Biogen announces topline results from phase II/III gene therapy study of BIIB 112 for X-linked retinitis pigmentosa.

Biogen Inc. announced topline results from the Phase II/III XIRIUS study of cotoretigene toliparvovec (BIIB 112), a gene therapy being investigated as a one-time therapy for patients with X-linked retinitis pigmentosa (XLRP). XLRP is a rare, inherited retinal disease that is associated with progressive vision loss as the light-sensing cells of the retina gradually deteriorate. Initial symptoms are difficulty seeing at night, followed by restriction of the field of vision and eventually blindness in most people by the age of 40. Patients living with XLRP currently have no approved treatments. The XIRIUS study did not meet its primary endpoint of demonstrating a statistically significant improvement in the proportion of treated study eyes with greater than 7 dB improvement from baseline at greater than 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 II/III 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,” said Katherine Dawson, M.D., head of the therapeutics development unit at Biogen. “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. Biogen is advancing its multi-franchise portfolio strategy by pursuing modalities including gene therapy to address significant unmet medical needs. In ophthalmology, in addition to cotoretigene toliparvovec, the company is currently evaluating the safety and efficacy of timrepigene emparvovec (BIIB 111/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.