HI-Bio Reports Positive Phase 2 Results for Felzartamab in Kidney Transplant Rejection

Human Immunology Biosciences (HI-Bio™), a biotechnology company focused on developing targeted treatments for severe immune-mediated diseases, has announced encouraging results from a Phase 2 clinical trial of felzartamab. This investigational monoclonal antibody aims to combat late antibody-mediated rejection (AMR) in kidney transplant patients. The findings were published in the New England Journal of Medicine and presented at the 61st European Renal Association (ERA) Congress.

Felzartamab works by targeting and depleting CD38+ cells, which include plasmablasts, plasma cells, and natural killer (NK) cells, all of which are thought to drive AMR. The Phase 2 study was double-blind and placebo-controlled, focusing on safety and tolerability in adults with late AMR occurring at least 180 days post-transplantation. A total of 22 patients were randomized to receive either felzartamab or a placebo over 20 weeks, followed by a 32-week observation period. Biopsies were performed at baseline, 24 weeks, and 52 weeks.

Results showed that felzartamab had a favorable safety profile, with most adverse events being mild to moderate. Infusion reactions were noted in eight patients, but there were no treatment-related discontinuations. Notably, 82% of patients treated with felzartamab experienced resolution of AMR at 24 weeks, compared to just 20% in the placebo group. One patient in the placebo group lost their graft at week 14 due to persistent AMR.

The study also demonstrated felzartamab's effectiveness in reducing disease-linked biomarkers and stabilizing kidney function. The median microvascular inflammation (MVI) score at week 24 was significantly lower in the felzartamab group, with 63% achieving an MVI score of zero. Additionally, 67% of those who had resolved AMR at 24 weeks maintained this resolution at 52 weeks without further treatment. There was also a notable reduction in donor-derived cell-free DNA (dd-cfDNA), an indicator of allograft injury, and stabilization of eGFR, which measures kidney function.

Principal Investigator Dr. Georg Böhmig from the Medical University of Vienna emphasized the unmet need for effective AMR treatments and highlighted the potential of felzartamab to preserve kidney function in these patients. The data support the advancement of felzartamab into late-stage development, with hopes of it becoming the first approved therapy for late AMR.

Antibody-mediated rejection remains a significant challenge in kidney transplantation, affecting approximately 23,000 recipients in the United States despite standard immunosuppressive treatments. AMR is a leading cause of transplant failure, with about 12% of kidney transplant recipients experiencing chronic AMR annually. Currently, effective treatments for chronic AMR are limited.

HI-Bio's Chief Medical Officer, Dr. Uptal Patel, expressed optimism about felzartamab's potential to address this critical need. The company plans to advance the drug into late-stage studies for both AMR and other immune-mediated diseases.

Felzartamab was originally developed for multiple myeloma by MorphoSys AG and has been exclusively licensed to HI-Bio for development and commercialization in all regions except China. The drug has shown promise in selectively depleting CD38+ cells, which are implicated in numerous immune-mediated conditions.

The findings from this Phase 2 trial mark a significant step forward in the quest for effective treatments for antibody-mediated rejection in kidney transplant recipients. With further research and development, felzartamab could potentially improve the clinical outcomes for thousands of patients facing this challenging condition.