A Phase 1 Study Of ARRY-520 With Bortezomib (BTZ) and Dexamethasone (dex) In Relapsed Or Refractory Multiple Myeloma (RRMM)

• Published in: Blood 2013-11, Vol.122 (21), p.1938-1938
• Main Authors: Chari, Ajai, Htut, Myo, Zonder, Jeffrey, Fay, Joseph W., Jakubowiak, Andrzej J, Harrison, Beverly, Lau, Kenneth, Hilder, Brandi, Ptaszynski, Ann, Rush, Selena A, Kaufman, Jonathan L., Burt, Steven Michael
• Format: Article
• Language: English
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood.V122.21.1938.1938

ARRY-520 is a novel KSP inhibitor with encouraging activity in patients (pts) with RRMM. In preclinical models, the activity of ARRY-520 is synergistic with BTZ, providing a rationale to combine these drugs in the clinic. ARRAY-520-111 is a Phase 1 study to identify the maximum tolerated dose of ARRY-520, BTZ and dex. Eligible pts have RRMM with ≥ 2 prior lines of therapy, including a proteasome inhibitor (PI) and an immunomodulatory agent. ARRY-520 is administered intravenously (IV) on Days 1, 2, 15 and 16 (Schedule 1) or on Days 1 and 15 (Schedule 2); BTZ is administered IV or subcutaneously (SC) on Days 1, 8 and 15; and 40 mg oral dex, if applicable, is taken on Days 1, 8 and 15 in a 28-day cycle. A total of 41 pts have been treated to date at various dose levels of ARRY-520 and BTZ. Patients had a median of 5 prior regimens (range 2-10). All pts received a prior PI, 39 pts received prior BTZ, and 25 pts received at least 2 prior PI- including regimens (range 1-6). In Schedule 1, the initial dose level of ARRY-520 (1.0 mg/m2/day) with BTZ (1.3 mg/m2/day) and dex was not tolerated, with dose-limiting toxicities (DLT) in 2/3 pts (pneumonia and pseudomonal sepsis). After a protocol amendment, dose escalation resumed at reduced doses of ARRY-520 (0.5 mg/m2/day) and BTZ (1.0 mg/m2/day) without dex. The addition of prophylactic filgrastim (G-CSF) enabled escalation to full dose ARRY-520 and BTZ (1.5 and 1.3 mg/m2/day, respectively). Only 1 DLT of pneumonia was observed during the further dose escalation, at 1.0 mg/m2/day ARRY-520 and 1.0 mg/m2/day BTZ. Dex has been added to the combination at 1.25 mg/m2/day ARRY-520 and 1.3 mg/m2/day BTZ and this dose level has been well tolerated. Enrollment is ongoing in the final planned dose level. In Schedule 2, the initial dose level of ARRY-520 (2.25 mg/m2/day) with BTZ (1.3 mg/m2/day) and dex was well tolerated and enrollment is ongoing at 3.0 mg/m2/day ARRY-520 and 1.3 mg/m2/day BTZ + dex, the maximum planned dose of both drugs. The most commonly reported adverse events (AEs) (in ≥ 15% of pts) include anemia, diarrhea, pyrexia, upper respiratory tract infection, thrombocytopenia, cough, neutropenia, constipation, headache, fatigue, hyperuricemia, nausea, vomiting, and dizziness. All Grade 3 – 4 non-hematologic AEs have an incidence of < 10%. Based on the laboratory data, Grade 4 neutropenia was observed in 15% of patients, Grade 4 thrombocytopenia was observed in 10%. Apart from the one pt described above with the DL