Merus N.V. (MRUS)

Merus N.V. was a clinical-stage oncology company headquartered in Utrecht, the Netherlands, with significant operations in the United States. The company developed full-length human bispecific and trispecific antibodies, which are designed to bind two or more targets at once. Its work was based on proprietary platforms that it called Biclonics and Triclonics.

Merus described its approach as producing antibodies that look and behave like conventional human antibodies while engaging multiple targets. Its pipeline focused on solid tumors, including cancers with specific genetic drivers and cancers of the head and neck. Lead candidates included petosemtamab, which targets EGFR and LGR5, and zenocutuzumab, which targets HER2 and HER3.

The company listed its shares on the Nasdaq market under the symbol MRUS following an initial public offering in 2016. It entered into collaborations with other drug developers, including Incyte Corporation, which provided funding and development partnership for certain programs. Like many clinical-stage companies, it relied on equity offerings and partnership payments rather than product revenue.

Zenocutuzumab, marketed as Bizengri, received U.S. Food and Drug Administration approval in December 2024 for certain cancers carrying NRG1 gene fusions. Merus had licensed rights to the product to a partner for commercialization, so its main internal late-stage focus remained petosemtamab, which it was testing in head and neck cancer. Clinical updates on that candidate drew interest from larger pharmaceutical companies.

On September 29, 2025, Genmab A/S, a Danish biotechnology company listed on Nasdaq under the symbol GMAB, announced an agreement to acquire Merus for $97.00 per share in cash, a transaction valued at roughly $8 billion. The acquisition was structured as a tender offer by a Genmab subsidiary, followed by back-end transactions to acquire any remaining shares. Genmab said the deal would give it a late-stage oncology asset and expand its pipeline of antibody therapeutics.

The tender offer expired at 5:00 p.m. New York City time on December 11, 2025, with about 94.2 percent of outstanding shares validly tendered. Genmab accepted the shares for payment, and a subsequent offering period ran through December 29, 2025 at the same price. Remaining shareholders were to be paid through the previously disclosed back-end transactions.

An SEC Form 25 was filed on December 30, 2025, to remove Merus shares from listing on Nasdaq. The MRUS ticker is no longer traded, and Merus's programs are now part of Genmab.