Shares of U.S. biotechnology company Moderna soared 177% on Wednesday after the company reported positive trial results for an experimental cancer therapy based on messenger RNA technology. The stock ranked among the strongest performers in the S&P 500, marking a dramatic reversal for a company that had struggled following the decline in demand for COVID-19 vaccines.

The treatment is a personalized melanoma vaccine jointly developed by Moderna and Merck. It uses mRNA technology to train a patient’s immune system to recognize neoantigens created by unique tumor mutations and attack cancer cells carrying those markers, with the goal of preventing the disease from returning.

Analysts expect the skin cancer vaccine could receive regulatory approval as early as next year. If approved, it would become the world’s first mRNA-based cancer treatment. Shares of Merck rose 12.6% on Wednesday and reached a record high.

Moderna Chief Executive Stéphane Bancel said the long-standing vision of creating customized mRNA cancer treatments for individual patients is moving closer to reality.

Germany’s BioNTech is also developing personalized cancer vaccines using similar technology. Its shares climbed 22% following Moderna’s announcement. Moderna currently has 15 cancer treatments in various stages of testing, compared with 14 experimental programs targeting respiratory diseases and other conditions.

The global market for cancer medicines continues to expand rapidly. According to the American Society of Clinical Oncology, spending by governments and patients worldwide rose 75% between 2020 and 2024 to $252 billion. That figure is projected to reach $441 billion by 2029.

Moderna’s revenue has declined sharply since the pandemic-era vaccine boom, falling from $6.8 billion in 2023 to $3.2 billion in 2024 and $1.9 billion in 2025. However, the potential of mRNA technology in cancer treatment has renewed investor interest. Analysts note that personalized vaccines are initially expensive to produce, but costs could decline as the technology improves and production expands.

Political controversy surrounding mRNA technology nevertheless continues in the United States. Eight Republican-led states introduced legislation this year seeking to restrict or prohibit the technology, although none of the proposals passed. U.S. Health Secretary Robert F. Kennedy Jr. also canceled $50 million in federal funding for mRNA research a year ago.

Moderna’s first influenza vaccine received approval from the U.S. Food and Drug Administration this month. Before the cancer trial results were released, Bancel said misinformation surrounding mRNA technology was regrettable, but that the clinical data spoke for itself.