Moderna's Cancer Vaccine Surge Faces Skepticism from Wall Street

Moderna's stock has surged more than sixfold in the past year, driven by its mRNA cancer vaccine breakthrough. However, Wall Street analysts are expressing caution, questioning whether the company's shares are overvalued.

The centerpiece of Moderna's rally is intismeran autogene, an experimental personalized cancer vaccine being developed with Merck (MRK). In August, Moderna reported that a Phase 3 trial combining the vaccine with Merck's immunotherapy Keytruda showed meaningful improvements in recurrence-free survival and distant metastasis-free survival for patients with completely resected Stage IIB-IV melanoma.

Since then, the stock has pulled back from its peak but remains near multiyear highs. On Monday, shares climbed more than 14% to around $176 after Moderna said three research abstracts on intismeran autogene had been accepted for presentation at the European Society for Medical Oncology (ESMO) Congress 2026.

Analysts remain unconvinced about the stock's prospects. According to Barron's, most analysts hold either neutral or hold ratings on Moderna, and at least two have downgraded the shares since the August surge. JPMorgan's Jessica Fye has maintained her sell rating, noting that the immediate economic implications of the melanoma trial already appear well-factored into the stock price.

Moderna has raised $2.6 billion through a convertible debt offering, with the notes convertible at $210.58 per share. This move may limit upside if the company's oncology pivot continues to drive the stock higher.