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Nirmatrelvir for Vaccinated or Unvaccinated Adult Outpatients with Covid-19
Jennifer Hammond1, Robert J Fountaine1, Carla Yunis1
1From Global Product Development, Pfizer, Collegeville, PA (J.H.); Global Product Development, Pfizer, Groton, CT (R.J.F.); Global Product Development, Pfizer, Lake Mary (C.Y.), and Global Product Development, Pfizer, Tampa (J.M.R.) - both in Florida; Global Product Development, Pfizer, Lexington, KY (D.F.); Global Product Development, Pfizer, New York (M.A., W.B., R.P.); Global Product Development, Pfizer, Lake Forest, IL (W.W.); Early Clinical Development, Pfizer, Cambridge, MA (M.L.B.); Pfizer, Sandwich, United Kingdom (V.M.H.); the Specialized Hospital for Active Treatment of Pneumo-Phthisiatric Diseases, Haskovo, Bulgaria (V.K.); and Méchnikov Project, Köhler and Milstein Research, Anahuac-Mayab University, Mérida, Mexico (J.A.S.-C.).
Background:
Nirmatrelvir in combination with ritonavir is an antiviral treatment for mild-to-moderate coronavirus disease 2019 (Covid-19). The efficacy of this treatment in patients who are at standard risk for severe Covid-19 or who are fully vaccinated and have at least one risk factor for severe Covid-19 has not been established.
Methods:
In this phase 2-3 trial, we randomly assigned adults who had confirmed Covid-19 with symptom onset within the past 5 days in a 1:1 ratio to receive nirmatrelvir-ritonavir or placebo every 12 hours for 5 days. Patients who were fully vaccinated against Covid-19 and who had at least one risk factor for severe disease, as well as patients without such risk factors who had never been vaccinated against Covid-19 or had not been vaccinated within the previous year, were eligible for participation. Participants logged the presence and severity of prespecified Covid-19 signs and symptoms daily from day 1 through day 28. The primary end point was the time to sustained alleviation of all targeted Covid-19 signs and symptoms. Covid-19-related hospitalization and death from any cause were also assessed through day 28.
Results:
Among the 1296 participants who underwent randomization and were included in the full analysis population, 1288 received at least one dose of nirmatrelvir-ritonavir (654 participants) or placebo (634 participants) and had at least one postbaseline visit. The median time to sustained alleviation of all targeted signs and symptoms of Covid-19 was 12 days in the nirmatrelvir-ritonavir group and 13 days in the placebo group (P = 0.60). Five participants (0.8%) in the nirmatrelvir-ritonavir group and 10 (1.6%) in the placebo group were hospitalized for Covid-19 or died from any cause (difference, -0.8 percentage points; 95% confidence interval, -2.0 to 0.4). The percentages of participants with adverse events were similar in the two groups (25.8% with nirmatrelvir-ritonavir and 24.1% with placebo). In the nirmatrelvir-ritonavir group, the most commonly reported treatment-related adverse events were dysgeusia (in 5.8% of the participants) and diarrhea (in 2.1%).
Conclusions:
The time to sustained alleviation of all signs and symptoms of Covid-19 did not differ significantly between participants who received nirmatrelvir-ritonavir and those who received placebo. (Supported by Pfizer; EPIC-SR ClinicalTrials.gov number, NCT05011513.).
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