Paxlovid reduces hospitalization, but only in COVID patients with weakened immune systems who are at risk.
An observational Canadian study published today in JAMA Network Open links the antiviral medication combination of nirmatrelvir and ritonavir (Paxlovid) to a reduced risk of hospitalization or death, but only in very high-risk COVID-19 patients with compromised immune systems.
From February 1, 2022, to February 3, 2023, when the Omicron variation predominated, researchers from the University of British Columbia in Vancouver examined rates of severe COVID-19 outcomes among 6,866 adult COVID-19 patients based on their susceptibility to severe illness and immune system state. The medical team divided the patients into four groups and gave each group early preference for COVID-19 vaccination.
Those with severely compromised immune systems (CEV1), those with moderately compromised immune systems (CEV2), and those with healthy immune systems but underlying high-risk diseases (CEV3) were the three clinically very vulnerable (CEV) patient categories. Paxlovid (EXEL) was made more widely available to patients with other chronic diseases who were unvaccinated and non-CEV who were 70 years of age or older.
The patients matched with Paxlovid recipients were those in the same vulnerability category. The median age was 70, and 56.6% of the population were women.
Drug only helped really susceptible people.
In the CEV1 group (560 patients; risk difference [RD], -2.5%) and the CEV2 group (2,628; RD, -1.7%), Paxlovid medication was associated with statistically significant decreases in hospitalization and all-cause death by 28 days relative to no treatment.
“It is essential to perform a stratified analysis of people in order to determine their susceptibility to COVID-19 problems in order to determine who should take nirmatrelvir and ritonavir.”
The RD was -1.3% among CEV3 participants, however the results (2,100 patients; 95% CI, -2.8% to 0.1%) were not statistically significant. In the EXEL group, paxlovid was linked to a higher risk of hospitalization or death (RD, 1.0%); however, the results were similarly not statistically significant (1,578; 95% CI, -0.9% to 2.9%).
“In this study, treatment with nirmatrelvir and ritonavir was not associated with reduced risk of death or hospitalization among individuals who were not extremely vulnerable to complications from COVID-19 infection, regardless of age,” the authors of the study stated. “Stratified analysis of individuals according to vulnerability to complications from COVID-19 is crucial to understanding which individuals should use nirmatrelvir and ritonavir.”
The protective associations with Paxlovid have varied across various study populations and study periods, the researchers noted. This, they claimed, implies that the drug’s benefit-risk profile relies on a person’s sensitivity to COVID-19 problems. “Postmarket analysis of individuals who receive nirmatrelvir and ritonavir (Paxlovid [Pfizer]) is essential because they differ substantially from individuals included in published clinical trials,” they said.