Amgen Inc.
Company History
Amgen History: Founding, Growth & Key Milestones
Founded 1980 in Thousand Oaks, United States
When was Amgen founded?
Amgen was founded in 1980 in Thousand Oaks, United States by George B. Rathmann and William K. Bowes Jr., making it 46 years old.
- Founded
- 1980
- Founding place
- Thousand Oaks, United States
- Founders
- George B. Rathmann and William K. Bowes Jr.
- Headquarters today
- Thousand Oaks, California
- Milestones documented
- 16 (1980–2026)
- Current CEO
- Robert A. Bradway
- Acquisitions
- 7
| Year | Event |
|---|---|
| 1980 | Applied Molecular Genetics is incorporated |
| 1983 | Nasdaq listing and the erythropoietin clone |
| 1984 | Kirin-Amgen joint venture formed |
| 1985 | G-CSF cloned, leading to Neupogen |
| 1989 | FDA approves Epogen |
| 1991 | Neupogen approved, giving Amgen a second franchise |
| 1991 | Amgen wins the erythropoietin patent fight |
| 2001 | FDA approves Aranesp, the longer-acting EPO |
| 2002 | US$16 billion Immunex acquisition brings Enbrel in-house |
| 2010 | Prolia and XGEVA create the bone health franchise |
| 2019 | US$13.4 billion purchase of Otezla from Celgene |
| 2020 | Amgen joins the Dow Jones Industrial Average |
| 2023 | US$27.8 billion Horizon Therapeutics acquisition closes |
| 2024 | Imdelltra becomes the first T-cell engager for small cell lung cancer |
| 2025 | VESALIUS-CV extends the Repatha case to primary prevention |
| 2026 | Medicare price setting reaches Enbrel and Otezla |
- Where was Amgen founded?
- Amgen was founded in Thousand Oaks, United States in 1980. wikidata.org
- Who founded Amgen?
- Amgen was founded by George B. Rathmann and William K. Bowes Jr.
- When did Amgen start?
- Amgen was founded in 1980.
- How old is Amgen?
- Amgen is 46 years old as of 2026.
Founding Story
Applied Molecular Genetics was incorporated on April 8, 1980 in Thousand Oaks, California, as the idea of venture capitalist William K. Bowes Jr. and a group of scientific collaborators that included UCLA molecular biologist Winston Salser. With a staff of three in a shared building, it recruited Abbott Laboratories research executive George B. Rathmann as its first chief executive and raised about US$19 million by early 1981. The first three years produced a scattered research record: organisms to extract oil from shale, faster-growing chickens, cloned firefly luciferase and a process for making indigo dye in E. coli that reached the cover of Science. The decision that mattered was assigning a young researcher from Taiwan, Fu-Kuen Lin, to find and clone the erythropoietin gene, which his team achieved in 1983 after about two years of work. That clone became Epogen.
Founders
George B. Rathmann
Amgen, originally incorporated as Applied Molecular Genetics, was founded in 1980 not by a single scientist, but by a calculated syndicate of venture capitalists and academics trying to commercialize the brand-new science of recombinant DNA. The driving force behind the formation was William K. (Bill) Bowes, a prominent San Francisco venture capitalist, alongside colleagues from the Bay Area. They recruited George Rathmann, a physical chemist and executive at Abbott Laboratories, to serve as the founding CEO. Rathmann was the true architect of Amgen's culture and success. While other early biotech companies (like Genentech) focused heavily on high-profile, academic research that often failed to translate into profitable products, Rathmann focused Amgen on applied science, specifically, using recombinant DNA to solve unmet medical needs that could generate significant revenue. He assembled a well-known team of effective, young scientists and established a collaborative, egalitarian culture in Thousand Oaks, California, far away from the intense academic rivalries of Boston and San Francisco. The foundational breakthrough for the company occurred in 1983 when a young Taiwanese-born researcher named Fu-Kuen Lin cloned the human gene for erythropoietin (EPO), a protein that stimulates the production of red blood cells. This discovery was considered almost impossible by rival companies due to the sheer complexity of the genome. Lin's discovery led directly to the creation of Epogen, a drug that cured the horrific anemia suffered by dialysis patients. Approved by the FDA in 1989, Epogen became one of the most successful and profitable drugs in the history of medicine, single-handedly transforming Amgen from a scrappy, cash-starved startup into the financial leader of the global biotechnology industry. (Exact birth year remains publicly undisclosed).
William K. Bowes Jr.
William K. Bowes Jr. Was the venture capital strategist whose vision catalyzed Amgen's formation. His approach to building Amgen differed from most biotech founding stories in that he began with the commercial and organizational framework, experienced management, sufficient capital, a culture that valued both science and business, and then recruited the scientific leadership rather than the other way around. This top-down approach to company formation, unusual in an industry dominated by scientist-founders, proved prescient: Amgen's early organizational discipline helped it survive the financially devastating pre-commercial years that destroyed many of its contemporaries. Bowes remained on Amgen's board for many years after the company's commercial launch, providing governance continuity during the company's critical growth phase. His legacy in the biotech industry extends beyond Amgen, he was an early investor in multiple pioneering biotechs and helped establish the venture capital model for funding science-based startups that became the template for Silicon Valley health technology investing. (Exact birth year remains publicly undisclosed).
Key Milestones
Applied Molecular Genetics is incorporated
Applied Molecular Genetics (AMGen) was incorporated on April 8, 1980 in Thousand Oaks, California, as the idea of venture capitalist William K. Bowes Jr. and a group of scientific collaborators. It began with a staff of three in a shared building, named Abbott Laboratories research executive George B. Rathmann as its first chief executive later that year, and raised about US$19 million in a private placement completed in early 1981.
Source: amgen.comNasdaq listing and the erythropoietin clone
Amgen completed its initial public offering on June 17, 1983, raising nearly US$40 million under chief financial officer Gordon Binder, and formally shortened its name to Amgen. In the same year a team led by Fu-Kuen Lin cloned the human erythropoietin gene, work that had required searching a single fragment of DNA among roughly 1.5 million fragments of the human genome and that became the basis of Amgen's first product.
Source: amgen.comKirin-Amgen joint venture formed
Amgen and Kirin Brewery Company of Japan formed Kirin-Amgen in 1984 as a joint venture for the worldwide commercialization of erythropoietin. The arrangement gave Amgen milestone payments and cash it needed during clinical development, and it defined the territorial split that later governed how Epogen was sold. The relationship lasted for decades.
Source: amgen.comG-CSF cloned, leading to Neupogen
While Fu-Kuen Lin's team worked on erythropoietin, researcher Larry Souza and his group cloned and expressed human granulocyte colony-stimulating factor in 1985. That discovery became Neupogen (filgrastim), the second product to reach the market and the basis of the supportive-care franchise Amgen sold to oncologists through the 1990s.
Source: amgen.comFDA approves Epogen
The FDA approved Epogen (epoetin alfa) on June 1, 1989 for anemia in patients with chronic kidney failure on dialysis. It was the first commercial recombinant human erythropoietin. Epogen's U.S. sales reached about US$148 million in the fiscal year ended March 31, 1990 and about US$305 million the following year, turning Amgen from a development-stage company into a profitable one.
Source: amgen.comNeupogen approved, giving Amgen a second franchise
The FDA approved Neupogen (filgrastim) in February 1991. By stimulating white blood cell production it reduced the risk of infection in cancer patients with chemotherapy-induced neutropenia. The launch validated the strategy of targeting serious conditions with large unmet need and gave Amgen a second billion-dollar product within three years of its first.
Source: amgen.comAmgen wins the erythropoietin patent fight
On March 6, 1991 the U.S. Court of Appeals for the Federal Circuit upheld the Kirin-Amgen erythropoietin patent and ruled against Genetics Institute in Amgen v. Chugai Pharmaceutical and Genetics Institute. The Supreme Court declined to hear an appeal in October 1991, ending a four-year fight over rights to recombinant EPO and setting an early precedent for how protein therapeutics could be protected.
Source: law.justia.comFDA approves Aranesp, the longer-acting EPO
Aranesp (darbepoetin alfa), an erythropoietin analogue with modified glycosylation and a longer half-life, was approved in 2001. Less frequent dosing than Epogen improved convenience and gave Amgen a newer, higher-priced product to migrate patients toward. Aranesp peaked above US$4 billion of annual sales before the 2007 safety restrictions, and still generated US$1.39 billion in fiscal 2025.
Source: en.wikipedia.orgUS$16 billion Immunex acquisition brings Enbrel in-house
Amgen completed its acquisition of Immunex Corporation on July 16, 2002, the largest biotechnology deal to that point at about US$16 billion in stock and cash. The prize was Enbrel (etanercept), a TNF inhibitor approved for rheumatoid arthritis in 1998 that Immunex had developed with Wyeth. Enbrel became Amgen's largest product for close to two decades and moved the company into immunology.
Source: investors.amgen.comProlia and XGEVA create the bone health franchise
The FDA approved Prolia (denosumab) for postmenopausal osteoporosis in June 2010 and XGEVA, the same molecule at a higher dose, for prevention of skeletal-related events in cancer patients in November 2010. Denosumab inhibits RANK ligand, a mechanism new to bone medicine. Combined Prolia and XGEVA sales reached US$6.50 billion in fiscal 2025, the largest franchise in the portfolio.
Source: en.wikipedia.orgUS$13.4 billion purchase of Otezla from Celgene
Amgen agreed in August 2019 to buy worldwide rights to Otezla (apremilast) from Celgene for US$13.4 billion in cash, or about US$11.2 billion net of the present value of US$2.2 billion of anticipated future cash tax benefits, and closed on November 21, 2019. The FTC had required the divestiture to clear the Bristol Myers Squibb merger with Celgene. Otezla gave Amgen an oral medicine in a portfolio dominated by injectables.
Source: amgen.comAmgen joins the Dow Jones Industrial Average
Amgen replaced Pfizer in the Dow Jones Industrial Average on August 31, 2020, becoming one of the thirty components in the index. Inclusion recognized the scale Amgen had reached and added passive demand from Dow-tracking funds. The company is also a member of the Nasdaq-100.
Source: en.wikipedia.orgUS$27.8 billion Horizon Therapeutics acquisition closes
Amgen completed the acquisition of Horizon Therapeutics plc on October 6, 2023 for US$116.50 per share in cash, an equity value of about US$27.8 billion, after settling FTC litigation with a behavioral consent decree. The deal added Tepezza for thyroid eye disease, Krystexxa for refractory gout and Uplizna for neuromyelitis optica, and it reshaped both the revenue mix and the balance sheet.
Source: amgen.comImdelltra becomes the first T-cell engager for small cell lung cancer
The FDA granted accelerated approval to tarlatamab, sold as Imdelltra, on May 16, 2024 for extensive stage small cell lung cancer that has progressed on or after platinum-based chemotherapy. It was the first bispecific T-cell engager approved in that disease and came from the same BiTE platform as Blincyto. Full approval followed on November 19, 2025, and fiscal 2025 sales were US$627 million.
Source: fda.govVESALIUS-CV extends the Repatha case to primary prevention
In November 2025 Amgen reported Phase 3 VESALIUS-CV results in more than 12,000 patients with atherosclerosis or diabetes but no prior heart attack or stroke. Repatha cut the risk of coronary heart disease death, heart attack or ischemic stroke by 25% and the risk of heart attack by 36%. The findings were presented at the American Heart Association Scientific Sessions and published in the New England Journal of Medicine. Repatha sales rose 36% to US$3.02 billion in fiscal 2025.
Source: prnewswire.comMedicare price setting reaches Enbrel and Otezla
Enbrel's negotiated Medicare price under the Inflation Reduction Act took effect on January 1, 2026, after it was named in the first round of ten drugs selected for negotiation. Otezla was selected in a later cycle, which led Amgen to record US$1.2 billion of intangible asset impairment charges during 2025. Enbrel sales fell 33% in fiscal 2025 on a 36% lower net selling price, and Amgen guided to 2026 revenue of US$37.0 billion to US$38.4 billion.
Source: amgen.comMajor Acquisitions
Immunex Corporation
2002Amgen acquired Seattle-based Immunex Corporation for about US$16 billion in stock and cash, completing the deal on July 16, 2002. It was the largest acquisition in biotechnology to that point. The objective was full ownership of Enbrel (etanercept), a TNF inhibitor that Immunex had developed with Wyeth and that the FDA approved for rheumatoid arthritis in 1998. The deal also brought Immunex cytokine biology research and its scientific staff.
DeCODE Genetics
2012Amgen acquired Reykjavik, Iceland-based deCODE Genetics in December 2012 for approximately $415 million. DeCODE had built one of the world's largest and most scientifically valuable human genetics databases, with genetic and health data from a substantial proportion of Iceland's 320,000-person population. The acquisition gave Amgen access to this unique genomic resource as a tool for identifying genetic variants associated with human diseases variants that could point to novel drug targets or help predict which patient populations would respond to specific therapies.
Onyx Pharmaceuticals, Inc.
2013Amgen agreed in August 2013 to buy South San Francisco based Onyx Pharmaceuticals for US$125 per share, a purchase price of US$10.4 billion or US$9.7 billion net of estimated Onyx cash, and completed the tender offer on October 1, 2013. The main asset was Kyprolis (carfilzomib), a proteasome inhibitor for multiple myeloma, which Amgen took worldwide. The deal also brought royalties on Bayer's Nexavar and Stivarga.
Celgene Otezla Business
2019Amgen agreed in August 2019 to acquire worldwide rights to Otezla (apremilast) from Celgene Corporation for US$13.4 billion in cash, or about US$11.2 billion net of the present value of US$2.2 billion of anticipated future cash tax benefits, and closed the transaction on November 21, 2019. The FTC had required the divestiture as a condition of the Bristol Myers Squibb merger with Celgene. Otezla was an oral PDE4 inhibitor with roughly US$1.6 billion of annual sales, approved in plaque psoriasis and psoriatic arthritis.
Five Prime Therapeutics
2021Amgen agreed on March 4, 2021 to buy South San Francisco based Five Prime Therapeutics for US$38.00 per share, an equity value of about US$1.9 billion, and completed the tender offer and merger on April 16, 2021. The lead asset was bemarituzumab, a first-in-class anti-FGFR2b antibody ready for Phase 3 in gastric and gastroesophageal junction cancer. Five Prime's work in receptor biology and antibody engineering was a secondary motivation.
ChemoCentryx, Inc.
2022Amgen acquired ChemoCentryx for US$52 per share in cash, aggregate merger consideration of about US$3.7 billion, completing the deal on October 20, 2022. The asset was Tavneos (avacopan), an orally administered selective complement 5a receptor inhibitor that the FDA approved in October 2021 as adjunctive therapy for adults with severe active ANCA-associated vasculitis. Three early-stage chemoattractant receptor programs came with it.
Horizon Therapeutics plc
2023Amgen acquired Horizon Therapeutics plc in October 2023 for approximately $27.8 billion in the largest acquisition in Amgen's history. The deal's strategic purpose was threefold: diversifying into rare diseases with high-pricing, durable commercial profiles; acquiring Tepezza's leadership position in thyroid eye disease, a condition affecting an estimated 200,000 patients in the U.S. With a treatment market estimated to ultimately exceed $3 billion; and adding Krystexxa's dominance in refractory gout a condition affecting approximately 100,000 patients annually who do not respond to standard urate-lowering therapy.
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Amgen Company History FAQ
What were the major milestones in Amgen's founding and 1980s breakthroughs?
Founded in 1980, Amgen completed its IPO in 1983, cloned erythropoietin (EPO) in 1983, cloned G-CSF in 1985, and received FDA approval for Epogen in June 1989, initiating the modern commercial biotechnology era.
When was Neupogen approved by the FDA and what was its clinical significance?
The FDA approved Neupogen (filgrastim) in February 1991. By stimulating white blood cell production it prevented severe infections in chemotherapy patients, and it became Amgen's second billion-dollar product within three years of the first.
When was Amgen added to the Dow Jones Industrial Average (DJIA)?
Amgen was added to the prestigious 30-stock Dow Jones Industrial Average on August 31, 2020, replacing Pfizer and representing the biotechnology sector in the historic index.
How did the 2002 Immunex merger transform Amgen into an immunology leader?
The $16 billion acquisition of Immunex in 2002 brought Enbrel into Amgen's portfolio, transforming the company from a hematology specialist into a global leader in autoimmune and inflammatory diseases.
When did the FDA approve Prolia (denosumab) for postmenopausal osteoporosis?
The FDA approved Prolia in June 2010 (followed by Xgeva for cancer bone metastases in November 2010), introducing the first RANK ligand inhibitor and growing into a $4+ billion annual franchise.
When did Amgen launch Lumakras as the first KRAS G12C inhibitor?
In May 2021, the FDA granted accelerated approval to Lumakras (sotorasib), breaking decades of scientific consensus that the KRAS oncogene was 'undruggable' and establishing a landmark precision oncology therapy.
What occurred during the FTC's antitrust challenge to the Horizon Therapeutics merger in 2023?
The FTC sued to block Amgen's $27.8B buyout of Horizon in May 2023 over novel bundling theories, before settling in September 2023 after Amgen agreed not to bundle rare disease therapies, allowing the transaction to close in October 2023.
What are Amgen's primary strategic milestones heading into 2025 and beyond?
Amgen's stated priorities are the Phase 3 MARITIME program for MariTide in obesity and related conditions, with the first chronic weight management readout scheduled for 2027 and Phase 3 diabetes studies starting in 2026; growing Imdelltra after its November 2025 full approval; expanding Uplizna into new autoimmune indications; continued debt reduction after closing 2025 with US$54.6 billion outstanding; and new biosimilar launches such as Pavblu and Wezlana.
When was Amgen founded?
Amgen was founded in 1980 in Thousand Oaks, California, initially named Applied Molecular Genetics.
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