Phase 2 Study of Carfilzomib (CFZ) with or without Filanesib (FIL) in Patients with Advanced Multiple Myeloma (MM)
Authors: Zonder Jeffrey A , Usmani Saad , Scott Emma C. , Hofmeister Craig C. , Lendvai Nikoletta , Berdeja Jesus G. , Anderson Larry D. , Hari Parameswaran , Singhal Seema , Orloff Gregory , Craig Michael , Valent Jason , Lee Wes , Hart Lowell , Hrom J , Tarantolo Stephano , Faber Edward , Schiller Gary J , Schreiber Jennifer , Oliver Colleen , Rush Selena A , Tunquist Brian , Ptaszynski Mieke , Raje Noopur S. 
Published: October 2019

Background: FIL (ARRY-520), a specific kinesin spindle protein (KSP) inhibitor, represents a novel class of agent under investigation for the treatment of patients (pts) with MM. Prognosis of pts refractory to immunomodulatory agents (IMiDs) and proteasome inhibitors (PIs) is poor. These pts have a median survival of 9 months underscoring the importance of novel therapeutic strategies incorporating new mechanisms of action. FIL has shown interesting preliminary activity as a single agent as well as in Phase 1 studies in combination with bortezomib (BTZ) and with CFZ, all with a manageable safety profile.

Methods: This trial is an ongoing, randomized, multicenter, open-label Phase 2 study for pts with relapsed and refractory MM who received at least 2 prior regimens, including BTZ and an IMiD, and with disease refractory to the last regimen as per IMWG criteria. No prior treatment with CFZ is allowed. Approximately 75 pts will be randomized 2:1 to receive CFZ (20/27 mg/m2 intravenous [IV] on Days 1, 2, 8, 9, 15 and 16) plus FIL (1.25 mg/m2 IV on Days 1, 2, 15 and 16) or single-agent CFZ, at the same dose as in the combination, in a 28-day cycle. Prophylactic filgrastim is administered in the CFZ + FIL arm. The primary endpoint is progression-free survival (PFS). Patients with progressive disease (PD) on CFZ are allowed cross-over to the CFZ + FIL arm if they continue to meet eligibility criteria.

Results: As of 15 June 2015, 72 pts have been randomized (23 CFZ, 49 CFZ + FIL) with a median age of 65 years. Pts who could have potentially received ≥ 2 cycles of treatment (20 CFZ, 30 CFZ + FIL) were evaluable for efficacy. These pts were heavily pretreated with a median of 4 and 5 prior regimens in the CFZ and CFZ + FIL arm, respectively. A total of 25% and 30 % of pts, respectively, received prior pomalidomide. The objective response rate (ORR) was 10% in the CFZ arm and 30% in the CFZ + FIL arm. In the CFZ arm, 2 pts achieved a partial response (PR) and 2 pts (10%) achieved an MR. In the CFZ + FIL arm, 3 pts achieved a very good partial response and 6 pts achieved a PR, with 2 additional pts (7%) achieving an MR. In the population of pts who were refractory to both prior BTZ and prior IMiDs, the ORR was 14% and 35%, respectively.

Grade 3-4 hematological laboratory abnormalities (≥ 5% of pts) were leukopenia (9% CFZ vs. 21% CFZ + FIL), neutropenia (14% vs. 24%), thrombocytopenia (14% vs. 24%), and anemia (9% vs. 26%). Neutropenia and thrombocytopenia were reversible. No adverse events (AEs) of febrile neutropenia were reported. The only Grade 3-4 non-hematological AE occurring in ≥ 5% of pts was dyspnea (5% vs.11%). The most common reason for treatment discontinuation was confirmed PD (39% vs. 28%) or Investigator discretion in case of unconfirmed PD or clinical PD (17% vs. 12%).

Conclusions: The combination of FIL and CFZ was well-tolerated and noticeably increased the ORR compared to CFZ alone in heavily pretreated pts with advanced MM. The preliminary efficacy in pts who are double refractory to IMiDs and BTZ who were randomized to CFZ + FIL appears higher than in pts treated with CFZ alone (in the CFZ arm of this trial and in previously published reports involving such pts). Updated safety and efficacy data, including PFS, will be presented at the meeting.

Table. Efficacy evaluable pts (potential to have received ≥ 2 cycles of treatment) CFZ (N = 20) CFZ + FIL (N = 30) Prior regimens, median (range) 4 (2,11) 5 (2,11) N cycles on study, median (range) 4 (1 - 16) 4 (1 - 15+) % ORR (≥ PR) 10 30 % CBR (≥ MR) 20 37 N (%) IMiD & BTZ Refractory 14 (70) 20 (67) % ORR (≥ PR) 14 35 % CBR (≥ MR) 21 40 CBR = clinical benefit rate

Disclosures

Zonder: Seattle Genetics: Membership on an entity's Board of Directors or advisory committees; Prothena: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees, Other: research support. Off Label Use: carfilzomib; treatment of myeloma, but not in combination with filanesib. Usmani:Celgene Corporation: Consultancy, Honoraria; Onyx: Consultancy, Honoraria, Research Funding; Janssen: Research Funding. Berdeja:Onyx: Research Funding; Array: Research Funding; Takeda: Research Funding; Acetylon: Research Funding; Janssen: Research Funding; BMS: Research Funding; MEI: Research Funding; Celgene: Research Funding; Novartis: Research Funding; Abbvie: Research Funding; Curis: Research Funding. Anderson:Onyx: Speakers Bureau; Takeda: Speakers Bureau; Celgene: Speakers Bureau. Hari:BMS: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Janssen: Honoraria; Onyx: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Research Funding; Sanofi: Honoraria, Research Funding. Singhal:Celgene: Speakers Bureau. Valent:Takeda/Millennium: Speakers Bureau; Celgene: Speakers Bureau. Faber:Celgene: Consultancy. Schiller:Sunesis: Honoraria, Research Funding. Schreiber:Array BioPharma: Employment. Oliver:Array BioPharma: Employment. Rush:Array BioPharma: Employment. Tunquist:Array BioPharma: Employment. Ptaszynski:Array BioPharma: Employment. Raje:Eli Lilly: Research Funding; Millenium: Consultancy; Takeda: Consultancy; Onyx: Consultancy; Acetylon: Research Funding; BMS: Consultancy; AstraZeneca: Research Funding; Novartis: Consultancy; Amgen: Consultancy; Celgene Corporation: Consultancy; Acetylon: Research Funding.