Merck reports success for cancer combination therapy in trial of 1,137 patients
Key Facts
Merck said adding intismeran to Keytruda delivered statistically significant and clinically meaningful improvements in recurrence-free survival and distant metastasis-free survival compared with Keytruda alone. The trial enrolled 1,137 patients, according to the company's statement on the study results, which researchers are preparing to present for the first time at the European Society for Medical Oncology congress. Participants were randomly assigned in a 2:1 ratio to receive either the combination therapy or Keytruda alone to assess the effect of adding the personalized treatment to the drug. On safety, Merck said "no new safety signals were observed" when the two treatments were used together during the trial. The study continues to evaluate other secondary endpoints, including overall survival, alongside the recurrence and distant metastasis endpoints covered by the announced results.
Intismeran is tailored to the unique biological characteristics of each patient's tumor, according to Merck's description of the personalized treatment used in the study. The treatment contains synthetic messenger RNA encoding up to 34 tumor neoantigens. The company described the formulation as "designed around the unique biology of the patient's tumor," explaining the nature of the treatment added to Keytruda. The pivotal trial follows an earlier phase IIb study in which the combination therapy reduced the risk of recurrence or death by 49% compared with pembrolizumab alone, according to The ASCO Post. Follow-up from the earlier study also showed a 59% reduction in the risk of distant metastasis or death with the combination therapy, according to the same source.
In trading ahead of the anticipated scientific presentation, Investing reported that Moderna shares rose 4.4% on the morning of October 19, 2026. The share price reached $227.50 during that coverage, according to the website, which reported on the move ahead of the presentation of details from the combination therapy trial. The stock had moved differently after the announcement of the trial's success in August, when it fell during midday trading. In its coverage dated August 20, 2026, Investing reported a 25.2% drop in Moderna shares. The share price stood at $130.47 at the time, according to the same coverage, in an earlier episode following the announcement of the results.
The next scientific milestone is the European Society for Medical Oncology congress, taking place in Madrid from October 23 to 27, 2026, according to Merck's statement on its participation. The company plans to present the first phase III results from the pivotal combination therapy trial during a presidential session at the congress. Merck described the presentation as the "first phase III results," as part of its program to present the trial data to the scientific community. Alongside the congress, the company plans to hold an oncology investor event on Monday, October 26, 2026, featuring an update on its strategy and program in the field. Merck also said the study data would be shared with regulatory authorities.