Biogen Announces Topline Results from Phase 3 Gene Therapy Study in Choroideremia

CAMBRIDGE, Mass. – Biogen Inc. (Nasdaq: BIIB) today announced topline results from the Phase 3 STAR study of timrepigene emparvovec (BIIB111/AAV2-REP1), an investigational gene therapy for the potential treatment of choroideremia. The STAR study did not meet its primary endpoint of proportion of participants with a ≥15 letter improvement from baseline in best corrected visual acuity (BCVA) at Month 12, in the interventional group in comparison to the non-interventional control group, as measured by the Early Treatment of Diabetic Retinopathy Study (ETDRS) chart. In addition, the study did not demonstrate efficacy on key secondary endpoints. Safety results from the Phase 3 STAR study were consistent with previous studies.

“We extend our deepest gratitude to all those who contributed to the STAR study, including the participants, investigators, site staff and the broader choroideremia community,” said Katherine Dawson, M.D., head of the Therapeutics Development Unit at Biogen. “While we are disappointed by the results of the STAR study, we are hopeful that the clinical insights gleaned from this study may help to shape therapeutic innovation for inherited retinal diseases including choroideremia, so that in the future there may be treatment options for the community affected by these debilitating disorders.”

Biogen will evaluate the complete data set before confirming next steps for the timrepigene emparvovec clinical development program. Detailed results of this study will be made available at a future scientific forum.

About timrepigene emparvovec (BIIB111/AAV2-REP1)
Timrepigene emparvovec is an investigational recombinant AAV2 vector designed to deliver a functional version of the human choroideremia gene into the retinal pigment epithelium and photoreceptor cells that aims to address the underlying genetic cause of choroideremia.

About the STAR Phase 3 Study (NCT03496012)
STAR was a Phase 3, multicenter, randomized, three-arm, parallel-controlled group study that enrolled 169 adult males with a genetically confirmed diagnosis of choroideremia. The study evaluated the safety and efficacy of a single subretinal injection of investigational timrepigene emparvovec. The primary endpoint was the proportion of patients with an improvement of at least 15 letters from baseline in best corrected visual acuity (BCVA) at 12 months post-treatment as measured by the Early Treatment Diabetic Retinopathy Study (ETDRS) chart. While the Phase 3 STAR study did not meet its primary endpoint, more information about the study is available here:

About Choroideremia
Choroideremia is a rare, inherited retinal disease resulting in progressive vision loss, ultimately leading to blindness. Choroideremia is an X-linked recessive chorioretinal disease that is caused by loss of function mutations in the choroideremia gene resulting in decreased Rab escort protein-1 (REP-1) expression which leads to degeneration of the retinal pigment epithelium, photoreceptors and choroid. Initially, patients with choroideremia experience poor night vision and over time, slow, progressive visual loss ultimately leads to blindness. Visual impairments due to choroideremia are associated with emotional, functional and economic burden.

About Biogen
At Biogen, our mission is clear: we are pioneers in neuroscience. Biogen discovers, develops and delivers worldwide innovative therapies for people living with serious neurological and neurodegenerative diseases as well as related therapeutic adjacencies. One of the world’s first global biotechnology companies, Biogen was founded in 1978 by Charles Weissmann, Heinz Schaller, Kenneth Murray and Nobel Prize winners Walter Gilbert and Phillip Sharp. Today Biogen has the leading portfolio of medicines to treat multiple sclerosis, has introduced the first approved treatment for spinal muscular atrophy, commercializes biosimilars of advanced biologics and is focused on advancing research programs in multiple sclerosis and neuroimmunology, Alzheimer’s disease and dementia, neuromuscular disorders, movement disorders, ophthalmology, neuropsychiatry, immunology, acute neurology and neuropathic pain.

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Allison Parks
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Mike Hencke
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