Wednesday, the New England Journal of Medicine published full study data from the Phase 2/3 trial of Pfizer Inc’s (NYSE:PFE) Paxlovid (Nirmatrelvir in combination with ritonavir). They shared initial data in 2022.

The study enrolled adult vaccinated patients with COVID-19 who had at least one risk factor for severe disease and patients without risk factors who had never been vaccinated or had not received a vaccine in the past year.

Participants were given either Paxlovid or a placebo.

Related: Pfizer’s COVID-19 Treatment Paxlovid Will No Longer Be Available For Emergency Use After This Date, FDA Revises Label.

The publication notes that 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 yet to be established.

The median time to sustained alleviation of all targeted signs and symptoms of COVID-19 was 12 days in the Paxlovid group and 13 days in the placebo group (P=0.60). 

Five participants (0.8%) in the Paxlovid group and 10 (1.6%) in the placebo group were hospitalized for Covid-19 or died from any cause. 

The time to sustained alleviation of all signs and symptoms of COVID-19 did not differ significantly between participants who received Pfizer’s famed Paxlovid and those who received placebo.

The percentages of participants with adverse events were similar in the two groups.

In an NEJM editorial published Wednesday, Harvard University medicine professors Rajesh Gandhi and Martin Hirsch wrote, “Clearly, the benefit observed among unvaccinated high-risk persons does not extend to those at lower risk for severe COVID-19. This result supports guidelines that recommend nirmatrelvir–ritonavir only for persons who are at high risk for disease progression.”

“As with many medical interventions, there is likely to be a gradient of benefit for nirmatrelvir–ritonavir, with the patients at highest risk for progression most likely to derive the greatest benefit,” they wrote. 

“Thus, it appears reasonable to recommend nirmatrelvir–ritonavir primarily for the treatment of Covid-19 in older patients (particularly those ≥65 years of age), those who are immunocompromised, and those who have conditions that substantially increase the risk of severe Covid-19, regardless of previous vaccination or infection status.”

Price Action: PFE shares are down 0.32% at $26.57 on the last check Friday.

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