SOUTH SAN FRANCISCO, Calif., – October 31, 2023 – Human Immunology Biosciences (HI-Bio™), a clinical-stage biotechnology company developing targeted therapies for patients with severe immune-mediated diseases (IMDs), today announced that the U.S. Food and Drug Administration (FDA) has granted Breakthrough Therapy designation for felzartamab in primary membranous nephropathy (PMN).

“The FDA’s decision to grant felzartamab Breakthrough Therapy designation is recognition of the promising data we have collected to date, as well as an acknowledgement of the need for major advances over available therapies in the treatment of patients with PMN,” said Uptal Patel, M.D., Chief Medical Officer at HI-Bio. “We believe that the cellular depletion strategy with felzartamab in PMN is applicable to many more immune-mediated diseases driven by antibodies produced in CD38+ plasma cells. For that reason, we are currently developing felzartamab in multiple diseases including PMN, IgA nephropathy, antibody-mediated rejection and lupus nephritis.” 

The FDA selectively grants Breakthrough Therapy designation to expedite the development and review of drugs that are intended to treat a serious or life-threatening condition and preliminary clinical evidence indicates the drug may demonstrate substantial improvement over available therapy on a clinically significant endpoint(s). The designation comes with eligibility for more frequent regulatory interactions to ensure collection of appropriate data needed to support drug approval, and the potential for accelerated approval, priority review, and rolling review of a Biologics License Application (BLA).

The designation for felzartamab was based on clinical data submitted to the FDA, including results from M-PLACE, a Phase 1b/2a proof-of-concept, open-label, study. The final analysis of the M-PLACE study has been accepted as an oral presentation at the American Society of Nephrology (ASN) Kidney Week 2023 Annual Meeting (Abstract TH-OR27) by Brad Rovin, M.D., Director of the Division of Nephrology at Ohio State University.

About Primary Membranous Nephropathy (PMN)

PMN is a rare autoantibody-mediated autoimmune kidney disease and a leading cause of nephrotic syndrome (NS) in adults worldwide. Disease onset and diagnosis typically occurs between 40 and 50 years of age, with 80% of patients presenting with nephrotic syndrome (i.e., edema, >3.5 g/day proteinuria, hypoalbuminemia). PMN is characterized by a thickening of the glomerular basement membrane (GBM) due to the formation and deposition of immune complexes in this space between podocytes and the glomerular endothelium of the kidney. 

Approximately 80% of PMN cases arise due to autoantibodies that recognize the phospholipase A2 receptor (PLA2R) antigen expressed on podocytes. Anti-PLA2R is both a diagnostic and prognostic biomarker, and total aPLA2R antibody level has been shown to be a biomarker for prognosis of outcome in patients with PMN. Other autoantibodies have been identified in patients with PMN including anti-THSD7A, NELL-1 and Sema3B, further supporting the role of antibody-secreting plasma cells in the pathophysiology of PMN. CD38+ long-lived plasma cells and plasmablasts are a main source of autoantibodies. 

There are no approved therapies for PMN. The current standard of care comprises off-label use of supportive care measures (e.g., angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, statins, and diuretics), conventional immunosuppressive treatments (ISTs) (e.g. cyclophosphamide combined with steroids and calcineurin inhibitors) or B-cell depleting agents (e.g. anti-CD20 antibodies). However, these treatments are not effective in all patients, with a significant proportion of patients not achieving remission or relapsing. In addition, conventional immunosuppressive treatments are associated with a high risk of toxicity.

About Felzartamab

Felzartamab is an investigational therapeutic human monoclonal antibody directed against CD38, a protein expressed on mature plasma cells. By targeting CD38, felzartamab has the potential to deplete CD38+ plasma cells while leaving other functionally important plasma cells intact, which may ultimately improve clinical outcomes in a broad range of autoantibody driven diseases.

HI-Bio is focused on developing felzartamab in a number of autoantibody-driven immune-mediated diseases, including primary membranous nephropathy (PMN), IgA nephropathy (IgAN), antibody-mediated rejection (AMR) and lupus nephritis (LN). In May, felzartamab received Orphan Drug Designation (ODD) from the FDA for treatment of PMN. ODD was achieved following data from two Phase 2 studies of felzartamab in PMN showing dose-dependent reductions in pathogenic antibody levels.

HI-Bio in-licensed felzartamab from MorphoSys in June 2022, and holds exclusive worldwide rights for felzartamab with the exception of Greater China. In 2017, MorphoSys entered into an exclusive regional licensing agreement with I-Mab Biopharma to develop and commercialize felzartamab in Greater China which encompasses Mainland China, Hong Kong, Macau and Taiwan. I-Mab is evaluating felzartamab in oncology and autoimmune diseases.  

Felzartamab is an investigational drug that has not yet been approved by any regulatory authorities.

About HI-Bio 

Human Immunology Biosciences, Inc. (HI-Bio™) is a clinical-stage biotechnology company focused on discovering and developing precision medicines for people suffering from immune-mediated diseases (IMDs). HI-Bio is leading clinical immunology into its next chapter by targeting cellular drivers of disease. To learn more about HI-Bio, visit us at www.hibio.com or follow us on LinkedIn and Twitter.