FDA Approves Rituximab Biosimilar for NHL, CLL, GPA, and MPA

The FDA has approved rituximab-arrx, a biosimilar to rituximab (Rituxan), for the treatment of adult patients with non-Hodgkin lymphoma (NHL), chronic lymphocytic leukemia (CLL), granulomatosis with polyangiitis (GPA; Wegener's Granulomatosis), and microscopic polyangiitis (MPA).

"The approval of [rituximab-arrx] represents an important milestone across our biosimilar and oncology portfolios," Murdo Gordon, executive vice president of Global Commercial Operations at Amgen, stated in a press release. "Following the proven success of Kanjinti [trastuzumab-anns] and Mvasi [bevacizumab-awwb] in the US marketplace, [rituximab-arrx] reaffirms Amgen's long-term commitment to providing high quality biosimilars that can potentially offer more affordable, effective treatment options for cancer and other serious diseases and that contribute to the sustainability of healthcare systems."

A CD20-targeted cytolytic antibody, rituximab-arrx was found to be highly similar to rituximab based on a totality of evidence, which comrpised comparative analytical, nonclinical, and clinical findings. Moreover, no clinically meaningful differences in safety or effectiveness were observed between the 2 products.

Notably, the data package included data from a pharmacokinetic (PK) similarity study, as well as a comparative clinical study.

In the randomized, double-blind, comparative clinical study, investigators set out to examine the efficacy, PK, pharmacodynamics (PD), safety, tolerability, and immunogenicity of the biosimilar versus rituximab in patients who had grade 1, 2, or 3a follicular B-cell NHL and low tumor burden.

A total of 256 patients were enrolled to the trial. Participants were randomized in a 1:1 fashion to receive an intravenous infusion of either the biosimilar or rituximab, at a dose of 375 mg/m², once weekly for the duration of 4 weeks; this was followed by dosing administered at weeks 12 and 20.

The primary end point of the trial was an assessment of overall response rate (ORR) by week 28. Results indicated that this was within the prespecified margin for the biosimilar versus the reference product. Rituximab-arrx was found to demonstrate clinical equivalence. Additionally, the data pertaining to the PK, PD, safety, and immunogenicity of rituximab-arrx also proved to be similar to that of rituximab.

Additionally, the Wholesale Acquisition Cost (WAC) of the biosimilar in the United States will be 23.7% lower than rituximab, according to Amgen. Specifically, rituximab-arrx the biosimilar will be made available at a WAC of $716.80 per 100 mg. For each 500-mg single-dose vial, the WAC for rituximab-arrx is $3,584.00. Notably, this is 23.7% less than both the WAC for rituximab, and 15.2% less than that Truxima rituximab biosimilar; it matches the WAC for the Ruxience rituximab biosimilar.

At the time of launch, rituximab-arrx will be priced 16.7% below the current Rituxan Average Selling Price, added Amgen.

The newly approved product will be made available to wholesalers and speciality distributors in the United States in January 2021.

Reference

FDA approves Amgen's Riabni (rituximab-arrx), a biosimilar to Rituxan (rituximab). News release. Amgen. December 17, 2020. Accessed December 17, 2020. http://prn.to/34oVHpX.