Merck & Co delivered stronger-than-expected first-quarter results, with sales climbing 5% to $16.29 billion, surpassing Wall Street forecasts of $15.85 billion. The pharmaceutical giant raised its full-year earnings guidance as demand for its flagship Keytruda cancer drug continues to grow, representing a critical growth driver for the company.

Keytruda specifically showed impressive performance, expanding by 12% during the quarter and contributing significantly to Merck's overall sales growth. This performance comes as Merck strategically builds out its product portfolio to prepare for the eventual loss of Keytruda's primary U.S. patent protection.

The company's ability to exceed expectations despite patent uncertainty demonstrates the strength of its current product lineup. Investors responded positively to the results and raised guidance, indicating confidence in Merck's strategy to navigate upcoming patent challenges while maintaining growth momentum.