The US Food and Drug Administration (FDA) has granted a breakthrough therapy designation for its monoclonal antibody felzartamab as a treatment for late antibody-mediated rejection without T cell-mediated rejection in kidney transplant patients.

The company has previously received breakthrough therapy designation for felzartamab in primary membranous nephropathy (PMN) indication and orphan drug designations for the therapy in PMN and antibody-mediated rejection. Biogen also plans to start Phase III trials evaluating felzartamab in three indications, antibody-mediated rejection, PMN and IgA nephropathy (IgAN), next year.

The news also resulted in a modest uptick of Biogen’s stock, which was up by 1.9% at the market close yesterday (9 October) compared to the market close on the previous day. The company’s stock has suffered a decline in recent months. July was a turbulent month for Biogen as the European Medicines Agency (EMA) refused to approve its Alzheimer’s therapy Leqembi (lecanemab), developed in collaboration with Eisai. Soon after, its essential tremor therapy, SAGE-324, developed in partnership with Sage Therapeutics failed in a Phase II trial and the companies abandoned development.

The FDA’s decision for the breakthrough therapy designation was based on positive data from a Phase II trial (NCT05021484). The study enrolled 22 patients who experienced late antibody-mediated rejection at least six months post-kidney transplantation. After 24 weeks, 82% of patients in the treatment arm saw a resolution of antibody-mediated rejection, compared to 20% in the placebo group. Of the nine patients who experienced resolution with felzartamab at 24 weeks, 67% maintained resolution at 52 weeks.

Biogen has also seen positive mid-stage results with felzartamab in both PMN and IgAN indications.

Felzartamab is an anti-CD38 targeting monoclonal antibody. It is a recent addition to Biogen’s portfolio and was added as part of the $1.15bn Human Immunology Biosciences (HI-Bio) acquisition in July 2024. Felzartamab was originally developed by MorphoSys as a possible competitor to Johnson & Johnson (J&J) and Genmab’s multiple myeloma therapy Darzalex (daratumumab). Celgene briefly acquired the rights to the therapy in 2013 before HI-Bio licensed it for development outside China in 2022.

GlobalData, the parent company of Pharmaceutical Technology, expects the monoclonal antibody to pull in over $776m by 2032, should the therapy get approved.