Cidara Antifungal Flunks in Phase 2 Clinical Trial, Sinking Shares

Xconomy San Diego — 

Cidara Therapeutics is halting work on an experimental topical antifungal drug designed to treat vaginal yeast infections after the compound wasn’t better than the current standard of care in a Phase 2 clinical trial.

San Diego-based Cidara (NASDAQ: CDTX) said in a statement on Tuesday it will now shift its resources to other compounds in its portfolio, including an intravenous form of the antifungal. But investors frowned on the news nonetheless, sending the company’s shares down more than 38 percent to $7.24 this morning.

Cidara’s drug, CD101, is part of a class of antifungal drugs called echinocandins that target the cell wall of a fungus. The company developed the compound in both gel and ointment formulations as a treatment for vulvovaginal candidiasis, more commonly called a yeast infection. Cidara was studying the compound in patients with moderate-to-severe forms of the infection.

Echinocandins have a history of being both safe and effective as intravenous drugs that treat systemic fungal infections, wrote Leerink Partners analyst Paul Matteis in a research note this morning. But they have not yet demonstrated success in topical formulations, Matteis wrote, which made the CD101 study “riskier” than the company’s other clinical trials. He believes that the early data for the IV form of the Cidara antifungal, called CD101 IV, “stack up favorably.”

Cidara enrolled 125 patients in its Phase 2 trial of CD101 and split patients into three like-sized groups. Patients got either a gel or ointment form of CD101, or fluconazole, an antifungal pill often prescribed for the infection. Cidara said that the patients who got the gel and ointment forms of the drug had similar cure rates. But cure rates in both groups were less than those treated with fluconazole.

In a statement, Cidara CEO Jeffrey Stein said the company believes an improved topical formulation could work better. But Cidara has no current plans to continue working on topical forms of CD101. Instead, Cidara is turning its attention to CD101 IV, which is in a Phase 2 trial for the fungal infection candidemia. Results for that clinical trial are expected in the fourth quarter.

Cidara will also continue working on CD201, a potential treatment for infections caused by drug-resistant Gram-negative bacteria.

Cidara was originally founded in Boston in 2012 as K2 Therapeutics. In 2014, backed by a $32 million Series A round of financing, the company moved to San Diego, changed its name, and started developing antifiungal drugs.

Public domain image of vulvovaginal candidiasis by the CDC.