REFLECTIONS B328-06 study of PF 05280586 meets primary endpoint in follicular lymphoma.- Pfizer.

Pfizer announced at the American Society of Hematology Annual Meeting that the REFLECTIONS B328-06 study, a comparative safety and efficacy study of PF 05280586 biosimilar versus Rituxan/MabThera (rituximab-EU), met its primary endpoint of overall response rate (ORR) at Week 26 of the 52-week study. In the 26-week data from the ongoing 52-week REFLECTIONS B328-06 study (n=394), there were no clinically meaningful differences in efficacy, in terms of ORR at Week 26, between PF 05280586 and MabThera, for the first-line treatment of patients with CD20-positive, low tumor burden, follicular lymphoma (LTB-FL). The ORR at Week 26 was 75.5% (PF 05280586) vs 70.7% (rituximab-EU), and was within the pre-specified equivalence margin. ORR is defined as the percentage of patients achieving complete response (CR) or partial response (PR), based on central review. Additionally, estimated rates of one-year progression-free survival were similar across groups (76.4% vs. 81.2% in the PF-05280586 and MabThera groups, respectively). The results also show that PF 05280586 had a similar safety profile to MabThera.

Comment: PF 05280586 has been accepted for review by the FDA, the BsUFA goal date for a decision by the FDA is in second-quarter 2019. Pfizer is also working towards making PF-05280586 available for patients in Europe. Further results on the safety and efficacy from this ongoing 52-week study in LTB-FL are expected to be presented next year.