Merck's MRK financial performance in the third quarter of 2026 will likely hinge on the sales of its flagship drug, Keytruda. This PD-L1 inhibitor accounts for over 55% of the company’s pharmaceutical sales and generated $16.40 billion in the first half of 2026, marking a 4.2% year-over-year increase. The subcutaneous formulation, Keytruda Qlex, contributed $590 million during this period, offering a faster administration time compared to the intravenous version.
Investors are closely watching Keytruda's sales ahead of Merck's Q3 earnings report on October 29, 2026. The drug's sales are expected to benefit from strong momentum in metastatic indications and rapid adoption in earlier-stage treatments. Recent label expansions, including its use with Pfizer’s Padcev for muscle-invasive bladder cancer, have broadened its patient base. The Zacks Consensus Estimate projects Keytruda’s Q3 sales at $7.45 billion.
Merck anticipates Keytruda's robust growth continuing until its patent expires in 2028, with peak sales projected at $35 billion. However, the drug faces significant biosimilar competition around 2028-2029, which could sharply reduce its sales. Keytruda also competes with other PD-L1 inhibitors like Bristol Myers’ BMY Opdivo, Roche’s RHHBY Tecentriq, and AstraZeneca’s AZN Imfinzi.
Year-to-date, Merck’s shares have surged 37.7%, outperforming the industry’s 15.1% rise. Valuation-wise, Merck trades at a forward P/E ratio of 17.94, slightly below the industry average of 18.33. The Zacks Consensus Estimate for 2026 earnings per share has declined from $2.78 to $2.66, while the 2027 estimate dropped from $9.67 to $9.27 over the past 60 days. Currently, Merck holds a Zacks Rank #4 (Sell).