Eli Lilly is acquiring Scorpion’s cancer program in a potential multi-billion deal. As part of the deal, Lilly will get STX-478, a selective PI3Kα in Phase I/II clinical trials for breast cancer and other advanced solid tumors.
The key word here is “selective,” because other such drug candidates have raised safety concerns. But there are already winners in the category. In October of last year, Roche won FDA approval for its PI3K inhibitor ITOVEBI, for breast cancer, with sales projections of $2B plus sales projections. Novartis’s PI3K-inhibiting breast cancer treatment, Piqray, was approved in 2019. It generated $505M in revenue in 2023.
“The selectivity profile of STX-478 has led to a differentiated clinical profile, enabling use in combinations with standard-of-care therapies to potentially deliver meaningful impact in earlier treatment settings when there is the best opportunity to improve outcomes for patients,” said Jacob Van Naarden, executive vice president and president of Lilly Oncology.
Lilly also gets the name “Scorpion” in the deal, while Scorpion itself will spin out its employees and non-STX-478 work into a new entity, whose name was not yet announced. The new company will be owned by Scorpion’s shareholders, with Lilly retaining a minority stake.
STX-478, is a novel small molecule that binds to phosphoinositide 3-kinase alpha (PI3Kα), one of the most commonly mutated genes across all cancer types, occurring in approximately 14% of all cancers. By selectively targeting the pathway in cancerous but not healthy cells, this approach could potentially offer better disease control through deeper pathway inhibition, as well as improved tolerability.
In September, Scorpion released interim Phase I/II data. The drug achieved a monotherapy overall response rate (ORR) of 23% in breast cancer and 21% in all tumors, and tumor reductions seen in 72% of patients as a monotherapy, with mutant PIK3CA circulating tumor DNA (ctDNA) declined in 86% of patients.
“PI3Kα mutations occur in a meaningful proportion of hormone-positive breast cancers, and there is significant unmet need for new treatment options that effectively and safely target this pathway,” said Van Naarden.
Under the terms of the agreement, Scorpion shareholders could receive up to $2.5 billion in cash, inclusive of an upfront payment and subsequent payments upon achievement of certain regulatory and sales milestones. Additionally, as part of the transaction, the new, independent company Scorpion spins out would be owned by Scorpion’s current shareholders, with Lilly holding a minority equity interest.
“Lilly has advanced scientific breakthroughs for some of the most difficult-to-treat cancers,” said Adam Friedman, MD, PhD, president and chief executive officer of Scorpion. “We believe Lilly’s global capabilities and strategic commitment to patients with breast cancer will accelerate our goal of developing STX-478 to improve outcomes for the many patients with solid tumors driven by PI3Kα mutations. This acquisition is a testament to the expertise of the Scorpion team and our drug discovery capabilities, which will become the foundation of our new company.”
