Lilly Buys Merida Biosciences for Up to $2.875B to Target Autoantibody-Driven Disease

Eli Lilly said Monday it will acquire Merida Biosciences, a privately held Cambridge, Massachusetts biotech, for up to $2.875 billion in cash to gain a precision platform that selectively degrades the pathogenic autoantibodies behind a range of immune-mediated diseases. The deal includes an upfront payment plus contingent milestone payments and is expected to close in the fourth quarter of 2026, subject to regulatory approvals and customary closing conditions.

Merida’s lead program, MER511, is in Phase 1 development for Graves’ disease and thyroid eye disease (TED), conditions driven by thyroid-stimulating immunoglobulins that activate the thyroid-stimulating hormone receptor. Graves’ disease affects roughly 3 million people in the U.S., and an estimated 25 to 40 percent of patients go on to develop TED, which can cause pain, disfigurement, and, in severe cases, vision loss. While treatments exist for both conditions, none directly targets the autoantibodies that cause them.

Early Phase 1 data showed MER511 produced deep reductions in those disease-causing antibodies with a favorable initial safety profile. The mechanism differs from Amgen’s Tepezza (teprotumumab), the approved TED therapy that blocks the IGF-1 receptor. MER511 is designed to eliminate the autoantibodies themselves while preserving normal immune function, an approach Lilly says could change the course of disease rather than only treating its downstream effects.

The platform reaches beyond the lead program. Merida’s pipeline also includes MER769, a preclinical candidate aimed at food allergy, asthma, and chronic spontaneous urticaria, plus earlier-stage programs in kidney diseases such as membranous nephropathy.

Lilly shares traded near $1,159 midday Monday, down about 1 percent from Friday’s close of $1,174.61. For a company of Lilly’s size, a sub-$3 billion bolt-on barely registers, but the deal extends a heavy year of dealmaking: it follows Lilly’s $2.8 billion buyout of AtaiBeckley in July and is one of more than a dozen acquisitions the drugmaker has struck in 2026.

The move gives Lilly a direct challenger to Amgen in thyroid eye disease and deepens an immunology franchise built around inflammatory and autoimmune disease. Watch for additional Phase 1 data from MER511 and whether Lilly advances the asset toward registrational trials in Graves’ disease.

The full press release is available from Lilly. For context on Lilly’s earlier M&A push, see our coverage of the AtaiBeckley acquisition.