The real-world use and efficacy of pomalidomide for relapsed and refractory multiple myeloma in the era of CD38 antibodies

Pomalidomide-dexamethasone (Pd) has been a standard care treatment for relapsed and refractory multiple myeloma since 2013. However, the outcomes of Pd after exposure to CD38 antibodies are not known. Here we describe the real-world use and efficacy of pomalidomide in a Danish, nationwide cohort of daratumumab-exposed patients. We identified 328 patients that were treated with pomalidomide. Of these, 137 received Pd, 65 daratumumab-pomalidomide-dexamethasone (DPd), 43 pomalidomide-cyclophosphamide-dexamethasone (PCd), 19 carfilzomib-pomalidomide-dexamethasone (KPD), 11 pomalidomide-bortezomib-dexamethasone (PVd), and 52 pomalidomide in other combinations. Patients treated with Pd in this cohort had a partial response or better (≥ PR) rate of 35.8% and median time to next treatment (mTNT) of 4.9 months, almost identical to the results of previous prospective clinical trials. Although treatment with the various pomalidomide-containing triplet regimens resulted in higher ≥ PR rates (PCd: 46.5%, PVd: 63.6%, DPd: 55.4%, KPd: 63.2%), the mTNT achieved was not significantly better than with Pd in most cases (PCD: 5.4, PVD: 5.3, DPD: 4.7 months). The exception to this was KPd (mTNT 7.4 months), but this regimen was mainly used earlier in the course of the disease (median time from diagnosis 2.3 years vs. 3.7-4.3 years). The most important predictor of outcomes was not the choice of index regimen (p = 0.72), but prior exposure (p = 0.0116). Compared to CD38 antibody-naïve patients, triple-class-exposed patients achieved reduced ≥ PR rate (38.0% vs. 47.3%), shorter mTNT (4.0 vs. 5.9 months), and shorter median overall survival (12.4 vs. 24.2 months) with pomalidomide treatment.