With a Jan. 30 target date fast approaching for approval of Libtayo as a second-line treatment in cervical cancer, Regeneron and Sanofi have voluntarily withdrawn their application.
The companies and the FDA were not “able to align on certain post-marketing studies,” they said in a release while adding that talks continue with regulatory authorities outside the U.S. on a potential approval in the indication for Libtayo.
The move is curious considering Libtayo has demonstrated an overall survival benefit in the indication.
A Regeneron spokesman responded to a request for more information but only referred Fierce Pharma to the press release.
The withdrawal also harkens to a decision in October of last year by Agenus to pull its application for accelerated approval for balstilimab, also in second-line cervical cancer.
That move came days after Merck’s Keytruda, already with an accelerated second-line approval in cervical cancer, gained a first-line approval in the indication, thereby converting the second-line approval to a full nod.
This, in effect, closed “the window for accelerated approval of balstilimab,” Agenus explained in a press release. It also hinted at preferential treatment for a Big Pharma company over a small biotech.
One difference in the applications was that Agenus was making the case for its treatment with biomarker data, while Regeneron and Sanofi were doing it with survival figures.
In March of last year, the companies showed in a phase 3 trial that Libtayo reduced the risk of death by 31% over chemotherapy, in recurrent or metastatic cervical cancer that had progressed on platinum-based chemotherapy. The drug also helped patients live longer regardless of their tumor’s PD-L1 biomarker status.
The survival win was the first for an immuno-oncology agent in cervical cancer. In an interim analysis, an independent data monitoring committee noted positive survival outcomes, with Libtayo patients living a median of 12 months versus 8.5 months for those on chemotherapy.
RELATED: Sanofi, Regeneron's Libtayo looks for new cervical cancer use with first-in-class survival win
The blow to Libtayo comes after it gained approvals last year in advanced basal cell carcinoma and advanced non-small cell lung cancer. The PD-1 inhibitor earned its first nod in advanced cutaneous squamous cell carcinoma in 2018.