Moderna (MRNA) shares made a sharp surge in premarket trading on Wednesday, rising more than 100% to reach $122.51. The reason for this impressive jump was the publication of positive results from the third phase of clinical trials of a personalized mRNA cancer vaccine, being developed jointly with pharmaceutical giant Merck (MRK).
Recall that on Tuesday, Moderna shares closed at $62.96, and the current growth is so far only recorded in over-the-counter trading before the main session opens. Nevertheless, the scale of the market's reaction speaks volumes.
A historic first success for personalized mRNA therapy
In the INTerpath-001 study, scientists used a fundamentally new approach. Instead of a standard drug, they analyzed mutations in each patient's tumor, creating an individual vaccine. Each dose encodes up to 34 tumor targets (neoantigens), effectively training the immune system to precisely recognize and attack exactly the cells that need to be destroyed.
The study involved 1,137 patients with stage IIB–IV melanoma after surgery. The results showed that the combination of the vaccine with Merck's Keytruda significantly increased the recurrence-free period and slowed the spread of metastases compared to Keytruda monotherapy. This is especially important because Keytruda is considered the standard of care for such patients, and previously no drug had managed to surpass it in adjuvant therapy.
Notably, this is the first time in history that an mRNA cancer therapy has successfully passed the third phase of trials. The safety profile remained the same — no new side effects were identified.
Outlook for Moderna shares
This breakthrough is a breath of fresh air for investors. Since August 2021, when shares traded above $480, they have lost more than 90% of their value amid declining demand for COVID vaccines. However, in 2026, the stock has already more than doubled, helped by the approval of a flu vaccine and the expansion of the product portfolio.
On Wednesday, shares briefly rose to nearly $130, closing around $122. Merck shares also gained about 6%. However, caution remains: detailed efficacy data have not yet been published, and information on patient survival is still being collected. The companies promise to disclose full results at medical conferences and discuss them with regulators.
The same drug combination is currently being tested in nine studies against lung, bladder, and kidney cancer. The key question is whether the premarket gain can hold after the main trading session opens.
My view: This is undoubtedly a landmark event for the entire biopharmaceutical industry. However, it is worth remembering that the path from successful trials to widespread commercial use is long and thorny. Investors should assess not only the potential but also the risks associated with regulatory and manufacturing challenges before making decisions.