Hours before America’s biggest cancer conference starts in Chicago, a small biotech may have stolen the show, touting late-stage results in a Thursday afternoon press release that added over $5 billion to its market capitalization — with one major caveat.
Summit Therapeutics said its experimental cancer drug beat Merck’s flagship immunotherapy Keytruda in a head-to-head Phase 3 study of non-small cell lung cancer patients in China. The Miami-based biotech said it was the first time a cancer drug has pulled off the feat of toppling Keytruda in this type of cancer.
The readout triggered a multibillion-dollar stock swing, with Summit $SMMT closing up 272% on Thursday and commanding a $7.7 billion market capitalization. Merck saw its shares $MRK fall just over 1%.
For all the market excitement, the results come from an interim analysis described in a press release without disclosing specific clinical results. Summit said the full dataset will be presented later this year at a medical conference.
The trial was also conducted only in China by Akeso, Summit’s China-based partner, and that re-opens questions about the willingness of FDA regulators and US oncologists to rely on China-based clinical results. China-only studies have turned into a contentious topic over the past few years as the FDA has pushed back against approving experimental cancer drugs based solely on China data.
Despite those qualifiers, the trial is a boon for the broader prospects of the drug, a PD-1/VEGF bispecific antibody called ivonescimab. Stifel analyst Bradley Canino said in a note to investors there’s “good reason” to expect the China-only data will translate to a global population. He added the readout also “offers confidence to open several new Phase 3 opportunities in lung cancer and beyond.”
The study’s results also raise the prospects of an unlikely repeat success for Summit CEO Bob Duggan, who previously ran Pharmacyclics until it was bought by AbbVie for $21 billion in 2015.
The Pharmacyclics deal, centered on the cancer drug Imbruvica, made Duggan a billionaire. He used some of that fortune to start buying Summit shares in 2018, eventually becoming the biotech’s largest shareholder and CEO in 2020. Summit’s then-lead antibiotic program ultimately failed a Phase 3 trial, but Summit agreed to pay $500 million upfront in December 2022 to Akeso for ivonescimab’s rights in the US, Canada, Europe, and Japan. Duggan owned 78% of Summit’s shares as of the company’s recent regulatory filing.
Ivonescimab won its first approval in China on May 24 as a second-line treatment for certain non-small cell lung cancer patients.
Summit is also running a pair of global Phase 3 trials with ivonescimab, testing the drug as a second-line treatment compared to placebo and as a first-line option compared to Keytruda in non-small cell lung cancer.
Summit’s leaders called the results from Akeso’s China study, called HARMONi-2, a “historic moment” for the drug and the two companies. In a statement, Duggan said “this is the beginning of a paradigm change for treatment options for patients living with cancer.”
Summit said it plans to host a conference call before the market opens on Monday to discuss recent updates for ivonescimab.