By Marie Daghlian

Biogen, best known for a strong focus on neurodegenerative diseases, is diversifying into ophthalmology and gene therapy with the acquisition of U.K.-based Nightstar Therapeutics for $25.50 in cash per shares, or about $800 million.

“Ophthalmology is an emerging growth area for Biogen, and we are excited about the opportunity to work with the talented employees at Nightstar to advance potentially transformative gene therapy programs for rare retinal diseases,” said Michel Vounatsos, CEO of Biogen. “Nightstar will accelerate our entry into ophthalmology by contributing two mid- to late-stage gene therapy assets, with the potential to create long-term shareholder value.”

Nightstar is focused on developing gene therapies for patients suffering from rare inherited retinal diseases that would otherwise lead to blindness, with two programs in the clinic and a pipeline of preclinical programs. Its lead asset is in late-stage development for choroideremia (CHM), a rare degenerative, X-linked inherited retinal disorder that leads to blindness and has no approved treatments.

CHM primarily affects males and is caused by loss of function in the CHM gene which encodes the Rab escort protein-1 (REP-1). The REP-1 protein plays a role in intracellular protein trafficking, and loss of function in the CHM gene leads to abnormal intracellular protein trafficking and impaired elimination of waste products from the retinal pigment epithelium and photoreceptors. Initially, patients with CHM experience poor night vision, and over time progressive visual loss ultimately leads to complete blindness.

Nightstar’s gene therapy, NSR-REP1, is comprised of an AAV vector administered by subretinal injection which provides a functioning CHM gene and expression of the REP-1 protein to restore membrane trafficking and thereby slow, stop, or potentially reverse the decline in vision. Data from an early trial demonstrated potentially meaningful slowing of decline in visual acuity as compared to natural history as well as signs of improved visual acuity in some patients. NSR-REP1 is currently being evaluated in an ongoing late-stage trial with data expected in the second half of 2020.

Nightstar also has a clinical program for treating X-linked retinitis pigmentosa (XLRP), another rare inherited retinal disease primarily affecting males with no approved treatments. XLRP is characterized by mutations in the retinitis pigmentosa GTPase regulator (RPGR) gene leading to a lack of active protein transport in photoreceptors. This abnormality leads to loss of the photoreceptor cells, resulting in retinal dysfunction by adolescence and early adulthood, progressing to legal blindness when patients reach their 40s.

The biotech’s preclinical pipeline includes a treatment in development for Stargardt disease and potential programs targeting Best vitelliform macular dystrophy (Best disease) and other genetic forms of retinitis pigmentosa.

Biogen will fund the acquisition with cash on hand and expects it to be completed by mid-year 2019.

Photo: Michel Vounatsos, CEO of Biogen