Merck KGaA: Stock Fluctuates in Q2 2026 – Cancer Therapy Data in Focus

Merck's stock (ticker: MRK) closed at $113.87 on June 18, 2026, falling 1.36% from the previous day. This is according to trading data from Zacks. The stock continued a volatile trend in the second quarter, characterized by price movements between $111.90 and $119.28.

Positive Keytruda Combination Trial Data Drives Stock Up in May

On May 22, 2026, Merck's stock rose after partner Kelun-Biotech released positive results from a Phase III trial of a combination therapy with Keytruda for lung cancer. Keytruda is Merck's highest-revenue cancer drug and is used to treat various tumor types. According to Barron's, the trial data shows that Merck is expanding its portfolio beyond the single product Keytruda.

Stock Losses in April and June Despite Positive Market Environment

On several trading days in the second quarter, Merck's stock fell even as overall markets gained. On April 24, 2026, the stock closed at $111.90, down 2.37%. On April 7, the closing price was $119.28, representing a decline of 1.3%. On June 18, the stock also recorded losses while the broader market advanced.

Patent Expiration and Growth Prospects as Central Issues

According to The Motley Fool, analysts are grappling with the question of how Merck will navigate the upcoming patent expiration of key drugs. A so-called patent cliff refers to the point in time when important patents expire and cheaper generics enter the market. This typically leads to revenue declines for the affected original drugs. On June 4, 2026, an analysis addressed the company's future growth prospects.

Trading Range in the Second Quarter

In the period from early April to mid-June 2026, Merck's stock moved within a range of approximately $7.38 between the lowest documented closing price of $111.90 on April 24 and the highest of $119.28 on April 7. The documented price declines each went against the trend of the overall markets, pointing to company-specific factors.