MedicalResearch.com: What is the background for this study? What are the main findings?
Response: Multiple myeloma accounts for approximately 1 percent of all cancers and slightly more than 10 percent of all hematologic malignancies. At present, more than 80,000 new cases are reported worldwide each year, and the disease prevalence is increasing.
Plitidepsin is a synthetic cyclic depsipeptide isolated from the marine tunicate Aplidium albicans targeting the proto-oncogene eEF1A2, which is over-expressed in multiple myeloma cells.
In ADMYRE trial 255 relapsed and refractory multiple myeloma patients with at least three but not more than six prior regimens, including at least bortezomib and lenalidomide/thalidomide, were randomized at 2:1 ratio to receive plitidepsin 5 mg/m2 D1 and 15 plus DXM 40 mg D1, 8, 15 and 22 (P+DXM), or DXM 40 mg D1,8,15 and 22 (DXM) every four weeks.
P+DXM met the primary endpoint, progression-free survival (PFS) assessed by an Independent Review Committee, showing a 35% risk reduction in the probability of progression or death. Indeed, a 20% risk reduction in the probability of death was also observed in spite of the fact that 44% of patients from control arm (DXM) switched to P+DXM arm after progression. Therefore, survival in the control arm might have been extended by the effect of plitidepsin, increasing the post progression survival and overestimating the survival observed in the control arm and consequently underestimating the actual difference between treatment arms.
Several methods were used to assess the impact of crossover and the robustness of the results even when penalizations were applied; PharmaMar believes that strong evidence in terms of survival benefit in favour of P+DXM has been established. Continue reading