ReGenTree LLC, a US joint venture company owned by GtreeBNT Co. and RegeneRx Biopharmaceuticals, announced the results of a randomized, double masked, placebo-controlled phase 3 clinical trial (SEER-1) using RGN-259 for the treatment of neurotrophic keratopathy (NK).
The study originally planned to recruit 46 patients using RGN-259, the same eye drop formulation used in the dry eye trials. However, because of slow patient recruitment and future pricing strategy for NK as a rare disease, the trial was closed early and 18 patients were analyzed. Six out of 10 patients in the RGN-259 treated group and 1 out of 8 patients in the placebo treated group achieved complete corneal healing in 4 weeks. In terms of the primary endpoint, “ratio of corneal wound healed patients after four weeks’ administration”, the statistical difference was slightly over 0.05 (P = 0.0656, Fisher’s exact test), due to the limited number of patients in each group. When another statistical analysis method was used to analyze the same primary endpoint (Chi square test), there was statistical significance (P=0.0400).
In addition, in a pre-specified secondary endpoint evaluating corneal epithelial healing at day 43 (two weeks post treatment) and the durability of RGN-259 treatment, the company also confirmed a clear statistical difference using the Fisher’s exact test (P=0.0359). Several other efficacy parameters were either highly significant or strongly trending toward statistical significance in the RGN-259 group indicating the depth of patient response to RGN-259.
“These results strongly demonstrated the efficacy of RGN-259 in NK, despite a very small number of patients. As expected, it was well tolerated and there were no safety issues associated with our drug,” the company stated in the news release.
During the past several years, ReGenTree began developing a modified eye drop formulation that it believes will enhance the efficacy of thymosin beta 4 for NK, improve the patient experience, and allow a proprietary valued orphan product price for this rare disease. The company has completed a preliminary formulation for NK patients that will be considered for use in future clinical study.
On April 30, 2020, the company met with the FDA for a discussion about future development directions and received a positive assessment of Biologics License Application (BLA) readiness for non-clinical animal testing, manufacturing methods, and quality control. A discussion on clinical design and trial requirements for BLA approval was also reviewed.
NK is a corneal disease with decreased sensitivity of the cornea resulting in corneal degeneration that worsens to corneal perforation in severe cases leading to blindness. It is a rare disease that occurs in about 5 per 10,000 people in the United States. So far, the only approved treatment to date is the Oxervate sold by Dompé Farmaceutici S.p.A., Italy. It is a recombinant protein drug comprising human nerve growth factor, which costs about $47,200 per month.
“Oxervate sales with extremely high-pricing have made global pharmaceutical companies interested in NK. We expect that the outcome in our NK trial will stimulate considerable interest in RGN-259 in the ophthalmology market space,” stated an official from the company.