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Medline ® Abstract for Reference 130

of 'Treatment of relapsed or refractory multiple myeloma'

Phase 1 study of twice-weekly ixazomib, an oral proteasome inhibitor, in relapsed/refractory multiple myeloma patients.
Richardson PG, Baz R, Wang M, Jakubowiak AJ, Laubach JP, Harvey RD, Talpaz M, Berg D, Liu G, Yu J, Gupta N, Di Bacco A, Hui AM, Lonial S
Blood. 2014 Aug;124(7):1038-46. Epub 2014 Jun 11.
Ixazomib is the first investigational oral proteasome inhibitor to be studied clinically. In this phase 1 trial, 60 patients with relapsed/refractory multiple myeloma (median of 4 prior lines of therapy; bortezomib, lenalidomide, thalidomide, and carfilzomib/marizomib in 88%, 88%, 62%, and 5%, respectively) received single-agent ixazomib 0.24 to 2.23 mg/m(2) (days 1, 4, 8, 11; 21-day cycles). Two dose-limiting toxicities (grade 3 rash; grade 4 thrombocytopenia) occurred at 2.23 mg/m(2). The maximum tolerated dose was 2.0 mg/m(2), which 40 patients received in 4 expansion cohorts. Patients received a median of 4 cycles (range, 1-39); 18% received≥12 cycles. Eighty-eight percent had drug-related adverse events, including nausea (42%), thrombocytopenia (42%), fatigue (40%), and rash (40%); drug-related grade≥3 events included thrombocytopenia (37%) and neutropenia (17%). Grade 1/2 drug-related peripheral neuropathy occurred in 12% (no grade≥3). Two patients died on the study (both considered unrelated to treatment). The terminal half-life of ixazomib was 3.3 to 7.4 days; plasma exposure increased proportionally with dose (0.48-2.23 mg/m(2)). Among 55 response-evaluable patients, 15% achieved partial response or better (76% stable disease or better). These findings have informed the subsequent clinical development of ixazomib in multiple myeloma. This trial was registered at www.clinicaltrials.gov as #NCT00932698.
Dana-Farber Cancer Institute, Boston, MA;