May 5, 2026 — Leads & Copy — Sensei Biotherapeutics, Inc. (Nasdaq: SNSE) has announced the first patient was dosed in Study FTH-PIK-101 (NCT07558733), a Phase 1b/2 trial of PIKTOR in patients with HR+/HER2- advanced breast cancer.
PIKTOR, an investigational, all-oral combination of serabelisib and sapanisertib, is designed to inhibit multiple nodes of the PI3K/AKT/mTOR pathway through PI3K-alpha and dual mTORC1/2 targeting. It became Sensei’s lead program after the company acquired Faeth Therapeutics in February 2026.
The multi-center, dose-escalation Phase 1b/2 trial is evaluating sapanisertib and serabelisib (PIKTOR) in combination with fulvestrant and/or other anticancer therapies in patients with HR+/HER2- advanced or metastatic breast cancer.
According to Sensei, approved drugs that target this pathway each block only one component, which often allows the cancer to reroute its growth signals through the parts that remain active. PIKTOR combines two oral drugs, serabelisib (which blocks PI3K-alpha) and sapanisertib (which blocks mTORC1 and mTORC2), to target multiple nodes of the pathway simultaneously.
PIKTOR has already been tested in cancer patients. In a completed investigator-initiated Phase 1b study (NCT03154294), patients with advanced breast, endometrial and ovarian tumors who had failed an average of four prior treatments and were largely out of standard options received PIKTOR plus paclitaxel. Nearly half responded (47% overall response rate, n=15). Among patients whose tumors carried PI3K pathway mutations, 71% responded. Three patients had complete responses, all in endometrial cancer.
Sapanisertib in combination with fulvestrant has also shown activity in HR+/HER2- advanced breast cancer in an earlier Phase 2 study.
Anand Parikh, Chief Operating Officer of Sensei Biotherapeutics, said that in their earlier trial, patients who had exhausted multiple lines of therapy, including chemotherapy, responded to the PIKTOR plus paclitaxel combination, and several had complete responses. He added that PIK-101 now takes that same oral combination into breast cancer, where a large share of tumors carry the pathway alterations that PIKTOR is designed to target.
As part of its broader clinical development program for PIKTOR, Sensei is also conducting Study FTH-PIK-201, an ongoing multicenter, open-label, single-arm Phase 2 study (n≈40) in patients with advanced endometrial cancer.
Sensei Biotherapeutics, Inc. (Nasdaq: SNSE) is focused on improving outcomes for cancer patients through multi-node inhibition of critical oncogenic pathways. Following the acquisition of Faeth Therapeutics, Sensei’s lead program is PIKTOR, an investigational multi-node inhibitor of the PI3K/AKT/mTOR pathway in development for endometrial and breast cancer. Sensei is also completing a Phase 1/2 trial of solnerstotug, its V-domain Ig suppressor of T cell activation (VISTA) inhibitor, in patients with advanced solid tumors.
PIKTOR is an investigational all-oral combination of serabelisib and sapanisertib that inhibits multiple nodes of the PI3K/AKT/mTOR pathway, including PI3K-alpha and dual mTORC1/2. In a completed Phase 1b trial, PIKTOR plus paclitaxel demonstrated an overall response rate of 47% in response-evaluable patients (n=15), averaging four prior lines of therapy (range 1–12), with a 71% response rate in patients with PI3K pathway mutations, including three complete responses, all in endometrial cancer. PIKTOR is currently in clinical development for endometrial and breast cancer.
Patients with HR+/HER2- advanced breast cancer whose tumors stop responding to current therapies have few effective options, particularly when their cancer is driven by the PI3K/AKT/mTOR signaling pathway. Study FTH-PIK-101, titled “Open-Label Umbrella Study to Evaluate Safety and Efficacy of Sapanisertib and Serabelisib (PIKTOR) in Various Combinations in Patients with HR+/HER2- Advanced or Metastatic Breast Cancer,” is evaluating PIKTOR across HR+/HER2-advanced breast cancer patients, regardless of mutational status.
Source: Sensei Biotherapeutics
