Eli Lilly and Company (NYSE: LLY) today announced that it has entered into a definitive agreement to acquire SiteOne Therapeutics, a privately held biotech company focused on developing non-opioid pain therapies, in a transaction valued at up to $1 billion. This Eli Lilly $1B deal non-opioid pain drug acquisition expands Lilly’s neuroscience pipeline and reinforces its commitment to delivering innovative, addiction-free treatments for chronic pain.

The acquisition includes STC-004, SiteOne’s phase 2-ready Nav1.8 inhibitor, a promising non-opioid candidate that may represent a next-generation approach to pain management. The transaction follows SiteOne’s $100 million Series C funding round in December, which supported the continued development of its selective ion channel modulators targeting pain, cough, and sensory disorders.

"The global burden of chronic pain continues to rise, and effective non-opioid treatments remain a critical unmet need," said Mark Mintun, M.D., Lilly’s Group Vice President of Neuroscience Research and Development. "We are excited to work alongside the talented SiteOne team to advance STC-004 and bring forward new therapies that can help patients manage pain without the risk of addiction."

SiteOne’s lead candidate, STC-004, targets the Nav1.8 sodium channel, predominantly expressed in the peripheral nervous system, which plays a key role in pain signaling. The approach has shown potential to deliver analgesia with reduced risk of side effects and abuse, distinguishing it from traditional central nervous system-focused pain medications.

In addition to STC-004, SiteOne is exploring a broader platform of genetically and clinically validated targets aimed at treating pain and sensory hyperexcitability disorders.

Under the terms of the agreement, SiteOne shareholders are eligible to receive up to $1 billion, inclusive of an upfront payment and subsequent milestone-based payments tied to regulatory and commercial achievements. The transaction is subject to customary closing conditions.

J.P. Morgan Securities LLC served as financial adviser to Eli Lilly, with Jones Day providing legal counsel. Centerview Partners LLC acted as financial adviser to SiteOne, while Skadden, Arps, Slate, Meagher & Flom LLP and Cooley LLP served as legal counsel.

This strategic acquisition underscores Lilly's commitment to advancing innovative, non-opioid solutions to help address the growing global need for safer and more effective pain therapies.