FDA Grants Fast Track Designation to Bemnifosbuvir for COVID-19

The FDA has granted Fast Track Designation to bemnifosbuvir (Atea Pharmaceuticals), an investigational oral antiviral for the treatment of COVID-19 in outpatients at high risk for disease progression regardless of vaccination status. This notably includes patients over the age of 80 years, those aged 65 years or older with at least 1 major risk factor, and anyone over the age of 18 years who is immunocompromised.

The Fast Track program is intended to facilitate the expedited development and review of new drugs or biologics to treat serious or life-threatening conditions and demonstrate the potential to address unmet medical needs. As part of the designation, Atea Pharmaceuticals may benefit from more frequent communications with the FDA and rolling review of any completed sections of any resulting New Drug Application.

“The decision to grant [Fast Track Designation] by the FDA for bemnifosbuvir reflects the continuing unmet medical need that remains for COVID-19 patients,” said Jean-Pierre Sommadossi, PhD, CEO and founder of Atea Pharmaceuticals, in a press release. “[Fast Track Designation] has the potential to expedite the development of bemnifosbuvir and we look forward to ongoing discussions with the FDA.”

Bemnifosbuvir is a nucleotide polymerase inhibitor targeting the SARS-CoV-2 RNA polymerase, a conserved gene that is unlikely to change as the virus mutates and new variants emerge. Bemnifosbuvir has a unique mechanism of action, with dual targets of RNA-dependent RNA polymerase (RdRp) and nucleotityltransferase (NiRAN), which has the potential to create a high barrier to resistance.

In vitro data have confirmed that bemnifosbuvir is active with similar efficacy against all variants of concern and variants of interest that have been tested, including Omicron subvariants BA.4 and BA.5. It is currently being evaluated in the SUNRISE-3 global, multicenter, phase 3 registrational trial for the treatment of COVID-19.

The trial is investigating bemnifosbuvir or placebo administered concurrently with locally available standard of care. Investigators anticipate the study to enroll at least 1500 high-risk patients who are not hospitalized with mild or moderate COVID-19, including patients aged 80 years or older, patients aged 65 years or older with at least 1 major risk factor, and immunocompromised patients 18 years of age or older, all regardless of COVID-19 vaccination status. Participants will be randomized 1:1 to receive either bemnifosbuvir 550 mg or placebo twice daily plus locally available standard of care for 5 days.

SUNRISE-3 is comprised of 2 populations derived from the type of standard of care received. First, a supportive care population in which the patients do not quality for an authorized oral antiviral treatment or who are in a region where oral antivirals are not locally available, which will assess bemnifosbuvir given as monotherapy. Second, a combination antiviral population will assess combination therapy with bemnifosbuvir plus standard of care if the standard of care includes treatment with other COVID-19 antivirals.

The primary endpoint is all-cause hospitalization or death through day 29 in the supportive care population of at least 1300 patients evaluating bemnifosbuvir as monotherapy. Secondary endpoints in both cohorts include COVID-19 complications, medically attended visits, symptom rebound or relapse, and viral load rebound.

“Due to the limitations of current antiviral treatments, including drug-drug interactions and potential risks for genotoxicity and reproductive toxicity, as well as the ability of the virus to evade vaccines and monoclonal antibodies, new treatment options are urgently needed,” Sommadossi said in the press release. “In SUNRISE-3, we are targeting the most vulnerable patient populations who are at the greatest risk for disease progression to severe COVID-19 or mortality, and for whom there are currently the fewest treatment options.”

REFERENCE

Atea Pharmaceuticals Announces US FDA Fast Track Designation Granted to Bemnifosbuvir, an Investigational Oral Antiviral, for the Treatment of COVID-19. News release. Atea Pharmaceuticals. April 25, 2023. Accessed April 25, 2023. https://ir.ateapharma.com/news-releases/news-release-details/atea-pharmaceuticals-announces-us-fda-fast-track-designation-0