On morning of FDA Covid-19 adcomm, Moderna completes PhIII enrollment, putting them neck-and-neck with Pfizer
Weeks away from a potential EUA application, Moderna announced they have completed enrollment in their 30,000-person Phase III Covid-19 vaccine trial, with over a third of volunteers non-white and a quarter over the age of 65.
The announcement caps what has been the most closely-watched recruitment race in the history of drug development, as Pfizer and Moderna rushed to get enough volunteers to prove whether or not experimental vaccines could actually protect people from contracting Covid-19. Pfizer reached that mark on Sept. 15. Moderna said around the same time that they would slow down enrollment to ensure they enrolled enough participants from minority and at-risk groups.
The race has cooled somewhat since then, as new FDA guidance demanding more safety data threw cold water on a potential October approval. Still, Moderna says it’s remained intensely focused, giving a rare shoutout to their CRO PPD in a press release for staying on top of things as they steered the Phase III in a new direction.
“The attention on this trial has been unlike anything anyone has ever been through before,” Moderna president Stephen Hoge told Endpoints News. “The amount of reporting before we even dosed a patient was amazing and almost daily since.”
The completed enrollment comes on the same day that a much-anticipated FDA advisory committee sits down to discuss the various vaccine trials, although they won’t dive into any specific candidates.
Since mid-September, Moderna has almost exclusively enrolled non-white participants, slides released today show. Their numbers now compare favorably with Pfizer, whose study was 75% white when it crossed the 29,000-person mark, although the Big Pharma has since blueprinted plans to enroll another 14,000 volunteers, particularly from populations under-represented in their initial cohorts.
Without offering specific benchmarks, the FDA has emphasized the need for this kind of diversity for months, noting the disproportionate toll the virus has taken on Black and Latino Americans and those who are older and have co-morbidities.
With enrollment completed, the future of Moderna’s vaccine candidate now lies in the hands of the FDA adcomm, the agency itself, and the vicissitudes of epidemiology. Hoge said that the company expects to have both an interim efficacy readout and enough safety follow-up to satisfy the FDA by mid-November, a timeline that would put them almost neck-and-neck with Pfizer.
Among the main questions facing the adcomm today is what happens to the trials if the vaccines look effective at that point. Pfizer asked the FDA to allow them to vaccinate those in the placebo. Hoge expressed a similar sentiment, though he acknowledged that raised questions about how other companies will be able to conduct trials for much-needed vaccines.
“It really depends on what the scope of an EUA or approval is,” he said. “Clearly, if there’s a volunteer in our study or any study and a vaccine becomes available to them, whether it’s under approval or EUA, ethically they have every right to go get that vaccine. And what that means is you also want them to know whether they got the vaccine or not. You don’t want them to go get double-vaccinated, which creates other risks.”
“One of the things we all have to wrestle with here — I don’t think it’s a company health matter, it’s a regulatory matter, it’s a public health matter — is how do we deal with that,” he added. “It’s complicated.”
Hoge offered that, if their vaccine was authorized only for those over 75, then other companies could test their vaccine in people under the age of 75 and extrapolate from there. He also speculated about synthetic controls where, rather than randomizing volunteers, vaccinated individuals are compared epidemiologically to “similar” unvaccinated people.
Huge market questions also loom for both Pfizer and Moderna. SVB Leerink’s Geoffrey Porges speculated yesterday that Pfizer could gain a multi-billion dollar market advantage by having the first vaccine out of the gate. Hoge, though, rejected that idea, pointing out that vaccines will be in short supply for considerable time after the first few are authorized, making them different than virtually any other new drug in recent memory.
“The reality is if you don’t have enough supply to satisfy all that demand, it’s really just gonna be maintaining that supply and satisfying as much as you can,” he said. “Frankly, I think if we only get two out there — Pfizer and Moderna — in the near term, I think that’s a big concern.”
Longer term, analysts have tried to parse how large the market is for booster shots and repeat vaccinations, while public health experts have puzzled over just how long immunity will last. Hoge offered a middle ground, arguing that the future for Covid may look similar to the future for RSV, where only the elderly need repeated booster shots. He argued the current data suggest young people wouldn’t need more than a single booster over a long-term period.
“Whether there’s going to be value for a booster or an endemic market down below the age of 55 or outside of those co-morbid conidtions — my hope is no,” he said. “That would suggest that we really don’t have control over this virus.”
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