Precision prowls for partnerships after FDA meeting leaves more questions on cell therapy future

Precision BioSciences' calls for partnerships to advance its off-the-shelf cell therapy pipeline have intensified following a post-phase 1 meeting with U.S. regulators.

The North Carolina biotech said Thursday that after meeting with the FDA, it’s now “advancing discussions with multiple potential strategic partners” to collaborate on two cell therapy assets: Azer-cel and next-generation option PBCAR19B. 

Precision was seeking guidance from the FDA to advance azer-cel into patients with diffuse large B cell lymphoma who have relapsed following CAR-T therapy. The company narrowed in on this specific population after an analysis of phase 1 data showed a potential benefit there. But the company would have to convince regulators to get on board and accept a single-arm, non-randomized trial for the next step. 

It seems there's more work to do to finalize the trial—and some outside help needed—following the meeting. A spokesperson told Fierce Biotech that "the FDA is amenable to pursuing the CAR T relapsed patient population" however declined to provide more details on the potential trial design given the partnership discussions. 

Chief Medical Officer Alan List added that Precision accomplished its objectives heading into the meeting: to get a sense of the registrational path for azer-cel by landing on phase 2 endpoints and a dose level for patients that had previously relapsed. What's unknown is whether or not the FDA was receptive to Precision's plans to have a single-arm phase 2 trial and the spokesperson did not comment on how that request went over with regulators.

Precision CEO Michael Amoroso said in a Thursday release that the new strategy will allow the biotech “to focus on core capabilities of in vivo gene editing.” Precision has sole ownership of only one asset in that pipeline, with the remaining six partnered with the likes of Novartis, Lilly and iEcure. 

In late May, Precision was touting the efficacy of azer-cel in patients that relapsed after prior autologous cell therapy. Azer-cel was found to spur an 83% response rate among 18 patients that fit this criterion, with durability lasting at least six months in 55% of patients.

Amaroso told investors at the time that he didn’t believe it made sense for a phase 2 trial to include a placebo-control arm, arguing that the Precision team didn’t “see anything you can randomize here.” He did acknowledge that a randomized trial may be necessary further down the line and teased partnerships as a leg-up, though the solicitation has more fervor now. 

Precision’s partnership hunt comes as the off-the-shelf cell therapy race is gaining steam. CRISPR-infused Caribou Biosciences is among the leaders in the space, and is still committed to tackling treatment-naive patients rather than the relapse population. 

A new slice of phase 1 data released earlier this month found that Caribou's lead asset spurred a 94% objective response rate, but durability questions remain. Caribou reported a 44% complete response rate at six months, but ultimately nine out of 16 patients experienced progressive disease.