Exhibit 99.1 News Release Merck & Co., Inc., Rahway, N.J., USA Announces First-Quarter 2026 Financial Results; Highlights Significant Regulatory Approvals and Clinical Milestones Sales Growth Driven by Continued Strength in Oncology and Animal Health, Plus Increasing Contributions From Launches RAHWAY, N.J., April 30, 2026 – Merck & Co., Inc., Rahway, N.J., USA (NYSE: MRK), known as MSD outside the United States and Canada, today announced financial results for the first quarter of 2026. Available in some m ...