Pfizer (NYSE:PFE) and its German partner BioNTech (NASDAQ:BNTX) reported incredible efficacy data from a phase 3 trial for their mRNA coronavirus vaccine candidate. This news, paired with the equally impressive data from Moderna (NASDAQ:MRNA) about its candidate that takes a similar approach, inspired much hope around the world and injected optimism into the stock market.

The Motley Fool sat down with Dr. Jeremy Brown, author of Influenza: The Hundred-Year Hunt To Cure The Deadliest Disease In History and Director of Emergency Care Research at the National Institutes of Health. Dr. Brown shared what investors should know about the probability of success.


Corinne Cardina: Looking beyond Pfizer and BioNTech, are there any other near-term catalysts that investors should be keeping an eye on any upcoming trial data? What are you going to be watching?

Dr. Jeremy Brown: Well, there are, I think around nine or 10 Phase 3 trials across the world that are currently running. So we have to wait and see what they show. They will use slightly different approaches and new Phase 3 trials are being announced all the time. One good piece of news is the fact that if Pfizer could do it in a short amount of time, as I said earlier, it is likely to mean that other companies are also going to be able to produce something. But which of those and how long it's going to take and which of those vaccine trials in Phase 3 will fail? That's an open question, as I said, if you look historically, at least 90% of all vaccine trials fail, if you look from the very earliest development of the vaccine all the way through to Phase 3. In terms of Phase 3 trial failure rate somewhere in the region of half of them may fail. We don't know again, if those are statistics based on what has happened in decades that have passed where the vaccines were not built in this laser-sharp focused way, or whether that failure rate is going to be a thing of the past that because we are now building vaccines with this amazing technology. The old failure rates in the old statistics about who is likely to succeed and fail maybe they're a thing of the past now. It could be the candidates that get to this final stage of testing with these newer techniques are actually far more likely to succeed. Again, we'll have to wait and see what happens with these other dozen or so Phase 3 trials, before we're able to look back over our shoulder in the rearview mirror and say, going forward, I think that new vaccine trials will have a success rate not of 10% but of 60%. That would change things greatly, certainly for people who are looking to invest in the companies that produce them.

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