Merck & Co., Inc.
Pharmaceuticals / Biotechnology / Animal HealthFounded 1891- Updated June 2026
Reviewed by Swet Parvadiya
Last reviewed: June 2026
CorpDigest
Merck & Co., Inc.
Company History
Founded 1891 in Rahway, New Jersey
Last reviewed: 2026-06-03 · By Swet Parvadiya
In 1891, E. Merck of Darmstadt, Germany, established an American subsidiary to import and distribute pharmaceutical products to the growing US market. For 26 years it operated as a German-owned enterprise. In April 1917, three weeks after the United States entered World War I, the federal government seized the American subsidiary under the Trading with the Enemy Act. The management team that had been running the American operations purchased it in 1919, creating an independent American corporation with no continuing ownership connection to the German parent.
The company that emerged from that seizure grew steadily through the first half of the twentieth century. The 1953 merger with Sharp and Dohme — a major distributor and manufacturer of vaccines — brought critical vaccine manufacturing capability into the Merck portfolio and enabled the vaccine research program that Maurice Hilleman would eventually make world-famous. In 1981, Merck became the first company to commercialize a recombinant DNA vaccine, for hepatitis B, demonstrating that biotechnology could be applied at pharmaceutical scale. In 1987, Mevacor became the first commercially available statin, establishing Merck's dominance in cardiovascular medicine.
The pembrolizumab licensing from Organon in 2009 set the modern Merck story in motion. The compound was in early clinical development and PD-1 pathway immunotherapy was scientifically credible but competitively crowded. Merck chose to invest heavily in clinical development, and the first pembrolizumab approval — for advanced melanoma — came in September 2014. From that initial indication, the drug has been approved for more than 40 cancer indications.
The 2009 acquisition of Schering-Plough, the 2021 acquisition of Acceleron Pharma for pulmonary arterial hypertension drugs, and the 2023 acquisition of Prometheus Biosciences for inflammatory disease assets each represent Merck's attempt to build pipeline depth beyond the Keytruda concentration.
George Merck established Merck & Co. As the American subsidiary of E. Merck of Darmstadt, Germany in 1891, tasked with managing the distribution and eventual domestic manufacture of pharmaceutical and chemical products in the rapidly expanding American market. Under his management in the 1890s and 1900s, the American business grew from a pure import operation into a domestic manufacturer with facilities in Rahway, New Jersey. The forced separation from the German parent company during World War I — when the U.S. Government seized German-owned American business assets under the Trading with the Enemy Act — created the opportunity for George Merck to purchase the confiscated business and reconstitute it as an independent American corporation in 1919. His son George W. Merck subsequently led the company through its most scientifically productive era in the mid-twentieth century, articulating the 'medicine is for the people' philosophy that became the foundation of Merck's research culture and corporate identity. The Merck family's involvement in the company's management diminished after the mid-twentieth century as professional pharmaceutical executives succeeded the founding lineage.
George Merck establishes Merck & Co. As the U.S. Subsidiary of E. Merck of Darmstadt, Germany, initially focused on importing and distributing German-manufactured pharmaceutical and chemical products for the American market. The company establishes early manufacturing operations in Rahway, New Jersey, which remains the corporate headquarters more than 130 years later.
The U.S. Government seizes Merck & Co.'s assets under the Trading with the Enemy Act following American entry into World War I, appointing an Alien Property Custodian to manage German-owned U.S. Businesses. In 1919, the American management team led by George Merck purchases the confiscated assets, permanently severing the corporate connection to E. Merck of Darmstadt and establishing Merck & Co. As an independent American pharmaceutical enterprise.
Merck completes its merger with Sharp & Dohme, a Philadelphia-based pharmaceutical company with particular strength in vaccines and biological products. The combination substantially expands Merck's vaccine manufacturing and development capability, laying the organizational and scientific groundwork for the extraordinary vaccine discovery program that Maurice Hilleman would lead over the following five decades.
Merck receives FDA approval for the world's first recombinant DNA vaccine — the Merck Hepatitis B vaccine developed by Maurice Hilleman and his team using yeast-expressed recombinant hepatitis B surface antigen. The approval represents a landmark in both vaccinology and recombinant DNA technology and establishes Merck as the scientific leader in biologic vaccine development.
The FDA approves Lovastatin, marketed as Mevacor — the first HMG-CoA reductase inhibitor (statin) to reach commercial availability anywhere in the world. The drug opens the era of statin therapy for cardiovascular disease prevention, a medical revolution that would eventually prevent millions of heart attacks and strokes globally and generate hundreds of billions of dollars in pharmaceutical revenue across the drug class.
Merck voluntarily withdraws Vioxx (rofecoxib) from global markets after clinical trial data in the APPROVe colorectal polyp prevention study reveal that patients taking the drug have approximately double the risk of serious cardiovascular events compared with placebo. The withdrawal — affecting a drug generating approximately $2.5 billion in annual sales at peak — triggers more than 27,000 personal injury lawsuits ultimately settled for approximately $4.85 billion and becomes one of the most studied drug safety episodes in pharmaceutical history.
The FDA approves Gardasil, Merck's quadrivalent HPV vaccine, becoming the first vaccine approved to prevent cancer by targeting human papillomavirus strains responsible for most cervical cancers globally. The approval represents one of the most significant preventive medicine advances since the polio vaccine and establishes Merck's dominance in the HPV vaccine market, a position subsequently reinforced by the approval of nine-valent Gardasil 9 in 2014.
Merck completes its $41.1 billion merger with Schering-Plough Corporation, acquiring key products including Remicade (shared commercialization rights), Nasonex, and the foundation of the immuno-oncology antibody program that would eventually produce Keytruda. The merger substantially expands Merck's scale, global commercial reach, and early-stage pipeline in immunology and oncology.
The FDA grants accelerated approval to Keytruda (pembrolizumab) for advanced melanoma in September 2014, making it the first PD-1 checkpoint inhibitor to receive FDA clearance. The approval launches what will become the most commercially successful pharmaceutical franchise in industry history, with the drug ultimately achieving approval across more than 40 cancer indications globally.
Merck completes its acquisition of Acceleron Pharma for approximately $11.5 billion, securing sotatercept — a first-in-class activin signaling inhibitor in Phase 3 development for pulmonary arterial hypertension. The acquisition proves highly value-creative: sotatercept is approved as Winrevair in March 2024 and achieves an exceptionally strong commercial launch, with analysts projecting peak sales of $3 to $5 billion annually.
Merck acquires Prometheus Biosciences for approximately $10.8 billion, adding tulisokibart — an anti-TL1A antibody that demonstrated remarkable Phase 2 remission rates in Crohn's disease that substantially exceeded existing biologic benchmarks. If Phase 3 data replicate the Phase 2 signal, tulisokibart could achieve peak annual sales of $5 billion or more and become a foundational asset in Merck's post-Keytruda revenue bridge.
FDA approval of Winrevair (sotatercept) for pulmonary arterial hypertension in March 2024 marks the launch of Merck's most important new commercial product in a decade. Simultaneously, Keytruda reaches approximately $29.5 billion in annual revenue — believed to be the highest annual sales ever recorded for a single pharmaceutical product in industry history — while Merck's total revenue reaches approximately $63.6 billion.
Merck acquired Schering-Plough to diversify its pipeline beyond blockbuster drugs facing patent cliffs, gaining access to biologics manufacturing capabilities, the animal health franchise (now Merck Animal Health), and key products including Remicade and the cholesterol franchise.
Merck acquired Acceleron to gain sotatercept, a first-in-class treatment for pulmonary arterial hypertension (PAH). The drug targets the underlying biology of PAH rather than just symptoms, representing a potential paradigm shift in treating the disease.
Merck acquired Prometheus to gain PRA023, a TL1A antibody for inflammatory bowel disease (ulcerative colitis and Crohn's disease). TL1A is considered one of the most promising new targets in immunology.
Merck acquired Medco, one of the largest pharmacy benefit managers (PBMs) in the United States, aiming to vertically integrate drug development with drug distribution and gain insights into prescribing patterns and patient outcomes.