Nirmatrelvir therapy proves efficacious in severe Covid-19 during omicron surge: NEJM

Israel: Nirmatrelvir use during the Omicron variant surge was associated with a significant decline in COVID-19 hospitalization and mortality rates in patients 65 and older states a study published in The New England Journal Of Medicine.

In late 2021, the rapidly proliferating B.1.1.529 (omicron) strain of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused a global recurrence of coronavirus illness. The oral antiviral nirmatrelvir received an Emergency Use Authorization (EUA) from the Food and Drug Administration (FDA) on December 22, 2021, to address mild to moderate COVID-19 in patients who are at a higher risk of developing serious disease. After receiving a positive COVID-19 diagnosis, the standard nirmatrelvir treatment plan entails five consecutive days of medication. There is a dearth of information on nirmatrelvir's propensity to shield against the B.1.1.529 (omicron) variety of the severe coronavirus illness of 2019 (Covid-19).

The researchers in their study assessed the ability of Nirmatrelvir to shield high-risk patients from COVID-19-related hospitalization and death.

The authors found that the oral protease inhibitor nirmatrelvir has demonstrated significant effectiveness in high-risk, unvaccinated patients infected with the B.1.617.2 (delta) strain.

For this purpose, they gathered information from the electronic medical records of Clalit Health Services (CHS). The drug was administered to CHS patients for the first time on March 10, 2022, which marked the conclusion of the study, which started on January 9, 2022. Participants in the trial have to have a diagnosis of COVID-19 by February 24, 2022. The link between nirmatrelvir treatment and hospitalization and mortality due to Covid-19 was estimated using a Cox proportional-hazards regression model with time-dependent covariates, with adjustments for sociodemographic characteristics, comorbid conditions, and prior SARS-CoV-2 immune status. 3902 (4%) of the 109,254 patients who met the inclusion criteria for treatment received nirmatrelvir.

Key findings of the study:

• The rate of Covid-19-related hospitalization among patients 65 years of age or older was 14.7 cases per 100,000 person-days among those who received treatment, versus 58.9 cases per 100,000 person-days among those who received no treatment (adjusted hazard ratio, 0.27).
• The risk ratio for Covid-19-related deaths was 0.21.
• With regard to patients aged 40 to 64, the rate of hospitalization caused by Covid-19 was 15.2 instances per 100,000 person-days among those who received treatment and 15.8 cases per 100,000 person-days of those who did not (adjusted hazard ratio, 0.74).
• With a 95% confidence interval of 0.16 to 10.75, the adjusted hazard ratio for Covid-19-related death was 1.32.

"It should be emphasized that the review of safety data reports and adverse event reports were outside the purview of this investigation. More research will be required to evaluate the treatment with nirmatrelvir's short- and long-term safety in practical contexts" added the researchers.

The authors concluded that Nirmatrelvir recipients had significantly reduced rates of severe Covid-19 outcomes than nirmatrelvir non-users during the omicron variant surge among people 65 years of age or older.

REFERENCE

Arbel R, Wolff Sagy Y, Hoshen M, Battat E, Lavie G, Sergienko R, Friger M, Waxman JG, Dagan N, Balicer R, Ben-Shlomo Y, Peretz A, Yaron S, Serby D, Hammerman A, Netzer D. Nirmatrelvir Use and Severe Covid-19 Outcomes during the Omicron Surge. N Engl J Med. 2022 Aug 24. doi: 10.1056/NEJMoa2204919. Epub ahead of print. PMID: 36001529.