Sanofi, Regeneron's Libtayo looks for new cervical cancer use with first-in-class survival win

Libtayo bottle and box
Sanofi and Regeneron tout a first-in-class win showing their PD-1 inhibitor Libtayo could extend the lives over chemotherapy among patients with previously treated ovarian cancer. (Sanofi Genzyme/Regeneron)

As a latecomer to the PD-1/L1 game, Sanofi and Regeneron have been angling Libtayo toward some niche indications where it can grow freely, unhindered by competition. But now, the pair has recorded a clinical win in cervical cancer that megablockbuster early entrants can't tout.

Libtayo monotherapy significantly reduced the risk of death by 31% over chemotherapy in recurrent or metastatic cervical cancer that had progressed on platinum-based chemo, Sanofi and Regeneron said Monday. The drug helped patients live longer regardless of their tumors’ PD-L1 biomarker status.

The two companies were quick to point out that the phase 3 overall survival win marked the first for an immuno-oncology agent in cervical cancer. Regulatory filings are planned for 2021 and exact results will be shared at a medical meeting, they said.

The good news came early after an independent data monitoring committee noted positive survival outcomes at an interim analysis. In the overall trial population, Libtayo patients lived a median 12 months versus 8.5 months among chemotherapy patients.

RELATED: Merck's Keytruda snags I-O's first cervical cancer nod to back up HPV fighter Gardasil

On the other co-primary endpoint of the study, the PD-1 inhibitor slashed the risk of death by 27% in a subgroup of patients with squamous cell carcinoma, as Libtayo patients lived a median 11.1 months, compared with 8.8 months in the chemo group. The squamous cell subtype constitutes 80% of all cervical cancer cases.

Merck & Co.’s Keytruda was the first I-O med to enter the cervical cancer field. Its conditional nod, limited to previously treated patients whose tumors express PD-L1, was based on tumor shrinkage and duration of response data.

Bristol Myers Squibb’s Opdivo, both by itself and with CTLA4 inhibitor Yervoy, did show promising results in the phase 1/2 CheckMate-358 trial with what the study lead investigator called “striking” overall survival curves for the dual I-O regimen, according to results unveiled at the ESMO 2019 meeting.

RELATED: Sanofi, Regeneron's Libtayo snags lung cancer nod, taking a stab at Keytruda's megablockbuster lead

Sanofi and Regeneron may be the first to tout an important life-extension benefit in second-line cervical cancer, but it’s entering a relatively small and dwindling market. In the U.S., 14,500 new patients are diagnosed with cervical cancer each year, the pair pointed out. As the CDC notes, the number of cases of cervical cancer has been decreasing significantly in the past few decades, partly thanks to the success of Merck’s HPV vaccine Gardasil 9 and partly due to early screening efforts that can catch precancer before it turns into cancer. Almost all cervical cancer cases are caused by HPV infection.

If eventually approved, second-line cervical cancer could be Libtayo’s fourth U.S. indication. Last month, the drug added newly diagnosed PD-L1-high non-small cell lung cancer to its label, jostling for a place in a lucrative market where Merck’s Keytruda-chemo combo has established as the standard of care. Before that, Libtayo’s green-lighted in two skin cancers, basal cell carcinoma and cutaneous squamous cell carcinoma.