Lilly Acquires Non-Opioid Pain Startup SiteOne for Up to $1B

Eli Lilly has strategically expanded its portfolio in pain management by acquiring SiteOne Therapeutics, marking its entry into the sodium channel inhibitor market. While the upfront financial terms were kept under wraps, the total transaction could reach a value of $1 billion, contingent upon achieving specific regulatory and commercial milestones. This acquisition follows a significant milestone for SiteOne, as the biotech firm recently secured a $100 million Series C funding round in December. Additionally, in January, the U.S. Food and Drug Administration (FDA) approved Vertex Pharmaceuticals' NaV1.8 inhibitor, Journavx (suzetrigine), marking the first non-opioid pain medication approval in over twenty years.

SiteOne Therapeutics is actively advancing its lead program, STC-004, which targets the NaV1.8 sodium channel. The company has shared Phase I trial results, indicating that the compound was well-tolerated and rapidly absorbed, making it suitable for once-daily oral administration. Building on these promising pharmacokinetic findings, SiteOne has outlined plans to initiate a Phase II clinical trial in the coming months. According to SiteOne CEO John Mulcahy, STC-004 aims to provide "the maximum level of efficacy that is possible" by effectively blocking the ion channel. Alongside STC-004, SiteOne is also working on several NaV1.7-targeting programs, one of which is in collaboration with Vertex under a 2022 agreement. Additionally, they are developing STC-002, a topical treatment candidate for ocular surface pain.

The non-opioid pain management space presents significant unmet needs and potential value, attracting several startups like SiteOne to explore sodium channel inhibitors. Another company, Latigo Biotherapeutics, has raised $150 million in a Series B funding round to support the development of NaV1.8 inhibitors LTG-001 and LTG-305, currently in Phase II trials for acute pain and Phase I trials for chronic pain, respectively. The success of Vertex's Journavx, which is projected to become a multi-billion-dollar product, has further fueled investor interest, as highlighted in a recent investor call where Vertex management praised the drug's initial market introduction.

Eli Lilly's current pain management pipeline, while lacking a NaV channel blocker, is robust, featuring three mid-stage programs and numerous early-stage assets yet to be disclosed. According to the company's website, three candidates are undergoing Phase II trials for pain management: LY3848575, a monoclonal antibody targeting human epiregulin; mazisotine (LY3556050), a small molecule SSTR4 agonist designed to modulate somatostatin signaling to reduce nerve excitability and inflammation; and LY3857210, an oral small molecule antagonist targeting the ATP ligand-gated ion channel P2X7, capable of penetrating the brain.

Mark Mintun, Lilly's group vice president of neuroscience research and development, emphasized the importance of finding effective non-opioid pain treatments, stating, "An effective non-opioid treatment remains elusive." He also expressed the company's commitment to advancing the development of STC-004, highlighting the potential impact of this acquisition on addressing significant gaps in pain management. With the addition of SiteOne's innovative approach to sodium channel inhibition, Eli Lilly is poised to make substantial contributions to the field of non-opioid pain therapies.