FDA puts partial hold on Oncopeptides' study of melflufen

Based on the observed large differences in overall survival in pre-specified subgroups, the US Food and Drug Administration has requested a partial clinical hold of all clinical studies with melflufen, pending further investigation, Swedish biotech Oncopeptides (Nasdaq Stockholm: ONCO) revealed on Thursday, sending the firm’s shares tumbling as much as 23%.

The news came as Oncopeptides released updated results and safety measures based on the head-to-head Phase III OCEAN study evaluating the efficacy and safety of melflufen (INN melphalan flufenamide) plus dexamethasone versus pomalidomide, Bristol Myers Squibb's (NYSE: BMY) Pomalyst, plus dexamethasone in patients with relapsed refractory multiple myeloma who have received 2 – 4 prior lines of therapy. The randomized study was initiated in 2017 and includes 495 patients from more than 100 hospitals in 21 countries around the world. The top-line results were announced on May 25.

The updated OCEAN results follow a blinded reassessment by the Independent Review Committee (IRC). During the preparations of the clinical study report and regulatory documents it became apparent that the IRC was not provided with all the information available in the clinical database during the time of their initial assessment. This led to a thorough investigation of all 495 patients where a comparison was made between the data provided to the IRC and what data was available in the clinical database. Consequently, data from 29 patients had to be reassessed. In the final analysis melflufen met the primary endpoint of superior Progression Free Survival (PFS) compared to pomalidomide with a Hazard Ratio (HR) of 0.792 (95% CI 0.640-0.979, p-value 0.0311) as determined by the IRC.