Pegourié, Brigitte

Abstract Background: The anti-apoptotic protein BCL-2 has been implicated in mediating the survival of multiple myeloma (MM) cells. Venetoclax is a potent, selective, orally bioavailable small-molecule BCL-2 inhibitor. Venetoclax induces cell death in MM cell lines in vitro and primary MM samples ex vivo. Certain genetic subtypes of MM cells are particularly sensitive to venetoclax, including t(11;14) cells, which express a high ratio of BCL2 to MCL1 (venetoclax resistance factor). The current Phase 1 study evaluates safety, efficacy, and pharmacokinetics (PK) in patients (pts) with relapsed/refractory MM. Methods: Primary objectives are to evaluate safety, PK, and recommended phase two dose; other objectives include assessing preliminary efficacy and the impact of chromosomal abnormalities. In dose-escalation (DE) cohorts, venetoclax was given orally daily at 300, 600, 900, or 1200 mg after a 2-week dose ramp-up (3+3 design). Patients in the safety expansion (SE) cohort received 1200 mg daily after ramp-up. All patients were monitored for tumor lysis syndrome (TLS). Results: As of June 17, 2015, 37 patients were enrolled in the study: 30 from DE cohorts and 7 from the SE. Median (range) age was 66 years; 19 (51%) were female. Fourteen were ISS stage I, 13 stage II, 8 stage III, 2 unknown. The median (range) number of prior lines of therapy was 6 (1-19). Thirty-two had prior bortezomib (20 refractory), 35 lenalidomide (18 refractory), and 26 had prior stem cell transplant. Fourteen patients had t(11;14), 4 had t(4;14), 5 had del 17p, and 17 had del 13q. Adverse events (AEs) in ≥20% of patients were nausea (49%), diarrhea (38%), vomiting (30%), anemia (27%), fatigue (24%). Grade 3/4 AEs (≥10%): thrombocytopenia (22%), anemia (19%), neutropenia (11 %). Serious AEs (≥2 patients): pyrexia (n=3), cough, malignant neoplasm progression, and sepsis (2 each); 2 (upper abdominal pain and anemia) were possibly related to venetoclax. Thirty (81%) patients have discontinued venetoclax: 24 due to PD, 3 for AEs (worsening shortness of breath, hypokalemia, and nausea), 2 withdrew consent, 1 due to death (brain hemorrhage following injury). Four deaths occurred (2 due to PD, 1 due to brain hemorrhage, 1 due to pneumopathy). Two of the 6 patients in the 600 mg cohort experienced DLTs of upper abdominal pain and nausea with abdominal pain. No patients met the criteria for laboratory or clinical TLS. Based on preliminary PK (n=21), the mean Cmax and AUC24 were ~dose-proportional at all studied doses (300, 600, 1200 mg) except 900 mg, and dose-normalized venetoclax exposure in MM was similar to that in CLL and NHL pts. Thirty-two of the 37 patients were evaluable for preliminary efficacy (Table). Two patients, both t(11;14), achieved a complete response (1 at 600 mg and 1 at 900 mg). Responses were first achieved at 1.8 and 1.1 months and were maintained for 9.7 and 9.0 months, respectively (900 mg pt remains in CR). Among the 16 patients receiving 1200 mg in the DE or SE cohort, 6 of whom had t(11;14), 5 achieved SD, 6 experienced PD, and 5 are not yet evaluable. Conclusions: Venetoclax monotherapy had a tolerable safety profile in heavily-pretreated relapsed/refractory MM, and no new safety signals were observed compared to other venetoclax studies. The study continues to enroll in the SE cohort at 1200 mg. Responses (including CR) and longer time on venetoclax were observed in t(11;14) patients. These early results suggest that venetoclax has single agent activity, most prominently in t(11;14) patients. Figure 1. Figure 1. Disclosures Kumar: Celgene: Research Funding; Millenium/Takeda: Research Funding; Onyx: Research Funding; AbbVie: Research Funding; Janssen: Research Funding; Sanofi: Research Funding; Celgene, Millenium, Sanofi, Skyline, BMS, Onyx, Noxxon,: Other: Consultant, no compensation,; Skyline, Noxxon: Honoraria. Off Label Use: Venetoclax is an investigational drug that is not yet approved in this indication.. Vij:Takeda, Onyx: Research Funding; Celgene, Onyx, Takeda, Novartis, BMS, Sanofi, Janssen, Merck: Consultancy. Kaufman:Janssen: Consultancy; Spectrum: Consultancy; Merck: Research Funding; Celgene: Consultancy; Onyx: Consultancy; Novartis: Consultancy; Novartis: Research Funding; Onyx: Research Funding. Mikhael:Sanofi: Research Funding; AbbVie: Research Funding; Celgene: Research Funding; Onyx: Research Funding. Moreau:Takeda: Other: Adboard; Janssen: Other: Adboard; Celgene: Other: Adboard; Novartis: Other: Adboard; Amgen: Other: Adboard. Alzate:AbbVie: Employment, Equity Ownership. Morris:AbbVie: Employment, Equity Ownership. Ross:AbbVie: Employment, Equity Ownership. Dunbar:AbbVie: Employment, Equity Ownership. Zhu:AbbVie: Employment, Equity Ownership. Maciag:AbbVie: Employment, Equity Ownership. Agarwal:AbbVie: Employment, Equity Ownership. Leverson:AbbVie: Employment, Equity Ownership. Enschede:AbbVie: Employment, Equity Ownership. Humerickhouse:AbbVie: Employment, Equity Ownership. Touzeau:AbbVie: Research Funding.

Abstract Background: Venetoclax (VEN) is a potent, selective, orally available small-molecule BCL-2 inhibitor that induces cell death in multiple myeloma (MM) cell lines and primary samples, particularly those with t(11;14), which mostly have a favorable high BCL-2, low BCL-XL, and low MCL-1 profile. Methods: In this Phase 1, open-label study, patients (pts) with relapsed/refractory (R/R) MM received VEN monotherapy. Objectives of the study were to assess safety, pharmacokinetics, maximum tolerated dose, recommended phase 2 dose, and efficacy (objective response rate [ORR], time to progression [TTP], and duration of response [DoR]) of VEN. After a 2-week lead in period with weekly dose escalation, VEN was given daily at final doses of 300, 600, 900, or 1200mg in dose escalation cohorts and 1200mg in the safety expansion. Pts who progressed during VEN monotherapy could receive VEN plus dexamethasone and continue in the study. Results: As of 01July2016, 66 pts were enrolled in the study (30 in dose escalation cohorts and 36 in safety expansion). Median age was 63 years and 39 (62%) pts were ISS stage II/III. The median number of prior therapies was 5 (range: 1-15), and 62 (94%) pts had received bortezomib (46 [70%] refractory), 62 (94%) received lenalidomide (51 [77%] refractory), and 50 (76%) had prior autologous stem cell transplant. Thirty (46%) pts had t(11;14) MM. Median time on VEN monotherapy for all pts was 2.5 months (.2-23); 17 (26%) elected to receive VEN and dexamethasone combination after disease progression for a median of 1.4 months (.1-11). Fifty-one (77%) pts discontinued the study for the following primary reasons: 39 related to disease progression, 5 due to AEs/toxicity, 2 withdrew consent, 1 was lost to follow up, and 4 for other reasons not specified. Common adverse events (AEs) in ≥20% of pts were nausea (48%), diarrhea (36%), neutropenia (32%), thrombocytopenia (32%), fatigue (27%), anemia (23%), back pain (21%), and vomiting (21%). Grade 3/4 AEs in ≥10% of pts were thrombocytopenia (26%), neutropenia (20%), lymphopenia (15%), anemia (14%), and decreased white blood cells (12%). Serious AEs in ≥2 pts were pneumonia (n=5), sepsis (3), pain, pyrexia, cough, and hypotension (2 each). Two pts experienced dose-limiting toxicities at 600mg of abdominal pain and nausea. Eight deaths were reported: 6 due to disease progression, 1 due to lung disorder, and 1 due to brain hemorrhage following injury; neither were considered by the investigator as related to VEN. Steady state VEN exposures were approximately dose proportional at all doses but 900mg. As of 20July2016, ORR for all pts on VEN monotherapy was 21% (14/66) and 10 (15%) achieved very good partial response (VGPR) or better (2 stringent complete response [sCR], 2 CR, 6 VGPR) (Figure); median DoR and TTP was 9.7 and 2.6 months, respectively. Most objective responses (12/14 [86%]) were reported in the subset of pts with t(11;14) MM. In this group, ORR was 40% (12/30) and 27% (8/30) achieved a response of ≥VGPR; median DoR for pts with t(11;14) was 9.7 months (95% CI: 6.3, -). Pts who achieved at least minimal response in the t(11;14) group (14/30) had a median of 4 prior therapies and were mostly refractory to bortezomib, lenalidomide, or double refractory (71% [10/14] each). For two pts with response in the non-t(11;14)/undetermined group, 1 had a translocation of chromosome 14 with an unidentified partner, and the other had no cytogenetics data available. DoR was 9.5 and 7.2 months in these pts and both are still ongoing. Median TTP for pts with or without/undetermined t(11;14) was 6.6 and 1.9 months, respectively. The median best percent change in primary M protein for pts with t(11;14) (n=23) was -53% vs +11% in the non-t(11;14)/undetermined group (n=23). Additional biomarker subgroup analyses (n=32) showed that efficacy was primarily observed in pts with myeloma cells expressing a favorable BCL-2 family expression profile (high BCL-2, low BCL-XL, low MCL-1) by immunohistochemistry, which was significantly enriched in the t(11;14) population. Indeed, although high BCL-2 expression was observed in a majority of bone marrow core biopsy samples (88%), the t(11;14) subgroup was enriched (81% vs 25%) for tumors expressing high BCL-2, low BCL-XL, and low MCL-1. Conclusions: VEN monotherapy has an acceptable safety profile and clear anti-myeloma activity in pts with R/R MM, primarily with t(11;14) having a high BCL-2, low BCL-XL and low MCL-1 expression levels. Figure Figure. Disclosures Kumar: Janssen: Consultancy, Research Funding; Sanofi: Consultancy, Research Funding; Noxxon Pharma: Consultancy, Research Funding; Skyline: Honoraria, Membership on an entity's Board of Directors or advisory committees; Onyx: Consultancy, Research Funding; Glycomimetics: Consultancy; AbbVie: Research Funding; Array BioPharma: Consultancy, Research Funding; Millennium: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Kesios: Consultancy; BMS: Consultancy. Kaufman:Novartis: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Pharmacyclics: Consultancy; Incyte: Consultancy. Mikhael:Abbvie: Research Funding; Celgene: Research Funding; Onyx: Research Funding; Sanofi: Research Funding. Facon:Amgen: Consultancy, Speakers Bureau; Novartis: Consultancy; Bristol: Consultancy; Millenium/Takeda: Consultancy; Janssen: Consultancy, Speakers Bureau; Celgene: Consultancy, Speakers Bureau; Karyopharm: Consultancy. Benboubker:Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: 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. Moreau:Celgene: Honoraria; Janssen: Honoraria; Takeda: Honoraria; Novartis: Honoraria; Amgen: Honoraria. Alzate:AbbVie: Employment. Ross:AbbVie: Employment, Equity Ownership. Dunbar:AbbVie Inc.: Employment, Other: may own stock. Xu:AbbVie: Employment. Agarwal:AbbVie: Employment. Leverson:AbbVie: Employment, Other: Shareholder in AbbVie. Maciag:AbbVie: Employment. Verdugo:AbbVie: Employment, Other: may own stock. Touzeau:AbbVie: Research Funding.

Key Points Venetoclax monotherapy at a daily dose up to 1200 mg has an acceptable safety profile in patients with relapsed/refractory MM. Venetoclax monotherapy has demonstrated antimyeloma activity in patients with relapsed/refractory MM positive for t(11;14).