Rewrites paragraphs 1 to 5 to include details about Revolution Medicines

By Christy Santhosh

June 1 (Reuters) - Shares of Revolution Medicines RVMD.O and Summit Therapeutics SMMT.O climbed in premarket trading on Monday after their experimental cancer treatments boosted survival outcomes for patients in late-stage trials.

Revolution's experimental pancreatic cancer pill, daraxonrasib, doubled survival when compared to chemotherapy, while Summit and China-based partner Akeso's 9926.HK ivonescimab therapy helped certain lung cancer patients live 15% longer than BeOne Medicines' 688235.SS Tevimbra.

The companies presented the data at the American Society of Clinical Oncology meeting in Chicago on Sunday.

Revolution's shares jumped 7.3% to $169 and Summit gained 3.6% to $18.17. Summit's shares have been mostly flat so far this year, while Revolution's stock has nearly doubled.

In a trial testing patients with advanced pancreatic cancer who had failed one round of chemotherapy, Revolution's once-daily pill, daraxonrasib, cut the risk of death by 60%, compared to standard chemotherapy.

At least two brokerages termed Revolution's trial data "compelling." Raymond James analyst Sean McCutcheon called daraxonrasib's overall survival results a "home run" and expects rapid and broad uptake in patients with advanced pancreatic cancer.

In Summit and Akeso's head-to-head study conducted in China, patients with advanced squamous non-small cell lung cancer who received ivonescimab and chemotherapy lived an average of 27.9 months, compared with 23.7 months for those who received Tevimbra and chemotherapy.

"This marks a notable advancement in a setting where no other treatments have ever found success," said TD Cowen analyst Tyler Van Buren.

Summit holds the rights for the drug in the U.S., Canada, Europe and Japan through a deal worth up to $5 billion, while Akeso retains the rights for China and the rest of the world.

Still, some analysts cautioned that questions remain about whether the China-only study will translate to broader patient populations.

Jefferies analyst Faisal Khurshid said investors are likely to focus on whether similar benefits can be replicated in global trials, particularly in the U.S. and Europe.