Pomalidomide plus low-dose dexamethasone in relapsed refractory multiple myeloma after lenalidomide treatment failure.

Patients with relapsed/refractory multiple myeloma (RRMM) for whom the benefits of lenalidomide have been exhausted in early treatment lines need effective therapies. In cohort A of the phase 2 MM-014 trial, we examined the safety and efficacy of pomalidomide plus low-dose dexamethasone immediately after lenalidomide-based treatment failure in patients with RRMM and two prior lines of therapy. Pomalidomide 4 mg was given on days 1 to 21 of 28-day cycles. Dexamethasone 40 mg (20 mg for patients aged >75 years) was given on days 1, 8, 15 and 22 of 28-day cycles. The primary endpoint was overall response rate (ORR), and secondary endpoints included progression-free survival (PFS), overall survival (OS) and safety. The intention-to-treat population comprised 56 patients; all received prior lenalidomide (87 center dot 5% lenalidomide refractory) and 39 (69 center dot 6%) received prior bortezomib. ORR was 32 center dot 1% (28 center dot 2% in the prior-bortezomib subgroup). Median PFS was 12 center dot 2 months (7 center dot 9 months in the prior-bortezomib subgroup). Median OS was 41 center dot 7 months (38 center dot 6 months in the prior-bortezomib subgroup). The most common grade 3/4 treatment-emergent adverse events were anaemia (25 center dot 0%), pneumonia (14 center dot 3%) and fatigue (14 center dot 3%). These findings support earlier sequencing of pomalidomide-based therapy in lenalidomide-pretreated patients with RRMM, including those who have become refractory to lenalidomide. Trial registration: identifier NCT01946477.