Daratumumab, pomalidomide, and dexamethasone in relapsed refractory multiple myeloma (RRMM): A comparison with contemporary clinical trials.

Abstract

e20011 Background: Multiple Myeloma (MM) is an incurable malignancy of terminally differentiated plasma cells. The combination of pomalidomide/dexamethasone with either daratumumab or isatuximab is FDA approved for relapsed refractory multiple myeloma (RRMM) based on randomized phase III trial data. Herein, we compare our center’s experience with published data to help identify the most appropriate patient population for this regimen outside of the context of clinical trials. Methods: We interrogated our internal plasma cell disorder database to identify all patients with RRMM at our institution who were treated with the combination of daratumumab, pomalidomide, and dexamethasone (Dara-Pd). We evaluated the best response achieved, overall response rate (ORR), progression free survival (PFS), and overall survival (OS) measured from initiation on Dara-Pd. Kaplan Meier methods were used to estimate PFS and OS curves. Fisher’s exact tests and log rank tests were used to determine the association between outcomes and variables of interest. Results: Between Dec 2015 and Dec 2020, 98 patients were identified, of which 97 were evaluable for response. Median number of prior lines of therapy was 2 (range 1-12), with 23 patients (23%) previously treated with 3 prior lines and 24 patients (25%) previously treated with ≥4 lines of therapy. Most patients were refractory to an IMiD (79.6%), a PI (65.3%), or both (56.1%). The ORR was 69.1%, > VGPR rate was 33%. ORR was significantly improved for patients who received Dara-Pd after 1 line (p = 0.03), but depth of response (≥VGPR), was similar (p = 0.62). At a median follow up of 10.8 months, 1-year PFS was 76.6% in patients after 1 line, 38.8% in patients after 2-3 lines, and 35% in patients after > 4 lines. Overall response rates appear comparable to published phase III trials comparing the combination of Pd with or without an anti-CD38 monoclonal antibody (Table 1). While PFS was somewhat lower in our population, subset analysis showed that PFS was significantly lower in patients who were PI refractory (10.8 months vs 6 months; p = 0.014), and in patients who were both IMiD and PI refractory (20.4 months vs 6 months p = 0.01), but OS was similar in these populations. Conclusions: Our data suggests that the combination of Dara-Pd has activity in heavily pretreated patients, including patients who are both IMiD and PI refractory and remains a viable option for these patients outside the context of a clinical trial.[Table: see text]