Atea Pharmaceuticals' Phase 3 SUNRISE-3 trial evaluating bemnifosbuvir, an oral nucleotide polymerase inhibitor, for the treatment of COVID-19 has failed to meet its primary endpoint. The trial, a global, multicenter, randomized, double-blind, placebo-controlled study, did not demonstrate a statistically significant reduction in all-cause hospitalization or death through Day 29 in the monotherapy cohort of 2,221 high-risk patients with mild to moderate COVID-19.
The SUNRISE-3 trial randomized patients 1:1 to receive either bemnifosbuvir 550 mg twice daily (BID) or placebo BID for five days, alongside the locally available standard of care (SOC). The primary endpoint was all-cause hospitalization or death through Day 29 in the supportive care monotherapy cohort, with secondary endpoints measuring patient outcomes through Day 60 post-treatment.
Impact of Evolving COVID-19 Landscape
Jean-Pierre Sommadossi, PhD, Chief Executive Officer and Founder of Atea Pharmaceuticals, noted the evolving nature of COVID-19 and its impact on the trial's outcome. "Variants of COVID-19 are constantly evolving and the natural history of the disease trended toward milder disease, which has resulted in fewer hospitalizations and deaths," he stated. "In particular, hospitalization due to severe respiratory disease caused by COVID was not observed in SUNRISE-3, in contrast to our prior study. In an environment where there is much less COVID-19 pneumonia, it becomes more difficult for a direct-acting antiviral to demonstrate impact on the course of the disease."
Safety and Tolerability
Despite the trial's failure to meet its primary endpoint, bemnifosbuvir was generally safe and well-tolerated among the study participants. This safety profile is consistent with previous findings and supports its continued development in other viral indications.
Future Directions for Bemnifosbuvir
While Atea will not pursue a regulatory pathway forward for bemnifosbuvir as a monotherapy for COVID-19, the company remains committed to its development in combination with ruzasvir for the treatment of hepatitis C. Atea anticipates announcing additional results from the Phase 2 trial of this combination therapy in the fourth quarter of 2024.
About Bemnifosbuvir
Bemnifosbuvir is an investigational, novel, orally administered guanosine nucleotide analog polymerase inhibitor. It is designed to inhibit enzymes central to viral replication, with a focus on single-stranded RNA viruses. The drug has demonstrated a low risk of drug-drug interactions and a high barrier to treatment resistance.
