6 December 2018 - - US-based pharmaceutical company Pfizer Inc. (NYSE: PFE) presented at the American Society of Hematology annual meeting that the REFLECTIONS B328-06 study, a comparative safety and efficacy study of PF-05280586 versus Rituxan/MabThera (rituximab-EU)i, met its primary endpoint of overall response rate at Week 26 of the 52-week study.

26-week data from the ongoing 52-week REFLECTIONS B328-06 study (n=394) demonstrated 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).1 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 or partial response, 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.

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.

PF-05280586 is a monoclonal antibody that is in development as a potential biosimilar to Rituxan/MabThera. Rituxan/MabThera is indicated for the treatment of patients with certain types of CD20-positive non-Hodgkin lymphoma; CD20-positive chronic lymphocytic leukemia; rheumatoid arthritis; granulomatosis with polyangiitis and microscopic polyangiitis; and other region-specific indications.

PF-05280586 is an investigational compound and has not received regulatory approval in any country. Biosimilarity has not yet been established by regulatory authorities.

REFLECTIONS B328-06 is a randomised, 52-week double-blind clinical trial evaluating the efficacy, safety and immunogenicity, pharmacokinetics and pharmodynamics of PF-05280586 versus MabThera for the first-line treatment of patients with CD20-positive, low tumor burden, follicular lymphoma.