A Systematic Review of Nirmatrelvir/Ritonavir and Molnupiravir for the Treatment of Coronavirus Disease 2019.

Background: To address the need for treatments for patients with coronavirus disease 2019 (COVID-19), 3 therapies have been given either full approval or Emergency Use Authorization. These were based on randomized data showing a reduction in deaths/hospitalization, but since then, circulating viral strains and population immunity have changed. Methods: We searched PubMed, Web of Science, Embase, and ClinicalTrials.gov for clinical trials testing nirmatrelvir/ritonavir and molnupiravir for COVID-19. We identified all trials testing nirmatrelvir/ritonavir and molnupiravir in patients with COVID-19 and assessed the pooled efficacy in a meta-analysis. We calculated pooled estimates of hospitalization and death in patients with COVID-19 and the number of studies with published/reported data. Results: Of the 23 studies found, 11 tested nirmatrelvir/ritonavir, 10 tested molnupiravir, and 2 tested both agents. The pooled estimate in reducing deaths and hospitalization for molnupiravir was 0.62 (95% confidence interval [CI], 0.15-2.53), and the pooled estimate for nirmatrelvir/ritonavir was 0.33 (95% CI, 0.03-3.35). The 1 nirmatrelvir/ritonavir trial that reported significant improvements tested people who were predominantly infected with earlier COVID-19 variants, whereas the 2 null trials were tested in people infected with more recent variants. The 2 positive molnupiravir trials included participants primarily with the Delta variant, whereas the null trials were tested later, against more recent variants. Conclusions: While early trial data show effectiveness of these therapies, the overall pooled effects are nonsignificant, suggesting that recommendations and use of approved oral COVID-19 treatment therapies need to be reevaluated in the context of current viral strains and population immunity.