FDA stalls F2G's plans to get first in new antifungal class to market

F2G’s hopes of getting the first in a brand-new class of antifungals to market have hit a setback courtesy of a complete response letter from the FDA. 

The regulator was due to make a call on approving the drug, called olorofim, on June 17. But F2G announced yesterday that it had received a letter from the FDA requesting further data and analyses before it could reconsider the approval request.

"The additional information requires time and resources that extend beyond the current review period,” the company said in a release. “The FDA encouraged the company to work with the agency to plan for the new analyses and develop the NDA package."

Olorofim, also known as F901318, is part of a new class of antifungal drugs, the orotomides. The Shionogi-partnered drug inhibits the dihydroorotate dehydrogenase enzyme to disrupt the synthesis of pyrimidines, compounds that are essential to fungi.

F2G submitted the approval application with data from the first 100 patients enrolled in a phase 2b study of the drug in various invasive fungal infections due to different resistant fungi. Since then, the study has completed enrollment, and the U.K.-based biotech will include a full data set from all 203 participants when it resubmits its application.

“While F2G is disappointed with this outcome, we remain optimistic about olorofim’s potential to address an unmet need for patients with invasive fungal infections who have exhausted their treatment alternatives,” said CEO Francesco Maria Lavino in the release. “We are assessing the details of the CRL, and we plan to meet with the FDA to discuss it further, but we are confident that we can identify a regulatory path forward in the US.”

In the meantime, the privately held biotech said it continues to enroll patients in a phase 3 trial comparing olorofim to the approved antifungal AmBisome in patients with or at risk of invasive aspergillosis, a fungal disease that affects people with weakened immune systems.

F2G has commercial responsibility for olorofim in North America, while Japan-based Shionogi will oversee development in Europe and the Asia-Pacific region.

While most drugmakers have lost interest in antifungals in recent years, GSK in particular continues to play in the space. The Big Pharma paid out $90 million to New Jersey biotech Scynexis in March for Brexafemme, which is approved in the U.S. to treat a type of vaginal infection. That same month, Cidara Therapeutics got approval for Rezzayo, a once-weekly antifungal to treat invasive candidiasis and candidemia, which are bloodstream infections in hospitalized patients that can be fatal.