Moderna Inc. and Merck & Co. announced on Wednesday that their personalized mRNA cancer vaccine, when combined with Merck's immunotherapy Keytruda, successfully cut the recurrence rate of melanoma in a large, late-stage trial. This trial met its primary objective, demonstrating that the vaccine-Keytruda combination was more effective at preventing cancer recurrence after surgical removal than Keytruda alone. The study also achieved a key secondary goal, showing that the shot helped prevent tumors from spreading to new areas of the body.
This success has significant implications for treating melanoma, the deadliest form of skin cancer. The initial data suggests this combination could offer a new treatment option for patients. Merck's shares climbed over 12% on Wednesday, while Moderna's stock soared about 177%. Analysts noted that Moderna's valuation already anticipated the cancer vaccine's potential across various cancer types.
Moderna's CEO, Stephane Bancel, called this a "big moment for medicine" and patients. Dr. Jane Healy, Merck's head of oncology early development, highlighted the therapy's "clinically meaningful improvement" over Keytruda, which is the current standard of care for melanoma. She also noted that side effects were similar to those of common vaccines. The personalized vaccine works by targeting specific mutations in each patient's tumor, training the immune system to recognize and attack these unique cancer markers, with Keytruda enhancing this immune response.
The Phase 3 study, which involved more than 1,100 patients with high-risk or advanced melanoma whose cancer had been surgically removed, will continue to assess other outcomes, including overall survival. The companies plan to present the detailed data at an upcoming international medical meeting and intend to discuss regulatory applications within the next few months. This breakthrough marks the first time a personalized mRNA cancer therapy has succeeded at this late stage of testing, reviving hopes for mRNA-based treatments beyond infectious diseases.
This achievement builds on previous positive Phase 2 trial data where the combination reduced the relative risk of death or recurrence by 44% over Keytruda alone. The companies are also studying the vaccine in trials for other cancers, including non-small cell lung cancer, bladder cancer, and renal cell carcinoma, which are considered more amenable to immune-based therapies.
