Why Moderna (MRNA) Stock Is Down Today

The iShares Biotechnology ETF (IBB) rose 23.1% through Oct. 23, driven by drug milestones. Merck and Moderna reported positive Phase 3 trial data for intismeran autogene. Roche's Enspryng gained FDA approval for thyroid eye disease. Eli Lilly plans to submit a weight-loss drug for FDA review in early 2027. IBB's expense ratio is 0.44%, while SPDR S&P Biotech ETF (XBI) has a 0.35% expense ratio.

Moderna and Merck's melanoma vaccine trial showed a 42% reduction in tumor recurrence and 38% in distant spread, impressing doctors. However, shares of both companies fell as investors questioned the vaccine's broader potential and commercial success. Analysts raised concerns about costs and competition. The full data will be presented at a medical conference.

A phase 3 trial showed intismeran autogene (V940; mRNA-4157) plus pembrolizumab (Keytruda) improved recurrence-free survival (RFS) and distant metastasis-free survival (DMFS) in resected stage IIB to IV melanoma. The combination reduced the risk of recurrence or death by 42% (HR, 0.58; P < .001) and distant metastasis or death by 38% (HR, 0.62; P = .002). 24-month RFS rates were 82.2% vs 70.0%, and DMFS rates were 88.5% vs 80.2%.

A Phase III trial showed that intismeran autogene, a personalized mRNA therapy, combined with pembrolizumab, reduced the risk of death or recurrence by 42% in high-risk melanoma patients. The study, presented at ESMO 2026, enrolled 1,137 patients and demonstrated improved recurrence-free and distant metastasis-free survival. Despite the positive clinical results, a data leak caused shares of manufacturers Moderna and Merck to fall.

Merck and Moderna's Phase 3 trial showed a 42% reduction in melanoma recurrence or death risk when combining their mRNA vaccine with Keytruda. The trial involved 1,137 patients with high-risk melanoma. Overall survival data is pending. The vaccine is not yet approved, and commercial success is uncertain. Moderna aims for approval in 2025.

Moderna and Merck reported that their cancer vaccine, combined with Merck's Keytruda, reduced melanoma death and recurrence risk by 42% in a trial of 1,100 patients. The results, based on two-year data, will be presented at the European Society for Medical Oncology meeting. Analysts expected a 40%+ risk reduction.