FDA Approves Biosimilar to Rituximab as Treatment for Hematologic Malignancies

A new rituximab biosimilar from Amgen is now FDA approved, providing more treatment options to patients with certain hematologic cancers.

The FDA has approved the CD20-directed cytolytic antibody rituximab-arrx (Riabni), a biosimilar to rituximab (Rituxan), for the treatment of adults with non-Hodgkin lymphoma (NHL), chronic lymphocytic leukemia, granulomatosis with polyangiitis (Wegener’s granulomatosis), and microscopic polyangiitis, according to Amgen, the developer of the biologic.

Rituximab-arrx was shown to be highly similar to reference rituximab based on a totality of evidence, which included comparative analytical, nonclinical, and clinical data. Importantly, no clinically meaningful differences in safety or effectiveness were observed. The data were partially composed of results from a pharmacokinetic (PK) similarity study and a comparative clinical study.

The randomized, double-blind, comparative clinical study evaluated efficacy, PKs, pharmacodynamics (PDs), safety, tolerability, and immunogenicity of rituximab-arrx versus rituximab in individuals with grade 1, 2, or 3a follicular B-cell NHL and low tumor burden. In total, 256 patients were enrolled and randomized 1:1 to receive a 375 mg/m2 intravenous infusion dose of either rituximab-arrx or rituximab once weekly for 4 weeks followed by dosing at weeks 12 and 20.

The primary end point of overall response rate (ORR) by week 28 was found to be within the prespecified margin for rituximab-arrx compared to rituximab, demonstrating clinical similarity. Additionally, PK, PD, safety, and immunogenicity of rituximab-arrx were also comparable to that observed with rituximab.

“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, said in a press release. “Following the proven success of Kanjinti (trastuzumab-anns) and Mvasi (bevacizumab-awwb) in the [United States] 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.”

Amgen indicated that rituximab-arrx will be made available in the United States in January 2021.


FDA approves Amgen’s RIABNI (rituximab-arrx), a biosimilar to Rituxan (rituximab). News release. Amgen. Published December 17, 2020. Accessed December 17, 2020. https://www.prnewswire.com/news-releases/fda-approves-amgens-riabni-rituximab-arrx-a-biosimilar-to-rituxan-rituximab-301195492.html