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Patients with refractory or relapsed acute myeloid leukemia (R/R AML) have a poor prognosis, with a high unmet medical need. Idasanutlin is a small-molecule inhibitor of MDM2, a negative regulator of tumor suppressor p53. By preventing the p53–MDM2 interaction, idasanutlin allows for p53 activation, particularly in patients with TP53 wild-type (WT) status. MIRROS (NCT02545283) is a randomized Phase III trial evaluating idasanutlin + cytarabine versus placebo + cytarabine in R/R AML. The primary end point is overall survival in the TP53-WT population. Secondary end points include complete remission rate (cycle 1), overall remission rate (cycle 1) and event-free survival in the TP53-WT population. MIRROS has an innovative design that integrates a stringent interim analysis for futility; continuation criteria were met in mid-2017 and accrual is ongoing. Trial registration number: NCT02545283

The prognosis remains poor for patients with relapsed or refractory (r/r) acute myeloid leukemia; thus, novel therapies are needed. We evaluated idasanutlin-a new, potent murine double minute 2 antagonist-alone or with cytarabine in patients with r/r acute myeloid leukemia, de novo untreated acute myeloid leukemia unsuitable for standard treatment or with adverse features, or secondary acute myeloid leukemia in a multicenter, open-label, phase 1/1b trial. Primary objectives were to determine the maximum tolerated dose (MTD) and recommended dose for expansion (RDE) and characterize the safety profile of idasanutlin monotherapy and combination therapy. Clinical activity and pharmacokinetics were secondary objectives. Two idasanutlin formulations were investigated: a microprecipitate bulk powder (MBP) and optimized spray-dried powder (SDP). Following dose escalation, patients (N = 122) received idasanutlin at the RDE in the extension cohorts. No formal MTD was identified. Idasanutlin was tolerable alone and in combination with cytarabine. The RDE was determined as 600 mg twice a day for the MBP formulation and 300 mg twice a day for the SDP formulation. Adverse events were mostly grade 1/2 (76.2 %). The most common any-grade adverse events were gastrointestinal (including diarrhea [90.2 %]). The early death rate across all patients was 14.8 %. Plasma idasanutlin exposure was dose related. In TP53 wild-type patients, composite complete remission rates were 18.9 % with monotherapy and 35.6 % with combination therapy. Based on these results, idasanutlin development continued with further investigation in the treatment of acute myeloid leukemia. ClinicalTrials.gov: NCT01773408.

Background Follicular lymphoma (FL) and diffuse large B-cell lymphoma (DLBCL) are the most common indolent and aggressive B-cell lymphomas, respectively. Although the combination of anti-CD20 therapies rituximab (R) or obinutuzumab (G) with chemotherapy has led to improved patient (pt) outcomes, R/R disease remains a challenge, with a high unmet need. The potent and selective MDM2 antagonist idasanutlin (idasa) activates the p53 pathway, leading to anti-tumor activity. The BCL-2 inhibitor venetoclax (ven) has shown clinical activity in hematologic diseases including R/R NHL. In a Phase Ib/II study (NCT02624986), idasa could be safely combined in a doublet treatment (tx) regimen with R or G in R/R FL or DLBCL pts. Here we report the tolerability, safety and preliminary efficacy of the triplet tx regimen of idasa plus ven and G in R/R NHL pts. Methods BH39147 (NCT03135262) was an open-label, multicenter, non-randomized, Phase Ib/II study with a dose-escalation phase followed by an expansion phase. The dose-escalation phase evaluated idasa and ven combined with G in all pts (FL and DLBCL) until the maximum tolerated dose (MTD) was reached. Idasa and ven dose escalations started at 100 and 200 mg PO QD, respectively, on days 1-5 of each 28-day cycle (safety cohort); in subsequent cohorts, ven was given on days 1-10 of each cycle. G was given at a fixed dose of 1000 mg IV on days 1, 8 and 15 of cycle 1 and day 1 of subsequent cycles. Pts received 6 cycles of induction tx. The primary objective of the dose-escalation phase was to determine recommended Phase II doses for idasa and ven in combination with G. Efficacy objectives included evaluating the complete response (CR) rate at the end of induction (EOI) per investigator based on PET-CT. The trial was stopped prior to initiation of the expansion phase; results are presented for the dose-escalation cohorts evaluating idasa plus ven and G. Results Of the 29 pts enrolled, 14 each had a diagnosis of FL or DLBCL at study entry, and 1 had an unknown diagnosis at study entry that was later confirmed as FL. The median age was 70 y (range, 25-82), 58.6% of pts were male, and 67.9% had an ECOG PS of 1 or 2. The majority of pts had advanced-stage disease at enrollment, with 58.6% having received ≥ 3 lines of prior anti-lymphoma therapy; 17.2% and 24.1% of pts had received 1 and 2 prior lines of tx, respectively. Median (range) tx durations during induction were 1.3 mo (0-6) for idasa, 1.5 mo (0-7) for ven and 1.5 mo (0-6) for G; post-induction median (range) tx durations (n = 4) were 3.8 mo (0-4), 3.8 mo (0-4) and 8.4 mo (0-11), respectively. The safety-evaluable population was composed of 29 pts. Grade 3/4 adverse events (AEs) occurred in 86.2% of pts, with neutropenia (79.3%), thrombocytopenia (62.1%), leukopenia (27.6%) and anemia (20.7%) as the most common. No Grade 5 AEs were reported. Serious AEs occurred in 48.3% of pts and were most commonly neutropenia (10.3%). AEs led to treatment discontinuation in 41.4% of pts, with thrombocytopenia (17.2%) and neutropenia (13.8%) being the most common. AEs related to idasa, ven and G were reported in 86.2%, 89.7% and 79.3% of pts, respectively. Dose-limiting toxicities were reported in 4 pts (13.8%): neutropenia (n = 3; 10.3%), hyperbilirubinemia (n = 1; 3.4%) and transaminitis (n = 1; 3.4%). The MTD for idasa was determined to be 150 mg in combination with 200-mg ven and G and 100 mg in combination with 400-mg ven and G. Preliminary efficacy data are shown in the table. Among all pts, 20.7% (FL, n = 5; DLBCL, n = 1) had a CR at EOI per investigator (PET-CT) based on modified Lugano 2014 criteria. Per investigator based on Lugano 2014 criteria, the CR rate at EOI (CT) was 13.8% (FL, n = 3; DLBCL, n = 1), and the complete metabolic response rate at EOI (PET-CT) was 24.1% (FL, n = 6; DLBCL, n = 1). Conclusions This study successfully showed the combinability of idasa and ven with an anti-CD20 agent. MTDs were determined for idasa and ven in combination with G in FL and DLBCL pts. No new safety signals related to any of the study drugs were identified, and the observed safety profiles were consistent with those of each individual study drug. While the combination is feasible and promising, other agents and approaches in the field make this combination less likely to proceed further. As a consequence, this trial has been discontinued following the dose-escalation/proof-of-concept phase to focus on new tx combinations. Figure Disclosures Kamdar: Roche:Research Funding.Augustson:Roche:Other: Support of parent study and funding of editorial support.Edwards:Roche:Other: Support of parent study and funding of editorial support.Hertzberg:Roche:Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Support of parent study and funding of editorial support;Gilead:Membership on an entity's Board of Directors or advisory committees;MSD:Membership on an entity's Board of Directors or advisory committees;Abbvie:Honoraria;BMS:Honoraria;Takeda:Honoraria, Membership on an entity's Board of Directors or advisory committees;Janssen:Honoraria, Membership on an entity's Board of Directors or advisory committees.Johnston:Roche:Other: Support of parent study and funding of editorial support.Kim:Alexion Pharmaceuticals Inc.:Honoraria, Research Funding.Kroschinsky:Riemsser:Research Funding;Roche:Consultancy, Honoraria, Other: Support of parent study and funding of editorial support;BMS/Celgene:Consultancy, Honoraria;Sandoz:Research Funding;Gilead:Consultancy.Smith:TG Therapeutics:Consultancy, Research Funding;Genentech/Roche:Consultancy, Other: Support of parent study and funding of editorial support, Research Funding;BMS:Consultancy;Karyopharm:Consultancy, Research Funding;FortySeven:Research Funding;Pharmacyclics:Research Funding;Acerta:Research Funding;Janssen:Consultancy;Celgene:Consultancy, Research Funding.Stevens:Amgen, MorphoSys:Consultancy.Monnet:Roche:Current Employment, Other: Support of parent study and funding of editorial support.Zhao:Roche:Current Employment, Other: Support of parent study and funding of editorial support.Nouet:Roche:Current Employment, Other: Support of parent study and funding of editorial support.Marinova:Roche:Current Employment, Other: Support of parent study and funding of editorial support.

For a trial with primary endpoint overall survival for a molecule with curative potential, statistical methods that rely on the proportional hazards assumption may underestimate the power and the time to final analysis. We show how a cure proportion model can be used to get the necessary number of events and appropriate timing via simulation. If Phase 1 results for the new drug are exceptional and/or the medical need in the target population is high, a Phase 3 trial might be initiated after Phase 1. Building in a futility interim analysis into such a pivotal trial may mitigate the uncertainty of moving directly to Phase 3. However, if cure is possible, overall survival might not be mature enough at the interim to support a futility decision. We propose to base this decision on an intermediate endpoint that is sufficiently associated with survival. Planning for such an interim can be interpreted as making a randomized Phase 2 trial a part of the pivotal trial: if stopped at the interim, the trial data would be analyzed and a decision on a subsequent Phase 3 trial would be made. If the trial continues at the interim then the Phase 3 trial is already underway. To select a futility boundary, a mechanistic simulation model that connects the intermediate endpoint and survival is proposed. We illustrate how this approach was used to design a pivotal randomized trial in acute myeloid leukemia, discuss historical data that informed the simulation model, and operational challenges when implementing it., Comment: 23 pages, 3 figures, 3 tables. All code is available on github: https://github.com/numbersman77/integratePhase2.git

Purpose Crizotinib confers improved progression-free survival compared with chemotherapy in anaplastic lymphoma kinase (ALK)-rearranged non–small-cell lung cancer (NSCLC), but progression invariably occurs. We investigated the efficacy and safety of alectinib, a potent and selective ALK inhibitor with excellent CNS penetration, in patients with crizotinib-refractory ALK-positive NSCLC. Patients and Methods Alectinib 600 mg was administered orally twice daily. The primary end point was objective response rate (ORR) by central independent review committee (IRC). Results Of the 138 patients treated, 84 patients (61%) had CNS metastases at baseline, and 122 were response evaluable (RE) by IRC. ORR by IRC was 50% (95% CI, 41% to 59%), and the median duration of response (DOR) was 11.2 months (95% CI, 9.6 months to not reached). In 96 patients (79%) previously treated with chemotherapy, the ORR was 45% (95% CI, 35% to 55%). Median IRC-assessed progression-free survival for all 138 patients was 8.9 months (95% CI, 5.6 to 11.3 months). CNS disease control rate was 83% (95% CI, 74% to 91%), and the median CNS DOR was 10.3 months (95% CI, 7.6 to 11.2 months). CNS ORR in 35 patients with baseline measurable CNS lesions was 57% (95% CI, 39% to 74%). Of the 23 patients with baseline CNS metastases (measurable or nonmeasurable) and no prior radiation, 10 (43%) had a complete CNS response. At 12 months, the cumulative CNS progression rate (24.8%) was lower than the cumulative non-CNS progression rate (33.2%) for all patients. Common adverse events were constipation (33%), fatigue (26%), and peripheral edema (25%); most were grade 1 to 2. Conclusion Alectinib is highly active and well tolerated in patients with advanced, crizotinib-refractory ALK-positive NSCLC, including those with CNS metastases.

TPS7063 Background: The prognosis for patients (pts) with relapsed or refractory (R/R) acute myeloid leukemia (AML) is poor, with 3-year overall survival rates ~10–30% after intensive chemotherapy-based approaches. Despite the advent of targeted therapies, considerable unmet medical need remains in this population. Idasanutlin (RG7388; RO5503781) is an orally available small molecule that binds to the murine double minute 2 (MDM2) protein and blocks MDM2 interaction with p53. This stabilizes and activates p53 and facilitates cell cycle arrest and apoptosis, preventing tumor growth. A phase 1b study of idasanutlin + ARA-C in pts with R/R AML, irrespective of TP53 mutation status (NCT01773408), has shown a composite complete remission (CR) rate (CR plus CR with incomplete platelet or hematologic recovery) of 29% (Martinelli et al. 2016). Methods: MIRROS (NCT02545283; WO29519) is an international, phase 3, double-blind, randomized study comparing idasanutlin (300 mg bid) + ARA-C (1 g/m2 qd) days 1–5 versus placebo + ARA-C in 440 pts with first or second R/R AML, with or without TP53 mutation. The primary endpoint is overall survival in pts with wild-type (WT) TP53. Secondary endpoints include CR, overall remission rates, event-free survival (EFS) and percentages of pts undergoing hematopoietic stem cell transplantation. MIRROS integrates phase 2 trial methodology into the phase 3 design by incorporating an interim analysis (IA) in 120 pts with WT TP53, using a high bar on the odds ratio for durable CR and EFS to assess for futility. Stop/go gating criteria for safety were also implemented. The IA was performed by an independent data monitoring committee and study continuation criteria were successfully met in mid-2017. This innovative strategy has allowed acceleration of the idasanutlin development program while maintaining a robust trial design. As of December 31 2018, 351 pts had been enrolled. The MIRROS study is ongoing and its results will inform the potential role of idasanutlin and MDM2 inhibition in the treatment of R/R AML. Clinical trial information: NCT02545283; WO29519.