Biogen Therapy for Retinal Disease Misses Endpoint

Biogen says its 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), did not meet its primary endpoint. XLRP is a rare, inherited retinal disease that is associated with progressive vision loss as the retina’s light-sensing cells 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.

Despite missing the primary endpoint of demonstrating a statistically significant improvement in the proportion of treated study eyes as assessed by Macular Integrity Assessment microperimetry, the company says it is still encouraged by positive trends in other pre-specified clinically relevant endpoints, such as a measure of visual acuity under low light conditions.