Pfizer released preliminary results Friday of its study of 775 adults. Patients taking the company’s drug along with another antiviral had an 89% reduction in their combined rate of hospitalization or death after a month, compared with patients taking a dummy pill. Fewer than 1% of patients taking the drug needed to be hospitalized and no one died. In the comparison group, 7% were hospitalized and there were seven deaths.
"We were hoping that we had something extraordinary, but it’s rare that you see great drugs come through with almost 90% efficacy and 100% protection for death,” said Dr. Mikael Dolsten, Pfizer’s chief scientific officer, in an interview.
Study participants were unvaccinated, with mild-to-moderate COVID-19, and were considered high risk for hospitalization due to health problems such as obesity, diabetes or heart disease. Treatment began within three to five days of initial symptoms, and it lasted for five days.
Pfizer reported few details on side effects but said rates of problems were similar between the groups at about 20%.
An independent group of medical experts monitoring the trial recommended stopping it early, standard procedure when interim results show such a clear benefit. The data have not yet been published for outside review, the normal process for vetting new medical research.
Top U.S. health officials continue to stress that vaccination will remain the best way to protect against infection. But with tens of millions of adults still unvaccinated — and many more globally — effective, easy-to-use treatments will be critical to curbing future waves of infections.
“We were hoping that we had something extraordinary, but it's rare that you see great drugs come through with almost 90% efficacy and 100% protection for death."
- Dr. Mikael Dolsten, Pfizer’s chief scientific officer
The FDA has set a public meeting later this month to review Merck’s pill, known as molnupiravir. The company reported in September that its drug cut rates of hospitalization and death by 50%. Experts warn against comparing preliminary results because of differences in studies.
Although Merck’s pill is further along in the U.S. regulatory process, Pfizer’s drug could benefit from a safety profile that is more familiar to regulators with fewer red flags. While pregnant women were excluded from the Merck trial due to a potential risk of birth defects, Pfizer’s drug did not have any similar restrictions. The Merck drug works by interfering with the coronavirus’ genetic code, a novel approach to disrupting the virus.