[ad_1]
The FDA announced Friday that there will be a Vaccine Advisory Committee meeting on October 22, and the agenda and materials will be released on October 20. We note that the latest date is just under two weeks after the election. The agency announced that the meeting would address general standards and not a specific application. But that could change. In addition, the agency recently published guidance on the agency’s proposed standards for the approval of a vaccine for COVID-19. Those standards include a probable efficacy of 50% with a confidence interval of less than 30% or higher. This contrasts with the more common standard of more than 80% and with a stricter confidence interval, although the original shingles vaccine was approved with 50% efficacy. The herpes zoster vaccine at the time, however, was limited for use in high-risk patients, such as those with a history of chickenpox and the elderly, those with immunosuppression, and / or ongoing cancer treatment. However, this is a relatively low bar. While it depends on the initial rate of infection, if known, the number of patients to be enrolled could be relatively small, in the few thousand. As an example, a baseline incidence of 10% in the placebo group would translate into a 5% incidence in the treated group for efficacy as long as there are enough patents to make the confidence interval plus or minus 20%. Recent outbreaks on college campuses have shown an incidence of> 10% once an outbreak has started, such as at a frat party, with up to 1% to 5% among those who do not attend but have contact. At least three vaccines are in clinical trials in Brazil and other places with high current incidence.
Additionally, in the guidance, the FDA stated that the agency could approve the vaccine based on submission, under the provisions of the Emergency Use Request (EUA), rather than requiring a full statistical review, that is, based on a summary of effectiveness. Based on ongoing review provisions, many companies have already submitted their manufacturing data. The guide also waives certain toxicology requirements if the vehicle has been previously approved in another vaccine. Therefore, for these applications, the summary clinical review could be the last threshold for commercialization.
To that end, most companies will conduct a blind review of the data to identify if targets could be met that could precipitate early study closure. For example, assume a baseline incidence of 10% in the population outside the study. Imagine that the rate within the study, blindly, is 7.5%. Divided equally, this could mean a 10% rate on the placebo and a 5% rate on the asset. If so, based on the blind analysis, the sponsor could issue a prediction as to when the company would close the study, archive and, if approved at filing, market under an EUA.
In that sense, and given that the studies began in the US and in high-incidence areas in South America, one wonders if such a prediction and preliminary data could be available for publication in late October. The data presented on October 22, including the advisory committee comment, could identify a potential date when a vaccine might be available.
This all depends, of course, on the data. What is the most important being if the initial incidence is met? Is there a possible “half” reduction in an arm? And, later, how protected will the vaccine be, even if the antibodies are raised for reinfection? There have been three recent reports of a second infection: two were in the detection phase, symptom-free, and potentially non-infectious. However, the third was seriously ill. This shows that, in at least these three people, natural infection did not prevent reinfection. That is true for many diseases for a number of reasons. But in general, the antibodies obtained from a highly targeted and highly effective vaccine can provide greater protection than natural infection.
