Germany’s Merck KGaA, which achieved solid sales growth in a difficult 2025, could find itself in an even tougher year. The company believes this is partly due to the anticipated onslaught of U.S. generic drugs to multiple sclerosis blockbuster Mavenclad.
Mavenclad, which was approved by the FDA in 2019, achieved its third consecutive year of blockbuster sales in 2025, growing nearly 17% year over year to €1.2 billion ($1.4 billion) worldwide, Merck KGaA reported Thursday. Particularly in North America, the drug generated sales of 635 million euros ($735 million) last year, Merck said in a detailed earnings report (PDF) published March 5.
This performance, along with broader momentum in Germany’s Merck & Co. Cardiology, Metabolism and Endocrinology franchise and growth in the Life Sciences CDMO division, helped the company achieve group-wide growth of 3.1% in 2025, reaching full-year sales of €21.1 billion ($24 billion). In addition to life sciences and healthcare, Merck’s electronics division represents the third pillar of the company’s business.
But in an unfortunate development for Merck, recent efforts to stop Mavenclad from infringing patents in the United States have failed, leaving Merck more or less abandoned on future growth of MS drugs in the United States.
In particular, Merck’s outlook for this year is for sales to grow between 20 billion euros and 21 billion euros, or -1% to 2%, but “assumes that Mavenclad will not be sold in the United States after March 2026 amid generic competition.”
Additionally, Merck KGaA is refusing to factor in potential U.S. sales of its fertility drug Pergoveris in its forecasts, even though management is aiming for a U.S. launch in the second half of 2026.
Merck KGaA’s bleak sales outlook for Mavenclad in the US comes after the US Court of Appeals for the Federal Circuit last October upheld an earlier ruling that deemed two of the company’s Mavenclad dosing regimen patents invalid. Merck’s detailed earnings report shows that the company’s request for reconsideration was denied in January.
In an effort to allay analyst concerns about the Mavenclad and Pergoveris warnings in Merck KGaA’s guidance, Kai Beckmann, vice chairman of the company’s board of directors, weighed in heavily on the uncertainty facing both drugs in the United States.
In response to an analyst question about the company’s 2026 outlook, Beckman said, “With respect to Mavenclad, we do not intend to speculate on the timing of potential generic entry or its market trends. Frankly, we believe there is little to be gained from this speculation.” “We therefore chose a more conservative approach on this item by clearly outlining our assumptions.”
And while Merck KGaA still plans to launch its fertility drug Pergoveris in the U.S. in the second half of this year, which it aims to achieve through the FDA Commissioner’s National Priority Review Voucher (CNPV), the company has excluded potential U.S. sales from its 2026 guidance because “the final decision regarding the approval of Pergoveris is beyond our control,” Beckmann said.
Dany Barzohar, CEO of Merck KGaA’s pharmaceutical-focused healthcare division, also sought to explain the situation further.
In light of recent U.S. court rulings, “we expect generic companies to ask district courts to lift the 30-month moratorium where applicable,” Bar-Zohar said of new room for Mavenclad generic drug launches in the U.S.
So far, one company, Apotex, has received final FDA approval for its generic drug and launched it in the U.S., Bar-Zohar said, adding that Merck KGaA is already starting to feel sales pressure from the December launch.
“Another generic drug has received interim FDA approval, and to our knowledge three additional companies are working on developing Mavenclad generic drugs,” he said.
Regarding Pergoveris, Bar-Zohar explained that the company submitted the first part of its application in November and is currently in the process of preparing the second part. Once the second part of the application is submitted, a shortened review schedule of one to two months under the new pathway will begin, he added.
Bar-Zohar acknowledged that the CNPV process is new to the company, saying for Pergoveris, “This is a one-shot game and we want to get it right.”
He added: “We are currently working hard to adapt the data we have collected primarily to satisfy former US officials to the FDA, and we are working closely with them to do so. This means there is some uncertainty as to the exact point of submission for Part 2.”
Still, Bar-Zohar emphasized that Merck is aiming for a “possible launch in the second half of this year,” and that the ambiguity in the timing of the CNPV filing is the main factor preventing Merck from incorporating sales of Pergoveris in the U.S. into its 2026 outlook.
The fertility drug Pergobellis has long been approved in other countries and is widely available outside the United States. This drug is a combination of recombinant human follicle-stimulating hormone (r-hFSH) and recombinant human luteinizing hormone (r-hLH), designed to stimulate follicular development in women who are severely deficient in these hormones.
The potential U.S. approval of the drug comes after Merck entered into a drug pricing agreement with the White House in October for a range of infertility drugs, particularly in vitro fertilization (IVF) products offered through its U.S. arm EMD Serono.
Merck KGaA also reached an agreement with the U.S. government that waives industry-specific import duties in exchange for investment in U.S. production and research and development.
