TOPLINE: 

Obeldesivir did not significantly reduce COVID-related hospitalization or all-cause death in adults at risk for severe COVID. However, it showed greater reductions in SARS-CoV-2 RNA levels and infectious titer compared with placebo. 

METHODOLOGY:

• Obeldesivir, an oral nucleoside analog prodrug that inhibits SARS-CoV-2 RNA polymerase, delivers broad-spectrum activity, minimal drug-drug interactions, and low pill burden.
• Researchers conducted a phase 3 randomized study at 72 international sites to evaluate the efficacy and safety of obeldesivir in nonhospitalized adults with SARS-CoV-2 infection who had risk factors for progression to severe COVID.
• The study included 465 high-risk participants (median age, 56 years; 56.3% female at birth; 73.8% White) within 5 days of COVID symptom onset. The participants were stratified by symptom duration and vaccination status and were randomly assigned to receive either 350 mg obeldesivir (n = 234) or placebo (n = 231) twice daily for 5 days.
• The primary endpoint was COVID-related hospitalization or all-cause death by day 29. Secondary endpoints included all-cause hospitalization and COVID-related medically attended visits or all-cause death.

TAKEAWAY:

• By day 29, COVID-related hospitalization or all-cause death was not reported in any of the participants who received obeldesivir and was reported in only one participant who received placebo (P = .32).
• Three COVID-related medically attended visits (including one all-cause hospitalization) were reported in the obeldesivir group, compared with one such visit and one all-cause death in the placebo group; no statistically significant differences were observed between the groups for secondary endpoints.
• By day 5, SARS-CoV-2 viral RNA copies decreased by 2.80 log₁₀ copies/mL with obeldesivir and by 2.22 log₁₀ copies/mL with placebo (treatment difference, -0.58 log₁₀ copies/mL; 95% CI, -0.83 to -0.33), favoring obeldesivir.
• The proportion of participants who experienced at least one treatment-emergent adverse event was similar in both the groups (obeldesivir: 22.2%; placebo: 20.8%); moreover, grade ≥ 3 adverse events occurred in 3.0% and 1.3% of participants in the obeldesivir and placebo groups, respectively.

IN PRACTICE:

“Given its antiviral activity against a broad spectrum of viruses and ability to reduce SARS-CoV-2 viral RNA copy number and infectious titer, obeldesivir may warrant further evaluation in populations at increased risk of severe disease or in the context of future variant or virus emergence,” the authors wrote.

SOURCE: 

The study was led by Anca Streinu-Cercel, MD, PhD, Carol Davila University of Medicine and Pharmacy and National Institute of Infectious Diseases “Prof. Dr. Matei Bals,” Bucharest, Romania. It was published online on July 22, 2025, in Clinical Infectious Diseases.

LIMITATIONS:

The study was limited by the low frequency of clinical events, underrepresentation of participants with the highest risk for severe COVID, a young population, and low vaccination rates among the participants. Outcomes may also have been influenced by a higher proportion of female participants in the obeldesivir group because their COVID hospitalization and mortality rates were generally lower. 

DISCLOSURES:

This study was funded by Gilead Sciences, Inc. Three authors reported receiving grants/research support and/or honoraria from and/or serving as speakers/consultants for various sources including Gilead Sciences, Inc. Some authors served as employees and may have owned stocks or stock options in Gilead Sciences, Inc.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.