Phase 2 study of dovitinib in patients with relapsed or refractory multiple myeloma with or without t(4;14) translocation

Objectives: Approximately 15% of patients with multiple myeloma (MM) exhibit a t(4;14) translocation, which often results in constitutive activation of the receptor tyrosine kinase (RTK) fibroblast growth factor receptor 3 (FGFR3). This study evaluated the efficacy and safety of dovitinib, an RTK inhibitor with in vitro inhibitory activity against FGFR, in patients with relapsed or refractory MM with or without t(4;14) translocation. Methods: Adult patients with relapsed or refractory MM who had received ≥2 prior regimens were enrolled in this multicenter, 2-stage, phase 2 trial. Patients were grouped based on their t(4;14) status. Dovitinib (500 mg/day orally) was administered on a 5-days-on/2-days-off schedule. The primary endpoint was overall response rate by local investigator review (per International Myeloma Working Group criteria). In non-responding patients, treatment could continue with the addition of low-dose dexamethasone. Results: In total, 43 patients (median age, 63 years) were enrolled (13 t(4;14) positive, 26 t(4;14) negative, and 4 t(4;14) status non-interpretable). Patients had received a median of 5 prior regimens. Median duration of treatment was 8.7 weeks in the t(4;14)-positive group and 3.7 weeks in the t(4;14)-negative group. None of the patients on dovitinib had objective responses. The stable disease rate was 61.5% in the t(4;14)-positive group and 34.6% in the t(4;14)-negative group. Overall, 39 patients (90.7%) had adverse events suspected to be related to study drug, most commonly diarrhea (60.5%), nausea (58.1%), vomiting (46.5%), and fatigue (32.6%). Conclusion: Dovitinib showed no single-agent activity in relapsed or refractory MM but may stabilize disease in some t(4;14)-positive patients.