On June 17, 2026, Biogen Inc. (Nasdaq: BIIB) announced that it has entered into a definitive agreement to acquire RayThera Inc., a private biotechnology company focused on the discovery and development of small molecule therapies in immunology. Under the agreement, Biogen has agreed to acquire RayThera for up to $1 billion, consisting of an upfront payment and, predominantly, payments contingent upon the achievement of future clinical and regulatory milestones.

WilmerHale is representing Biogen in the transaction, with a team led by Partners Chris Barnstable-Brown and Eric Levine that also included Senior Associate Shaina Hourizadeh and Associates Joseph Odegaard and Sophie Bonadeo on M&A and corporate matters, and Partners Kim Wethly, Judith Hasko, Ariella Feingold, Amanda Albert, Michael Kaplan, Dominic Vote, Kirk Nahra, and Bruce Manheim, Counsels Ben Kelsey, Mike Sweeney, Sarah Pugh, and Michael Lenzi, and Associates Cole Swaffield, Himani Nadgauda, Sarah Litwin, and Ashley Leon on equity compensation, tax, employment, technology transactions, employee benefits, antitrust, intellectual property, privacy, and regulatory matters. Summer Associate Katelyn Schwarz also provided assistance on M&A and corporate matters.