After delivering solid sales growth in a difficult 2025, Germany’s Merck KGaA may have a tougher go of things this year, which the company is crediting in part to a predicted onslaught of U.S. generics to its multiple sclerosis blockbuster Mavenclad.
Approved by the FDA in 2019, Mavenclad delivered its third straight year of blockbuster sales in 2025, charting nearly 17% growth over the previous year to 1.2 billion euros ($1.4 billion) worldwide, Merck KGaA reported Thursday. In North America specifically, the drug reeled in 635 million euros ($735 million) last year, Merck noted in a detailed earnings report issued (PDF) March 5.
That performance, plus broader momentum in the German Merck’s cardiovascular, metabolism and endocrinology franchises, as well as growth from its life sciences CDMO arm, helped the company deliver 3.1% growth across the group in 2025, reaching full-year sales of 21.1 billion euros ($24 billion). Aside from life sciences and healthcare, Merck’s electronics division makes up the third pillar of its business.
However, in an unfortunate turn for Merck, recent efforts to stave off Mavenclad patent challenges in the U.S. have fallen short, prompting the drugmaker to more or less throw in the towel on future growth for the MS med stateside.
In particular, Merck’s guidance for the year—anticipating sales between 20 billion euros and 21 billion euros, or -1% to 2% growth— “assumes no U.S. sales of Mavenclad from March 2026 amid generic competition.”
What’s more, Merck KGaA is also declining to factor in potential U.S. sales of its fertility drug Pergoveris into its forecast, despite executives aiming for a launch in the States in the second half of 2026.
Merck KGaA’s dim sales expectations for Mavenclad in the U.S. come after the U.S. Court of Appeals for the Federal Circuit last October affirmed an earlier decision that deemed two of the company’s Mavenclad dosing regimen patents invalid. The company filed a petition for a rehearing, which was denied in January, according to Merck’s detailed earnings report.
Seeking to allay analyst concerns about the Mavenclad and Pergoveris caveats in Merck KGaA’s guidance, Kai Beckmann, the deputy chair of the firm’s executive board, leaned heavily on the uncertainty facing both drugs in the U.S.
“Regarding Mavenclad, we will not speculate on the timing of potential entries of generics, nor their market behavior, and frankly, we believe there’s very little to gain on this speculation,” Beckmann said in response to an analyst question about the company’s 2026 forecast. “Hence, we have opted for a more conservative approach concerning this item by clearly outlining our assumptions.”
And while Merck KGaA still expects to launch its fertility medicine Pergoveris in the U.S. in the second half of the year—which it aims to achieve via an FDA Commissioner’s National Priority Review Voucher (CNPV)—the company is excluding potential U.S. sales from its 2026 guidance given that the “ultimate decision regarding the Pergoveris approval is beyond our control,” Beckmann said.
Danny Bar-Zohar, CEO of Merck KGaA’s pharmaceutical-focused healthcare division, also sought to provide more color on the situation.
Given the recent U.S. court decisions, “we expect generic companies to request the district court to lift their 30 month stays where applicable,” Bar-Zohar said of the new leeway for U.S. Mavenclad generic launches.
So far, one company—Apotex—has received final FDA approval for its generic and launched in the States, Bar-Zohar said, adding that Merck KGaA already started to feel the sales pressure from that launch in December.
“Another generic has received tentative FDA approval … and three additional companies, to the best of our knowledge, are working on developing Mavenclad generics as well,” he said.
As for Pergoveris, Bar-Zohar explained that the company submitted the first part of its application in November and is now in a rolling phase as it prepares the second half. Once that second portion of the filing is in, the abbreviated review timeline of one to two months under the new pathway will kick in, he added.
Admitting that the CNPV process is new to the company, Bar-Zohar noted that with Pergoveris, “we have this one shot, and we want to get it right.”
He continued: “Now, we are diligently working through adaptations from data collected primarily to satisfy ex-U.S. authorities to the FDA, and we’re doing that in close collaboration with the FDA. This means there is some uncertainty about the exact point for the submission of the second part.”
Still, Bar-Zohar stressed that Merck is aiming for a “potential launch in the second half of this year,” with the ambiguous timing of its CNPV submission the main factor stopping the company from baking U.S. Pergoveris sales into its 2026 guidance.
Fertility med Pergoveris has long been approved in other countries and is widely available outside the U.S. The drug is a combination of recombinant human follicle-stimulating hormone (r-hFSH) and recombinant human luteinizing hormone (r-hLH) that’s designed to stimulate follicular development in women with severe deficiencies of those hormones.
The potential U.S. approval of the drug comes after Merck in October struck a drug-pricing deal with the White House, also concerned with fertility drugs, and in particular the suite of in vitro fertilization (IVF) products offered through its U.S. arm EMD Serono.
Merck KGaA has also reached a deal with the U.S. government, exempting it from industry-specific import tariffs in exchange for U.S. production and R&D investments.