Pomalidomide plus cyclophosphamide and dexamethasone (PomCyDex) resulted in a higher overall response rate as compared with pomalidomide plus low-dose dexamethasone (PomDex) in patients with refractory multiple myeloma, a study published in the journal Blood has shown.1
Because PomDex is a standard treatment for patients refractory to lenalidomide who have received 3 or more prior therapies, researchers sought to evaluate the safety and efficacy of adding oral weekly cyclophosphamide to PomDex in the refractory setting.
Researchers first conducted a dose escalation phase 1 study with 10 patients to determine the maximum tolerated phase 2 dose of cyclophosphamide in combination with PomDex. A dose of 400 mg was identified as the recommended dose.
Then for the multicenter phase 2 study, researchers enrolled 70 patients and randomly assigned them 1:1 to receive pomalidomide 4 mg on days 1 to 21 of each 28-day cycle in combination with weekly dexamethasone, or PomDex plus cyclophosphamide 400 mg orally on days 1, 8, and 15 of each 28-day cycle.
Results showed that overall response rate was 38.9% (95% CI, 23 – 54.8) with PomDex and 64.7% (95% CI, 48.6 – 80.8) with PomCyDex (P = .035); however, at the time of this analysis, 62 of the 70 patients had experienced disease progression.
Researchers found that the median progression-free survival was 4.4 months (95% CI, 2.3 – 5.7) and 9.5 months (95% CI, 4.6 – 14) for PomDex and PomCyDex, respectively (P = .106).
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In terms of safety, there was no significant increase in toxicity with the addition of cyclophosphamide compared with PomDex alone. Most treatment-related adverse events were hematological toxicities.
The findings ultimately suggest that PomCyDex is an effective oral regimen for patients with refractory multiple myeloma.
- Baz RC, Martin, TG III, Lin H-Y, et al. Randomized multicenter phase II study of pomalidomide, cyclophosphamide, and dexamethasone in relapsed refractory myeloma [published online ahead of print March 1, 2016]. Blood. doi: 10.1182/blood-2015-11-682518.