Safety and efficacy of pomalidomide (POM), dexamethasone (DEX), and pegylated liposomal doxorubicin (PLD) for patients with relapsed/refractory multiple myeloma (RRMM).

8591 Background: Treatment with POM and DEX has shown efficacy in RRMM patients (pts), even in those refractory to lenalidomide (LEN). In this phase (Ph) 1/2 trial, we investigated the POM-DEX-PLD combination using a modified dose and schedule (28-days) for RRMM pts. Methods: Ph1 pts had progressive MM at study entry. Ph2 pts were refractory to LEN (progressive disease (PD) while receiving LEN or relapsed within 8 weeks of last dose). POM was administered orally on days 1-21 of a 28-day cycle, while DEX (40 mg) and PLD (5 mg/m2) were infused on days 1, 4, 8, and 11. The maximum tolerated dose (MTD) of POM was established at 4 mg; however, because 58.8% of the pts enrolled in Ph2 developed ≥ grade 3 (Gr3) neutropenia, the dose of POM was reduced to 3 mg. Results: As of December 1st 2014, 56 pts were enrolled, 44 of them in Ph2 and 45 pts had discontinued treatment. Pts had received a median of 4 prior treatments (range, 1-18). Median number of cycles for all pts and those enrolled in Ph2 was 3 (range, 1-8). Median follow-up time for all pts was 4 months (range, 0.2-22 months), whereas that of Ph2 pts was 3.8 months (range, 0.2-12 months). Overall response (ORR) and clinical benefit rates (CBR) were 35%and 47%, respectively. Nine pts (16%) showed stable disease (SD) while 13 (24%) pts exhibited PD. For LEN refractory pts (N = 44), ORR and CBR were 32 % and 48%, respectively, with 6 pts (14%) showing SD and 15 pts (34%) displaying PD.Ph2 pts receiving POM at 3 mg (N = 28) showed an ORR and CBR of 43% and 61%, respectively. Progression-free survival was 5.23 months. Common ≥ Gr3 adverse events were neutropenia (38.2%), lymphopenia (20.0%), hyponatremia (9.1%), and thrombocytopenia (5.5%). One pt died of Gr5 sepsis. Conclusions: The combination of POM at 3 mg, PLD and DEX given in 28-day cycles is safe and effective for the treatment of MM pts refractory to LEN. Clinical trial information: NCT01541332.