Biogen’s Phase 2/3 Gene Therapy Study for XLRP Fails to Meet Primary Endpoint
Biogen announced topline results from the phase 2/3 XIRIUS study of cotoretigene toliparvovec (BIIB112), a gene therapy being investigated as a one-time therapy for patients with X-linked retinitis pigmentosa (XLRP).
The XIRIUS study did not meet its primary endpoint of demonstrating a statistically significant improvement in the proportion of treated study eyes with ≥7 dB improvement from baseline at ≥5 of the 16 central loci of the 10-2 grid assessed by Macular Integrity Assessment (MAIA) microperimetry. This assessment was performed at 12 months and compared to the study eye of patients randomized to the untreated control group. Positive trends were observed across several clinically relevant prespecified secondary endpoints.
“Although the phase 2/3 XIRIUS study of cotoretigene toliparvovec did not meet its primary endpoint, we are encouraged by positive trends in other pre-specified clinically relevant endpoints, such as a measure of visual acuity under low light conditions,” Katherine Dawson, MD, head of the therapeutics development unit at Biogen, said in a company news release. “XLRP is a serious, early-onset form of retinitis pigmentosa, and people living with it face almost certain blindness by the end of the fourth decade, commonly leading to loss of independence, depression and unemployment. We are working to further evaluate the data from the XIRIUS study before communicating potential next steps for the cotoretigene toliparvovec clinical development program.”
Most adverse events were ocular in nature, mild-to-moderate in severity, and resolved.
Complete analysis of the XIRIUS study is ongoing, and detailed results will be shared in a future scientific forum.
In ophthalmology, in addition to cotoretigene toliparvovec, Biogen is currently evaluating the safety and efficacy of timrepigene emparvovec (BIIB111/AAV2-REP1), a gene therapy being investigated for the one-time treatment of choroideremia, a rare inherited retinal disease. The company also announced a global collaboration and licensing agreement with ViGeneron GmbH to develop and commercialize gene therapy products based on adeno-associated virus (AAV) vectors with the aim of treating inherited eye diseases as well as a licensing agreement with Massachusetts Eye and Ear to develop a gene therapy for the potential treatment of inherited retinal degeneration due to mutations in the PRPF31 gene. In addition to Biogen’s gene therapy candidates for various ophthalmic conditions, the company also entered into an agreement with Catalyst Biosciences to develop and commercialize pegylated CB 2782 for the potential treatment of geographic atrophy, an advanced form of dry age-related macular degeneration that leads to blindness that has no approved therapies.