Moderna and Merck’s experimental personalised cancer vaccine has delivered positive results in its first Phase 3 trial, sending Moderna shares sharply higher and bringing the treatment closer to potential regulatory approval.
The companies said Wednesday that the mRNA-based vaccine, when combined with Merck’s Keytruda immunotherapy, significantly extended the period patients with high-risk melanoma remained free of cancer compared with Keytruda alone.
The combination also reduced the risk of melanoma spreading to distant parts of the body, according to initial results from the trial involving more than 1,100 patients.
The participants had higher-risk or advanced melanoma that had been completely removed through surgery but remained at significant risk of recurrence.
The results triggered a sharp market reaction. Moderna shares surged about 90% in premarket trading, while Merck gained more than 8%.
Moderna Chief Executive Officer Stéphane Bancel described the results as a major moment for medicine and patients.
The Phase 3 trial will continue to assess other outcomes, including whether the treatment improves overall survival. Merck and Moderna plan to present the full findings at an upcoming international medical meeting.
The companies have not yet disclosed when they will formally seek US approval for the treatment, although Merck Research Laboratories President Dr Dean Li said the companies expect to begin discussions with regulators about the treatment and its safety in the coming months.
How Vaccine Works
The vaccine represents a different approach to cancer treatment because it is individually designed for each patient.
Unlike conventional vaccines that target the same disease markers across large populations, the Moderna-Merck treatment analyses mutations in an individual patient’s tumour and creates a personalised mRNA vaccine designed to train the immune system to recognise those specific cancer markers.
The vaccine is then combined with Keytruda, which helps activate the immune system’s ability to attack cancer cells.
Researchers say the approach could potentially be applied to cancers beyond melanoma.
Melanoma accounts for only about 1% of skin cancers but causes the majority of deaths from the disease. Recurrence is particularly concerning because most melanoma relapses occur within two to three years after initial treatment and surgical removal.
The latest results build on positive Phase 2 findings reported earlier this year and provide the strongest clinical evidence yet for the personalised vaccine strategy.
Merck and Moderna are already testing the vaccine in other cancers, including non-small cell lung cancer, bladder cancer and renal cell carcinoma.
The success of the melanoma trial could therefore have implications beyond the treatment of skin cancer, potentially establishing personalised mRNA vaccines as a new class of cancer therapy.
For Moderna, the results are particularly significant after the company’s valuation came under pressure as demand for its Covid-19 vaccine declined.
The companies, however, still need to complete the Phase 3 trial and provide additional data, including overall survival results, before the treatment can be assessed for regulatory approval.
