Biogen acquires Nightstar Therapeutics and with it NSR-REP1 for the treatment of choroideremia

Biogen announced that it has entered into an agreement to acquire Nightstar Therapeutics, a clinical-stage gene therapy company based in London, United Kingdom, which is focused on adeno-associated virus (AAV) treatments for inherited retinal disorders. Under the terms of the proposed acquisition, Biogen will pay $25.50 in cash for each NST share. This offer represents a total transaction value of approximately $800 million on a fully diluted basis, after taking into account expected transaction expenses and anticipated cash at closing. NST�s lead asset is NSR-REP1 for the treatment of choroideremia (CHM), a rare, degenerative, X-linked inherited retinal disorder, which 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.