Shares of Summit Therapeutics (SMMT -27.85%) have plunged 31% as of 1:23 p.m. ET Friday, following the release of some trial data this morning.

Summit has been a tremendous winner over the past year, as its bispecific antibody lung cancer drug ivonescimab outperformed prior standards of care in phase 3 trials performed in China by Summit's partner Akeso (AKES.F -5.51%).

While today's results weren't all bad by any means, apparently investors had hoped for more conclusive information about survival rates. With such high expectations, it appears investors are taking profits or de-risking in a big way.

"Mixed" data gets a thumbs-down from investors, but analysts aren't worried

Today's release showed results of the fourth phase 3 trial known as "HARMONi," the first to include a significant Western patient population (about a third of participants). Last year's positive results largely came from a China-only study.

On the positive side, today's data did show that ivonescimab in combination with chemotherapy reduced the risk of disease progression or death by 48%. In addition, the company noted no significant differences between the Asian and Western patient populations. However, the trial didn't show a "statistically significant" benefit in overall survival.

Summit has been hoping to apply for FDA approval for ivonescimab in the U.S., but the FDA has told the company it will need to show that statistically significant survival benefit in order to get it. Investors may be getting nervous about that eventual approval.

However, analysts don't believe investors should panic. Jefferies biotech analyst Kelly Shi noted the survival endpoint still has a chance of being reached as the data matures further and Western trial patients continue to show survival benefits. So basically, it doesn't appear as though the trial has lasted long enough to reach the statistically significant survival threshold, which doesn't mean that it won't get there.

Image source: Getty Images.

Analysts still encouraged: A buying opportunity?

Another analyst was also bullish on the data, despite today's drop. Cantor Fitzgerald biotech analyst Eric Schmidt said, "We think it is fairly clear that this is a drug! ... In each of these four trials, the data posted by ivonescimab appear differentiated from and superior to PD-1 therapy."

Therefore, investors may want to take a look at Summit on this drop. While today's data didn't meet the threshold many investors had been hoping for, there is still a chance that it will with more time. Given the success ivonescimab has demonstrated over the past year, it seems likely, though not certain, the drug will eventually be approved.

Of course, it's a bit difficult to value a stock like Summit, which has a promising drug candidate but no real current revenues and a market cap that, even down 30% today, is still over $13.5 billion.