The FDA’s Vaccines and Related Biological Products Advisory Committee (VRBAC) was divided on whether two months of safety data was sufficient to evaluate a COVID-19 vaccine under emergency use, with many favoring more data. If the agency follows the advice of the external panel of medical experts, it could push the timeline for a vaccine into early 2021.
At the Oct. 22 meeting of the VRBAC, the FDA presented its evaluation criteria for a COVID-19 vaccine under an emergency use authorization (EUA) as well as what would be required for a full licensure, or a biologics license application (BLA). There are similarities between the criteria for an EUA and for a BLA. In both cases, a reduction in the number of severe COVID-19 cases must be included as a primary or secondary endpoint. Additionally, for an EUA or a BLA, the vaccine must demonstrate 50% efficacy on the primary endpoint, with at least 30% as the lower bound of the 95% confidence interval for the primary endpoint. The Phase III trial should have at least 3,000 people enrolled.
For an EUA, the application must include interim analysis of at least 50% of participants with two months of follow-up for safety and effectiveness, and the EUA request should include a plan for “active safety follow up.” For a BLA, the applicant must enroll a sufficient number of ethnic minorities, older adults and those with comorbidities, as well as submit six months of safety and efficacy data.
At the meeting, Doran Fink, deputy director in the FDA’s division of vaccines and related products applications, said the approval of a “weakly effective vaccine could cause more harm than good.” Fink explained that approval of such a vaccine could provide the public with a false sense of security, interfere with the development of potentially better vaccines and perhaps open the door to even less effective vaccines.
Some panel members thought the EUA criteria were reassuringly similar to those of the BLA. “I have a much better understanding of what the subtle differences are between licensure and EUA,” Dr. Paul Offit, professor of pediatrics in the division of infectious diseases at Children’s Hospital of Philadelphia and co-inventor of a rotavirus vaccine, said at the meeting. “This is much, much closer to a typical BLA license process than…how I perceived the EUA process so far. It’s a relatively high standard that we’re holding these vaccines to.”
Nevertheless, many on the panel voiced desire for at least two more months of safety data. They also expressed support for additional requirements to have sufficient data on minorities before granting an EUA. “I really feel like we haven’t gone far enough in terms of safety,” said Dr. Hayley Altman-Gans, a professor of pediatrics at Stanford University Medical Center. Dr. James Hildreth, professor, president and CEO of Meharry Medical College, said, “Since severe disease and death occur primarily among minorities, if we put a vaccine out there that doesn’t address that issue, I’m concerned it will perpetuate the perception that that segment of that population doesn’t matter.”
At least one company has said it could submit its EUA application for a COVID-19 vaccine as early as November based on two months of safety data. But a requirement of additional time to collect safety data could mean a COVID-19 vaccine won’t be available until January at the earliest. At the same time, some vaccine manufacturers are taking extra steps to enroll Black and Latinx participants in their Phase III trials, including extending enrollment periods to ensure a sufficient representation of minority groups most at risk of adverse outcomes due to COVID-19.
Additionally, the National Institutes of Health (NIH) hopes to use its HIV clinical trials framework as one tool to encourage minority enrollment in COVID-19 trials. HIV predominantly affects Black (45%) and Latinx (22%) populations and people of multiple races (19%). The Phase III vaccine and therapeutic trials being managed by the NIH are using the COVID-19 Prevention Network, which includes as partners the HIV Vaccine Trials Network, the HIV Prevention Trials Network and the AIDS Clinical Trials Group.
During the meeting, representatives from the Centers for Disease Control and Prevention (CDC) said the center expects to work with pharmacies from the get-go to administer vaccines to people in high-risk groups likely to receive the first wave of vaccines, including workers and residents at long-term care facilities. HRI’s analysis of the COVID-19 vaccine value chain identified retail pharmacies as one potential outlet from which to develop consumer-centric vaccination models. These models, which account for consumer preferences in their site of care, may help improve uptake and minimize concerns over vaccine hesitancy.