What You Should Know
- The Deal: Sensei Biotherapeutics has acquired Faeth Therapeutics in a stock-for-stock transaction. Concurrently, Sensei raised a massive $200M in private placement financing to fuel the combined company.
- The Asset: The centerpiece of the deal is PIKTOR, an oral drug combination that targets the PI3K/AKT/mTOR pathway. Unlike previous drugs that hit just one “node,” PIKTOR hits multiple nodes simultaneously to prevent the tumor from finding a workaround.
- The Promise: In early trials, PIKTOR showed a 71% response rate in patients with specific mutations, including complete responses in advanced endometrial cancer. The new funding will carry the drug through Phase 2 data expected by the end of 2026.
The “Multi-Node” Innovation
In oncology, the PI3K pathway is like a hydra. It is one of the most common drivers of cancer, yet every time drugmakers try to cut off one head (inhibiting one node), two more grow back (the tumor activates feedback loops to survive). The problem with previous PI3K drugs has always been a tradeoff: hit the pathway hard enough to kill the cancer, and the toxicity kills the patient. Hit it gently, and the cancer adapts.
“In the PI3K pathway, the field has repeatedly run into the same constraint. Single-node inhibitors force a tradeoff between efficacy and tolerability,” said Anand Parikh, Co-founder of Faeth Therapeutics and new Chief Operating Officer and director of Sensei. “PIKTOR is designed to change that tradeoff by inhibiting PI3K-alpha and mTORC1/2 simultaneously, and we believe we can achieve more complete pathway suppression with improved tolerability. We saw the signal in our Phase 1b, including a number of complete responses in endometrial cancer patients after multiple prior lines of therapy. This financing takes us through topline Phase 2 data in that population and advances the Phase 1b breast cancer program.”
The $200M raise will be used to push PIKTOR through key milestones:
- Endometrial Cancer: Topline data from an ongoing Phase 2 trial is expected by year-end 2026.
- Breast Cancer: Initiation of a Phase 1b trial in HR+/HER2- patients.
71% Response Rate
The results are backed by compelling Phase 1b data. In a study of heavily pre-treated patients (some who had failed 12 prior therapies), PIKTOR combined with paclitaxel showed:
- 47% Overall Response Rate (ORR) in all evaluable patients.
- 71% Response Rate in patients with PI3K pathway mutations.
- Complete Responses (CR): Three patients saw their cancer disappear entirely, including two with advanced endometrial cancer.
