Eli Lilly (LLY) on Sunday shared new lung cancer data for its experimental drug olomorasib, reporting a 62% tumor response rate when the treatment was combined with Keytruda and chemotherapy in first-line KRAS G12C-mutant lung cancer. The results were presented at the 2026 European Society for Medical Oncology congress in Madrid. The announcement did not include any stock price movement. The findings come from studies testing the oral KRAS G12C inhibitor with and without chemotherapy in the first-line setting.

Olomorasib targets KRAS G12C, a mutation found in about 13% of non-small cell lung cancer patients. The drug is an oral pill designed to lock the mutated protein in an inactive state, which stops the protein from sending growth signals to cancer cells.

One of the studies covered 77 patients who had not been treated before. They received olomorasib together with Merck's (MRK) Keytruda and chemotherapy. Confirmed tumor shrinkage appeared in 62% of them, or 48 of 77 patients. Responses lasted a median of 14.5 months. Patients went a median of 11.6 months before their cancer worsened or they died — a measure known as progression-free survival.

Results Without Chemotherapy

A second study looked at 85 patients who took olomorasib plus Keytruda alone. After a median follow-up of 20.7 months, median response duration and progression-free survival had not been reached — in plain terms, many patients were still doing well when the data were collected. Median response duration and progression-free survival are standard measures of how long a treatment keeps working. At 18 months, 55% of those patients were alive and their cancer had not worsened. Results held across PD-L1 levels. About 64% of patients in this group had PD-L1 expression of 50% or higher.

Dr. Marcelo Negrao of MD Anderson Cancer Center presented the work. He said responses lasting more than a year across all PD-L1 levels are the kind of progress doctors want to see in the first-line setting. He noted that many of these patients had low expression.

Jacob Van Naarden, who leads Lilly Oncology, said the first line is often the only line for these patients because the disease is so aggressive. He said the results deepen the company's conviction in the drug.

Safety Data

Safety findings were reported for both treatment groups. In the Keytruda-only group, the most common serious side effects were increased ALT at 15.3%, increased AST at 12.9%, and diarrhea at 8.2%. Olomorasib doses were reduced in 31.8% of patients, and treatment was stopped in 11.8%.

In the chemotherapy group, the most common serious side effects were neutropenia at 21% and anemia at 17%. Increased ALT and low platelet counts each affected 12% of patients. Dose reductions occurred in 19.5% of patients, and 7.8% stopped treatment.

No Grade 5 treatment-related events, meaning deaths, occurred in either group. The protocol does not require preventive medications for olomorasib, which Lilly views as a possible edge over other drugs in this class.

What Comes Next

No targeted therapy is currently approved for first-line KRAS G12C lung cancer. Standard care is immunotherapy with or without chemotherapy, and most patients never reach second-line treatment.

Both studies were single-arm, with no comparison group. That makes it too early to say olomorasib improves on existing options, and the randomized Phase 3 trials are built to answer that question.

SUNRAY-01 is a global program with two randomized, double-blind Phase 3 trials. Part B, which tests olomorasib plus chemoimmunotherapy against placebo plus chemoimmunotherapy, has finished enrolling. Part A covers patients with PD-L1 expression of 50% or higher, a level at or above which about 64% of patients in the Keytruda-only study fell.

Olomorasib has FDA Breakthrough Therapy designation for certain lung cancer patients but remains unapproved. Lilly expects the first randomized Phase 3 data from SUNRAY-01 in the first half of 2027.