Efficacy of pomalidomide plus low-dose dexamethasone in multiple myeloma patients despite previous use of lenalidomide.

8067 Background: Pomalidomide (CC4047 or Pom) is the newest oral immunomodulatory agent. It yields less neuropathy than thalidomide (thal) and less myelosuppression than lenalidomide (len). Pom/dex has demonstrated response rates (>PR) of 63% in relapsed MM (Lacy, JCO 2009) and 32% in len-refractory MM (Lacy, Leukemia 2010) using a 2mg/day dose. The MTD has been determined to be 4 mg/day but the optimal dose has not yet been defined. We report a phase II trial using the Pom 4mg with dex to study its efficacy in patients with prior len. Methods: Patients must have had 1-3 lines of prior therapy (including len). Pom 4mg daily was given orally on days 1–28 (28-day cycle) with oral dex given 40 mg daily on days 1, 8, 15 and 22. All patients received DVT prophylaxis with aspirin 325 mg daily or therapeutic anticoagulation. Results: 61 patients with relapsed MM were enrolled. Median age was 65 years (32-82), and 40 were male. Median time from diagnosis to enrollment was 37 months (1-84). Fifteen (25%) patients had high risk disease as defined by mSMART (mSMART.org). Sixty (98%) patients received prior len, 29 (47%) had bortezomib, 13 (21%) thal, 47 (77%) auto transplant and 3 (5%) allo transplant. Toxicities at least possibly attributed to drug included grade 3/4 anemia (7/0%), grade 3/4 leukopenia (27/2%), grade 3/4 thrombocytopenia (3/2%). Grade 3 non-hematologic toxicities occurred in 18% of patients and included fatigue 5%, thrombosis 5%, hyperglycemia 5% and pneumonia 5% (no grade 4). Grade 1/2 neuropathy occurred in 18/8%, (no grade 3 or 4). Twenty three (38%) patients required dose reductions in dex. Confirmed responses (>PR) were seen in 21 patients (35%), of which 7 (12%) were VGPR, 14 (23%) PR, 8 (13%) MR, 25 (42%) SD and 6 (10%) PD. Median time to response was 1.1 months (0.8-2.8). With a median follow-up 4.1 months, 67% remain progression free, and 97% remain alive. Conclusions: This large phase II demonstrates that Pom/dex is active and very well tolerated in patients who have already been treated with len. Objective response is seen in 48% despite being heavily pre-treated with IMiDs, bortezomib and transplant. This study reconfirms therapeutic benefit for Pom/dex in patients relapsing after other novel therapies.