UPDATED: Regeneron/Sanofi team hustling to the FDA with stellar PhIII dupilumab data

Elias Zerhouni, Sanofi R&D chief

Regeneron ($REGN) and Sanofi ($SNY) have rung up stellar late-stage data from a pair of large Phase III studies of the blockbuster antibody contender dupilumab, putting it on a straight path to the FDA.

Tapped by a number of analysts as one of the biggest blockbusters in the industry's late-stage pipeline, the drug came through on atopic dermatitis, clearing skin, reducing itching and improving the quality of a significant number of patients' lives. And the close biopharma partners say they'll be ready to file for an approval in a matter of months, handing over an application for a drug already designated as a "breakthrough" therapy by the FDA.

The data were consistently impressive, with a better safety profile for the drug compared to a placebo arm. 

• On the primary endpoint, 37%/36% and 38%/36% of the 300 mg weekly and 300 mg every two weeks dosing group in the two Phase III studies saw their skin cleared or nearly cleared of lesions. For the two placebo arms, the score was 10% and 8.5%.

• Using a standard assessment measure, there was a 72%/69% and 72%/67% improvement over baseline in the two drug arms, compared to 38%/31% for the placebo comparison. In a key secondary endpoint in the U.S., and a primary for Europe, 52.5% and 48% of patients who received dupilumab 300 mg weekly, and 51%/44% of patients who received dupilumab 300 mg every two weeks achieved the EASI-75 goal compared to 15 and 12% with placebo.

If the data hold up under regulatory review, Regeneron and Sanofi will likely kindle renewed expectations of blockbuster peak sales that could exceed $2.5 billion a year. Some optimistic buy-siders have pushed their peak estimates to $4 billion or $5 billion.

"The safety data in PIII which was a focus of investor speculation appears clean with serious adverse events and serious infections reportedly higher in the placebo group," noted Jefferies analyst Biren Amin this morning. "We view the data as positive and should be approvable upon Q3 BLA filing."

Shares of Regeneron jumped 3% this morning, while Sanofi stock declined 1.3%.

The Phase III successes mark the latest big pipeline advance for this powerhouse biopharma duo. Regeneron has emerged as a consistent winner in late-stage development in recent years, and Sanofi has made their close partnership a central feature in the architecture of innovation designed by R&D chief Elias Zerhouni.

"There are no approved systemic therapies in the U.S. for people with moderate-to-severe atopic dermatitis, underscoring the clear unmet need. These results may bring new hope to atopic dermatitis patients, many of whom have suffered for years," said Zerhouni in a statement. "In the U.S., where dupilumab in AD has been granted Breakthrough Therapy designation by the U.S. FDA, we plan to submit a regulatory application in the third quarter of this year and will work to bring this innovative therapy to patients as quickly as possible."

- here's the release