Pfizer’s Covid-19 antiviral did not improve symptoms in patients with long Covid compared to placebo — the latest disappointment for patients with the post-infection condition.
Scientists at Stanford University found that patients receiving a 15-day course of the treatment did not have significant improvements in core symptom severity compared to patients that received ritonavir and placebo. The scientists said in a JAMA paper released Friday that while Paxlovid was safe, they “did not find a significant benefit of this therapy for a subset of PASC [postacute sequelae of SARS-Cov-2 infection] symptoms among a mostly vaccinated cohort with prolonged PASC symptoms.”
Still, the researchers said more studies were necessary to be sure that antivirals were not a potential treatment course for long Covid patients. They said that to their knowledge, the results were the first to come from a randomized study testing Paxlovid as a remedy for the condition. Pfizer itself says it does not expect the data to impact ongoing research.
“We do not anticipate the STOP-PASC study results will impact the continuation of our other planned collaborative studies evaluating PAXLOVID for the potential treatment of long COVID,” a Pfizer spokesperson said. “These studies have been designed to better inform our collective understanding of this complex condition and potential treatment approaches.”
The trial recruited 155 patients randomized 2-to-1 to receive a 15-day course of Paxlovid versus ritonavir and placebo, almost all of whom had received at least an initial Covid vaccination course. At the 10-week mark, the trial investigators assessed six core symptoms associated with long Covid: fatigue, brain fog, body aches, cardiovascular symptoms, shortness of breath and gastrointestinal symptoms. Patients did not show significant differences compared to placebo, and both treatment courses were associated with declines in symptom severity.
Long Covid has so far perplexed scientists and federal researchers alike who have tried to crack the biology of the condition and possible treatments. Identification of symptoms and remedies has largely fallen to patient advocates and decentralized consortiums, like the Long COVID Alliance and the Patient-Led Research Collaborative.
The National Institutes of Health has committed more than $1 billion to researching the condition through the RECOVER initiative, and announced in February that it was infusing the program with another $515 million.