Biogen earns breakthrough status for transplant anti-rejection drug

Biogen has achieved a significant milestone as the U.S. Food and Drug Administration (FDA) has granted breakthrough therapy designation for its monoclonal antibody, felzartamab. This designation applies to the treatment of late antibody-mediated rejection in kidney transplant patients, specifically where there is no T cell-mediated rejection.

Previously, felzartamab also received breakthrough therapy designation for treating primary membranous nephropathy (PMN), along with orphan drug designations for both PMN and antibody-mediated rejection. Biogen is preparing to initiate Phase III trials for felzartamab in 2025, focusing on three conditions: antibody-mediated rejection, PMN, and IgA nephropathy (IgAN).

This piece of news positively influenced Biogen's stock, which saw a 1.9% increase by the close of the market on October 9th compared to the previous day. This is a notable improvement given the company's recent struggles. In July, Biogen faced challenges when the European Medicines Agency (EMA) declined to approve its Alzheimer’s treatment, Leqembi, which was developed in collaboration with Eisai. Furthermore, the development of its essential tremor therapy, SAGE-324, was discontinued following an unsuccessful Phase II trial conducted in partnership with Sage Therapeutics.

The FDA’s decision to grant breakthrough therapy designation for felzartamab was underpinned by promising results from a Phase II trial (NCT05021484). This study involved 22 patients who experienced late antibody-mediated rejection at least six months after kidney transplantation. At the 24-week mark, 82% of patients in the treatment group showed a resolution of antibody-mediated rejection, compared to just 20% in the placebo group. Furthermore, 67% of those who experienced resolution at 24 weeks maintained it through the 52-week point.

Biogen has also reported favorable mid-stage outcomes for felzartamab in treating both PMN and IgAN. These positive results have reinforced the company's decision to proceed with further trials.

Felzartamab is an anti-CD38 targeting monoclonal antibody and has become a significant part of Biogen’s therapeutic arsenal. It was acquired through the $1.15 billion Human Immunology Biosciences (HI-Bio) acquisition in July 2024. Originally developed by MorphoSys, felzartamab was positioned as a potential competitor to Johnson & Johnson and Genmab’s multiple myeloma therapy, Darzalex (daratumumab). The rights to this therapy were briefly held by Celgene in 2013 before HI-Bio licensed it for development outside China in 2022.

According to GlobalData, felzartamab is expected to generate over $776 million in revenue by 2032, should it receive regulatory approval. This projection underscores the therapy’s potential significant impact on the market and the treatment landscape for patients experiencing antibody-mediated rejection post-kidney transplantation.