It's hard to find a biotech company that has performed better than Summit Therapeutics (SMMT 2.86%) in the past year. The stock is up by a whopping 512%, and it's no secret why.

Summit, a specialist in oncology, has made excellent clinical progress with its leading candidate, ivonescimab. There's more where that came from, too; Ivonescimab just knocked it out of the park in another study, a piece of news that jolted the share price.

With the drugmaker's market-crushing performance  over the trailing-12-month period, is it too late to invest in the stock? Let's find out.

Ivonescimab's progress continues to impress

Summit Therapeutics licensed ivonescimab from a China-based biopharmaceutical company, Akeso. Summit now owns the rights to market the drug in most countries outside of China, including in the most lucrative regions for biotech companies, the U.S. and Europe.

The medicine isn't approved in the U.S. yet, but it is in China, and is still undergoing many clinical trials in the country. On March 23, Summit reported positive results from a phase 3 clinical trial conducted in China for ivonescimab in advanced squamous non-small cell lung cancer (NSCLC).

Investigators pitted ivonescimab and chemotherapy against Tevimbra and chemotherapy. Tevimbra is a cancer medicine owned by BeiGene. In the trial, the ivonescimab combo achieved a statistically significant improvement in progression-free survival compared to the Tevimbra combo. This was yet another impressive result that sent Summit Therapeutics' stock soaring.

It's not too late to jump on the bandwagon

It wasn't all rainbows and sunshine for Summit last week. The company provided updated data from a phase 3 clinical trial for ivonescimab in NSCLC, where it went head-to-head against the leading medicine in this market (and the world's best-selling drug): Merck's Keytruda. The reading of the data so far shows that ivonescimab has yet to achieve a statistically significant improvement in overall survival compared to Keytruda.

Because preliminary news that ivonescimab was beating out Keytruda had been a massive catalyst for the stock, and phase 3 studies have yet to be completed in the U.S., some investors saw this development as a negative sign and sold off their shares. In other words, last week was a volatile one for Summit. Still, with its latest phase 3 results against another approved cancer medicine, ivonescimab is showing that it wasn't just a one-hit wonder.

Perhaps the medicine won't deliver a conclusive, statistically significant victory against Keytruda in overall survival, but it hardly needs to do so to be massively successful. Moreover, ivonescimab is undergoing over a dozen other clinical trials and targeting various other forms of cancer. The NSCLC market looks like the most attractive, since lung cancer is the leading cause of cancer death in the world, and most patients with lung cancer (up to about 85%) suffer from the NSCLC variety.

Even so, part of ivonescimab's appeal is that it could turn out to be a "pipeline in a drug," grinding out label expansions well beyond whatever initial indication it earns. In my view, Summit's crown jewel still looks likely to gain approval and become a blockbuster. As it records more clinical and regulatory wins, the stock should move in the right direction again.

So I think it's not too late to invest in Summit Therapeutics, at least if you're intending to hold onto the stock for a long time. The company may still experience some volatility in the short term, due to both its status as a clinical-stage biotech and broader market issues. But it could deliver outsize returns down the road.