An antifungal drug whose global rights GSK acquired earlier this year is being voluntarily recalled from the market due to potential cross contamination issues in its manufacturing process.

The drug, Brexafemme, treats vulvovaginal candidiasis, more commonly called vaginal yeast infection. It is unknown whether any of the drug supply has been contaminated nor have there been any reports of adverse events due to possible cross contamination, Brexafemme’s developer, Scynexis, said in a Monday regulatory filing. However, Scynexis has decided to recall the drug “in light of this risk and out of an abundance of caution.”

News of the recall sent shares of Jersey City, New Jersey-based Scynexis tumbling more than 30% Monday morning.

Brexafemme’s main pharmaceutical ingredient is a small molecule called ibrexafungerp. The drug blocks glucan synthase, an enzyme that is a key component of the fungal cell wall. The FDA approved Brexafemme in 2021, making it an alternative to the decades-old oral drug fluconazole, which targets a different fungal enzyme.

Brexafemme is Scynexis’s first and only FDA-approved product. The drug has not become a big seller for the biotech, which reported just shy of $5 million in product revenue in 2022. GSK hasn’t been able to turn around Brexafemme’s sales yet. Sales for the drug in the first half of this year were $1.6 million, down more than 20% compared to the same period last year.

Slow Brexafemme sales factored into Scynexis’s decision last year to seek a new commercialization partner for the drug. In March, GSK agreed to pay Scynexis $90 million up front for Brexafemme’s rights globally, except for China, where Hansoh holds the drug’s rights. The deal put Scynexis in line for milestone payments that could exceed $500 million. Even though GSK holds rights to Brexafemme, the pharmaceutical giant has not taken over manufacturing of the drug.

“We have relied on third-party contract manufacturers for synthesis of our clinical compounds and manufacture of drug product,” Scynexis said in its 2022 annual report. “We expect to continue to rely on either existing or alternative third-party manufacturers to supply ibrexafungerp for our performance of clinical trials and for supplying GSK needs for clinical and commercial product until it obtains its own source of supply.”

A recent GSK review of the manufacturing process and equipment at an unnamed third-party manufacturer found equipment used to make a non-antibacterial beta-lactam drug substance is also used in the manufacturing of ibrexafungerp, Scynexis said in the regulatory filing. FDA guidance recommends segregating the manufacturing processes because beta-lactam compounds may trigger hypersensitivity or allergic reactions in some people. The filing states that without the FDA recommended segregation of manufacturing processes, there is a risk of cross contamination.

The recall is also a setback to efforts to expand Brexafemme to other indications. A Phase 3 clinical trial was testing the drug in invasive candidiasis and other difficult-to-treat fungal infections. Though GSK has rights to the drug in all indications, Scynexis is responsible for this Phase 3 clinical trial. In the regulatory filing, Scynexis said the Brexafemme recall means a temporary halt to clinical tests of the drug until the company comes up with a mitigation strategy and resupply plan.

Public domain image by the CDC