Only a couple of months ago, Sensei Biotherapeutics was laying off staff and mulling winding down the company. But the biotech has found a new lease on life—and a new lead drug—via a merger with Faeth Therapeutics.
Shareholders of privately owned Faeth come out on top of the all-stock transaction, owning 40.8% of the merged company compared to 4.9% owned by current shareholders of Nasdaq-listed Sensei. The rest of the company will be owned by investors that participated in a $200 million private placement, which Sensei also disclosed in a Feb. 18 release.
The merger gives Sensei a new lead candidate in the form of Faeth’s PIKTOR, an oral combination of two investigational PI3K/AKT/mTOR pathway inhibitors called serabelisib and sapanisertib.
The enlarged Sensei will be focused on a phase 2 study of PIKTOR in second-line advanced endometrial cancer as well as gearing up for a phase 1b trial in HR+/HER2- advanced breast cancer. Both the phase 2 readout and launch of the phase 1b study are expected to occur before year-end, Sensei explained.
A number of PI3K inhibitors have been approved to treat cancers, including Novartis’ Piqray, Roche’s Itovebi and Gilead Sciences’ Zydelig. Anand Parikh, who co-founded Faeth in 2019 and will now become chief operating officer at Sensei, claimed in the release that the PI3K pathway has “repeatedly run into the same constraint—single-node inhibitors force a tradeoff between efficacy and tolerability.”
“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,” Parikh added. “We saw the signal in our phase 1b, including a number of complete responses in endometrial cancer patients after multiple prior lines of therapy.”
The company will bankroll the PIKTOR strategy with the $200 million private placement also announced this morning. The likes of Cormorant Asset Management, Fairmount and RA Capital Management all signed up to buy series B nonvoting convertible preferred stock. The deal will give the array of investors a combined ownership of 54.3% of the expanded Sensei.
“This financing takes us through topline phase 2 data in that population and advances the phase 1b breast cancer program,” Parikh said.
The merger with Faeth and infusion of cash marks a new chapter for Sensei, which laid off two-thirds of its staff over recent months as the company considered its shrinking strategic options. One of the options on the table had been to wind down entirely, but Faeth coming aboard has kept the Sensei brand intact.
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Sensei will use some of the private placement funds to complete an ongoing phase 1/2 study of its own drug solnerstotug. The biotech had previously said that it was planning to wind down the study, despite pointing to data that tied the anti-VISTA monoclonal antibody to six-month progression-free survival of 50% in patients with so-called “hot” tumor types.
The layoffs linked to that decision came less than a year after Sensei trimmed its workforce by 46% and closed its research site in Rockville, Maryland. That decision was explained at the time as necessary to keep the money pumping to the solnerstotug program.
Sensei went public in 2021 in a $133 million IPO. At the time, the biotech’s pipeline was headed up by a clinical-stage vaccine that targeted the tumor antigen aspartate beta hydroxylase to treat head and neck cancer. However, within months, the company had discontinued development of that asset after viewing trial data.
By the time Sensei was considering whether to shut up shop toward the end of last year, the company was down to $25 million in cash and equivalents.