FDA Approves New Indication for Rituximab Biosimilar for Rheumatoid Arthritis

The FDA has approved rituximab-arrx (Riabni; Amgen), a biosimilar to the reference rituximab (Rituxan), in combination with methotrexate for patients with moderate to severely active rheumatoid arthritis (RA) who have shown an inadequate response to 1 or more tumor necrosis factor (TNF) antagonist therapies.

Riabni has already approved for the treatment of adult patients with non-Hodgkin lymphoma (NHL), chronic lymphocytic leukemia, granulomatosis with polyangiitis (GPA), and microscopic polyangiitis (MPA).

"The approval of Riabni is an important advancement for adults living with moderate to severe rheumatoid arthritis, a chronic inflammatory joint disease, who now have access to a proven and affordable treatment option," said Murdo Gordon, executive vice president of Global Commercial Operations at Amgen, in a press release. "Our fully integrated portfolio of innovative and biosimilar medicines for inflammatory diseases reinforces our commitment to providing patients with high-quality and affordable treatment options that deliver substantial value to our health care system."

Riabni is a CD20-directed cytolytic antibody found to be highly similar to, with no clinically meaningful differences in safety or efficacy from reference rituximab, based on the totality of data, which included comparative analytical, non-clinical, and clinical data, according to Amgen.

The active ingredient of Riabni is a biosimilar to rituximab, with the same amino acid sequence, the same strength, and with identical dosage form and route of administration, according to Agmgen. The biosimilar is not currently indicated for children with mature B-cell NHL, mature B-cell acute leukemia, MPA, or GPA. It is also not indicated in adults with moderate to severe pemphigus vulgaris, for which rituximab has been granted orphan drug status.

The efficacy, safety, pharmacokinetics, and immunogenicity of Riabni was analyzed compared with rituximab in patients with moderate to severe RA in a randomized, double-blind, comparative clinical study. The trial randomized 311 patients to be administered Riabni, rituximab RP approved in the EU (rituximab-EU), or rituximab RP approved in the United States (rituximab-US).

The rituximab-US cohort was transitioned over to Riabni in the second period of the study. The primary efficacy endpoint—change in disease activity score 28 using C-reactive protein (DAS28-CRP) from baseline at week 24—was within the predefined equivalence margin, which indicates equivalence in clinical efficacy between Riabni and rituximab RP, according to the study investigators.

They also noted that the safety, pharmacokinetics, and immunogenicity of Riabni were similar to rituximab RP.

Reference:

FDA Approves Riabni (Rituximab-Arrx), a Biosimilar To Rituxan (Rituximab), For Adults With Moderate To Severe Rheumatoid Arthritis. Amgen. News release. June 6, 2022. https://www.amgen.com/newsroom/press-releases/2022/06/fda-approves-riabni-rituximabarrx-a-biosimilar-to-rituxan-rituximab-for-adults-with-moderate-to-severe-rheumatoid-arthritis