The US Food and Drug Administration (FDA) has granted orphan drug designation (ODD) to Human Immunology Biosciences’ (HI-Bio) investigational therapeutic felzartamab, to treat antibody-mediated rejection (AMR) in kidney transplant recipients.

The designation is a significant step in the development of felzartamab, a monoclonal antibody targeting cluster of differentiation 38 (CD38), which is involved in the production of pathogenic antibodies. It selectively depletes CD38+ plasma cells.

Clinical trials demonstrated its potential to improve outcomes in diseases caused by these pathogenic antibodies.

HI-Bio is developing felzartamab for immune-mediated diseases including AMR, IgA nephropathy, lupus nephritis and primary membranous nephropathy (PMN).

The FDA has previously awarded felzartamab both breakthrough therapy and orphan drug statuses for PMN treatment.

HI-Bio acquired exclusive global rights to felzartamab, excluding Greater China, through a licensing agreement with MorphoSys in 2022.

The FDA’s ODD provides HI-Bio with development incentives such as tax credits for qualified clinical studies, a waiver of FDA application fees and the potential for seven-year market exclusivity upon regulatory approval.

AMR is a leading cause of kidney transplant failure with no current effective treatment.

The condition is associated with donor-specific antibody production by plasma cells and the infiltration of natural killer cells, which contribute to microvascular inflammation.

HI-Bio chief medical officer Uptal Patel said: “Following the FDA’s granting of breakthrough therapy designation for felzartamab in primary membranous nephropathy, we are encouraged to receive orphan drug designation for felzartamab for antibody-mediated rejection.

“We are confident in the clinical progress of our anti-CD38 cellular depletion strategy, which to date, has resulted in proof-of-concept data in multiple severe immune-mediated diseases, including antibody-mediated rejection, IgA nephropathy and primary membranous nephropathy.”