Byrd, John C

Background: Acute myeloid leukemia (AML) therapy in older patients (age ≥ 60) has undergone a transformation with the introduction of multiple targeted therapies, which has allowed more patients to receive therapy than before. The most successful has been the combination of venetoclax + azacitidine (VA) which generated higher overall complete response rates in phase 2 studies than would be expected with azacitidine alone, leading to accelerated FDA approval on 21Nov2018. The VIALE-A phase 3 study confirmed the improved overall survival (OS, median 14.7 versus 9.6 months) of VA, leading to full FDA approval for marketing. This retrospective analysis provides real world data on the impact of baseline clinical and genomic markers of individuals receiving intensive chemotherapy versus VA. Methods: The precision medicine Beat AML Master Trial (NCT03013998) assigns patients to biomarker specific sub-study treatments based on targeted DNA sequencing and cytogenetics. However, a large subset of patients did not enroll on a sub-study, but were followed for off-study treatment and OS. From this subset, patients enrolled onward from 21Nov2018, when VA received accelerated approval, were examined for differences in clinical/genetic characteristics and OS in those receiving venetoclax + hypomethylating agent (V/HMA), any form of intensive chemotherapy (IC), alternative non-intensive therapy (NIT), or no therapy. The genetic mutations identified in this study are characterized by a variant allele frequency of 20%+, as defined in the trial for determining the dominant clone. The method of Kaplan-Meier was used to estimate OS, and the Cox model was fit to associate patient characteristics with OS. Results: From 21Nov2018, a total of 468 AML patients consented to the Beat AML trial and did not enroll to a sub-study. Treatment was chosen by the investigator based upon available clinical and genomic data. Of these 468 patients, 62 did not receive treatment, 2 had treatment data missing, 226 were treated with V/HMA, 112 with IC, and 66 with NIT. Demographics for all patients include median age 71 (60-90), 40% female, performance status (PS) (0-20%; 1-55%; 2-22%; 3-3%), median white blood cell (WBC) 4.1 (range 0.3-298.6), complex karyotype (CK) 20.6%, core binding factor (CBF) 7.8%, KMT2A-rearranged 3.6%, NPM1-mutated (m) 15.6%, IDH2m 14.6%, TP53m 13.2%, FLT3-ITD/TKD 12.9%, and NRASm/ PTPN11m/ KRASm/ NF1m/ CBLm 23.6%. Demographics that were significantly different (p<0.01) among the three groups (V/HMA, IC, and NIT) include age (younger in IC), PS (worse in NIT), AST/ALT (worse in NIT), CBF (more in IC), CK and TP53m (less in IC). Of the 404 patients who underwent treatment with V/HMA, IC, or NIT, 208 have died with those surviving having a median follow-up of 22.3 months. Figure 1 summarizes the OS of each treatment group. The median OS (95% CI) from time of initiating therapy is 13.6 (10.9-16.8) for V/HMA, 33.8 (20.7-not reached) for IC, and 11.6 (5.2-21.3) months for NIT. Univariable analysis for OS was significant at p<0.05 for increased age, WBC, PS, hemoglobin, CBF, CK, NPM1m, TP53m, TET2m and IC versus V/HMA. Multivariable analysis was significant at p<0.05 (hazard ratio) for increased age (1.14), PS (1.83), WBC (1.08), hemoglobin (0.91), and select genomic aberrations including CBF (0.37), NPM1m (0.35), and TP53m (2.1). Conclusions: These results from a large cohort of older AML patients treated with V/HMA, IC, or NIT show that their outcome is best defined by pre-treatment clinical features previously identified including age, performance status, WBC and hemoglobin along with limited genomic characteristics including CBF, NPM1m, and TP53m. While univariate analysis of OS favored IC over V/HMA and NIT, multivariable analysis supports that this advantage was most likely due to the favorable clinical and genomic features. The OS of V/HMA patients in this cohort is similar to that in the VIALE-A registration study of VA, providing further justification for this treatment for older AML patients deemed ineligible for intensive chemotherapy. Additionally, this data supports use of the patient cohort in this study for ongoing work in understanding and/or validating biomarkers associated with survival with V/HMA.

Background. Acute myeloid leukemia (AML) is a heterogenous disease that occurs primarily in older adults with a median age of 69 years at diagnosis. Most studies that characterize the genomic landscape of AML include younger adults with the majority of patients being younger than 60 years of age. We aimed to study the mutational landscape of newly diagnosed AML patients aged 60 years or older. Methods.Samples were collected from the multi-center Beat AML Master Trial (Burd, Nat Med 2020). Patients were enrolled between 2016 and 2023. Informed consent was obtained according to the Declaration of Helsinki. Patients diagnosed with non-APL AML and who were aged ≥ 60 years old were included. Patients underwent bone marrow aspiration and biopsy, cytogenetic analysis, FLT3-ITD ratio assessment (LeukoStrat CDx FLT3 Mutation Assay, Invivoscribe) and next generation sequencing (NGS) using FoundationOne®Heme(Foundation Medicine) to interrogate the entire coding region of 406 genes and select introns of 31 genes involved in rearrangements, as well as RNA sequencing to interrogate 265 genes known to be somatically altered in human hematological malignancies. The presence of multiple hotspot mutations within one gene in an individual patient was counted as one gene mutation. Patterns of co-occurrence between gene mutations were calculated using the Phi correlation coefficient. Statistical analyses were performed using R statistical software. P<0.01 was considered statistically significant. Results. A total of 1088 newly diagnosed AML patients were identified, of whom 1032 were 60 years or older. Patients had a median age of 72 years at time of diagnosis (range 60-92 years). Forty-two percent of the patients were female, most patients were non-Hispanic and 79% were Caucasian. NGS data were available for 1024 patients and mutations were identified in 461 different genes. Patients had a median number of 11.0 mutations (range 3.0 to 28.0). The most frequently mutated genes were DNMT3A (n=257; 25.1%), TP53(n=255; 24.9%), TET2 (n=243; 23.7%), RUNX1 (n=225; 22.0%), SRSF2 (n=221; 21.6%), ASXL1 (n=216; 21.1%), NPM1 (n=206; 20.1%), FLT3 (n=205; 20.0%), IDH2 (n=190; 18.6%), NRAS (n=208; 16.9%), PTPN11(n=104; 10.2%), STAG2 (n=101, 9.9% and IDH1 (n=99; 9.7%) (Figure 1A). FLT3-ITD was present in 98 (12.1%) of the 810 patients who were tested. Strongest significant co-occurrence was found between FLT3and NPM1 (n=103), STAG2 and ASXL1 (n=63), ASXL1 and RUNX1 (n=92), ASXL1 and SRSF2 (n=88), RUNX1 and SRSF2 (n=94), STAG2 and SRSF2 (n=51) and DNMT3A and NPM1 (n=92) (p<0.01). Pairwise negative correlations were observed between TP53 and NPM1 (n=6), TP53 and SRSF2 (n=17), and between NPM1 and RUNX1 (n=6) (p<0.01) (Figure 1B). The cytogenetic profiles and the full genomic landscape will be presented during the ASH meeting. Discussion. This is the largest study investigating the mutational profile in older adults with AML aged 60 years and older. Due to the 7-day screening period of the Beat AML study, patient selection was biased towards less-rapidly proliferative AML. We showed that the pattern of gene mutations was markedly different from other studies in AML that mainly included younger AML patients (Papaemmanuil, NEJM 2016; TCGA, NEJM 2013 ). The frequency of mutated TP53 was substantially higher in older AML patients, as was the occurrence of myelodysplasia-related gene mutations (e.g., SRSF2, RUNX1, ASXL1, STAG2, U2AF1, and SF3B1) and gene mutations in IDH1, IDH2 and TET2. In contrast, NPM1 mutation was less frequently mutated in older AML patients. Furthermore, we demonstrated that a large proportion (46%) of the AML patients older than 60 years of age do have a mutation that is potentially targetable for treatment ( FLT3 IDH1 IDH2 and NPM1). The high incidence of mutated TP53 and MDS-related gene mutations underscores the increased incidence of high-risk AML and the need for innovative personalized therapies in this older age group. Figure 1. A. Co-occurrence of the 15 most frequently mutated genes, and B. co-correlation between the 15 most frequently mutated genes. Blue indicates positive correlation, red indicated negative correlation. Only significant correlations (p<0.01) are shown.

Background: Treatment of chronic lymphocytic leukemia (CLL) has been transformed with targeted therapies including inhibitors of Bruton's tyrosine kinase (BTKi). Currently three covalent BTK inhibitors (cBTKi) are approved for CLL, but most patients eventually relapse, commonly through acquisition of the C481S BTK mutation (Woyach et al. 2014). Pirtobrutinib and nemtabrutinib are non-covalent BTK inhibitors (ncBTKi) developed to target and inhibit C481S mutant BTK. However novel secondary site mutations in BTK, namely T474I and L528W, have been found to confer resistance to both cBTKi and ncBTKi (Wang et al. 2022). Regardless of these mutations, BCR signaling remains intact, suggesting that inhibition of BTK maintains its therapeutic importance. LP-168 is a novel ultra-selective 4 th generation BTKi with an active warhead capable of covalent interaction with WT BTK or non-covalent binding when a BTK C481 mutation is present. Methods: To determine the target selectivity of LP-168 we screened the compound against 468 kinases in the scanMAX Kinase Assay. For validation of covalent binding, dialysis against WT BTK was performed. Primary CLL B cells were isolated by negative selection and treated with LP-168 for all experiments. BCR signaling alterations were assessed via immunoblot to observe changes in target protein phosphorylation. Changes in CLL migration towards CXCL12 or CXCL13 were interrogated by transwell migration. Cytotoxicity towards primary CLL cells was measured via Annexin V/PI flow cytometry with and without HS-5 stromal cell support. Experiments using TMD8 cells were performed following CRISPR modification to insert WT, C481S, or T474I BTK. In vivo survival studies were performed using both the Eμ-TCL1 and Eμ-MTCP1 mouse engraftment models. Results: LP-168 demonstrated selectivity towards BTK with roughly 700-fold selectivity for BTK vs its next off-target. In an enzymatic assay, LP-168 displayed nanomolar potency towards both WT BTK (IC 50=0.11 nM) and C481S BTK (IC 50=1.0 nM). Following 2-hour drugging, LP-168 inhibited BCR signaling in primary CLL B cells at increasing concentrations, demonstrated by reduced phosphorylation of BTK (92%, p<0.0001, n=8) and its immediate downstream target PLCγ2 (41%, p=0.0013, n=8). Migration capacity of primary CLL cells towards CXCL12 and CXCL14 was also found to decrease after 2-hours of treatment with LP-168 (52%, p<0.001, n=10 and 51%, p<0.001, n=10, respectively). After 48 hours of exposure, LP-168 was able to induce cytotoxicity of primary CLL cells alone and in co-culture with HS-5 stromal cells in a dose-dependent manner, with similar or improved efficacy to other BTKi. LP-168 decreased CLL cell production of CCL3 and CCL4 chemokines (CCL3: 93%, p<0.001, n=8; CCL4: 93%, p<0.001, n=8). LP-168 also demonstrated modest cytotoxicity towards TMD8 cells harboring either C481S BTK (24%, p=0.0008 , n=3) or T474I BTK (13%, p=0.0690, n=3), as well as decreased production of CCL3 (C481S: 95%, p<0.0001, n=3; T474I: 99%, p<0.0001, n=3) and CCL4 (C481S: 97%, p<0.0001, n=3; T474I: 98%, p<0.0001, n=3) (Figure 1A). Further, we observed inhibition of downstream BCR signaling in primary CLL B cells harboring C481S via immunoblotting and cytokine production. Finally, to evaluate the in vivo efficacy of LP-168 we tested this compound in both the Eµ-TCL1 and Eµ-MTCP1 models. We treated mice daily via oral gavage and found that 50 mg/kg of LP-168 significantly improved survival in the Eµ-TCL1 model when compared to vehicle (median 51 vs 44 days; p=0.0018) or ibrutinib at 50 mg/kg (median 51 vs 45 days; p=0.0098) and the Eµ-MTCP1 model when compared with vehicle (median 122 vs 62 days; p<0.0001) or ibrutinib at 50 mg/kg (median 122 vs 96 days; p=0.0162) (Figure 1B). Conclusions: Collectively, our data demonstrate that LP-168 is a potent and selective inhibitor of BTK with activity against CLL, even in the presence of mutations that mediate resistance to cBTKi and ncBTKi. These data support the continued preclinical and clinical investigation of LP-168, which is currently being studied in the phase 1 setting of CLL (NCT04775745) and NHL (NCT04993690).

Background: Richter Transformation (RT) refers to the development of an aggressive lymphoma in the setting of chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL). Small molecule inhibitors (SMI), such as the Bruton tyrosine kinase inhibitors (BTKi) and BCL2 inhibitors (BCL2i), have revolutionized the treatment of CLL/SLL. Prior studies evaluated outcomes of patients (pts) with RT in an era where chemoimmunotherapy (CIT) was typically used to treat CLL/SLL. Now that SMI are standard of care, fewer pts with CLL/SLL receive CIT, therefore we sought to determine which variables predict survival in pts who developed RT without prior CIT exposure for CLL/SLL. Methods: We conducted an international multicenter retrospective study of pts from 11 academic centers. Pts with RT occurring as large B-cell lymphoma who did not previously receive CIT (e.g., fludarabine, cyclophosphamide, bendamustine, chlorambucil) for their CLL/SLL were included. We collected pt, disease, and treatment (tx) characteristics. RT was categorized into 3 groups: “Concurrent RT,” defined as RT and CLL/SLL diagnosed simultaneously (within 3 months [mos]); “RT w/o prior CLL/SLL tx,” defined as RT and CLL/SLL diagnosed >3 mos apart with the CLL/SLL never treated; and “RT with prior non-CIT tx for CLL/SLL” defined as having received prior CLL/SLL tx. Overall survival (OS) was measured from RT diagnosis (Dx) and estimated using the Kaplan-Meier method. Cox regression model was used to identify prognostic factors associated with OS. Results: 242 pts were identified. At CLL/SLL Dx, 66% of pts had unmutated IGHV, 37% had del17p/ TP53 disruption, and 20% had trisomy 12. At RT Dx, 56% of the RT with prior non-CIT tx for CLL/SLL group had a del17p/ TP53 disruption versus 27% for the concurrent RT group and 18% for the RT w/o prior CLL/SLL tx groups. Median time from CLL/SLL Dx to RT Dx was 47 mos (range 3-394) for RT w/o prior CLL/SLL tx and 46 mos (range 4-218) for RT with prior non-CIT tx for CLL/SLL. Pts with prior non-CIT tx for CLL/SLL received a median of 1 (range 1-5) prior tx. 86% of pts previously received a BTKi or a BCL2i for tx of CLL/SLL (54% BTKi only, 5% BCL2i only, 27% both). The remaining 14% had been treated with an anti-CD20 monoclonal antibody (MoAb), steroids, lenalidomide, radiation, or alemtuzumab. 85% of pts developed RT while on active tx with SMI. Median age at RT Dx was 69 years (range 37-92). At RT Dx, 38% and 21% of pts had del17p/ TP53 disruption, and trisomy 12 in CLL/SLL tissue, respectively. At RT Dx, there was no difference in highest SUV on PET (median 16, range 2.9-65.6), LDH (median 325, range 103-8162, ULN range 180-271), largest lymph node in diameter (median 4.9 cm, range 0-17.1), Ki-67 (median 80%, range 5%-100%), rate of GCB subtype (27%), presence of MYC translocation (20%), or CLL/SLL and RT clonal relationship (81%) for those pts tested amongst the 3 groups ( Table). The most common 1 st line tx for RT was CIT with or w/o radiation and/or steroids (76%), followed by CIT plus SMI (13%), SMI single agent or combination (7%), and other (4%, which includes anti-CD20 MoAb). Median follow-up from RT Dx was 42.3 mos; the median OS for the entire cohort was 25.8 mos (95% CI: 16.8-49.1). Pts with RT after non-CIT tx for CLL/SLL had a significantly worse OS (median 8.2 mos [95% CI: 5.6-14.3]) than pts with concurrent RT (median 46.3 mos [95% CI: 23.8-96.9]) and RT w/o prior CLL/SLL tx (median 63.5 mos [95% CI: 28.3-70.3]) ( Figure). From an exploratory univariable analysis, we found RT after non-CIT tx for CLL/SLL compared to concurrent RT (HR 2.32 [95% CI: 1.55-3.46]), RT Dx age (HR for 5-year increase 1.14 [95% CI: 1.05-1.23]), del17p/ TP53 disruption (HR 2.27 [95% CI: 1.45-3.56]), and LDH (HR for 2-fold increase 1.37 [95% CI: 1.20-1.58]) were prognostic for worse OS. Conclusions: This is the largest cohort of pts who developed RT having received only SMI with no CIT for their CLL reported, thus reflecting the current treatment landscape. Despite being CIT-naïve, pts in our series who received tx for their CLL/SLL and then developed RT had a short OS, underscoring the need to develop better therapies for these pts. In contrast, as in other published analyses (Wang Haematologica 2020), pts w/o prior tx for CLL/SLL had more favorable outcomes, with a median OS of approximately 5 years. Further analysis to determine PFS and OS by tx for RT for pts who have been treated with SMI for their CLL/SLL is ongoing.

Abstract Enasidenib (ENA) is an inhibitor of isocitrate dehydrogenase 2 (IDH2) approved for the treatment of patients with IDH2-mutant relapsed/refractory acute myeloid leukemia (AML). In this phase 2/1b Beat AML substudy, we applied a risk-adapted approach to assess the efficacy of ENA monotherapy for patients aged ≥60 years with newly diagnosed IDH2-mutant AML in whom genomic profiling demonstrated that mutant IDH2 was in the dominant leukemic clone. Patients for whom ENA monotherapy did not induce a complete remission (CR) or CR with incomplete blood count recovery (CRi) enrolled in a phase 1b cohort with the addition of azacitidine. The phase 2 portion assessing the overall response to ENA alone demonstrated efficacy, with a composite complete response (cCR) rate (CR/CRi) of 46% in 60 evaluable patients. Seventeen patients subsequently transitioned to phase 1b combination therapy, with a cCR rate of 41% and 1 dose-limiting toxicity. Correlative studies highlight mechanisms of clonal elimination with differentiation therapy as well as therapeutic resistance. This study demonstrates both efficacy of ENA monotherapy in the upfront setting and feasibility and applicability of a risk-adapted approach to the upfront treatment of IDH2-mutant AML. This trial is registered at www.clinicaltrials.gov as #NCT03013998.

AbstractNext-generation sequencing (NGS) to identify pathogenic mutations is an integral part of acute myeloid leukemia (AML) therapeutic decision-making. The concordance in identifying pathogenic mutations among different NGS platforms at different diagnostic laboratories has been studied in solid tumors but not in myeloid malignancies to date. To determine this interlaboratory concordance, we collected a total of 194 AML bone marrow or peripheral blood samples from newly diagnosed patients with AML enrolled in the Beat AML Master Trial (BAMT) at 2 academic institutions. We analyzed the diagnostic samples from patients with AML for the detection of pathogenic myeloid mutations in 8 genes (DNMT3A, FLT3, IDH1, IDH2, NPM1, TET2, TP53, and WT1) locally using the Hematologic Neoplasm Mutation Panel (50-gene myeloid indication filter) (site 1) or the GeneTrails Comprehensive Heme Panel (site 2) at the 2 institutions and compared them with the central results from the diagnostic laboratory for the BAMT, Foundation Medicine, Inc. The overall percent agreement was over 95% each in all 8 genes, with almost perfect agreement (κ > 0.906) in all but WT1, which had substantial agreement (κ = 0.848) when controlling for site. The minimal discrepancies were due to reporting variants of unknown significance (VUS) for the WT1 and TP53 genes. These results indicate that the various NGS methods used to analyze samples from patients with AML enrolled in the BAMT show high concordance, a reassuring finding given the wide use of NGS for therapeutic decision-making in AML.

Abstract ELEVATE-RR demonstrated noninferior progression-free survival and lower incidence of key adverse events (AEs) with acalabrutinib vs ibrutinib in previously treated chronic lymphocytic leukemia. We further characterize AEs of acalabrutinib and ibrutinib via post hoc analysis. Overall and exposure-adjusted incidence rate was assessed for common Bruton tyrosine kinase inhibitor–associated AEs and for selected events of clinical interest (ECIs). AE burden scores based on previously published methodology were calculated for AEs overall and selected ECIs. Safety analyses included 529 patients (acalabrutinib, n = 266; ibrutinib, n = 263). Among common AEs, incidences of any-grade diarrhea, arthralgia, urinary tract infection, back pain, muscle spasms, and dyspepsia were higher with ibrutinib, with 1.5- to 4.1-fold higher exposure-adjusted incidence rates. Incidences of headache and cough were higher with acalabrutinib, with 1.6- and 1.2-fold higher exposure-adjusted incidence rate, respectively. Among ECIs, incidences of any-grade atrial fibrillation/flutter, hypertension, and bleeding were higher with ibrutinib, as were exposure-adjusted incidence rates (2.0-, 2.8-, and 1.6-fold, respectively); incidences of cardiac events overall (the Medical Dictionary for Regulatory Activities system organ class) and infections were similar between arms. Rate of discontinuation because of AEs was lower for acalabrutinib (hazard ratio, 0.62; 95% confidence interval, 0.41-0.93). AE burden score was higher for ibrutinib vs acalabrutinib overall and for the ECIs atrial fibrillation/flutter, hypertension, and bleeding. A limitation of this analysis is its open-label study design, which may influence the reporting of more subjective AEs. Overall, event-based analyses and AE burden scores demonstrated higher AE burden overall and specifically for atrial fibrillation, hypertension, and hemorrhage with ibrutinib vs acalabrutinib. This trial was registered at www.clinicaltrials.gov as #NCT02477696.

7500 Background: The Bruton’s tyrosine kinase inhibitor (BTKi) ibrutinib +/- anti-CD20 antibody obinutuzumab (IO) is a standard frontline regimen for older adults with CLL. BTKi alone do not often lead to complete response (CR) or undetectable minimal residual disease (uMRD), thus are given indefinitely. Smaller trials showed that IO plus venetoclax (IVO) can induce uMRD CRs which may allow successful discontinuation. Methods: Alliance for Clinical Trials in Oncology A041702 is a multicenter trial designed to evaluate if IVO with response-guided discontinuation of I improves progression free survival (PFS) versus IO with indefinite I in treatment-naïve, older CLL pts. IO is given in standard fashion, and in the IVO arm V is added at C3D1 and continued until C14D28. After 14 cycles, pts undergo response evaluation including CT scans and bone marrow biopsy with central MRD assessment by flow cytometry. Pts in IVO arm with uMRD CR discontinue I; all others continue I until progression or unacceptable toxicity. Eligible pts were age ≥70 years (amended to ≥65). Pts had CrCl ≥ 40 mL/min, bilirubin ≤ 1.5 x ULN, and no other life-limiting intercurrent illness. Pts were stratified based on Rai stage and +/- del17p13.1 by FISH, and randomized 1:1 to IO:IVO. With 431 evaluable pts, the trial had 90% power to detect significant improvement in PFS using a one-sided log-rank test with one-sided type 1 error rate of 2.5%. The Alliance DSMB approved release of data on Nov 4, 2022 after meeting the protocol defined futility threshold at the second planned event-driven interim analysis. Data were locked on December 15, 2022. Results: Between January 4, 2019 and July 15, 2022, 465 pts were registered (IO:232, IVO:233). Median age was 74; 67% of pts were men. Rai stage 3-4 was seen in 55% and del17p in 13%. With median follow-up of 14 months, PFS of IO was 87.5% compared to 85% on IVO. Events were observed in 29 pts on IO (4 progressions, 23 deaths, 2 pts started other therapy) and 35 on IVO (7 progressions, 28 deaths). The predefined futility boundary was crossed, with a hazard ratio (HR) of 1.20 (95% CI: 0.73-1.97) in favor of IO. COVID-19 was the leading cause of death in both arms, (11 COVID-19 deaths on IO, 19 on IVO), with 13 and 11 additional deaths from other causes, respectively. Censoring pts with COVID-19 related deaths, PFS HR is 0.82 (95% CI: 0.44-1.53) in favor of IVO. Grade 3+ toxicity and discontinuation in year 1 of therapy were similar between arms. Conclusions: This study demonstrates that PFS for IVO is not superior to IO for treatment-naive older CLL pts in the setting of the COVID-19 pandemic. Study treatment is ongoing, and long-term follow-up will determine if there are advantages to IVO, with special attention to MRD and therapy discontinuation. Support: U10CA180821, U10CA180882, U24 CA196171; https://acknowledgments.alliancefound.org . Clinical trial information: NCT03737981 .

AbstractBackgroundPatients with acute myeloid leukemia (AML) who have tumor protein p53 (TP53) mutations or a complex karyotype have a poor prognosis, and hypomethylating agents are often used. The authors evaluated the efficacy of entospletinib, an oral inhibitor of spleen tyrosine kinase, combined with decitabine in this patient population.MethodsThis was a multicenter, open‐label, phase 2 substudy of the Beat AML Master Trial (ClinicalTrials.gov identifier NCT03013998) using a Simon two‐stage design. Eligible patients aged 60 years or older who had newly diagnosed AML with mutations in TP53 with or without a complex karyotype (cohort A; n = 45) or had a complex karyotype without TP53 mutation (cohort B; n = 13) received entospletinib 400 mg twice daily with decitabine 20 mg/m2 on days 1–10 every 28 days for up to three induction cycles, followed by up to 11 consolidation cycles, in which decitabine was reduced to days 1–5. Entospletinib maintenance was given for up to 2 years. The primary end point was complete remission (CR) and CR with hematologic improvement by up to six cycles of therapy.ResultsThe composite CR rates for cohorts A and B were 13.3% (95% confidence interval, 5.1%–26.8%) and 30.8% (95% confidence interval, 9.1%–61.4%), respectively. The median duration of response was 7.6 and 8.2 months, respectively, and the median overall survival was 6.5 and 11.5 months, respectively. The study was stopped because the futility boundary was crossed in both cohorts.ConclusionsThe combination of entospletinib and decitabine demonstrated activity and was acceptably tolerated in this patient population; however, the CR rates were low, and overall survival was short. Novel treatment strategies for older patients with TP53 mutations and complex karyotype remain an urgent need.