Dubin, Franck

8004 Background: The primary objective of this phase 3 trial was to demonstrate progression free survival (PFS) improvement of isatuximab (Isa), a novel anti-CD38 monoclonal antibody, combined with pomalidomide (P)/dexamethasone (d) versus (vs) Pd. Methods: Patients (pts) with RRMM who received ≥2 prior lines, including lenalidomide (len) and a proteasome inhibitor (PI), refractory to last therapy were enrolled. IsaPd arm received Isa 10 mg/kg IV weekly for first 4 weeks (wks), then every 2 wks. Both arms received approved schedules of pom and dex (4mg PO days 1-21; 40mg [20mg if >75 yrs] PO or IV weekly) every 28 days until progression or unacceptable toxicity. Results: 307 pts (154 IsaPd, 153 Pd) were randomized and analyzed (ITT). Patient characteristics were well balanced across arms. Median age: 67 (36-86) yrs; median prior lines of therapy: 3 (2-11); estimated GFR: <60ml/min in 33.9% pts; 92.5% refractory to len, 75.9% to PI; and 19.5% pts had high-risk cytogenetics. At median follow-up of 11.6 months (mos), median PFS was 11.5 mos IsaPd vs 6.5 mos Pd; HR 0.596 (95% CI 0.44-0.81), P=0.001. PFS benefit was consistent across all major subgroups. ORR (≥PR) was 60.4% IsaPd vs 35.3% Pd, P<0.0001. VGPR rate or better was 31.8% IsaPd vs 8.5% Pd, and MRD negativity (NGS, 10-5) was seen in 5.2% IsaPd pts vs 0% Pd. At analysis date, overall survival (OS) was immature (99 events) but a trend to OS improvement in IsaPd (vs Pd) was observed (HR 0.687; 95% CI 0.461-1.023). Median treatment duration was 41 wks IsaPd vs 24 wks Pd; median Isa infusion (inf.) duration was 3.3h at 1st inf. and 2.8h at subsequent inf. Grade ≥3 AEs were observed in 86.8% IsaPd vs 70.5% Pd; 7.2% IsaPd and 12.8% Pd pts discontinued due to AEs; 7.9% IsaPd and 9.4% Pd pts died due to AEs. Inf. reactions were reported in 38.2% (2.6% grade 3-4) IsaPd. Grade ≥3 infections were seen in 42.8% IsaPd and 30.2% Pd, grade ≥3 neutropenia in 84.9% (febrile 11.8%) IsaPd and 70.1% (febrile 2.0%) Pd. Conclusions: IsaPd significantly improved PFS and ORR vs Pd, with a manageable safety profile. IsaPd is an important new treatment option for the management of RRMM. Clinical trial information: NCT02990338.

Abstract Background: Isatuximab (ISA) is an anti-CD38 monoclonal antibody with multiple modes of action for killing tumor cells through immune cell engagement and direct tumor targeting. In preclinical studies, pomalidomide (Pom) enhanced both the direct and indirect anti-tumor activity of ISA to a greater degree than lenalidomide (Len) (Jiang et al. Leukemia 2016). Here, we report the preliminary results of an ongoing Phase Ib dose-escalation study of ISA plus Pom and dexamethasone (Dex) in patients with relapsed and refractory multiple myeloma (RRMM) (NCT02283775). Methods: Patients with RRMM (≥2 prior MM therapies, including Len and a proteasome inhibitor) with adequate bone marrow reserve/organ function were sequentially enrolled to receive ISA 5, 10 or 20 mg/kg (weekly × 4 doses, then every 2 weeks until disease progression or intolerable toxicity) in combination with Pom 4 mg (days 1-21) and Dex 40 mg (days 1, 8, 15, and 22; 20 mg if ≥75 years old), in 28-day cycles. Pom or Dex dose reductions were permitted after Cycle 1, or during Cycle 1 in response to dose-limiting toxicities (DLTs). The primary objective was to determine the maximum tolerated dose (MTD) or recommended dose, based on the occurrence of treatment-related DLTs. Secondary objectives included evaluation of efficacy (by objective response assessment according to IMWG criteria), safety, and pharmacokinetics (PK). Results: At data cut-off (May 11, 2016), 14 patients had been treated in the first 2 dose-escalation cohorts: 8 patients at 5 mg/kg and 6 patients at 10 mg/kg. Overall, median age was 65.5 (range, 42-77) years and median time from diagnosis was 4.25 (1.0-12.5) years. Half of the patients (7/14) had received at least 5 prior regimens (median 4.5 [2-11]; prior carfilzomib in 50% of patients). Ten patients (71%) had received at least one prior stem cell transplant. Median duration of dosing was 21.2 (4-42) and 8.1 (4-12) weeks in the 5 mg/kg and 10 mg/kg cohorts, respectively, with the latter cohort also having the shortest follow-up. Three patients discontinued treatment, all in the 5 mg/kg cohort: 2 due to confirmed disease progression (discontinuation after 2 and 4 treatment cycles, respectively) and 1 due to patient withdrawal (discontinuation in Cycle 1 and patient not evaluable for response). There were no discontinuations due to treatment-emergent adverse events (TEAEs) in either cohort. Two DLTs were reported: one in the 5 mg/kg cohort (prolonged grade [Gr] 4 neutropenia), and the other in the 10 mg/kg cohort (Gr 4 neutropenic infection); both DLTs resolved with Pom dose delay/reduction. MTD has not yet been reached; the 20 mg/kg dose level is under enrollment. Overall, Gr 3/4 TEAEs were reported in 10 (71%) patients; serious TEAEs in 6 (43%) patients. The most frequent TEAEs were fatigue (64%), upper respiratory tract infection, tremor, dyspnea, and cough (29% each). The most common Gr 3/4 hematologic abnormality (laboratory assessment) was neutropenia (Gr 1, 0%; Gr 2, 7%; Gr 3, 43%; Gr 4, 43%). Gr 3/4 thrombocytopenia was reported in 4 (29%) patients (Gr 3, n=2; Gr 4, n=2). Infusion-associated reactions (IARs) occurred in 8 (57%) patients, with all cases Gr 1/2 in severity. IARs occurred during the first infusion in most patients; 3/14 (21%) patients experienced IARs at a subsequent infusion, of whom only one had IARs after Cycle 1. Of the patients evaluable for confirmed response, 8/13 (62%) achieved at least partial response (PR), and 10/13 (77%) at least minimal response (MR). At 5 mg/kg, 1 patient achieved complete response (CR), 2 very good partial response (VGPR) and 2 PR. At 10 mg/kg, 2 patients achieved VGPR, 1 PR, and 2 MR. Of the eight patients who achieved at least PR, all continued to respond without confirmed disease progression at data cut-off. The PK parameters of ISA were not affected by co-administration with Pom/Dex. Conclusions: These preliminary data suggest that the combination of ISA and Pom/Dex is generally well tolerated and clinically active in patients with heavily pre-treated RRMM. Enrollment continues and longer term follow-up from this study, including data from the 20 mg/kg cohort, will be presented. A Phase III trial to evaluate ISA plus Pom/Dex is planned. Disclosures Richardson: Jazz Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees. Mikhael:Sanofi: Research Funding; Celgene: Research Funding; Abbvie: Research Funding; Onyx: Research Funding. Usmani:Pharmacyclics: Research Funding; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Skyline: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Sanofi: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Amgen: Consultancy, Research Funding, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Millenium: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Britsol-Myers Squibb: Consultancy, Research Funding; BioPharma: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Onyx: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Array: Research Funding; Novartis: Speakers Bureau. Raje:Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees; Merck: Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Roche: Consultancy, Membership on an entity's Board of Directors or advisory committees; BMS: Consultancy, Membership on an entity's Board of Directors or advisory committees; AstraZeneca: Research Funding; Eli Lilly: Research Funding. Bensinger:Takeda: Honoraria, Research Funding; Bristol Myers Squibb: Consultancy, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Sanofi: Consultancy, Research Funding; Acetylon: Research Funding; Bayer: Research Funding. Campana:Sanofi: Employment. Gao:Sanofi: Employment. Dubin:Sanofi Oncology: Employment. Wack:Sanofi: Employment. Anderson:Gilead: Membership on an entity's Board of Directors or advisory committees; Oncoprep: Equity Ownership; Oncoprep: Equity Ownership; Millennuim: Membership on an entity's Board of Directors or advisory committees; C4 Therapeutics: Equity Ownership; Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Acetylon: Equity Ownership; Acetylon: Equity Ownership; Millennuim: Membership on an entity's Board of Directors or advisory committees; C4 Therapeutics: Equity Ownership; Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees.

Background:Despite recent advances, multiple myeloma (MM) remains incurable, and new treatment options are needed to continue to improve patient outcomes. This is the first randomized, phase 3 trial of an anti‐CD38 antibody in combination with pomalidomide (P) and dexamethasone (d) in RRMM.Aims:The primary objective of this phase 3 trial (NCT02990338) was to demonstrate progression free survival (PFS) improvement of isatuximab (Isa), a novel anti‐CD38 monoclonal antibody targeting a specific epitope, combined with Pd versus (vs) Pd in RRMM.Methods:Patients (pts) with RRMM who received ≥2 prior lines, including lenalidomide (len) and a proteasome inhibitor (PI), refractory to last therapy were enrolled. IsaPd arm received Isa 10 mg/kg IV weekly for first 4 weeks (wks), then every 2 wks. Both arms received approved schedules of pom and dex (4 mg PO days 1–21; 40 mg [20 mg if >75 yrs] PO or IV weekly) every 28 days until progression or unacceptable toxicity.Results:307 pts (154 IsaPd, 153 Pd) were randomized and analyzed (ITT). Patient characteristics were well balanced across arms. Median age: 67 (36–86) yrs; median prior lines of therapy: 3 (2–11); estimated GFR: <60 ml/min in 33.9% pts; 92.5% refractory to len, 75.9% to PI; and 19.5% pts had high‐risk cytogenetics. At median follow‐up of 11.6 months (mos), median PFS was 11.5 mos IsaPd vs 6.5 mos Pd; HR 0.596 (95% CI 0.44–0.81), P = 0.001. PFS benefit was consistent across all major subgroups. ORR (≥PR) was 60.4% IsaPd vs 35.3% Pd, P < 0.0001. VGPR rate or better was 31.8% IsaPd vs 8.5% Pd, and MRD negativity (NGS, 10−5) was seen in 5.2% IsaPd pts vs 0% Pd. At analysis date, overall survival (OS) was immature (99 events) but a trend to OS improvement in IsaPd (vs Pd) was observed (HR 0.687; 95% CI 0.461–1.023). Median treatment duration was 41 wks IsaPd vs 24 wks Pd; median Isa infusion (inf.) duration was 3.3 h at 1st inf. and 2.8 h at subsequent inf. Grade ≥3 AEs were observed in 86.8% IsaPd vs 70.5% Pd; 7.2% IsaPd and 12.8% Pd pts discontinued due to AEs; 7.9% IsaPd and 9.4% Pd pts died due to AEs. Inf. reactions were reported in 38.2% (2.6% grade 3–4) IsaPd. Grade ≥3 infections were seen in 42.8% IsaPd and 30.2% Pd, grade ≥3 neutropenia in 84.9% (febrile 11.8%) IsaPd and 70.1% (febrile 2.0%) Pd.Summary/Conclusion:Isatuximab in combination with pomalidomide and dexamethasone significantly improved PFS and ORR vs pomalidomide and dexamethasone, with a manageable safety profile. Isatuximab in combination with pomalidomide and dexamethasone is an important new treatment option for the management of RRMM.