Moderna Stock Soars on Positive Cancer Vaccine Results

Moderna's stock price rose by approximately 510% between September 2025 and September 2026, from around $25 to about $173. This significant increase was largely driven by the company's cancer vaccine, intismeran autogene, which had been in development with Merck. On August 19, 2026, it was announced that a Phase III trial of this vaccine met its endpoints for both recurrence-free and distant metastasis-free survival.

The signs pointing to this positive result were present well before the stock's surge. In June 2024, Moderna reported promising three-year Phase II data for intismeran autogene in adjuvant melanoma. By early 2025, the company stated that the Phase III trial was fully enrolled and that a readout by 2026 was possible and plausible.

However, not all indicators were positive at the time. In its Q2 2025 results, Moderna's revenue had declined significantly year-over-year, down 38.8% to $3.06 billion. The company also announced in July 2025 that it would be cutting about 10% of its workforce due to declining sales of its COVID-19 vaccines.

The fact that management continued to fund the cancer work despite these challenges was seen as a sign that they believed the vaccine's potential outweighed the decline in their existing business. With Merck sharing the cost, Moderna funded the trial through the cuts.