT and/or AST (34.0% vs 8.3% [G3/4: 22.0% vs 2.3%]), pleural effusion (5.2% vs 1.9% [G3/4: 0.7% vs 0.4%]) and increased blood creatinine (6.7% vs 8.3% [G3/4: 0.4% vs 0.4%]). GI, liver, effusion and renal TEAEs infrequently led to Tx discontinuation (1.9%, 7.8%, 0.7% and 0.7% vs 1.1%, 0.8%, 0% and 0.4%). Conclusions: The safety profiles of BOS and IMA in BFORE were distinct, with no new safety signals identified after 5 yrs follow-up. Onset of TEAEs occurred primarily during yr 1 (eg, GI and liver), with an increased incidence of some TEAEs (eg, effusion and renal) in later yrs. Discontinuations due to AEs generally occurred early into Tx, with few due to GI, liver, effusion and renal AEs. These safety results support the use of first-line BOS as a standard of care in pts with CP CML. Clinical trial information: NCT02130557. [Table: see text]

8043 Background: There are considerable outcome disparities among patients with multiple myeloma (MM). African-Americans have higher risk of developing MM, earlier age at diagnosis, and higher mortality compared to Whites. While outcomes have multifactorial socioeconomic etiologies, race and ethnicity (R&E) correlate with genomic ancestry, and any role of genetics should be explored. This requires equitable representation in biological databases like The Cancer Genome Atlas (TCGA). Here, we characterize disparities in MM cases of TCGA and clinical trials (CT). Methods: MM incidence was obtained from North American Association of Central Cancer Registries (NAACCR) for R&E, sex and age ( < 50, 50-64, 65+ years). Race includes White, Black, and Asian, along with Hispanic ethnicity, as TCGA MM is limited to these groups. Genes with oncogenic potential and > 5% mutation were stratified by R&E and age. TCGA MM cases are from USA, Canada, Italy, and Spain. On ClinicalTrials.gov, completed MM CT limited to these countries were identified. Student’s t-test and chi-square test were used to analyze disparities and gene mutations. Kaplan-Meier curve was generated to evaluate survival. Results: TCGA MM representation is in Table, calculated as (demographic TCGA cases divided by total TCGA cases) divided by (demographic incidence divided by total incidence). Race was not reported in 20% of TCGA, 4% of CT, and 3% of NAACCR. Of cases reporting R&E, Hispanics are underrepresented by 26% in TCGA and 47% in CT relative to incidence, Blacks by 22% in TCGA and 41% in CT, and Asians by 40% in TCGA and 10% in CT. Whites are overrepresented, by 8% in TCGA and 7% in CT. More men are in TCGA than women, in all R&E. Less than 25% of patients age < 50 relative to incidence are in TCGA, in all R&E. BCL7A is mutated more in Blacks age < 50 (n = 20, 50%) than Whites (n = 39, 10%) (p < 0.01). FAT4 is mutated in Whites age 65+ (n = 31, 10%) but not Blacks. In all ages, KRAS is mutated more in Blacks than Whites (31-35% vs. 20-25%, p < 0.05). Black patients have lower survival than Whites (p < 0.02). In patients age 65+, KRAS mutation is associated with 10% lower 4.5-year survival. Conclusions: Substantial disparities in Black, Hispanic, women, and age representation exist for MM cases in TCGA and CT. This stratification by R&E and age offers new insight on BCL7A, FAT4, and KRAS mutation in MM. Mutation status is associated with survival in older patients. Equitable demographic representation should be pursued to improve quality of available data and access to medical resources for all populations. [Table: see text]

6531 Background: There are significant inequities in cancer care and outcomes in the United States (US) and worldwide. Race, ethnicity, and sex all define sub-groups affected by these inequities. Randomized controlled trials (RCTs) provide new therapies in cancer care. Many new drugs have been recently approved for the management of lymphoma. We examined whether pivotal clinical trials included populations representative of those affected. Methods: Lymphoma clinical trials were collected from the US Food and Drug Administration (FDA) Databases ‘Oncology (cancer)/Hematologic Malignancies approval notifications’ and ‘Novel Drug Approvals’ between 2011 and 2021. Trials were also reviewed for demographic data on ClinicalTrials.gov (CT.gov) and Primary Literature related to the drug approval. Only studies for adult patients were included; one study was excluded due to inconsistencies in the total patients enrolled and the totals by race. Chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) RCTs were not included. The burden of diseases based on Surveillance, Epidemiology, and End Results (SEER) data was used as a comparison for US participants. Results: Thirty-three pivotal trials were identified from the FDA databases (2011-2021); 18 (54.5%) had available race data on CT.gov or in Primary Literature. Three trials focused on classical Hodgkin’s Lymphoma (cHL) and 15 on Non-Hodgkin’s Lymphoma (NHL). Two of the three trials for cHL with available data for race reported ethnicity data. Only 10 of 15 NHL trials that reported race demographics had available ethnicity data. Table 1 shows trials that had available data for race and ethnicity along with proportions from the SEER data. There was underrepresentation of Blacks and to some extent Hispanics in both cHL and NHL trials. Females were also underrepresented, particularly in NHL trials. Conclusions: There is racial, ethnic, and sex misrepresentation within clinical trials that led to approval of drugs for lymphomas in the US between 2011 and 2021. In addition, there was significant underreporting of racial and ethnic subgroups noted in the clinical trials.[Table: see text]

7039 Background: Bosutinib (BOS) is approved for patients (pts) with Philadelphia chromosome-positive chronic myeloid leukemia (CML), at a starting dose of 400 mg QD in newly diagnosed pts in chronic phase (CP). This analysis evaluated the impact dose reduction has on the outcomes of BOS and imatinib (IMA) in pts with CP CML. Methods: In the open-label BFORE trial, 536 pts with newly diagnosed CP CML were randomized to receive 400 mg QD BOS (N = 268) or IMA (N = 268; 3 untreated). Dose could be reduced to 300 mg QD for toxicity. Following sponsor approval, dose reduction to BOS 200 mg QD was permitted for 4 wks maximum; after this time, dose escalation or treatment discontinuation was required. Maintenance of response after dose reduction was defined as having a response > 6 mo after the first reduction. Database lock: June 12, 2020, 5 y after the last pt enrolled. Results: In the BOS arm, dose reduction to 300 (without further reduction) or 200 mg QD was seen in 82 (31%) and 33 (12%) pts, and median time to dose reduction was 85 and 205 d. In the IMA arm, 50 (19%) pts had a dose reduction to 300 mg QD, and median time to dose reduction was 92 d. Most common (≥2% of pts) treatment-emergent adverse events (TEAEs) leading to dose reduction were increased alanine aminotransferase (8%), thrombocytopenia (7%), diarrhea (7%), increased lipase (6%), increased aspartate aminotransferase (4%), nausea (4%), neutropenia (3%), rash (3%) and abdominal pain (2%) with BOS, and neutropenia (4%) with IMA. Of the pts who remained on 400 mg QD BOS (n = 153) or IMA (n = 214), respectively, 120 (78%) and 139 (65%) achieved major molecular response (MMR). Among pts who had a BOS dose reduction to 300 mg QD, 51/82 (62%) had MMR > 6 mo after dose reduction: 14 (17%) maintained MMR before and after dose reduction and 37 (45%) achieved MMR for the first time after dose reduction. Seven (9%) pts had MMR before dose reduction but discontinued treatment before the next > 6 mo assessment. In the IMA arm, 32/50 (64%) pts had MMR > 6 mo after dose reduction: 9 (18%) maintained MMR before and after dose reduction and 23 (46%) achieved MMR for the first time after dose reduction. One (2%) pt had MMR before dose reduction but discontinued treatment before the next > 6 mo assessment and 1 (2%) pt lost a previously attained MMR after dose reduction. Among pts who had a BOS dose reduction to 200 mg QD, 12/33 (36%) had MMR > 6 mo after dose reduction: 7 (21%) maintained MMR before and after dose reduction and 5 (15%) achieved MMR for the first time after dose reduction. Six (18%) pts had MMR before dose reduction but discontinued treatment before the next > 6 mo assessment. Similar trends were seen for complete cytogenetic response. Conclusions: Management of TEAEs through BOS or IMA dose reduction enabled pts to continue treatment, with a substantial number of pts achieving MMR for the first time after dose reduction. Clinical trial information: NCT02130557.

7037 Background: Bosutinib (BOS) is approved for the treatment (Tx) of Philadelphia chromosome–positive (Ph+) chronic myeloid leukemia (CML) resistant/intolerant to prior therapy and newly diagnosed Ph+ chronic phase (CP) CML. Body mass index (BMI) was shown to influence Tx response with front-line dasatinib vs imatinib (IMA). We report the efficacy and safety of BOS and IMA by BMI in patients (pts) with newly diagnosed CP CML. Methods: In the open-label BFORE trial, pts were randomized to receive 400 mg once daily BOS or IMA. Outcomes were assessed according to baseline BMI ≥25 or = 25 kg/m2. This post hoc analysis was based on the final 5-y analysis (database lock: June 12, 2020). Results: In the BOS and IMA arms, respectively, 149 (56.4%) vs 115 (43.6%) pts and 145 (54.3%) vs 122 (45.7%) pts had BMI ≥25 vs = 25. In both the BOS and IMA arms, median Tx duration and time on study was 55 mo for pts with BMI ≥25 or = 25; respective median dose intensity was 394 vs 393 mg/d and 400 vs 400 mg/d. Molecular response (MR) rates are shown in the table. Cumulative incidence of major MR was similar in pts with ≥25 vs = 25 receiving BOS (HR 0.99; 95% CI 0.74−1.31) or IMA (HR 1.09; 95% CI 0.81−1.47). Event-free survival (EFS) and overall survival (OS) rates at 60 mo are shown in the table. Most common reasons for Tx discontinuation were adverse events (AEs) (BOS 28.2 vs 20.0%; IMA 13.3 vs 10.7%) and lack of efficacy (BOS 5.4 vs 5.2%; IMA 16.1 vs 19.8%). In pts with BMI ≥25 vs = 25, dose reductions and interruptions due to Tx-emergent AEs (TEAEs) occurred in 43.6 % vs 46.2% and 66.4% vs 69.7% of pts with BOS and 24.5% vs 24.6% and 40.6% vs 50.8% with IMA. Any grade TEAEs in ≥30% of pts with BMI ≥25 vs = 25 were diarrhea (73.8 vs 73.1%), nausea (40.9 vs 31.9%), thrombocytopenia (30.9 vs 41.2%), increased alanine (37.6 vs 28.6%) and aspartate aminotransferase (30.2 vs 20.2%) with BOS and diarrhea (49.0 vs 29.5%), nausea (46.2 vs 37.7%), muscle spasms (33.6 vs 26.2%), neutropenia (14.7 vs 32.0%) and thrombocytopenia (10.5% vs 30.3%) with IMA. Conclusions: Efficacy of BOS was consistent in pts with BMI ≥25 or = 25; however, with IMA a low (vs high) BMI appeared to be associated with worse survival outcomes. Differences in certain TEAEs were observed between BMI subgroups in both treatment arms. Clinical trial information: NCT02130557. [Table: see text]

7009 Background: BOS is approved for Philadelphia chromosome (Ph)+ CML resistant/intolerant to prior therapy and newly diagnosed Ph+ CP CML. In a phase 1/2 study, second-line BOS showed durable efficacy and manageable toxicity in pts with imatinib-resistant (IM-R) or -intolerant (IM-I) Ph+ CP CML. Methods: This final efficacy and safety analysis of the phase 1/2 study and extension study was based on ≥10 y of follow-up (FU). Ph+ CP CML pts who received BOS starting at 500 mg/d after prior treatment (Tx) with imatinib only were included. Results: 19% of pts were on BOS at y 10, and 13% were still on BOS at study completion after ≥10 y; 19% completed ≥10 y of FU. Median duration of Tx and FU were 26 and 54 mo, respectively. Median (range) dose intensity was 436 (87–599) mg/d. The most common primary reasons for permanent Tx discontinuation were lack of efficacy (unsatisfactory response or disease progression; 27%) and adverse events (AEs; 26%). In pts with a valid baseline assessment, cumulative complete cytogenetic response (CCyR), major molecular response (MMR) and MR4 rates (95% CI), respectively, were 50% (43–56), 42% (35–49) and 37% (30–44) (IM-R: 48% [41–56], 46% [37–55] and 39% [31–48]; IM-I: 53% [41–64], 36% [25–48] and 33% [22–45]). Responses were durable, with estimated probabilities of maintaining CCyR, MMR and MR4 > 50% after ≥10 y (Table). At 10 y, cumulative incidence of on-Tx progression/death was 24% and Kaplan-Meier (K-M) overall survival 72% (Table); 55 deaths (IM-R: n = 41; IM-I: n = 14) occurred on study, none BOS-related. Any grade Tx-emergent AEs (TEAEs) in ≥40% of pts were diarrhea (86%), nausea (46%) and thrombocytopenia (42%). Pleural effusion, cardiac and vascular TEAEs occurred in 13%, 12% and 11% of pts, respectively. 28% of pts had AEs leading to permanent Tx discontinuation; most common (≥2% of pts) were thrombocytopenia (6%), neutropenia (2%) and alanine aminotransferase increased (2%). Conclusions: These 10-y data are consistent with prior results of durable efficacy and manageable toxicity with second-line BOS and support long-term BOS use in CP CML pts after imatinib failure. Clinical trial information: NCT00261846 and NCT01903733. [Table: see text]

7006 Background: Olutasidenib, a potent, selective, oral, small molecule inhibitor of mutant IDH1 (m IDH1), has exhibited favorable tolerability and clinical activity in high-risk AML patients (pts) in a phase 1 trial (Watts, Blood 2019). Here, we present interim analysis results of a phase 2 trial (NCT02719574) in R/R m IDH1 AML pts receiving olutasidenib monotherapy 150 mg twice daily. Methods: The efficacy evaluable (EE) set comprised m IDH1R132X pts whose first dose was ≥180 days before the data cut-off (18-JUN-20). The primary endpoint was CR+CRh (complete remission [CR] or CR with partial hematologic recovery [CRh] according to modified IWG 2003 criteria) rate. CRh was defined as bone marrow blasts 0.5×109/L, and platelet count >50×109/L. Overall response rate (ORR) comprised CR+CRh+CR with incomplete recovery (CRi) + morphologic leukemia-free state (MLFS) + partial response (PR). Duration of treatment (DOT), duration of response (DOR), and overall survival (OS) were estimated using Kaplan-Meier methodology. Results: This clinical trial met its pre-specified early enrollment-stopping criteria for efficacy. A total of 153 pts with R/R AML received olutasidenib; median DOT, 5.5 mo (95% CI: 4.4, 8.7). 43 pts (28%) remain on treatment and 110 (72%) discontinued, most commonly due to: disease progression, 31%; AEs, 14%; death, 10%; and transplant, 8%. For the EE set (123 pts), the median age was 71 y (range: 32‒87) with a median number of prior therapies of 2 (1‒7). The CR+CRh rate was 33% including 30% of pts in CR (Table). Median duration of CR+CRh was not reached (NR) and 13.8 mo in a sensitivity analysis when HSCT or relapse was deemed end of response. ORR was 46% and median duration of ORR was 11.7 mo. Of responders who were transfusion-dependent at baseline, 56-day platelet transfusion independence (TI) and RBC TI were gained by 100% and 83%, respectively, of pts who achieved CR+CRh, and by 56% and 50% who did not. Median OS was 10.5 mo (EE set). In CR+CRh responders, median OS was NR and the estimated 18-mo OS was 87%. TEAEs in ≥25% of pts were nausea, 38%; constipation, 25%; leukocytosis, 25%. Grade 3/4 all-causality TEAEs in >10% of pts were febrile neutropenia, 20%; anemia, 19%; thrombocytopenia, 16%; neutropenia, 13%. Investigator-assessed IDH1 differentiation syndrome (any grade) was observed in 21 pts (14%); most cases resolved with treatment management; one case was fatal; 19 pts had concomitant leukocytosis. Conclusions: Olutasidenib was well tolerated and induced durable CR in a subset of high-risk R/R m IDH1 AML pts. TI was achieved in all response groups. Clinical benefit, per DOR and OS, extended beyond CR+CRh responders. Clinical trial information: NCT02719574. [Table: see text]

7000 Background: PON, a third-generation tyrosine kinase inhibitor (TKI), demonstrated deep and long-lasting responses and survival in patients (pts) with chronic-phase chronic myeloid leukemia (CP-CML) resistant/intolerant to second-generation TKI therapy (PACE; NCT01207440); post hoc analysis suggested a relationship between dose and both adverse events and response. Here we present the primary analysis of OPTIC (NCT02467270), an ongoing, randomized, phase 2 trial with a novel response-based dosing regimen of PON in pts with resistant/intolerant CP-CML. Methods: Pts with CP-CML resistant/intolerant to ≥2 TKIs or with the BCR-ABL1 T315I mutation were randomized to PON starting doses of 45 mg (cohort A; 45 mg → 15 mg), 30 mg (B; 30 mg →15 mg), and 15 mg (C) once daily. Doses were reduced to 15 mg with achievement of ≤1% BCR-ABL1IS in cohorts A and B. The primary endpoint is ≤1% BCR-ABL1IS at 12 mo; secondary endpoints include cytogenetic and molecular responses and safety outcomes. AOEs were adjudicated prospectively by an independent review committee. Results: 283 pts were randomized (A/B/C: n=94/95/94) and had the following baseline characteristics: median age 48 y (18‒81 y); 98% received ≥2 (55% ≥3) TKIs; 99% had resistant disease; 40% had ≥1 baseline mutations (23% T315I). At the primary analysis with 32 mo median follow-up, 134 pts (47%; n=50/41/43) remained on treatment and 204 pts (72%) had PON exposure ≥12 mo. At 12 mo, 44% (41/93) in A, 29% (27/93) in B, and 23% (21/91) in C achieved ≤1% BCR-ABL1IS (Table); primary endpoint was met by cohort A. Dose reductions to 15 mg after achieving response (A/B) were 48/29%. Most common grades ≥3 TEAEs were thrombocytopenia, 27%; neutropenia, 17%; and anemia, 7%. AOEs/serious AOEs were reported in cohorts A (10%/4%), B (5%/4%), and C (3%/3%). Dose reductions or discontinuations for TEAEs (A/B/C) were 46/35/32% and 19/16/14%, respectively. Conclusions: The OPTIC primary analysis demonstrates the optimal benefit:risk profile for PON was achieved with a response-based dosing regimen starting with 45 mg/d, followed by dose reduction to 15 mg/d upon achieving ≤ 1% BCR-ABL1IS; 30 mg→15 mg and 15 mg cohorts may provide benefit, especially in pts without T315I mutation (Table). The observed ≤1% BCR-ABL1IS responses are supported by robust survival outcomes in pts with CP-CML resistant to second-generation BCR-ABL1 TKI therapy, both with and without BCR-ABL1 mutations. Clinical trial information: NCT02467270. [Table: see text]

7502 Background: In PACE (NCT01207440) heavily pretreated patients (pts) with chronic-phase CML (CP-CML) had deep, lasting responses to PON; long-term follow-up showed increasing rates of arterial occlusive events (AOEs). We present IA results from OPTIC (NCT02467270), evaluating the association between PON exposure, efficacy, and safety, and response-based dose reduction in pts with CP-CML. Methods: This ongoing, multicenter, randomized phase 2 trial enrolled pts with CP-CML resistant or intolerant to ≥2 TKIs or with a T315I mutation to receive PON at a starting dose of 45 mg (cohort A), 30 mg (B), and 15 mg (C) qd. Doses were reduced to 15 mg qd on achievement of ≤1% BCR-ABL1IS in A/B. Primary endpoint: 12 mo ≤1% BCR-ABL1IS; secondary endpoints include cytogenetic and molecular response and AOE, VTE, and TEAE rates. Results are descriptive at this IA and will be inferential by adjusting multiplicity across 3 cohorts at final analysis. Results: 283 pts were randomized (A/B/C: n = 94/95/94); median age 48 y (18‒81 y). 26% had hypertension history; 2/43/55% received 1/2/≥3 TKIs; 40% had ≥1 baseline (BL) mutations, with 23% T315I. At IA data cutoff (20 Jul 2019), 162 pts (57%; n = 57/51/54) remained on study treatment. Among 282 pts in the safety population, median duration of exposure was ≈1 y (A/B/C, 12.9/11.2/11.0 mo). At 12 mo, 39% (95% CI, 27.6, 50.6), 27% (17.6, 39.1), and 26% (16.5, 38.6) in A, B, and C, respectively, achieved ≤1% BCR-ABL1IS. Additional efficacy in Table. Dose reductions due to efficacy (A/B): 35/21%. Most common TEAEs (any grade/≥3): thrombocytopenia 39/27%, neutropenia 25/17%. AOEs/serious AOEs were reported by (A, B, C) 5%/2%, 4%/3%, and 1%/0%. Dose reductions due to TEAEs: (A/B/C): 44/31/28%; discontinuations due to TEAEs: 18/15/14%. There were 4 (1.4%) on-study deaths; A, sudden death, n = 2; C, pneumonia, n = 2; no deaths were due to AOEs. Clinical trial information: NCT01207440 . Conclusions: OPTIC IA shows a trend toward dose-dependent efficacy and safety and may provide a refined understanding of the PON benefit:risk profile and its relation to dose. Data from longer follow-up may support an alternate dosing regimen for pts with CP-CML. [Table: see text]

TPS7561 Background: The growth factor receptor bound protein-2 (Grb2) is vital to oncogene signaling and tumor progression. BP1001 is a liposome-incorporated Grb2 antisense oligonucleotide that inhibits Grb2 expression. Grb2 inhibition suppresses cancer growth and survival. A Phase I/Ib single center study in patients with refractory/relapsed leukemias demonstrated the safety of BP1001 up to 90 mg/m2 dose and the efficacy of BP1001 in combination with low dose cytarabine (LDAC) in refractory/relapsed acute myeloid leukemia (AML) patients (Ohanian, Lancet Haematol 2018). Based on pharmacokinetic (PK) considerations, the recommended Phase II dose was 60 mg/m2. A phase II study was initiated to explore the clinical impact of BP1001 in combination with LDAC in untreated AML patients. Interim safety and efficacy of BP1001 + LDAC in untreated AML patients was presented at the 2018 Annual ASH Meeting. BP1001 was safely administered to 25 patients with untreated AML, who were considered unfit for standard chemotherapy. Efficacy data compared favorably to what has been reported with available options for unfit patients largely with secondary AML or adverse-risk AML. Since the Interim Data presentation, the study was amended to investigate BP1001 + decitabine combination and include myelodysplastic syndrome (MDS) patients. This is because BP1001 enhanced decitabine anti-leukemic effects in preclinical studies. Methods: This is a multi-center, open-label study with 2 parallel cohorts of BP1001 + decitabine treatment in untreated AML/high risk MDS patients and refractory/relapsed AML/high risk MDS patients who are considered by the investigator unsuitable for or refused intensive chemotherapy. BP1001 is given intravenously (IV) at 60 mg/m2 twice weekly. Decitabine is given 20 mg/m2 IV daily for 5 consecutive days. Each cycle is 28 days. Each cohort can enroll 19 patients, with a decision to stop or proceed to 54 patients. The primary objective of this study is to assess whether BP1001 + decitabine provides higher complete remission rates than decitabine alone (by historical comparison) in AML/high risk MDS patients. The secondary objectives of this study are to assess: Safety of BP1001 + decitabine; partial remissions and blast count reductions; overall survival, time to response and duration of response; minimal residual disease status in patients who achieve complete remission; and plasma PK profile of BP1001. The exploratory objective of this study is to evaluate the association of treatment response with cytogenetic and molecular characteristics. Clinical trial information: NCT02781883 .

7550 Background: The final 5-year analysis of the PACE trial, which evaluated use of PON in pts with refractory chronic myeloid leukemia (CML) and Ph+ acute lymphoblastic leukemia, identified a 25% incidence of AOEs (Cortes, Blood 2018) from a search utilizing > 400 preferred terms (PTs) defined by MedDRA and related to vascular ischemia or thrombosis. We performed a retrospective review using an independent Endpoint Adjudication Committee (EAC) to better understand clinically relevant AOE rates in PACE. Methods: The EAC consisted of 3 cardiologists, 1 hematologist, and 1 neurologist to review AOEs (identified using > 500 terms) in PACE using American College of Cardiology/American Heart Association (ACC/AHA) definitions for major adverse cardiovascular events (MACE), and to review pt profiles including event, severity, concomitant medication, and hospitalization data. These results were compared with MedDRA PT search results. The EAC was blind to dose, dose modification, and investigator causality opinion. Results: The PACE review included 449 heavily pretreated pts with Ph+ leukemia (median age, 59 y; 47% female; 93% ≥2 tyrosine kinase inhibitors). With median follow-up 37.3 mo in all pts, AOEs were identified by MedDRA PT search in 25% of pts and EAC-verified in 17% (Table). In each category listed in the table, the EAC verification identified fewer AOEs and serious AOEs. Serious AOEs were identified by MedDRA PT search in 20% of pts and EAC-verified in 16%. Events that were not associated with a cardiovascular etiology or failed to meet the MACE definition set forth by the ACC/AHA were determined by the EAC not to be an AOE. Conclusions: The independent EAC review showed a lower rate of clinically relevant AOEs than was reported in PACE, suggesting an earlier possible overestimation that may not accurately reflect the risk of AOEs with PON. The ongoing PON dose-ranging OPTIC study will further evaluate the PON risk:benefit profile. Clinical trial information: NCT01207440 . [Table: see text]

7549 Background: BOS is approved for newly diagnosed CP CML and CML resistant/intolerant to prior therapy. In a phase I/II study, BOS showed durable efficacy and manageable toxicity in patients (pts) with CP CML after IMA failure. We report an ≥8-y update of this phase I/II and ongoing extension study. Methods: Pts with CP CML resistant/intolerant to IMA (CP2L) or IMA + dasatinib and/or nilotinib (CP3L) or with accelerated/blast phase (AP/BP) CML or Philadelphia chromosome+ acute lymphoblastic leukemia with prior tyrosine kinase inhibitor (TKI) therapy (ADV) received BOS starting at 500 mg/d. Results: 54/284 (19%) CP2L pts were still on BOS after ≥9 y and 8/119 (7%) CP3L and 5/167 (3%) ADV pts after ≥8 y; 61 CP2L pts discontinued BOS since y 5 and 21 CP3L and 12 ADV pts since y 4. Overall, the most common reason for discontinuation was disease progression/lack of efficacy in CP2L (27%), CP3L (42%) and ADV (50%) pts; last dose before discontinuation was ≥500 mg/d in 59 (21%), 28 (24%) and 46 (28%) pts, respectively. In CP2L pts, median (range) of follow-up was 54 (1–155) mo, treatment duration 26 (

7509 Background: In newly diagnosed AML or high-risk MDS, primary analysis of the randomized phase 2 BRIGHT AML 1003 trial (data cutoff Jan 2017) showed superior OS for GLAS+LDAC vs LDAC alone. The trial then continued to predefined completion 4 years from randomization of all patients (pts), reached in Mar 2019 and presented herein. Methods: Pts with newly diagnosed AML or high-risk MDS and unsuitable for intensive chemotherapy were randomized 2:1 to GLAS+LDAC (n=88) or LDAC alone (n=44). For these groups, median (range) treatment duration was 83 (3-1575) and 47 (6-239) days; median follow-up for survival 47.6 and 48.1 months; 4 (4.5%) and 1 pt (2.3%) completed ≥4 years’ follow-up. Results: Consistent with the primary findings (OS HR 0.51; 80% CI 0.39, 0.67 p=0.0004), GLAS+LDAC prolonged OS vs LDAC alone (table). Results were consistent in AML pts and cytogenetic risk/disease history subgroups (table), as were analyses by pt characteristics and baseline risk factors (not shown). Survival probability was 39.5% vs 9.5% at 1 year and 18.0% vs 2.4% at 2 years. GLAS+LDAC induced higher complete remission (CR) rates overall (16/88 vs 1/44; RR 8.12, 95% CI 1.05, 62.78, p=0.010) and across subgroups. Notably, fewer pts discontinued GLAS+LDAC due to AEs (38.1% and 46.3%) and there was no increased sepsis or bleeding vs LDAC alone despite longer glasdegib treatment. With GLAS+LDAC, SMO-inhibitor-associated AEs included dysgeusia (25.0%), muscle spasms (22.6%) and alopecia (10.7%), with only 1 pt discontinuing due to dysgeusia. Conclusions: Consistent with primary analyses, GLAS+LDAC continued to have an acceptable safety profile and improved OS vs LDAC alone. HRs were consistent across cytogenetic risk subgroups and support use of GLAS+LDAC in de novo and secondary AML. Clinical trial information: NCT01546038 . [Table: see text]

7512 Background: Pts with R/R Ph+ ALL and CML LBP have poor outcomes. INO is an anti-CD22 antibody drug conjugate approved for R/R ALL. BOS is a 2nd generation BCR-ABL TKI approved for CML. Methods: This was a phase I/II study of INO + BOS for R/R Ph+ ALL and CML LBP. Primary objective was to determine safety and the maximum tolerated dose (MTD) of the combination. Secondary objective was to assess efficacy. Pts with T315I mutation were excluded. Pts needed to have adequate organ function (Cr ≤2 gm/dL, total bilirubin ≤2 mg/dL, ALT & AST ≤3xULN). BOS was dosed once daily starting on cycle 1 day 1, and 3 dose levels were evaluated (300, 400, 500 mg) in a standard 3+3 design. INO was given IV weekly during cycle 1 (0.8 mg/m2 day 1; 0.5 mg/m2 day 8; 0.5 mg/m2 day 15). In responding pts, INO was subsequently administered at 1 mg/m2 once every 4 weeks for a total of 6 cycles. Results: Between June 2015 and December 2019 we enrolled 18 R/R pts (16 Ph+ ALL, 2 CML LBP). The median age was 62 yrs (range 19-74), median no. of prior therapies was 1 (range 1-5) and 9 pts had ABL kinase domain mutations at screening. There were no early deaths (

1574 Background: Improvements in prevention, early detection and therapy of cancer have decreased cancer related mortality yet health disparities continue to exist. We investigated the impact of such disparities in cancer survival. Methods: In the Surveillance, Epidemiology, and End Results, we identified 784,341 patients with cancer from 1990 to 2016 in Georgia; 68,493 in 1990-1999, 371,353 in 2000-2009, and 322,932 in 2010-2016. We assessed overall survival (OS) of patients with all cancers, chronic myeloid leukemia (CML), and lung cancer given the dramatic improvement in patient outcomes in CML since 2000 compared to the consistently poor outcome in lung cancer. We assessed distance from each county to the one National Cancer Institute-designated cancer center (NCI-CC) in Georgia. Results: The 5-year OS of patients with any cancer was 55% with median OS 80 months; the 5-y OS of each county ranged from 33% to 82% (interquartile range[IQR], 51%-65%)(P < 0.001). The improvement of OS was minimal over decades: 5-year OS was 52%, 55%, and 55% in 1990-1999, 2000-2009, and 2010-2016, respectively; the median was 69 months, 80 months, not reached, respectively (P < 0.001). In patients with lung cancer and CML, the 5-year OS was 15% and 52% with the median of 9 months and 67 months, respectively. The geographic difference between counties was relatively small and constant over time in patients with lung cancer, represented by the width in the range and IQR: range 5%-17%, IQR 9%-13%, median 13% in 1990-1999; range 2%-24%, IQR 10%-14%, median 14% in 2000-2009; and range 4%-24%, IQR 12%-17%, median 17% in 2010-2016. However, the geographic difference was more prominent in patients with CML and widened after introduction of modern therapy: range 20%-42%, IQR 26%-34%, median 32% in 1990-1999; range 14%-83%, IQR 38%-64%, median 53% in 2000-2009; and range 14%-80%, IQR 40%-57%, median 57% in 2010-2016. Multivariate Cox regression showed age (hazard ratio[HR],1.040;95% confidence interval[CI],1.039-1.040;P < 0.001), median county income (HR,0.919;95% CI,0.916-0.921;P < 0.001), African American (HR,1.021;95% CI,1.210-1.227;P < 0.001), and distance to NCI-CC (each 100 kilometers) (HR,1.021;95% CI,1.017-1.025;P < 0.001) as predictive factors. Conclusions: The disparity of cancer care exists between geographic locations. The geographic difference of survival seems more prominent when highly effective therapies are available.

7510 Background: CPX-351 (Vyxeos; daunorubicin and cytarabine liposome for injection), a dual-drug liposomal encapsulation of cytarabine [C] and daunorubicin [D], is approved by the FDA and EMA for the treatment of adults with newly diagnosed therapy-related AML or AML with myelodysplasia-related changes. Primary analysis of the pivotal phase 3 study (NCT01696084) that formed the basis for these approvals evaluated patients (pts) aged 60-75 y with newly diagnosed high-risk/secondary AML and found that CPX-351 significantly improved median overall survival (OS) vs conventional 7+3, with a comparable safety profile. Here, we report the prospectively planned final 5-y follow-up results from this phase 3 study. Methods: Pts were randomized 1:1 to receive ≤2 induction cycles of CPX-351 (100 units/m2 [C 100 mg/m2 + D 44 mg/m2] as a 90-min infusion on Days 1, 3, 5 [2nd induction: Days 1, 3]) or 7+3 (C 100 mg/m2/d continuously for 7 d + D 60 mg/m2 on Days 1-3 [2nd induction: 5+2]). Pts achieving complete remission (CR) or CR with incomplete platelet or neutrophil recovery could receive up to 2 consolidation cycles. Pts could receive a hematopoietic cell transplant (HCT) at the physician’s discretion. Pts were followed until death or up to 5 y following randomization. Results: In total, 309 pts were randomized to CPX-351 (n = 153) or 7+3 (n = 156). The survival rate at 5 y was higher for CPX-351 vs 7+3 (18% vs 8%; Table). Among pts who died, the most common primary cause of death was progressive leukemia in both arms (CPX-351: 56%; 7+3: 53%). After a median follow-up of 60.65 mo, improved median OS with CPX-351 vs 7+3 was maintained: 9.33 vs 5.95 mo; Kaplan-Meier (KM) OS curves plateaued at ~30 mo. HCT was received by 53 (35%) vs 39 (25%) pts after CPX-351 vs 7+3; among these pts, the survival rate at 5 y was higher for CPX-351 vs 7+3 (52% vs 23%), and median OS landmarked from the HCT date was not reached for CPX-351 vs 10.25 mo for 7+3 (Table). Conclusions: After 5 y of follow-up, improved OS was maintained in this phase 3 study, supporting that CPX-351 has the ability to produce or contribute to long-term remission and survival in older pts with newly diagnosed high-risk/secondary AML. Clinical trial information: NCT01696084 . [Table: see text]

7525 Background: Addition of glasdegib (GLAS) to LDAC approximately doubled OS without significant worsening of myelosuppression-related complications, ostensibly by targeting leukemic stem cells dependent on the hedgehog pathway, which is not involved in normal adult hematopoiesis. We assessed potential association of early blood counts and OS. Methods: In BRIGHT AML 1003, patients (pts) with newly diagnosed AML were randomized to GLAS + LDAC (n = 78) or LDAC alone (n = 38). GLAS was given once daily continuously and LDAC on days 1–10 of a 28-day cycle. We evaluated peripheral blood counts measured early in the study (cycle 2 day 1 [C2D1]), approximately 1 month before the first bone marrow assessments. OS was compared for GLAS+LDAC vs LDAC alone subgroups meeting thresholds of absolute neutrophil count (ANC; ≥1000 or 500/µL), hemoglobin (Hb; ≥10 or 9 g/dL) or platelets (≥100,000 or 50,000/µL). Data cut-off was Apr 2019. Results: Among all pts regardless of baseline values, achievement of ANC, Hb and platelet thresholds at C2D1 was associated with improved OS with GLAS+LDAC (table, left side). Notably, in pts who did not meet ANC, Hb or platelet thresholds (table, right side), OS benefit with GLAS+LDAC was also observed (table, all p≤0.05). Among pts below threshold at baseline, C2D1 recovery of platelets ≥50,000 or 100,000 and Hb ≥9 or 10 was associated with improved OS (not shown). Clinical trial information: NCT01546038 . Conclusions: In pts with newly diagnosed AML, improved OS was associated with various blood count thresholds after 1 cycle of GLAS+LDAC vs LDAC alone. In pts with baseline measurements below threshold, recovery of specific thresholds was associated with improved OS. These exploratory results are consistent with the hematopoiesis-sparing mechanism of GLAS, and merit further evaluation. [Table: see text]

7000 Background: The FLT3 inhibitor, gilteritinib, showed superior response and overall survival (OS) compared with salvage chemotherapy (SC) in patients (pts) with FLT3mut+ R/R AML in the phase 3 ADMIRAL study. We analyzed the impact of baseline co-mutations and FLT3-ITD allelic ratio (AR) on response and OS. Methods: A total of 37 recurrently mutated genes in AML (Archer Core Myeloid Panel) were analyzed by next-generation sequencing; the cutoff for co-mutation positivity (co-mut+) was ≥0.027. Baseline FLT3-ITD AR ( FLT3-ITD to FLT3 wild-type DNA) was measured by the LeukoStrat CDx FLT3 Mutation Assay. The median FLT3-ITD AR value of 0.77 was used to define high (≥0.77) vs low (mut+ pts identified four major co-mutation cohorts, each with ≥10% of pts: NPM1 (n=173; 47.9%), DNMT3A (n=115; 31.9%), DNMT3A/NPM1 (n=86; 23.8%) , and WT1 (n=65; 18.0%). In addition, seven pts (1.9%) had all three co-mutations (ie, NPM1, DNMT3A, and WT1). The gilteritinib arm had superior response rates and OS across all four major co-mutation cohorts, with the greatest survival benefit in pts with DNMT3A/NPM1 co-mut+ (Table). In FLT3-ITD AR analyses (n=335), gilteritinib conferred longer OS than SC in pts with a high or low FLT3-ITD AR (gilteritinib: high FLT3-ITD AR, 7.1 mos vs low FLT3-ITD AR, 10.6 mos; SC: high FLT3-ITD AR, 4.3 mos vs low FLT3-ITD AR, 6.9 mos). In both arms, OS was longer in the low FLT3-ITD AR cohort than the high FLT3-ITD AR cohort but the difference in the gilteritinib arm was not statistically significant (gilteritinib: HR=1.341, P=0.0712; SC: HR=2.01, P=0.0021). Conclusions: The ADMIRAL trial shows that the clinical benefit of gilteritinib in FLT3mut+ R/R AML is maintained regardless of NPM1, DNMT3A, DNMT3A/ NPM1, or WT1 co-mut+ or high FLT3-ITD AR. Clinical trial information: NCT02421939. [Table: see text]

7043 Background: The RTK AXL represents a therapeutic target promoting AML cell proliferation and survival by pleiotropic mechanisms and is a negative regulator of anti-tumour immunity. Bemcentinib is a first-in-class, highly selective, oral AXL inhibitor that has previously shown encouraging anti-leukaemic activity as a monotherapy in r/r AML and hr-MDS. Methods: A monotherapy dose-escalation and expansion part of this trial is complete. In this second, phase II part of the study, 11 and 15 AML pts unfit for intensive chemotherapy received bemcentinib at RP2D (200 mg po/d) in combination with low-dose cytarabine (LDAC) and decitabine, respectively. Median age was 77 yr (range: 50-83), median screen myeloblast count 39% (3-95%) and 2/19 (11%) of pts evaluable for FLT3 were FLT3+. Plasma protein biomarker levels were measured using the DiscoveryMap v3.3 panel (Myriad RBM) at screen and following treatment. Results: The most common TRAEs (≥ 15% of pts) were ECG QT prolongation (35%) and diarrhoea (15%). Among these, 3 were Grade 3, and none 4 or 5. All TRAEs were manageable and/or reversible. As of Feb ‘19, 9 pts (2 de novo, 1 secondary, 6 r/r) in the bemcentinib + LDAC group were evaluable for response and 4 (44%; 2 de novo + 2 relapsed) achieved rapid CRi at C2D1. Responses were durable (range: 7 – 11 cycles) in 3 of the 4 responders. A further 2 pts (22%, 1 secondary + 1 relapsed) achieved durable SD (5 and 6 cycles). mPFS among the 5 pts with durable CRi or SD was 5 months (range: 3.5-7.7). Further, at the time of writing, 11 pts (8 de novo, 3 r/r) in the bemcentinib + decitabine group were evaluable for response of which 4 (36%, all de novo) achieved CRi after ≥ 4 cycles. One additional de novo pt achieved durable SD lasting for 5 cycles. Conclusions: Bemcentinib in combination with LDAC exerted early durable responses in patients with both de novo and relapsed AML whilst the combination of bemcentinib + decitabine exerted comparably fewer and later responses in de novo AML. Soluble biomarker correlations will be presented at the meeting. Both combinations were generally well-tolerated and further exploration is warranted. Clinical trial information: NCT02488408.

e18515 Background: Ph+ AML and CML MBP have poor outcomes. VEN synergizes with BCR-ABL TKIs in vitro and may eradicate Ph+ leukemic stem cells. However, the clinical activity of VEN+TKI regimens is unknown. Methods: We conducted a retrospective study on patients (pts) with Ph+ AML and CML MBP who received regimens with VEN+TKI at our institution. Results: We identified 6 pts with relapsed/refractory (R/R) Ph+ AML and 7 with CML MBP (2 transformed from chronic phase, 5 R/R). 10 pts (77%) were refractory to prior therapy and 3 (23%) had relapsed disease. Pt characteristics are shown in the Table. 5 AML pts (83%) had complex cytogenetics. Pts with CML MBP had received a median of 2 prior TKIs (range 1-3). 7 pts received decitabine-based combinations and 6 pts received intensive chemotherapy in combination with VEN+TKI. TKIs included ponatinib (n=7), dasatinib (n=4), bosutinib (n=1) and nilotinib (n=1). Among 12 evaluable pts, the overall response rate (CR + CRi + MLFS) was 50% (Table). In addition, 1 pt with AML developed aplastic marrow, underwent stem cell transplantation, and is still alive. Pts with CR/CRi vs. those without CR/CRi had higher median number of Ph+ metaphases (100% vs. 32%, p

7034 Background: Mutations in TP53 are associated with low response rates to standard therapy and poor outcomes in patients (pts) with acute myeloid leukemia (AML). Combination therapy with the BCL2 inhibitor venetoclax (VEN) has emerged as an effective treatment option for pts with AML. Methods: We reviewed pts with TP53-mutated AML treated with VEN-based therapy between 2014-2018. Mutation testing was performed using a whole-exome next-generation sequencing panel. We analyzed the characteristics of these pts, responses to therapy, and outcomes. Results: Sixty nine pts with TP53-mutated AML treated with VEN were identified, 36 (52%) in frontline & 33 (48%) in the salvage (R/R) setting (Table). The median follow up was 4.5 [0.5 - 48.5] and 8 [1 - 46.5] months for frontline & R/R pts, respectively. Karyotype was complex in 32 (88%) and 29 (88%) pts in the frontline & R/R cohorts, respectively. In the R/R cohort, the number of median prior treatments was 2 [0 – 8]. VEN was given in combination with: 1) Hypomethylating agents (HMA) (87%), 2) FLAG-Ida (3%), 3) Low dose Ara-C (4%), or 4) CPX-351 (6%). The overall response rate (ORR) was 47% & 24% in frontline and R/R pts, respectively. All 6 pts with negative minimal residual disease (MRD) achieved complete cytogenetic response after taking VEN % remain in complete remission (CR) with a median of 3.4 [1.7-4.7] months. Two pts (both R/R) underwent allogeneic stem cell transplantation. Conclusions: VEN based therapy was associated with similar ORR, but higher CR rates in TP53 mutated AML compared with HMAs alone. Larger studies with longer follow up are needed to determine the role of VEN-based therapy in this difficult subset. Patient characteristics and outcome. [Table: see text]

7052 Background: Dasatinib, a potent BCR-ABL tyrosine kinase inhibitor (TKI), is approved for the treatment of chronic phase CML (CML-CP) in the frontline and salvage settings. Notable side effects include pleural effusions and myelosuppression. We previously reported dasatinib 50 mg daily to be active and better tolerated than the approved 100 mg daily dose (CANCER. 2018 Jul 1;124(13):2740-2747). We present an update on the efficacy and toxicity profile of lower dose dasatinib 50 mg orally daily in patients with early CML-CP. Methods: All patients presenting to our institution in early CML-CP were eligible to participate. Prior TKI therapy for up to 1 month was allowed. Responses were assessed according to the European LeukemiaNet guidelines (Baccarani et al. Blood 2013 122.872:884). Results: From March 2016 to March 2018, 81 patients have been enrolled. Median age is 47 years (20-84). Patients categorized by Sokal risk are: low 53; intermediate 22 and high 6. Median follow-up is 18 months (9-31). Cumulative response rates over time are shown below: At 3 months, 96% patients achieved early molecular response ( BCR-ABL PCR ≤10%). Median time to CCyR was 4.6 months, MMR 6.0 months, MR4.0 11.4 months and MR4.5 12.2 months. Eighteen patients had treatment interruption: pleural effusion 4 (possibly related 3, unrelated 1 due to pneumonia); gastrointestinal bleed 2; thrombocytopenia 3; transaminitis 2; renal dysfunction 1; asthma exacerbation 1; pneumonitis 1; lower extremity edema 1; myalgias 1, and pregnancy 2. Four patients had dose reductions: pleural effusion 3; myalgias 1. Four patients had dasatinib dose increased to 100mg: lack of CCyR at 6 months, 3; lack of MMR at 12 months, 1. Four patients are off study: no response 2, pneumonitis 1, and insurance 1. None of the patients have transformed or died. Conclusions: These updated results continue to support dasatinib 50 mg daily as an effective and safe dose for early CML-CP. Clinical trial information: NCT02689440. [Table: see text]

7051 Background: Tyrosine kinase inhibitor therapy has been linked to cardiac and vascular events. Cardiac, vascular and hypertension treatment-emergent adverse events (TEAEs) with bosutinib or imatinib for newly diagnosed chronic phase chronic myeloid leukemia were analyzed. Methods: Patients (pts) who received ≥1 dose of bosutinib (n = 268) or imatinib (n = 265) 400 mg/d in the phase 3 BFORE trial were included. Prespecified MedDRA terms comprised the clusters of investigator assessed TEAEs. Exposure-adjusted TEAE rate was defined as the number of pts with TEAEs / total pt-yr (pt-yr = sum of total time to first TEAE for pts with TEAEs and treatment duration for pts without TEAEs). Results: After ≥36 mo follow-up, 65% vs 62% of pts in the bosutinib vs imatinib arm were still on treatment. Rates of TEAEs, treatment withdrawals and drug-related TEAEs in the clusters of interest were low in both arms (Table). The most common cardiac, vascular and hypertension TEAEs, respectively, were sinus bradycardia (2%), angina pectoris (3%) and hypertension (7%) vs prolonged QT (3%), peripheral coldness (1%) and hypertension (9%) with bosutinib vs imatinib; corresponding grade 3/4/5 TEAE rates in the respective clusters were 3%, 3% and 4% vs 1%, 0.4% and 4%. Hypertension was the only grade 3/4 TEAE occurring in ≥1% of pts in either arm (4% each); 1 grade 5 TEAE each was noted for bosutinib (cardiac failure) and imatinib (cerebrovascular accident). Exposure-adjusted rates of cardiac, vascular and hypertension TEAEs, respectively, were 0.04, 0.03 and 0.04 vs 0.03, 0.01 and 0.04 (grade 3/4/5 only: 0.01, 0.01 and 0.02 vs 0.01, 0.002 and 0.02) for bosutinib vs imatinib. Conclusions: Cardiac, vascular and hypertension TEAE rates were low with bosutinib and imatinib. A majority of TEAEs were low grade and few led to treatment withdrawal. Clinical trial information: NCT02130557. [Table: see text]

7039 Background: Treatment of acute leukemia with intensive chemotherapy (IC) leads to increased risk of infection and bleeding because of myelosuppression. Luteinizing hormone (LH) blockade was found to improve hematopoietic recovery in mice after radiation or chemotherapy through protection of the hematopoietic stem cells (HSCs) which express the LH receptor (Velardi et al, Nat Med 2018). We hypothesized that LH blockade improves hematopoietic recovery following IC in patients (pts) with leukemia. Methods: We assessed gene expression of the LH receptor (LHR) in lineage-specific normal and AML hematopoietic cells from a reference dataset (Corces et al, Nat Gen 2016). We conducted a retrospective analysis on pre-menopausal women with acute myeloid leukemia (AML) or acute lymphoblastic leukemia (ALL) who received IC and Lupron, given for prevention or treatment of abnormal uterine bleeding. Results: LHR was greatest in HSCs, with little or no expression in mature subtypes within the hematopoietic hierarchy. Surprisingly, LHR was expressed on blasts. Since Lupron was more commonly given in younger pts, we performed propensity matching between the Lupron groups (AML N = 64; ALL N = 49) and control (Ctrl) groups (AML N = 128; ALL N = 98 pts). Baseline characteristics including blood counts were well balanced. Pts with AML who had received Lupron had a significantly higher increase in their platelet count following IC (13.8x109/L/year vs Ctrl; p = 0.02). Pts with ALL who had received Lupron had significantly higher increase in their absolute neutrophil count (0.37x109/L/year vs Ctrl; p = 0.02). AML pts in the Lupron group received significantly less blood transfusions vs Ctrl (mean: 23.9 vs 34.7 units; P = 0.002) and less platelet transfusions (mean: 24.4 vs 32.8 units; P = 0.06). There was no difference in event-free and overall survival between the groups in each leukemia cohort. Conclusions: Lupron use in leukemia pts receiving IC was associated with improved long-term blood count recovery. It was also associated with decreased transfusion requirements in AML. Despite expression of the LHR in blasts in addition to normal HSCs, there was no effect of LH blockade on rates of leukemia relapse or death.

e18513 Background: EFS is not considered a robust end-point for AML trials. We hypothesized that rather than a surrogate for overall survival (OS), improvement in EFS may be valuable due to patients (pts) staying in remission and thus decreasing health care utilization (HCU). Methods: In this retrospective study we identified AML pts treated on frontline therapy trials at our institute from 2003-2013 with EFS ≥2 months (mo) and OS of 12-36 mo. We captured the amount of HCU from diagnosis till death, including number of clinic and emergency room (ER) visits, hospitalizations, consultations, blood product transfusions, invasive procedures, laboratory and imaging studies. Linear regression and product-moment correlation were used to determine the relation between these parameters and EFS. Results: Among 337 pts meeting inclusion criteria, the median age was 65 years, 30% had adverse risk AML, 47% received intensive chemotherapy (IC) and 27% received hypomethylating agents (HMA). The median EFS was 10.8 mo. Increasing EFS led to statistically significant decline in HCU for all patients regardless of OS and the correlations were stronger for pts achieving a complete remission (CR, Table). These observations held true across European LeukemiaNet risk groups, younger and older pts, and those receiving IC, HMA, and non-IC, with or without other agents. Conclusions: In newly diagnosed AML, improvement in EFS is correlated with decrease in all HCU irrespective of OS duration. [Table: see text]

7042 Background: CPX-351, a liposomal encapsulation of cytarabine (C) and daunorubicin (D) at a synergistic ratio, is approved as Vyxeos in the US and EU for adults with newly diagnosed therapy-related AML or AML with myelodysplasia-related changes. In a phase 3 study, CPX-351 significantly improved OS and remission rates vs 7+3 in patients (pts) aged 60-75 y with newly diagnosed high-risk/sAML. Some studies suggest a high baseline blast percentage may portend a worse prognosis in AML. This post hoc analysis of phase 3 data assessed outcomes by baseline BM blast percentage. Methods: Pts diagnosed with AML per 2008 WHO criteria (≥20% blasts in peripheral blood or BM) were randomized 1:1 to receive ≤2 inductions of CPX-351 (100 units/m2 [C 100 mg/m2 + D 44 mg/m2] on Days 1, 3, 5 [2nd induction: Days 1, 3]) or 7+3 (C 100 mg/m2/d continuously for 7 d [2nd induction: 5 d] + D 60 mg/m2 on Days 1-3 [2nd induction: Days 1-2]). Pts achieving complete remission (CR) or CR with incomplete platelet or neutrophil recovery (CRi) could receive ≤2 consolidations. Results: CPX-351 had longer median OS and higher remission rates vs 7+3 irrespective of baseline BM blast percentage; median OS was worse in higher blast groups for both treatments (Table). The incidence of grade ≥3 TEAEs was >80% for both arms; febrile neutropenia was the most common. Conclusions: Improved outcomes were observed with CPX-351 vs 7+3 irrespective of baseline BM blast percentage in older adults with newly diagnosed high-risk/sAML. Clinical trial information: NCT01696084. [Table: see text]

7041 Background: Combining PD-1/PD-L1 blockade with hypomethylating agents (HMA) shows encouraging preliminary efficacy in AML, but immune features predictive of response are lacking. Methods: We treated 11 relapsed/refractory (R/R) AML patients with azacitidine (AZA) and nivolumab (Nivo) in a phase 2 clinical trial ( Daver N et al Cancer Discovery 2018). Patient characteristics: median (med) age 65 years (47-73), 63% adverse cytogenetics, 27% TP53 mutated. Pretreatment bone marrow aspirates had immune-phenotypic 17-color flow analysis and NanoString RNA quantification of 1469 immune-relevant genes. Results were correlated with clinical, pathological and molecular data. Results: The median courses of AZA+Nivo administered was 3 (range 1-17). The CR/CRi rate was 45% (including 2 CR, 1 CRi, 1 CRN and 1 CRP), with a median time to response of 1.8 months (range 0.8-4.9 months). The median overall survival was 13 months with 27% patients alive at 1 year. We found significant positive correlations between proportions of T-effector cells at baseline, and CD3+, CD8+, and T-regulatory cells at end of cycle (EOC) 1 (r > 0.75, p < 0.01 for all). At EOC2, these correlations were no longer significant. However, there was a significant positive correlation between T-effector cells at baseline and T-regulatory cells (r = 1, p < 0.001) at EOC4. Using NanoString analysis, we found 105 differentially expressed genes (fold change = 1.5, p < 0.05) between responders (5/11) and non-responders (6/11) at pretreatment. IL2-STAT5, TP53 and TNF Hallmark pathways and immune response from GO gene sets were highly enriched (q < 5x10-4) in responders. We then utilized z-score distribution analysis to quantify the degree of activation of known immunologic pathways. We found that signatures highly specific to neutrophils, NK cells, T-cells and eosinophils were significantly (p < 0.05) upregulated in patients with CR compared to non-responders at pretreatment. Conclusions: Our data demonstrates that a signature suggestive of lymphocyte activation in the pretreatment BM may be associated with augmented clinical response to PD-1 based therapies. Similar underlying pathways that have consistently predicted for responses to PD-1 inhibition in solid cancers, primarily IL2-STAT5 genes, may have predictive relevance in AML. Such pretreatment flow and NanoString signatures may help select AML patients most likely to benefit from PD-1 blockade plus HMA, further enhancing the benefit-risk ratio with such therapies.

7022 Background: Granulocyte transfusions (GTX) have been proposed to improve clinical outcome of neutropenic patients (pts) with serious infections. We evaluated the impact of unirradiated GTX in pts with skin and soft tissue infections (SSTI) and leukemia. Methods: We did a retrospective analysis of pts with leukemia and SSTI that received GTX from 2014 to 2018. We analyzed infection outcome and changes in ANC after GTX. Donors were mobilized using G-CSF plus oral dexamethasone 12 hours prior to apheresis. Results: Twenty-seven pts received 141 GTX for 33 SSTI. Transfusions were unirradiated, except for 10 (7%) radiated units administered due to availability. Twenty pts were male (74%); median age was 59 yrs (20–83 yrs). Hematologic diagnoses included AML (23, 70%), MDS (3, 9%), ALL (3, 9%), CLL (2, 6%), CML (1, 3%), and MF (1, 3%). In 24 (73%) SSTI, pts had a baseline ANC9/L, 3 (9%) had ANC between 0.51x109L to 0.99 x 109L, and 6 (18%) with ANC >1 x109/L. After GTX, ANC increased in 99 (70%) cases by a median of 0.7 x 109/L (0.02 to 10.03) with a median peak time of 9 hrs (4 to114 hrs), with a median time from GTX to first drop of 34 hrs (10 to 136 hrs). ANC decreased in 27 (19%) (by a median -0.5 x 109/L,-0.02 to -2.41). There was no change of ANC in 15 (11%). Improvement was determined by reduction in fever and inflammation, or resolution of SSTI 7 days after first GTX. Twenty-seven (82%) episodes improved. In those improved, ANC remained 9/L in 15 (56%) episodes after last GTX and after improvement. Main adverse reactions were fever in 21% (29), and respiratory complications in 6% (9) (pulmonary effusion, respiratory distress and acute hypoxemia). One pt (3%) required intubation. There was no transfusion-related GVHD. Cumulative survival from first GTX on each SSTI by Kaplan-Meier Survival was 82% (8) at 30 days, 49% (17) at 90 days, 41% (17) at 180 days, and 24% (12) at 360 days. Eight of this pts died of infections, 4 of which were SSTI described on this paper. Conclusions: GTX have a beneficial effect on clinical improvement in patients with SSTI and underlying hematological malignancies and severe neutropenia. It can be safely administered without GVHD. Further prospective studies are warranted.

Purpose Bosutinib is an oral Src/Abl tyrosine kinase inhibitor. The phase III Bosutinib Efficacy and Safety in Newly Diagnosed Chronic Myeloid Leukemia (BELA) trial compared bosutinib with imatinib in newly diagnosed, chronic-phase chronic myeloid leukemia (CML). Patients and Methods A total of 502 patients were randomly assigned 1:1 to bosutinib 500 mg per day or imatinib 400 mg per day. Results The complete cytogenetic response (CCyR) rate at 12 months was not different for bosutinib (70%; 95% CI, 64% to 76%) versus imatinib (68%; 95% CI, 62% to 74%; two-sided P = .601); therefore, the study did not achieve its primary end point. The major molecular response (MMR) rate at 12 months was higher with bosutinib (41%; 95% CI, 35% to 47%) compared with imatinib (27%; 95% CI, 22% to 33%; two-sided P < .001). Time to CCyR and MMR was faster with bosutinib compared with imatinib (two-sided P < .001 for both). On-treatment transformation to accelerated/blast phase occurred in four patients (2%) on bosutinib compared with 10 patients (4%) on imatinib. A total of three CML-related deaths occurred on the bosutinib arm compared with eight on the imatinib arm. The safety profiles of bosutinib and imatinib were distinct; GI and liver-related events were more frequent with bosutinib, whereas neutropenia, musculoskeletal disorders, and edema were more frequent with imatinib. Conclusion This ongoing trial did not meet its primary end point of CCyR at 12 months, despite the observed higher MMR rate at 12 months, faster times to CCyR and MMR, fewer on-treatment transformations to accelerated/blast phase, and fewer CML-related deaths with bosutinib compared with imatinib. Each drug had a distinct safety profile.

Purpose The response definitions proposed by the European LeukemiaNet (ELN) are defined on the basis of imatinib front-line therapy. It is unknown whether these definitions apply to patients treated with second-generation tyrosine kinase inhibitors (TKIs). Patients and Methods One hundred sixty-seven patients with newly diagnosed chronic myelogenous leukemia (CML) in chronic phase were treated with second-generation TKIs in phase II trials (nilotinib, 81; dasatinib, 86). Median follow-up was 33 months. Event-free survival (EFS) was measured from the start of treatment to the date of loss of complete hematologic response, loss of complete or major cytogenetic response, discontinuation of therapy for toxicity or lack of efficacy, progression to accelerated or blastic phases, or death at any time. Results Overall, 155 patients (93%) achieved complete cytogenetic response (CCyR), including 146 (87%) with major molecular response (MMR; complete in 46 patients [28%]). According to the ELN definitions, the rates of suboptimal response were 0%, 2%, 1%, and 12% at 3, 6, 12, and 18 months of therapy, respectively. There was no difference in EFS and CCyR duration between patients who achieved CCyR with and without MMR across all the landmark times of 3, 6, 12, and 18 months. Conclusion The use of second-generation TKIs as initial therapy in CML induces high rates of CCyR at early time points. The ELN definitions of response proposed for imatinib therapy are not applicable in this setting. We propose that achievement of CCyR and partial cytogenetic response at 3 months should be considered optimal and suboptimal responses, respectively. The achievement of MMR offered no advantage over CCyR in defining long-term outcome in patients with newly diagnosed CML treated with second-generation TKIs.

Purpose To determine the prognostic impact of persistent cytogenetic abnormalities at complete remission (CR) on relapse-free survival (RFS) and overall survival (OS) in patients with acute myeloid leukemia (AML) and to examine the potential role of allogeneic stem-cell transplantation (SCT) in this setting. Patients and Methods Data from 254 adult patients with AML (excluding acute promyelocytic leukemia) who achieved CR after induction chemotherapy on various first-line protocols were examined. Results Median follow-up for surviving patients was 43 months. Patients with cytogenetic abnormalities at CR (n = 71) had significantly shorter RFS (P = .001) and OS (P < .001) compared with patients with normal cytogenetics at CR (n = 183); 3-year RFS was 15% and 45%, and 3-year OS was 15% and 56%, respectively. Among the patients with persistent cytogenetic abnormalities at CR, those who underwent SCT in first CR (CR1; n = 15) had better RFS and OS compared to those without SCT (n = 56; P = .04 and .06, respectively). In multivariate analysis, persistent cytogenetic abnormalities at CR was an independent predictor for RFS (P < .001) and OS (P = .001), but among patients with persistent cytogenetic abnormalities at CR, no significant differences in OS (P = .25) was observed between those who did or did not receive SCT with a trend favoring SCT for RFS (P = .08). Conclusion Persistent cytogenetically abnormal cells at CR predict a significantly shorter RFS and OS. SCT in CR1 may improve the clinical outcome of patients lacking cytogenetic remission after induction although this depends on patient selection.

Purpose Myelofibrosis is a myeloid malignancy associated with anemia, splenomegaly, and constitutional symptoms. Patients frequently harbor JAK-STAT activating mutations that are sensitive to TG101348, a selective small-molecule Janus kinase 2 (JAK2) inhibitor. Patients and Methods In a multicenter phase I trial, oral TG101348 was administered once a day to patients with high- or intermediate-risk primary or post–polycythemia vera/essential thrombocythemia myelofibrosis. Results Fifty-nine patients were treated, including 28 in the dose-escalation phase. The maximum-tolerated dose was 680 mg/d, and dose-limiting toxicity was a reversible and asymptomatic increase in the serum amylase level. Forty-three patients (73%) continued treatment beyond six cycles; the median cumulative exposure to TG101348 was 380 days. Adverse events included nausea, vomiting, diarrhea, anemia, and thrombocytopenia; corresponding grades 3 to 4 incidence rates were 3%, 3%, 10%, 35%, and 24%. TG101348 treatment had modest effect on serum cytokine levels, but greater than half of the patients with early satiety, night sweats, fatigue, pruritus, and cough achieved rapid and durable improvement in these symptoms. By six and 12 cycles of treatment, 39% and 47% of patients, respectively, had achieved a spleen response per International Working Group criteria. The majority of patients with leukocytosis or thrombocytosis at baseline (n = 28 and n = 10, respectively) achieved normalization of blood counts after six (57% and 90%, respectively) and 12 (56% and 88%, respectively) cycles. A significant decrease in JAK2 V617F allele burden was observed at 6 months in mutation-positive patients (n = 51; P = .04), particularly in the subgroup with allele burden greater than 20% (n = 23; P < .01); the decrease was durable at 12 months. Conclusion TG101348 is well tolerated and produces significant reduction in disease burden and durable clinical benefit in patients with myelofibrosis.

Abstract 118 Clofarabine (CLO) is a second generation deoxyadenosine nucleoside analog with activity in patients (pts) with acute myeloid leukemia (AML). Early reports also suggestedactivity of iv CLO in myelodysplastic syndrome (MDS), but the role of CLO in MDS therapy remains largely undefined. Due to the molecular characteristics of CLO it can also be administered as an oral formulation with a bioavailability of around 50%. As an oral agent has obvious advantages over parenteral administrations, we designed a phase 2 study to evaluate the activity and safety of oral CLO in patients with MDS. Pts were eligible if they had MDS and ≥ 5% blasts (including RAEB-t by FAB) or IPSS intermediate-2 and high-risk, and CMML. Hematopoietic growth factor support prior to and during the study was permitted. Thirty-two pts (2 RA, 11 RAEB-1, 11 RAEB-2, 2 RAEB-t, 5 CMML-1, 1 CMML-2) were treated. Twenty-two pts (69%) had intermediate-2 or high-risk disease by IPSS. Median age was 70 yrs (range 53–86). Overall, ≥ 27 pts (84%) were older than 60 yrs. Thirteen pts (41%) had a history of a prior malignancy and 20 pts (66%) failed prior hypomethylator therapy (6 pts azacitidine, 12 pts decitabine, 2 pts both). Cytogenetics were intermediate and poor in 9 (28%) and 10 (31%) pts, respectively. The starting dose of CLO was 40 mg/m2 orally daily × 5 days every 4–6 weeks (6 pts), which was decreased due to toxicities to 30 mg/m2 orally daily × 5 days (19 pts), and eventually 20 mg/m2 orally daily × 5 days (7 pts). Twenty-eight pts (88%) received treatment in an outpatient facility and almost all pts (94%) received anti-infectious prophylaxis. Responses of 31 evaluable pts are summarized in the Table: Dose (mg/m2) N CR (%) HI (%) CB (%) Total (%) 40 6 - - 1 (17) 1 (17) 30 18 7 (39) 2 (11) 2 (11) 11 (61) 20 7 1 (14) 1 (14) - 2 (28) Total 31 8 (26) 3 (10) 3 (10) 14 (46) CR, complete remission (≤ 5% marrow blasts; ANC ≥ 1×109/L; plts ≥ 100×109/L) HI, hematologic improvement (as for CR, but plts 30×109/L, ANC increase by 100% and > 1×109/L, hemoglobin increase by 2g/dL or transfusion-independent) Among 20 pts who failed prior hypomethylator therapy responses were CR in 2 (10%), HI in 2 (10%), and CB in 2 (10%). The median number of cycles to response was 1 (range 1–3). Of 10 pts who received further consolidation cycles, the median number was 1 (range 1–8+). No pts died within 6 wks of induction. Acute renal failure occurred in 4 pts (1 pt 40 mg/m2, 3 pts 30 mg/m2) in the context of myelosuppresssion-associated infectious complications; 4 pts died. Common adverse events were nausea/vomiting, rashes, reversible transaminase elevations and hyperbilirubinemia, and fatigue and were mainly ≤ grade 2. The most frequent ≥ grade 3 toxicity were reversible elevations of transaminases. Myelosuppression was ubiquitous, but prolonged myelosuppression (> 42 days) was rare in responding pts. Infectious episodes occurred in 16 pts and were more frequent in pts receiving CLO at 40 or 30 mg/m2. Oral CLO has an ORR of 46% in pts with higher-risk MDS. Responses are lower in pts failing prior hypomethylator therapy. The optimal dose and schedule to balance activity and toxicity remain to be defined. Disclosures: Faderl: Genzyme: Consultancy, Research Funding. Off Label Use: Clofarabine in MDS. Kantarjian: Genzyme: Consultancy, Research Funding.

7020Background: Bemcentinib (BGB324) is a first-in-class, oral selective inhibitor of the RTK AXL currently in ph II clinical development across several cancer types. AXL overexpression has been es...

e19022Background: Occasionally, patients with CML-BP present extramedullary disease (EMD), frequently concomitantly with bone marrow disease (EMD-BM). Characteristics, treatment and outcome of thes...

7064Background: The AZA-001 trial has shown a survival advantage for patients with high-risk MDS treated with HMA as compared to IC. However, this study was conducted mainly in an older population....

7041Background: In vitro studies showed that ofatumumab (O), a type I human antibody that targets a different CD20 epitope compared to rituximab, induces more potent antibody-dependent and compleme...

103Background: Until recently, therapy options for AML patients (pts) were limited. The advent of NGS and novel targeted agents raise the question of how broader use of testing will impact treatmen...

7069Background: Balanced and unbalanced chr 3q21;q26.2 abnormalities result in aberrant expression of the oncogene ecotropic viral integration site 1 implicated in leukemogenesis, and correlate wit...

7062Background: Bosutinib has a distinct adverse event (AE) profile vs other TKIs used to treat Ph+ leukemia. Methods: Pts with chronic phase (CP) chronic myeloid leukemia (CML; n=403) or accelerat...

7016Background: Better defining the immune checkpoint landscape of Acute Myeloid Leukemia will facilitate the rational selection of immune checkpoint targets and combination approaches for future c...

7014Background: Frontline AML induction produces 60-70% complete remission (CR) rates but relapse is a major source of failure. Beside stem cell transplant (SCT), few options exist for post-CR main...

7040Background: CPX-351, a liposomal encapsulation of cytarabine (C) and daunorubicin (D) at a synergistic ratio, is approved in the US for treatment of adults with newly diagnosed therapy-related ...

TPS7081Background: Several tyrosine kinase inhibitors (TKIs) targeting the BCR-ABL1 ATP-binding site are available to treat CML. However, new options are needed for patients (pts) with resistance/i...

7046Background: Mutations in PTPN11, encoding tyrosine phosphatase SHP2, are present in 4-6% of AML. Largest report includes 27 patients (pts). Methods: Analysis included AML patients (pts) treated...