FDA Grants QIDP & Fast Track Designations to Rezafungin Prophylaxis Development Program

*Updated on 9/28/2018 at 5:11 PM EST

The US Food and Drug Administration (FDA) has granted Qualified Infectious Disease Product (QIDP) and fast track designations to Cidara Therapeutics’ prophylaxis development program for injectable rezafungin. The agent is being developed for the prevention of invasive fungal infections in adults who are undergoing allogeneic bone marrow transplantation.

“Patients highly vulnerable to invasive fungal infections (IFIs) are present in many clinical settings and require preventative strategies to reduce the rates of fungal infections," Taylor Sandison, MD, MPH, Cidara's chief medical officer told Contagion^®. "The best strategy for prevention is one that safely and effectively prevents IFIs, and doesn’t interfere with underlying disease, treatments, or procedures. We are delighted with the QIDP and Fast Track designations as it reinforces the importance of this proposed indication for rezafungin, and we now have the opportunity to work more closely and quickly with the FDA on our prophylaxis program."

Rezafungin—formally known as CD101—is a broad-spectrum, long-lasting echinocandin that is being developed to fulfill unmet needs in the treatment of candidemia and invasive candidiasis; it is also being assessed to be used as prophylaxis of invasive fungal infections caused by Candida, Aspergillus, and Pneumocystis.

To date, no agents have been approved to prevent infections caused by these pathogens and prophylaxis that is currently available require several antifungal drugs, all of which have issues pertaining to safety and tolerability. The pharmacokinetic profile of the treatment might allow for overcoming current challenges faced with the standard of care.

"The complex nature of the immunocompromised patient and the complexity of the current antifungal drugs used today for prophylaxis (azoles and trimethoprim/sulfamethoxazole), create a significant opportunity for improvement," Dr. Sandison explained. "The unique spectrum of rezafungin, along with a long half-life, very favorable drug-drug interaction and tolerability profiles, with no signals of myelosuppression, hepatotoxicity, or renal toxicity, make rezafungin an attractive candidate to potentially address the significant unmet needs in the prevention of IFI in immunocompromised patients."

Compared with other drugs of its class that need to be administered on a daily basis, rezafungin is delivered once-weekly intravenously. "This is the first time an echinocandin can easily be administered on an outpatient basis during routine weekly follow-up clinic visits post-transplant," he stressed.

Following these designations, Cidara has initiated a phase 3 clinical trial, referred to as ReSTORE, which will compare the safety and efficacy of once-weekly intravenous dosing of rezafungin with once-daily dosing of caspofungin in patients with candidemia and/or invasive candidiasis. Specifically, the trial will evaluate 1 rezafungin dosing regimen of 400 milligrams for the first week followed by 200 mg of rezafungin once-weekly for up to 4 weeks.

The company plans on using the primary efficacy endpoint—all-cause mortality at day 30—of the trial for an FDA New Drug Application submission.

Rezafungin previously received a QIDP designation from the FDA for the treatment of invasive fungal infections caused by Candida.