Novartis has agreed to acquire SNV4818, a pan-mutant-selective PI3Kα inhibitor for breast cancer, from Synnovation Therapeutics in a deal worth up to $3 billion – $2 billion upfront and up to $1 billion in milestone payments. The transaction is expected to close in the first half of 2026.
The drug targets a well-defined patient population: Approximately 40% of women with HR+/HER2- breast cancer carry PIK3CA mutations that drive worse disease prognosis. Existing PI3Kα inhibitors block both the mutated and normal forms of the enzyme, leading to tolerability issues that make it difficult to keep patients on treatment. SNV4818 is designed to selectively target only the mutated form in cancer cells while sparing healthy cells – an approach aimed at reducing side effects, supporting more consistent dosing, and enabling earlier combination with hormonal therapy and other treatments.
“While mutated PI3Kα is a well-established driver in HR+/HER2- breast cancer, there remains a challenge in achieving effective pathway inhibition with a tolerable therapeutic profile,” said Shreeram Aradhye, MD, president of development at Novartis. “SNV4818 applies new mutant-selective chemistry to more precisely target tumor biology while sparing normal cells.”
SNV4818 is currently in a Phase 1/2 clinical study for breast cancer and other advanced solid tumors. Preclinical studies have shown strong activity against common PIK3CA mutations with clear selectivity over the normal enzyme.
The $3 billion deal size underscores how much commercial value exists in breast cancer therapeutics when the science targets a clearly defined mutation with a large patient population – and how much room remains for improvement in tolerability, which has been the limiting factor for PI3Kα inhibitors to date.
