Single-cell epigenomics in cancer: charting a course to clinical impact

Cancer is a disease of global epigenetic dysregulation. Mutations in epigenetic regulators are common events in multiple cancer types and epigenetic therapies are emerging as a treatment option in several malignancies. A major challenge for the clinical management of cancer is the heterogeneous nature of this disease. Cancers are composed of numerous cell types and evolve over time. This heterogeneity confounds decisions regarding treatment and promotes disease relapse. The emergence of single-cell epigenomic technologies has introduced the exciting possibility of linking genetic and transcriptional heterogeneity in the context of cancer biology. The next challenge is to leverage these tools for improved patient outcomes. Here we consider how single-cell epigenomic technologies may address the current challenges faced by cancer clinicians. </jats:p

Intensive care unit outcomes in patients with hematological malignancy

Hematological malignancies are usually life-limiting conditions. Limitations of care need to be decided early, based on acceptability to the patient, family, physician, and community. Inappropriate intensive care unit (ICU) admission is likely to result in significant physical, psychological, and economic burden. There is little published on the impact of non-acute preadmission disease factors on ICU outcomes in hematological malignancies. AIM: To identify baseline performance and disease-associated factors before admission to ICU in patients with hematological malignancy that contribute to subsequent ICU mortality. METHODS: A retrospective analysis of electronic medical records, laboratory results, and Intensive Care data for all patients (n = 184) with hematological malignancy admitted to the Calvary Mater Hospital ICU between January 1, 2013 and June 30, 2017 was undertaken. Baseline age, gender, condition, Eastern Cooperative Oncology, and Charlson Comorbidity scores were compared to ICU outcome and overall survival. Disease-specific prognostic risk scores were compared to ICU outcome. RESULTS: Overall, 73.9% survived the ICU admission, with 31.6% surviving at 12 months. Superior ejection fractions (>55%) and prognosis >12 months (based on disease-specific risk scores) were significantly associated with overall survival (P = 0.024 and P = 0.001). Induction and posttransplantation therapy were predictive of poor ICU survival outcome (P < 0.0001 and P = 0.041). APACHE scores were significant predictors of ICU mortality (P = 0.002 for APACHE II and P < 0.0001 for APACHE III). CONCLUSION: Survival outcomes for patients with hematological malignancy admitted to the ICU correlate with functional and comorbidity status. Disease-specific prognostic scores can assist in recognizing patients likely to benefit from ICU admission

A Phase-Ib/II Clinical Evaluation of Ponatinib in Combination with Azacitidine in <i>FLT3</i>-ITD and <i>CBL</i>-Mutant Acute Myeloid Leukemia (PON-AZA study)

Abstract Introduction Despite the advent of targeted therapy for FLT3-mutated AML, unmet need still exists for patients unfit for intensive chemotherapy, with no evidence that overall survival (OS) can be improved by combining either venetoclax (Konopleva et al., ASH 2020) or gilteritinib (Astellas press release, December 2020) with azacitidine. Although gilteritinib has been shown to improve median OS from 5.5 to 9.8 months, the majority will relapse (Perl et al., 2019). Adaptive on-target gilteritinib resistance may be due to the FLT3-F691L gatekeeper mutation, whereas off-target resistance may be due to loss-of-function variants in CBL, which encodes an E3 ubiquitin-protein ligase that negatively regulates FLT3 (McMahon et al, 2019). Ponatinib is a type-1 FLT3 inhibitor that is active in vitro against FLT3 F691L (Smith et al., 2013) and had an overall response rate (ORR) of 43% in a small pilot phase-I study (Talpaz et al., 2011). Combination of a FLT3 inhibitor with azacitidine may antagonize the synergistic hypermethylation reported for FLT3-ITD in association with epigenetic mutations (Shih et al., 2015). CBL loss-of-function mutations may also enhance responsiveness to FLT3 inhibitors (Taylor et al, 2015). We thus hypothesize that the combination of ponatinib and azacitidine could mitigate the rapid evolution of drug resistance typical of more selective FLT3 inhibitors used as single agents. Methods A phase-Ib study was conducted with the primary objective safety and key secondary objective preliminary efficacy of azacitidine in combination with ponatinib in patients with FLT3-ITD AML failing prior therapy or unfit for intensive chemotherapy. Exploratory objectives included mechanisms of ponatinib resistance and responsiveness of CBL-mutant AML to FLT3 inhibition. At dose level 1 (DL1), patients received azacitidine 60 mg/m 2 on days 1-5 and 8-9 and ponatinib 30 mg daily on days 5-25 of each cycle. In patients not achieving CR or CRi after cycle 1, the ponatinib dose was increased to 45 mg during cycle 2. For dose level 2 (DL2), the dose of azacitidine was increased to 75 mg/m 2. Results Thirty-one patients were evaluable for response. Median age was 67 years (range, 26-87). Frequency of prior lines of therapy was 0 (15%), 1 (46%), 2 (23%) or 3 (8%). Four patients had a history of prior allogeneic hematopoietic cell transplant and one had previously received a FLT3 inhibitor. FLT3-ITD was present in 28 patients (median VAF 0.33; range, 0.009-17.95) and 3 had inactivating CBL mutations. A total of 20 patients were treated at DL1 and 12 patients at DL2. There were two grade-4 DLTs (raised AST/ALT [DL1] and tubulointerstitial nephritis [DL2]). Three grade-2 thromboembolic events were observed (two cannula-related DVTs and a distal lower-limb DVT). There were two grade-5 AEs (infection and cardiac failure), which were not considered drug related. The most common grade-3-4 AEs were febrile neutropenia (57%), neutropenia (47%), infections (47%), thrombocytopenia (40%) and anaemia (27%). Cardiac arrhythmias (atrial fibrillation/flutter, bradycardia, sinus tachycardia and ventricular tachycardia [1 patient]) were observed in 30% of patients. Of these, 80% were grade 1 or 2 and only one was considered by the investigator to be related to study treatment. Response was evaluable in 23 of 31 patients. Nine patients (39%) achieved CR or CRi, 3 (13%) achieved a PR and 8 (35%) achieved SD (ORR 52%). ORR at DL1 and DL2 was 43% and 66%, respectively. Median time to best response was 1.4 months (range 1.0-11.9). Median duration of best response was 12.9 months at both dose levels. Median OS for DL1 was 6.5 months and not reached for DL2. Despite shorter follow-up, DL2 patients experienced better OS than DL1 patients (p = 0.015). Responses were seen in 2 of 4 patients with post-allograft relapse. Two of three patients with a CBL mutation responded (1 CR and 1 CRi). Eradication of the CBL mutation was seen in one patient, who remains on therapy after 15 cycles. Molecular studies to investigate dynamic changes in molecular architecture are ongoing. Conclusions The recommended phase-II dose of ponatinib is 30 mg on days 5-25 and that of azacitidine is 75 mg/m 2 for seven doses each cycle. The ORR was 52% and durable disease control was observed, especially in patients receiving DL2. Preliminary efficacy was observed in CBL-mutated patients. Further clinical investigation of this regimen is warranted in patients with FLT3- or CBL-mutant AML. Figure 1 Figure 1. Disclosures Kipp: Novartis: Honoraria. Perkins: Celgene: Consultancy; Novartis: Consultancy, Honoraria, Speakers Bureau; Abbvie: Honoraria, Speakers Bureau. Lane: Novartis: Consultancy; Geron: Consultancy; BMS: Consultancy, Research Funding; Abbvie: Honoraria; Astellas: Membership on an entity's Board of Directors or advisory committees. Enjeti: Sanofi: Honoraria; Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; AbbVie: Honoraria; Roche: Speakers Bureau; Astra Zeneca: Honoraria. Bajel: Abbvie, Amgen, Novartis, Pfizer: Honoraria; Amgen: Speakers Bureau. Reynolds: Novartis AG: Current equity holder in publicly-traded company; Abbvie: Research Funding; Alcon: Current equity holder in publicly-traded company. Wei: Abbvie, Amgen, Astellas, AstraZeneca, Celgene/BMS, Genentech, Janssen, MacroGenics, Novartis, Pfizer, and Servier: Membership on an entity's Board of Directors or advisory committees; Novartis, Abbvie, Celgene/BMS: Speakers Bureau; Former employee of Walter and Eliza Hall Institute: Patents &amp; Royalties: Prof. Andrew Wei is a former employee of the Walter and Eliza Hall Institute and is eligible for a fraction of the royalty stream related to Venetoclax; Abbvie, Amgen, Astellas, AstraZeneca, Celgene/BMS, Genentech, Janssen, MacroGenics, Novartis, Pfizer, and Servier: Honoraria; Servier: Consultancy; Abbvie, Amgen, AstraZeneca, Celgene/BMS, Novartis, Servier and F. Hoffmann-La Roche: Research Funding. OffLabel Disclosure: Ponatinib - used as an experimental therapy for AML in combination with azacitidine </jats:sec

Phosphoproteomics Uncovers Synergy between DNA-PK and FLT3 Inhibitors in Acute Myeloid Leukaemia

*These authors contributed equally to this work Background:Acute Myeloid Leukaemia (AML) is the most common and aggressive form of acute leukaemia, with a 5-year survival rate of just 24%. Activating mutations in the receptor tyrosine kinase FLT3 are the most common driver mutations in AML (25-30% of patients). Inhibiting the FLT3 receptor as a mono-therapeutic strategy in AML has proven difficult however, due to the development of treatment resistance and relapse. In order to identify improved therapeutic targets, the oncogenic signalling pathways downstream of mutant FLT3 require characterisation. Methods:Quantitative, label-based phosphoproteomics was performed on primary blasts from 7 AML patients (4 mutant-FLT3, 3 wildtype-FLT3). Differentially phosphorylated pathways were identified using Ingenuity Pathway Analysis, and kinase activation was assessed by kinase substrate enrichment analysis. Validation of results was performed using targeted mass spectrometry. Proliferation, apoptosis, and cell cycle assays were used to assess drug toxicity; drug synergy was evaluated using Chou-Talalay and Webb analyses. Results:Analysis of differentially expressed phosphoproteins in mutant-FLT3 compared to wildtype-FLT3 AML patient blasts revealed dysregulation of DNA repair pathways. Specifically, mutant-FLT3 samples displayed increased phosphorylation of proteins within the error-prone Non-Homologous End Joining (NHEJ) repair pathway, indicating NHEJ pathway activation. Kinase enrichment analysis predicted increased activity of the NHEJ core kinase, DNA-dependent protein kinase (DNA-PK), in mutant-FLT3 samples. Accordingly, proliferation assays revealed that mutant-FLT3 cell lines were sensitive to inhibition of DNA-PK. FLT3-inhibitor treatment reduced DNA-PK phosphorylation in mutant-FLT3 cells, suggesting that activation of DNA-PK is downstream of FLT3 activation. Inhibition of DNA-PK kinase activity combined with FLT3 inhibitors led to synergistic induction of cell death, selectively in mutant-FLT3 cell lines. DNA-PK inhibitors combined with FLT3 inhibitors also co-operatively induced cell death in mutant-FLT3 primary AML patient samplesex vivo, and significantly prolonged survival compared to either monotherapy in a human AML xenograft mouse model. Conclusions:Mutant-FLT3 AML is associated with activation of the error-prone NHEJ repair pathway, which may contribute to genomic instability. Targeting the NHEJ kinase, DNA-PK, in combination with FLT3 inhibitors has the potential to improve outcomes for this poor-prognosis AML subtype. Disclosures Enjeti: Bayer:Speakers Bureau;AbbVie:Membership on an entity's Board of Directors or advisory committees;Alexion:Speakers Bureau;Novartis:Membership on an entity's Board of Directors or advisory committees;Astellas:Membership on an entity's Board of Directors or advisory committees;Sanofi:Speakers Bureau. </jats:sec

Efficacy of Ibrutinib, Rituximab and Mini-CHOP in Very Elderly Patients with Newly Diagnosed Diffuse Large B Cell Lymphoma: Primary Analysis of the Australasian Leukaemia & Lymphoma Group NHL29 Study

Introduction: R-mini-CHOP is an established standard of care in elderly patients with DLBCL, with a 2yr OS of 59% and PFS of 47% (Peyrade et al, Lancet Oncol 2011). The addition of ibrutinib to full dose R-CHOP in younger pts with DLBCL has efficacy, but significant toxicity limits the ability to complete therapy in pts ≥60 yrs (Younes et al, JCO 2019). We previously demonstrated the deliverability of ibrutinib with R-mini-CHOP in 80 pts ≥75yrs with DLBCL with a median average relative total dose of 97%; 77% of pts received 6 cycles of R-mini-CHOP despite SAEs in 62% (Verner et al, Haematol Oncol 2019). Here we present the primary efficacy endpoint and key secondary and exploratory endpoints. Methods: This was a prospective, multicenter, single-arm, phase 2 study of patients aged ≥75yrs with newly diagnosed DLBCL. Pts received six 21-day cycles of ibrutinib 560mg/d and R-mini-CHOP (Rituximab 375mg/m 2, cyclophosphamide 400mg/m 2, doxorubicin 25mg/m 2, vincristine 1mg on day 1 & prednisone 40mg/m 2 or 100mg/d x 5) followed by an additional two 21-day cycles of rituximab + ibrutinib (or high dose methotrexate for CNS prophylaxis). The efficacy primary endpoint was 2yr OS. Sample size calculations were made using a one-sample two-sided approach to detect a 15% improvement on the fixed reference OS (59%) and PFS (47%) rates (Peyrade et al, Lancet Oncol 2011). Results: Eighty pts were recruited from Nov 2015 to Dec 2018. One died prior to receiving treatment and is not included in the analysis. Median age was 82yrs (75-95); 51% female, 81% stage III/IV and 63% IPI 3-5: 47% had a CIRS-G score of ≥6 (range 0-17). On centralized immunohistochemistry (IHC), 57% (45/79) were non-Germinal Centre B cell-like (GCB) subtype; 43% (34/79) were GCB. At a data cut-off of 6June 21, median follow-up was 29.5 months (m) (0.2 to 66.3). Two-year OS was 68% (95% CI 55-77%), not differing significantly from the null hypothesis of 59% (p=0.10), (Figure 1A). Median OS was not reached (NR) (95% CI 34m to NR), and was longer in those with lower IPI (IPI 1-3: NR, IPI 4: 35m, IPI 5: 19m). Two-year PFS was 60% (95% CI 47-70%), significantly different from the reference 47% (p<0.03), (Figure 1B). Median PFS was NR (95% CI 20m to NR). Two-year DFS was 85% (95% CI 60-95%), median NR (95% CI 32m to NR). COO had no impact on either 2yr OS [median GCB NR (95% CI 29m to NR), median non-GCB NR (95% CI 24m to NR) p=0.99] or 2yr PFS [median GCB 39m (95% CI 17m to NR), median non-GCB NR (95% CI 19m to NR) p=0.97]. Cause of death in 28/79 pts (35%) was: 16 progressive lymphoma, 5 infection, 2 respiratory failure, 2 other malignancy, 1 cardiac arrest, 1 intra-abdominal hemorrhage, 1 gastric hemorrhage. At least one adverse event (AE) occurred in 99% pts (78/79): 30% (24/79) grade 1-2, 64% (49/79) grade 3-4, and 6% (5/79) grade 5. Most common grade ≥3 AEs were lung infection (13%), other infections (11%), anemia (11%), febrile neutropenia (9%), thrombocytopenia (9%), and atrial fibrillation (8%). Serious AEs occurred in 67%: most commonly lung infection (11%), atrial fibrillation (9%), fever (9%), and other infection (9%). 12/14 pts with atrial fibrillation/flutter were new onset. Ibrutinib was temporarily ceased in 62% of patients, and permanently ceased in 25%, mostly due to adverse events. As previously reported, the overall response rate on an intention to treat basis was 57/80 (71%) (Verner et al, ASH 2019). Response rates did not differ by cell of origin (COO) (ORR: non-GCB 76%, GCB 68% p=0.44). When recorded, pt's EORTC-QLQ-C30 global health status significantly improved between screening [n=78; mean (SD) 58(25)], end of treatment [n=57; 63(23)] and 18mo post-treatment [n=29; 74(19)] p=0.007. Significant reductions in fatigue, nausea and vomiting, pain, insomnia, appetite loss, constipation and diarrhea were also observed in respondents. There was no impact of CIRS-G score on disease response rate or risk of death. Conclusion: The addition of ibrutinib to R-mini-CHOP was deliverable and improved 2-yr PFS compared to R-mini-CHOP alone. However, while there was a trend towards improvement in 2-yr OS, a target 15% increase was not achieved in this small sample size. Despite considerable and not unexpected toxicity in this elderly cohort, the QOL and functional improvements in survivors are also promising. These data support further study of the addition of ibrutinib to R-mini-CHOP in elderly patients with DLBCL.No Full Tex

The Impact of Sorafenib on Phospho-FLT3 Inhibition and <i>FLT3</i>-ITD MRD after Chemotherapy: Correlative Studies from the Phase 2 Randomized Study of Sorafenib Versus Placebo in Combination with Intensive Chemotherapy in Previously Untreated Patients with <i>FLT3</i>-ITD Acute Myeloid Leukemia (ALLG AMLM16)

Introduction The Australasian Leukaemia and Lymphoma Group (ALLG) conducted a randomized trial (AMLM16) combining the FLT3 inhibitor sorafenib (SOR) or placebo (PBO) with intensive induction and consolidation chemotherapy, followed by 12 months of maintenance therapy in patients with FLT3-ITD mutant AML. The clinical results of the AMLM16 study are detailed in a companion abstract co-submitted to ASH 2020. We hypothesized that the optimal time to administer sorafenib would be d4-10 of induction in order to limit overlap with anthracyclines on d1-3 and to avoid high FLT3 ligand (FLT3L) levels beyond d10, which could abrogate FLT3 on-target activity and diminish the therapeutic index. Key objectives of the correlative studies were to correlate in vivo SOR activity on suppression of FLT3 phosphorylation (P-FLT3) using the plasma inhibitory assay (PIA) with relapse risk and to assess for the presence of FLT3-ITD measurable residual disease (MRD) after therapy. Methods Patients aged 18-65 years with newly diagnosed AML (excluding APML) were enrolled to a National Blood Cancer Registry; those with a FLT3-ITD mutant: wild-type allelic ratio (AR) ≥ 0.05 were eligible for enrolment to the AMLM16 study. Patients were randomized 2:1 to SOR or PBO 400mg orally bd on d4-10 of induction and each consolidation cycle in combination with intensive chemotherapy and for 12 months as maintenance monotherapy. Serum FLT3-L levels were measured by ELISA, SOR and its metabolites by mass spectrometry. SOR mediated inhibition of FLT3 was measured in serum samples using the PIA as previously described (Levis, Blood 2006) in which P-FLT3 inhibition to ≤15% baseline is defined as response. Quantitation of FLT3-ITD levels by NGS was performed at study screening and after each induction and consolidation chemotherapy cycle. Quantitation was by amplicon-based sequencing which detected ITDs &amp;gt;6 bp with a sensitivity of 0.001%: levels below and above this were termed measurable residual disease (MRD) negative and positive respectively. Prepared libraries were sequenced (Illumina) using 150 bp paired-end reads with a minimum coverage of 400,000 reads. Bioinformatics analysis was performed using getITD (Blätte, Leukemia, 2019). Results 98 evaluable patients were randomized to induction with either SOR (n=65) or PBO (n=33) with a FLT3-ITD AR ranging from 0.05 to 8.4. FLT3-ITD AR was ≥ 0.5 or ≥ 0.7 in 48% and 29%, respectively. During induction, FLT3-L levels increased by an average of 150-fold from d4 to d10 and a further 1.6-fold to d15, with a return to baseline by d28. Serial plasma samples to assess PIA were available for 63 patients (Fig A). Response to ≤15% on d10 (relative to d4) was observed in 88% of SOR patients, compared with 4.5% receiving PBO. The relapse risk was 32% and 62% among PIA responders and non-responders, respectively (Fig A). Among patients with PIA response to ≤15% by d10 (the last day of SOR/PBO), only 8.3% had evidence of a sustained PIA response by d15. Reduction of FLT3-ITD to undetectable levels (VAF &amp;lt;0.001%) after induction, consolidation 1 and 2 was achieved in 43%, 63% and 77% of patients in the SOR arm and 32%, 59% and 75% in the PBO arm, respectively (Fig B, C). Patients with FLT3-ITD MRD detected or not detected after induction had a relapse risk of 54% vs 32%, respectively. Additional MRD results will be presented, along with serum SOR and metabolite levels. We compared the relationship between inhibition of P-FLT3 on d10 and bone marrow FLT3-ITD MRD after induction with relapse risk (Fig D, E). In the SOR arm, if P-FLT3 was not reduced to ≤15%, all patients had persistent FLT3-ITD MRD after induction and the relapse risk was 80% (Fig D). In contrast, if P-FLT3 inhibition was ≤15% and FLT3-ITD MRD not detected, the relapse risk was only 20%. In the PBO arm after induction, persistent and undetectable FLT3-ITD MRD (VAF &amp;lt;0.001%) were associated with relapse risks of 81% vs 50%, respectively (Fig E). Conclusions These studies demonstrate that in vivo SOR inhibited P-FLT3 to ≤15% during induction in the majority of cases and was associated with reduced relapse risk. Persistent FLT3-ITD MRD post-induction was associated with a high relapse risk in both treatment arms. For patients receiving SOR, failure to reduce P-FLT3 response to ≤15% was associated with a high risk of persistent FLT3-ITD MRD and clinical relapse. Disclosures Anstee: Walter and Eliza Hall Institute: Patents &amp; Royalties: milestone and royalty payments related to venetoclax.. Levis:Menarini: Honoraria; Amgen: Honoraria; FujiFilm: Honoraria, Research Funding; Daiichi-Sankyo: Honoraria; Astellas: Honoraria, Research Funding. Enjeti:Novartis: Membership on an entity's Board of Directors or advisory committees; Astellas: Membership on an entity's Board of Directors or advisory committees; Alexion: Speakers Bureau; AbbVie: Membership on an entity's Board of Directors or advisory committees; Bayer: Speakers Bureau; Sanofi: Speakers Bureau. D'Rozario:Abbvie: Membership on an entity's Board of Directors or advisory committees; BMS/ Celgene: Membership on an entity's Board of Directors or advisory committees. Marlton:AbbVie: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; F. Hoffmann-La Roche Ltd: Membership on an entity's Board of Directors or advisory committees; Astra-Zeneca: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Astellas: Membership on an entity's Board of Directors or advisory committees. Roberts:Janssen: Research Funding; Servier: Research Funding; AbbVie: Research Funding; Genentech: Patents &amp; Royalties: for venetoclax to one of my employers (Walter &amp; Eliza Hall Institute); I receive a share of these royalties. Wei:Astra Zeneca: Honoraria, Research Funding; Novartis: Honoraria, Research Funding, Speakers Bureau; Abbvie: Honoraria, Research Funding, Speakers Bureau; Walter and Eliza Hall Institute of Medical Research: Patents &amp; Royalties: AW is eligible for royalty payments related to venetoclax; Roche: Honoraria; Macrogenics: Honoraria; Servier: Consultancy, Honoraria, Research Funding; Amgen: Honoraria, Research Funding; Pfizer: Honoraria; Bristol Myers Squibb: Honoraria, Research Funding, Speakers Bureau; Janssen: Honoraria. OffLabel Disclosure: Sorafenib for FLT3-ITD AML </jats:sec

Efficacy of Ibrutinib, Rituximab and Mini-CHOP in Very Elderly Patients with Newly Diagnosed Diffuse Large B Cell Lymphoma: Primary Analysis of the Australasian Leukaemia &amp; Lymphoma Group NHL29 Study

Abstract Introduction R-mini-CHOP is an established standard of care in elderly patients with DLBCL, with a 2yr OS of 59% and PFS of 47% (Peyrade et al, Lancet Oncol 2011). The addition of ibrutinib to full dose R-CHOP in younger pts with DLBCL has efficacy, but significant toxicity limits the ability to complete therapy in pts ≥60 yrs (Younes et al, JCO 2019). We previously demonstrated the deliverability of ibrutinib with R-mini-CHOP in 80 pts ≥75yrs with DLBCL with a median average relative total dose of 97%; 77% of pts received 6 cycles of R-mini-CHOP despite SAEs in 62% (Verner et al, Haematol Oncol 2019). Here we present the primary efficacy endpoint and key secondary and exploratory endpoints. Methods This was a prospective, multicenter, single-arm, phase 2 study of patients aged ≥75yrs with newly diagnosed DLBCL. Pts received six 21-day cycles of ibrutinib 560mg/d and R-mini-CHOP (Rituximab 375mg/m 2, cyclophosphamide 400mg/m 2, doxorubicin 25mg/m 2, vincristine 1mg on day 1 &amp; prednisone 40mg/m 2 or 100mg/d x 5) followed by an additional two 21-day cycles of rituximab + ibrutinib (or high dose methotrexate for CNS prophylaxis). The efficacy primary endpoint was 2yr OS. Sample size calculations were made using a one-sample two-sided approach to detect a 15% improvement on the fixed reference OS (59%) and PFS (47%) rates (Peyrade et al, Lancet Oncol 2011). Results Eighty pts were recruited from Nov 2015 to Dec 2018. One died prior to receiving treatment and is not included in the analysis. Median age was 82yrs (75-95); 51% female, 81% stage III/IV and 63% IPI 3-5: 47% had a CIRS-G score of ≥6 (range 0-17). On centralized immunohistochemistry (IHC), 57% (45/79) were non-Germinal Centre B cell-like (GCB) subtype; 43% (34/79) were GCB. At a data cut-off of 6June 21, median follow-up was 29.5 months (m) (0.2 to 66.3). Two-year OS was 68% (95% CI 55-77%), not differing significantly from the null hypothesis of 59% (p=0.10), (Figure 1A). Median OS was not reached (NR) (95% CI 34m to NR), and was longer in those with lower IPI (IPI 1-3: NR, IPI 4: 35m, IPI 5: 19m). Two-year PFS was 60% (95% CI 47-70%), significantly different from the reference 47% (p&amp;lt;0.03), (Figure 1B). Median PFS was NR (95% CI 20m to NR). Two-year DFS was 85% (95% CI 60-95%), median NR (95% CI 32m to NR). COO had no impact on either 2yr OS [median GCB NR (95% CI 29m to NR), median non-GCB NR (95% CI 24m to NR) p=0.99] or 2yr PFS [median GCB 39m (95% CI 17m to NR), median non-GCB NR (95% CI 19m to NR) p=0.97]. Cause of death in 28/79 pts (35%) was: 16 progressive lymphoma, 5 infection, 2 respiratory failure, 2 other malignancy, 1 cardiac arrest, 1 intra-abdominal hemorrhage, 1 gastric hemorrhage. At least one adverse event (AE) occurred in 99% pts (78/79): 30% (24/79) grade 1-2, 64% (49/79) grade 3-4, and 6% (5/79) grade 5. Most common grade ≥3 AEs were lung infection (13%), other infections (11%), anemia (11%), febrile neutropenia (9%), thrombocytopenia (9%), and atrial fibrillation (8%). Serious AEs occurred in 67%: most commonly lung infection (11%), atrial fibrillation (9%), fever (9%), and other infection (9%). 12/14 pts with atrial fibrillation/flutter were new onset. Ibrutinib was temporarily ceased in 62% of patients, and permanently ceased in 25%, mostly due to adverse events. As previously reported, the overall response rate on an intention to treat basis was 57/80 (71%) (Verner et al, ASH 2019). Response rates did not differ by cell of origin (COO) (ORR: non-GCB 76%, GCB 68% p=0.44). When recorded, pt's EORTC-QLQ-C30 global health status significantly improved between screening [n=78; mean (SD) 58(25)], end of treatment [n=57; 63(23)] and 18mo post-treatment [n=29; 74(19)] p=0.007. Significant reductions in fatigue, nausea and vomiting, pain, insomnia, appetite loss, constipation and diarrhea were also observed in respondents. There was no impact of CIRS-G score on disease response rate or risk of death. Conclusion The addition of ibrutinib to R-mini-CHOP was deliverable and improved 2-yr PFS compared to R-mini-CHOP alone. However, while there was a trend towards improvement in 2-yr OS, a target 15% increase was not achieved in this small sample size. Despite considerable and not unexpected toxicity in this elderly cohort, the QOL and functional improvements in survivors are also promising. These data support further study of the addition of ibrutinib to R-mini-CHOP in elderly patients with DLBCL. Figure 1 Figure 1. Disclosures Verner: Janssen-Cilag Pty Ltd: Research Funding. Hawkes: Merck KgA: Research Funding; Bristol Myers Squib/Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Specialised Therapeutics: Consultancy; Antigene: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Janssen: Speakers Bureau; Gilead: Membership on an entity's Board of Directors or advisory committees; Regeneron: Speakers Bureau; Merck Sharpe Dohme: Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees, Other: Travel and accommodation expenses, Research Funding, Speakers Bureau; Astra Zeneca: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Lee: Roche: Honoraria; BeiGene: Membership on an entity's Board of Directors or advisory committees. Cheah: BMS: Consultancy, Research Funding; Abbvie: Research Funding; Janssen: Consultancy, Honoraria; MSD: Consultancy, Honoraria; Gilead: Consultancy, Honoraria; Ascentage Pharma: Consultancy, Honoraria; AstraZeneca: Consultancy, Honoraria; Lilly: Consultancy, Honoraria; TG therapeutics: Consultancy, Honoraria; Beigene: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Roche: Consultancy, Honoraria, Other: travel, Research Funding. Purtill: Novartis: Honoraria; Gilead: Honoraria; BMS Celgene: Honoraria. Enjeti: Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Roche: Speakers Bureau; AbbVie: Honoraria; Sanofi: Honoraria; Astra Zeneca: Honoraria. Curnow: Bayer: Consultancy, Research Funding; Pfizer/BMS: Consultancy, Honoraria; Mylan: Consultancy; Norgine: Consultancy, Honoraria. Butcher: WriteSource: Current Employment, Other: Medical writing for Pharma companies. Not pertinent to this abstract for which author is study Statisticiam. Trotman: JANSSEN: Research Funding; TAKEDA: Research Funding; BMS: Research Funding; PCYC: Research Funding; roche: Research Funding; beigene: Research Funding. OffLabel Disclosure: Ibrutinib is not approved for use in DLBCL </jats:sec

An Australasian Leukemia Lymphoma Group (ALLG) Phase 2 Study to Investigate Novel Triplets to Extend Remission with Venetoclax in Elderly (INTERVENE) Acute Myeloid Leukemia

Abstract Background: Adaptive resistance mechanisms leading to treatment failure have been identified in older patients receiving venetoclax (VEN) in combination with either azacitidine or low dose cytarabine (LDAC) as frontline therapy for acute myeloid leukemia (AML). These include the expansion or secondary emergence of kinase activating mutations, including FLT3-ITD in patients with non-adverse karyotype (NON-ADV), as well as TP53 mutations among patients with adverse karyotype (ADV)(DiNardo &amp; Tiong et al, Blood 2020). INTERVENE is a phase 2 study evaluating the safety and efficacy of the "risk-stratified" addition of a novel third agent to VEN-LDAC, delivered in tandem to LDAC to minimize the risk of myelotoxicity (Figure 1A). To mitigate VEN resistance associated with activated kinases in NON-ADV risk AML, midostaurin (MIDO), a FLT3/multi-kinase inhibitor, was incorporated in combination with VEN. To address VEN resistance associated with TP53 defects in ADV risk AML, a HDAC inhibitor pracinostat (PRAN) was incorporated in accordance with pre-clinical studies suggesting synergistic induction of TP53 independent cell death with VEN plus HDAC inhibition (Salmon et al, ASH 2018). We hereby report the results of the dose-finding safety run-in phase of the study. Methods: Eligibility: Patients with treatment naïve AML (excluding APL), aged ≥60 years and unfit for intensive chemotherapy were included. Prior hypomethylating agents for antecedent myeloid neoplasms were permitted with a 14-day washout. Patients were stratified according to cytogenetic risk, as per Medical Research Council 2010 criteria. Treatment: VEN D1-28 (with dose ramp-up in cycle 1) was combined with LDAC (20mg/m 2 SC D1-10), with the third agent starting after/on the last day of LDAC (Fig 1A). Each cycle was 28 days. In the NON-ADV stratum (VEN-LDAC-MIDO), 2 dose levels were explored: (L1) VEN 400mg + LDAC + MIDO 50mg BD D11-28; (L2) VEN 600mg + LDAC + MIDO 50mg. In the ADV stratum (VEN-LDAC-PRAN), 3 dose levels were tested: (L1) VEN 400mg + LDAC + PRAN 45mg starting D10 and given 3x/week orally for a total of 9 doses; (L2) VEN 600mg + LDAC + PRAN 45mg; (L3) VEN 600mg + LDAC + PRAN 60mg. Azole antifungals were prohibited in cycle 1 but allowed from cycle 2 with VEN dose modification. Endpoints (safety run-in): Primary: occurrence of dose-limiting toxicities (DLT) during cycle 1 and determination of recommended phase 2 doses (RP2D) using a Bayesian Logistic Regression Model. Secondary: Preliminary response rates. Molecular studies: Next generation sequencing using a custom 48-gene Roche KAPA HyperCapture myeloid panel and FLT3-ITD targeted amplicon sequencing were performed on baseline bone marrow samples. First patient enrolled: 7SEP2020. Data cut-off: 29JUN2021. Results: 32 patients were enrolled: 18 in NON-ADV and 14 in ADV strata, respectively. Two patients in the NON-ADV stratum withdrew within the first 7 days due to non-therapy related reasons (1=personal, 1=incidental lung lesion) and were not DLT/response evaluable. Median age was 77 years (68-87; 69% ≥75 years). 43.8% (14/32) had secondary/therapy related AML. Although gastrointestinal adverse events (AE) during cycle 1 were more common in VEN-LDAC-PRAN arm with nausea (57 vs 17%), vomiting (36% vs 6%) and diarrhea (50% vs 22%), grade 3+ toxicities were uncommon (0-7%)(Table 2). Occurrence of febrile neutropenia was similar between the two arms. 30-day mortality was 0% and 14% (2/14: 1=infection, 1=disease progression) for NON-ADV and ADV strata, respectively. No DLTs were observed in either stratum across all dose levels, thus the RP2D was the highest dose level explored for both triplet combinations. The intention-to-treat overall response rate CR+CRi+CRh was 72.2% (13/18) in the NON-ADV arm and 57.1% (8/14) in ADV arm. The expanded response rate including PR and MLFS was 77.8% (14/18) and 71.4% (10/14) in the NON-ADV and ADV strata, respectively. Median time to best response was 1 cycle (range 1-6). Updated response and survival outcomes will be presented at the meeting. Conclusion: The addition of MIDO or PRAN to VEN-LDAC was tolerable in older/unfit patients with treatment naïve AML. Preliminary efficacy with this risk-stratified approach compared favorably to prior studies with VEN-LDAC alone (Wei et al Blood 2020: CR+CRi 56% in NON-ADV, 28% in ADV). The randomized phase 2 part of this tandem triplet strategy with the goal of preventing adaptive resistance is underway. Figure 1 Figure 1. Disclosures Chua: Abbvie: Other: Conference travel and accommodation . Reynolds: Alcon: Current equity holder in publicly-traded company; Abbvie: Research Funding; Novartis AG: Current equity holder in publicly-traded company. Enjeti: Astra Zeneca: Honoraria; Sanofi: Honoraria; AbbVie: Honoraria; Roche: Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Hiwase: AbbVie: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees. Marlton: Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; AstraZeneca: Honoraria, Membership on an entity's Board of Directors or advisory committees; Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees; F. Hoffmann-La Roche Ltd: Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; AbbVie: Honoraria, Membership on an entity's Board of Directors or advisory committees; Astellas: Honoraria, Membership on an entity's Board of Directors or advisory committees; Queensland Health: Current Employment; BeiGene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Jazz: Honoraria, Membership on an entity's Board of Directors or advisory committees. Bajel: Abbvie, Amgen, Novartis, Pfizer: Honoraria; Amgen: Speakers Bureau. Grove: Astellas: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Abbvie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Cooney: Amgen: Other: Travel, accommodation, expenses ; Roche: Other: Travel, accommodation, expenses ; Novartis: Other: Online conference registration . Beligaswatte: Astellas: Membership on an entity's Board of Directors or advisory committees. Anstee: Walter and Eliza Hall Institute: Patents &amp; Royalties: Dr Anstee was a former employee of the Walter and Eliza Hall Institute and is eligible for a fraction of the royalty stream related to Venetoclax. Perera: Abbvie: Speakers Bureau; BMS: Speakers Bureau. Ritchie: Takeda: Research Funding; BMS: Research Funding; Novartis: Honoraria; CRISPR Therapeutics: Research Funding; Amgen Inc: Honoraria, Research Funding; CSL: Honoraria. Wei: Genentech: Membership on an entity's Board of Directors or advisory committees; Agios: Membership on an entity's Board of Directors or advisory committees; Celgene/BMS: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees; Macrogenics: Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees; Servier: Membership on an entity's Board of Directors or advisory committees, Research Funding; Astellas: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees; Astra Zeneca: Membership on an entity's Board of Directors or advisory committees, Research Funding; Pfizer: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Abbvie: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. OffLabel Disclosure: This presentation will focus on the ALLG INTERVENE clinical trial combining venetoclax+LDAC+midostaurin or venetoclax+LDAC+pracinostat. Although venetoclax and midostaurin are individually FDA-approved in some indications, the combinations examined in this clinical trial have not been approved by FDA. </jats:sec