Merck & Co. Inc. has delivered impressive first-quarter results, highlighted by $3.25 billion in sales from its COVID-19 antiviral pill Lagevrio and a 23% year-over-year increase to $4.81 billion from its cancer drug Keytruda. The company reported earnings of $2.14 per share, exceeding analyst expectations and leading to a revised annual sales forecast of $56.9 billion to $58.1 billion. This robust financial performance has driven a 10.1% rise in Merck's stock year-to-date, reflecting strong market confidence.