Pfizer and partner BioNTech said they will halt a government-ordered post-marketing study for their COVID-19 vaccine because of recruitment issues that, in turn, have impaired data collection.
The companies confirmed Wednesday, following a report from Reuters, that they are suspending the trial as a result of lower-than-expected enrollment due to a slow season of COVID cases. Pfizer and BioNTech said the study is not ending as a result of any safety or benefit-risk concerns.
The trial is tied to a post-marketing commitment that Food and Drug Administration Commissioner Martin Makary put in place last year for all approved COVID vaccines.
“We intend to stop the study due to slow enrollment and therefore the inability to generate relevant post-marketing data,” a spokesperson for Pfizer wrote in an emailed statement to BioPharma Dive.
The study was meant to evaluate if the COVID vaccine was more effective than a placebo in healthy adults aged 50 to 64 years old. It was expected to amass 25,500 participants and designed to measure safety, immune response and prevention of COVID cases.
The COVID vaccines have been heavily scrutinized under new leadership at the Department of Health and Human Services and, as a result, have faced stricter approval standards. Requirement of a placebo control arm in instances when an effective vaccine exists is not a typical trial design.
The shot’s availability has also been severely limited by the Centers for Disease Control and Prevention. Last year, HHS Secretary Robert F. Kennedy Jr. said the vaccines would no longer be recommended for healthy children and pregnant people, though the CDC broadly recommends what’s known as shared clinical decision making for anyone aged 6 months and older.
Additionally, the CDC emphasizes that children and adults younger than 65 should be informed of the benefits and risks of vaccination.
Attacks against the vaccine have continued, despite scientific evidence that the shot, which has been received by billions of people, is safe and effective.
The strict regulations, coupled with waning access, have put COVID vaccine developers in a bind. Makers like Pfizer and Moderna continue to grapple with declining revenue. Moderna has been especially hard hit, recently pulling back on late-stage vaccine trials and focusing more on its oncology assets.
Pfizer and BioNTech have not disclosed next steps.
