GSK

GSK plc
Type	Public
Traded as	LSE: GSK; NYSE: GSK; FTSE 100 component
Industry	Pharmaceuticals, vaccines, biotechnology
Founded	2000, by the merger of Glaxo Wellcome and SmithKline Beecham; predecessors from 1715
Headquarters	New Oxford Street, London, United Kingdom
Area served	Worldwide
Key people	Sir Jonathan Symonds (chairman), Luke Miels (chief executive from 2026), Emma Walmsley (chief executive 2017 to 2025)
Products	Prescription medicines, vaccines
Revenue	Approximately £42.4 billion (2025)
Employees	Approximately 65,000
Website	gsk.com

GSK plc, known as GlaxoSmithKline until May 2022, is a British multinational pharmaceutical and biotechnology company headquartered in London. It was formed in 2000 by the merger of Glaxo Wellcome and SmithKline Beecham, and is among the largest pharmaceutical companies in the world, with particular strength in vaccines, respiratory medicine, HIV and immunology.

GSK's corporate ancestry runs through four distinct businesses: Glaxo, founded in New Zealand in the 1870s as a dried milk producer; Burroughs Wellcome, founded in London in 1880 and notable for its research foundation; Beecham, founded in Lancashire in 1842 selling laxative pills; and Smith, Kline and French, founded in Philadelphia in 1830. The 2000 merger produced what was briefly the largest pharmaceutical company in the world.

In July 2022 GSK separated its consumer healthcare business, which held brands including Sensodyne, Panadol, Voltaren and Centrum, as Haleon, leaving a company concentrated on prescription medicines and vaccines. It reported revenue of approximately £42.4 billion and earnings of US$9.32 billion in 2025 and was ranked 388th on the Fortune Global 500 in 2025.

The company has been the subject of substantial controversy, including a US$3 billion settlement with the United States government in 2012 over unlawful promotion and the withholding of safety data, at the time the largest healthcare fraud settlement in American history, and a £297 million fine in China in 2014 for bribing doctors and officials.

History

Glaxo

The Glaxo line begins with Joseph Edward Nathan, who founded a general trading business in Wellington, New Zealand, in 1873. In 1904 the firm acquired rights to a process for producing dried milk and began selling it as a baby food under the name Glaxo, an invented word derived from lacto, with the slogan Glaxo builds bonnie babies. A London office opened in 1908, and Glaxo Laboratories was established as a subsidiary in 1935.

The company's entry into pharmaceuticals came through vitamin D, which it extracted and sold to fortify its milk products, and then through the industrial production of penicillin during the Second World War, in which Glaxo was among the principal British manufacturers. It became a substantial producer of antibiotics, including the cephalosporins developed from work at Oxford, and separated from its parent in 1947.

Under Paul Girolami, chief executive from 1980, Glaxo was transformed by a single product. Ranitidine, marketed as Zantac and launched in 1981, treated peptic ulcers by blocking histamine H2 receptors. It was the second such drug, following SmithKline's cimetidine, and Glaxo's decision to price it above the incumbent rather than below, and to market it through a partnership with Hoffmann-La Roche's American sales force, made it the best-selling medicine in the world and the first to exceed US$1 billion in annual sales. Glaxo acquired Wellcome in 1995 for £9 billion, then the largest takeover in British corporate history.

Burroughs Wellcome

Burroughs Wellcome and Company was founded in London in 1880 by two American pharmacists, Silas Burroughs and Henry Wellcome. It introduced the compressed tablet to Britain, displacing powders and pills, and registered the trademark Tabloid, a word that subsequently entered the language.

Wellcome, who took sole control after Burroughs's death in 1895, established the Wellcome Physiological Research Laboratories in 1894 and the Wellcome Chemical Research Laboratories in 1896, among the first industrial research institutions in the pharmaceutical industry. On his death in 1936 his shares passed to the Wellcome Trust, a charitable foundation that owned the company outright and applied its profits to medical research. The trust floated a minority of the company in 1986 and sold its remaining shares to Glaxo in 1995, becoming one of the largest medical research charities in the world with an endowment in the tens of billions of pounds.

The company's scientific record was exceptional. Gertrude Elion and George Hitchings, working at Burroughs Wellcome in the United States, developed drugs by studying the differences in nucleic acid metabolism between normal and diseased cells, producing azathioprine, allopurinol, acyclovir and mercaptopurine, and shared the 1988 Nobel Prize in Physiology or Medicine with James Black. Their approach replaced empirical screening with rational design and is among the most consequential methodological changes in twentieth-century pharmacology. The company also produced zidovudine, the first treatment for HIV/AIDS, approved in 1987, whose pricing at US$10,000 a year provoked the first sustained campaign of activist protest directed at a pharmaceutical company.

Beecham

Thomas Beecham began selling Beecham's Pills, a laxative, in Wigan in 1842, and is credited with some of the earliest modern consumer advertising, including the slogan worth a guinea a box. The company built a factory at St Helens in 1859 and expanded into a wide range of proprietary medicines and later into consumer products including Lucozade, Ribena, Macleans toothpaste and Brylcreem.

Its transformation into a research-based pharmaceutical business came from the Beecham Research Laboratories at Brockham Park, where in 1957 a team isolated 6-aminopenicillanic acid, the core of the penicillin molecule, which allowed semi-synthetic penicillins to be produced with modified properties. The result was a family of antibiotics including methicillin, ampicillin and amoxicillin, and later Augmentin, the combination of amoxicillin with clavulanic acid that overcomes bacterial resistance and which remains among the most widely prescribed antibiotics in the world.

Thomas Beecham's grandson Sir Thomas Beecham, the conductor, funded much of his musical career, including the founding of the London Philharmonic and the Royal Philharmonic orchestras, from the family business.

Smith, Kline and French

John K. Smith opened a drugstore in Philadelphia in 1830, and the business became Smith, Kline and Company and then Smith Kline and French. Its products included Benzedrine, the first amphetamine marketed in the United States, introduced as an inhaler for nasal congestion in 1933 and subsequently in tablet form, and Dexedrine.

Its most important contribution was chlorpromazine, licensed from Rhône-Poulenc and marketed as Thorazine from 1954. The first effective antipsychotic, it transformed the treatment of schizophrenia and is the principal reason the populations of psychiatric hospitals in Western countries fell by an order of magnitude over the following three decades, an outcome regarded both as a medical achievement and, in the absence of adequate community provision, as the origin of a continuing social problem.

Cimetidine, marketed as Tagamet from 1976 and developed by a team under James Black, was the first histamine H2 receptor antagonist and the first medicine to reach a billion dollars in annual sales, until Zantac displaced it.

Smith Kline and French merged with Beckman Instruments in 1982 to form SmithKline Beckman, and merged with the Beecham Group in 1989 to form SmithKline Beecham.

The 2000 merger and its aftermath

Glaxo Wellcome and SmithKline Beecham announced a merger in January 2000, completing in December after regulatory clearance and the divestment of certain products. The combined company, GlaxoSmithKline, had approximately 7 per cent of the world pharmaceutical market and the largest research budget in the industry, and was briefly the largest pharmaceutical company in the world by market value.

Jean-Pierre Garnier led the company from 2000 to 2008. The period was characterised by the expiry of patents on Zantac, Augmentin, Paxil and Wellbutrin, by a research organisation restructured into competing Centres of Excellence for Drug Discovery in an attempt to reproduce the agility of small biotechnology companies, and by the litigation and regulatory action described below.

Andrew Witty led the company from 2008 to 2017. He substantially changed its public posture, ending the payment of sales commissions to representatives based on prescription volume, committing to publish clinical trial data including negative results, joining patent pools for HIV medicines and waiving patents in the poorest countries. These measures were widely praised and were adopted in part by competitors.

The largest transaction of his tenure was a three-part exchange with Novartis agreed in 2014 and completed in 2015: GSK sold its oncology portfolio to Novartis for US$16 billion, bought Novartis's vaccines business excluding influenza for US$7.1 billion plus milestones, and combined the two companies' consumer healthcare businesses into a joint venture that GSK controlled. The transaction strengthened vaccines and consumer health at the cost of oncology, a judgement that appeared sound at the time and which the company spent the following decade reversing at considerable expense.

Emma Walmsley and the separation of Haleon, 2017 to 2022

Emma Walmsley became chief executive in April 2017, the first woman to lead a major pharmaceutical company. She had joined from L'Oréal and had run GSK's consumer healthcare business, and her appointment was questioned by those who considered that a pharmaceutical company should be led by a scientist.

Her strategy rested on separating the consumer business and rebuilding the pharmaceutical pipeline, which had become one of the weakest among large companies. She recruited Hal Barron from Alphabet's Calico as chief scientific officer in 2018 and redirected research toward immunology, human genetics and oncology, using a large genetic dataset obtained through an arrangement with 23andMe.

In December 2018 GSK agreed to combine its consumer healthcare joint venture with Pfizer's consumer business, taking 68 per cent of the combined entity, with the stated intention of separating it within three years. In January 2019 it acquired Tesaro, an American oncology company, for US$5.1 billion, obtaining the PARP inhibitor niraparib and re-entering the field it had sold to Novartis four years earlier.

The activist investor Elliott Management built a stake in 2021 and published a letter arguing that the company had underperformed for two decades, that its pharmaceutical and consumer businesses should be separated more aggressively, and that the board should consider whether Walmsley was the right person to lead the remaining company. The board supported her, and the separation proceeded as planned.

Haleon was listed on the London Stock Exchange in July 2022 in the largest European flotation for a decade, holding Sensodyne, Panadol, Voltaren, Centrum, Advil, Otrivin and Theraflu. GSK retained a shareholding that it sold down progressively, disposing of the final 4.2 per cent in May 2024 for US$1.58 billion.

The company changed its name from GlaxoSmithKline to GSK on 16 May 2022, adopting a new identity intended to signal a research-focused business rather than a conglomerate of consumer and pharmaceutical operations.

Recent history, 2022 to 2026

GSK acquired Sierra Oncology for US$1.9 billion in April 2022, obtaining momelotinib for myelofibrosis, and Affinivax in May 2022 for up to US$3.3 billion, obtaining a 24-valent pneumococcal vaccine candidate. Bellus Health followed in April 2023 for US$2 billion, obtaining camlipixant for chronic cough, and Aiolos Bio in February 2024 for more than US$1 billion, obtaining a long-acting antibody targeting thymic stromal lymphopoietin for asthma.

The company moved its headquarters from Brentford to New Oxford Street in central London in July 2024, leaving a suburban campus for a building intended to place it closer to the scientific and financial communities of the city.

Its commercial performance in this period rested substantially on vaccines. Shingrix, a recombinant shingles vaccine introduced in 2017 and considerably more effective than the earlier live vaccine, became one of the largest vaccine products in the world. Arexvy, approved in 2023, was the first vaccine against respiratory syncytial virus for older adults, a target that had defeated the industry for half a century after a failed trial in the 1960s caused enhanced disease in children.

In November 2023 GSK sued Moderna in federal court in Delaware, alleging that the Spikevax COVID-19 vaccine and the mResvia RSV vaccine infringed patents relating to lipid nanoparticles used to deliver messenger RNA, patents deriving from work at Novartis that GSK acquired in the 2015 vaccines transaction. It brought comparable proceedings against Pfizer and BioNTech. The litigation is part of a wider set of disputes over the ownership of the delivery technology on which the mRNA vaccines depend.

Capital flows into the company's American depositary receipts exceeded those into its primary London listing by 2025, prompting speculation that GSK would follow other British companies in moving its primary listing to New York, which its executives denied.

In September 2025 the company announced that Emma Walmsley would step down at the beginning of 2026 and that Luke Miels, chief commercial officer since 2017, would succeed her. In October 2025 GSK acquired rights to a prostate cancer candidate from the French biotechnology company Syndivia for £268 million. In January 2026 it agreed to acquire Rapt Therapeutics for US$2.2 billion, and entered a licence with Alteogen through its Tesaro subsidiary for technology enabling a subcutaneous formulation of dostarlimab. In February 2026 it agreed to acquire the Canadian company 35Pharma for US$950 million, obtaining an early-stage candidate for pulmonary arterial hypertension. In June 2026 it announced the acquisition of Nuvalent for US$10.6 billion, its largest transaction in more than a decade, subject to regulatory and shareholder approval.

Products and research

Vaccines

GSK is among the largest vaccine manufacturers in the world, supplying more than a billion doses a year. Its portfolio includes Shingrix for shingles; Arexvy for respiratory syncytial virus; Bexsero and Menveo against meningococcal disease, Bexsero being the first broadly protective vaccine against meningococcal group B, developed by reverse vaccinology in which the bacterial genome was searched computationally for candidate antigens; Infanrix and Boostrix for diphtheria, tetanus and pertussis; Rotarix against rotavirus; Havrix and Engerix against hepatitis; Cervarix against human papillomavirus; and Fluarix and FluLaval against influenza.

RTS,S, marketed as Mosquirix, is the first vaccine against any parasitic disease in humans and the first against malaria. Developed over more than three decades with the Walter Reed Army Institute of Research and funded substantially by the Bill and Melinda Gates Foundation and PATH, it received a positive regulatory opinion in 2015 and was recommended by the World Health Organization for broad use in children in October 2021 following pilot implementation in Ghana, Kenya and Malawi. Its efficacy is partial, in the region of 30 to 40 per cent against severe disease, and it requires four doses, but in high-transmission settings it prevents a substantial number of deaths. GSK committed to supply it at no more than the cost of production plus a small margin to be reinvested in research, and transferred the majority of production to Bharat Biotech in India.

Respiratory

Respiratory medicine has been a GSK strength since salbutamol, marketed as Ventolin and developed at Allen and Hanburys, a Glaxo subsidiary, by a team under David Jack in 1968. It was the first selective beta-2 agonist and remains the standard rescue treatment for asthma worldwide. Fluticasone, salmeterol and their combination as Seretide or Advair became among the best-selling medicines in the world.

The current portfolio comprises Trelegy Ellipta, a triple combination for chronic obstructive pulmonary disease and asthma; Nucala, an interleukin-5 antibody for severe eosinophilic asthma and related conditions; and candidates including depemokimab, a long-acting antibody requiring only two doses a year.

HIV

GSK's HIV medicines are held through ViiV Healthcare, a joint venture formed in 2009 with Pfizer and later Shionogi, in which GSK holds a majority. Its principal products are dolutegravir, an integrase inhibitor that has become the backbone of first-line treatment recommended by the World Health Organization, and the combinations Tivicay, Triumeq, Dovato and Juluca.

Cabenuva and Apretude, long-acting injectable formulations of cabotegravir given every one or two months, represent the most significant change in HIV treatment and prevention since combination therapy, because adherence to daily tablets is the principal reason treatment and prophylaxis fail. ViiV has entered voluntary licensing arrangements permitting generic production of cabotegravir for prevention in low-income countries.

Oncology and immunology

Having sold its oncology business to Novartis in 2015, GSK rebuilt it through the Tesaro acquisition and subsequent transactions. Products include Jemperli, an anti-PD-1 antibody that produced complete responses in a small trial in mismatch repair deficient rectal cancer that attracted considerable attention; Zejula, a PARP inhibitor for ovarian cancer; Blenrep, an antibody-drug conjugate for multiple myeloma which was withdrawn from the American market in 2022 after a confirmatory trial failed and subsequently resubmitted on the basis of new data; and Ojjaara for myelofibrosis.

Immunology and inflammation, supported by the human genetics work, is the area the company has identified for its next generation of products, alongside infectious disease.

Facilities

GSK's principal research sites are at Stevenage in Hertfordshire, at Upper Providence and Collegeville in Pennsylvania, and in Cambridge in Massachusetts. Vaccine research and manufacture is concentrated at Rixensart and Wavre in Belgium, inherited from the acquisition of SmithKline's Belgian vaccine business, and at Siena in Italy, acquired from Novartis. Manufacturing sites include Barnard Castle in County Durham, Ware in Hertfordshire, Montrose in Scotland, Singapore and several sites in the United States.

The Stevenage site has developed into one of Europe's largest biotechnology clusters through an incubator GSK established, which has become a significant contributor to the British life sciences sector independent of the company.

COVID-19

GSK was the only one of the largest vaccine manufacturers not to produce a successful vaccine against COVID-19, an outcome that attracted considerable criticism and which the company has acknowledged as a failure.

Its principal effort was a protein-based vaccine developed with Sanofi, combining Sanofi's antigen with GSK's adjuvant, an immune-stimulating substance added to a vaccine to increase and prolong the response. The programme was delayed by an error in the concentration of antigen in the initial formulation, which produced an inadequate response in older adults and required the trials to be restarted, and by the time the vaccine was approved in 2022 the mRNA products had supplied most of the world's requirement. The company also supplied its adjuvant to other developers, including Medicago, SK bioscience and Clover Biopharmaceuticals, and manufactured doses of other companies' vaccines under contract.

Its therapeutic contribution was sotrovimab, a monoclonal antibody developed with Vir Biotechnology, which was effective against early variants and retained activity longer than most competing antibodies before being rendered ineffective by omicron subvariants, and which was widely used in immunocompromised patients.

The company's explanation for the vaccine failure is that it had no mRNA platform and that its protein and adjuvant approach, though ultimately successful, was slower by design. Critics have observed that a company with the largest vaccine business in the industry outside Pfizer should not have been absent from the most significant vaccine development programme in a century, and the episode informed the decision to invest in mRNA capability subsequently, including through the litigation asserting ownership of parts of the underlying delivery technology.

Manufacturing and supply

GSK operates approximately 30 manufacturing sites. Vaccine production is technically distinct from pharmaceutical manufacture, involving the growth of biological material under conditions that cannot be accelerated and quality testing that can take months, so that capacity decisions must be taken years before demand is known. Its Belgian sites at Wavre and Rixensart are among the largest vaccine manufacturing complexes in the world.

Barnard Castle in County Durham, which fills and packages injectable medicines, became briefly famous in Britain in 2020 for reasons unconnected with the company, when a government adviser stated that he had driven there during lockdown to test his eyesight.

The company has invested in supply chain resilience following the disruptions of the pandemic and the shortages of medicines that have affected European and American markets, and has repatriated some production of starting materials from Asia, part of a wider industry response to the concentration of active pharmaceutical ingredient manufacture in China and India.

Regulation and policy

As a company operating in more than 70 countries, GSK is regulated by the European Medicines Agency, the Medicines and Healthcare products Regulatory Agency in Britain, the Food and Drug Administration in the United States, and national authorities elsewhere, and its manufacturing is subject to inspection by all of them.

Its commercial environment is determined substantially by how governments pay for medicines. In the United Kingdom the voluntary scheme for branded medicines pricing caps total National Health Service expenditure on branded medicines, requiring companies to rebate revenue above an agreed growth rate; the rebate reached levels in the mid-2020s that the industry described as unsustainable and which prompted several companies to reduce investment in Britain. In the United States the Inflation Reduction Act introduced Medicare price negotiation, and GSK's products are within its scope.

The company has been prominent in British life sciences policy, arguing for a regulatory and fiscal environment that retains research in the country, and the Stevenage cluster and the company's clinical trial activity are among the principal industry arguments in that debate. Its 2024 move to central London and its continued investment in British manufacturing have been cited by the government as evidence of commitment, while its executives have warned publicly that the conditions for such investment have deteriorated.

Environment

GSK has committed to net zero emissions across its value chain by 2045 and to a net positive impact on nature by 2030. The principal difficulty for a pharmaceutical company lies in its propellant inhalers: the metered dose inhalers used for asthma and chronic obstructive pulmonary disease contain hydrofluorocarbon propellants that are potent greenhouse gases, and GSK's inhaler portfolio accounts for a very large proportion of its measured emissions.

The company has developed a next-generation propellant with a global warming potential approximately 90 per cent lower and has begun converting its Ventolin inhaler to it, a change requiring regulatory approval in every market and the reformulation of a product used by tens of millions of people. Dry powder inhalers, which require no propellant, are an alternative but are unsuitable for some patients, particularly in acute attacks.

Other environmental matters include the discharge of antibiotic residues from manufacturing, which contributes to antimicrobial resistance and on which the industry has adopted voluntary standards, and water use at fermentation sites.

Assessment

GSK entered the twenty-first century as the largest pharmaceutical company in the world and spent the following two decades declining relative to its peers, through a combination of patent expiries, a research organisation repeatedly reorganised without sustained improvement in output, and the reputational cost of the conduct settled in 2012.

Its recovery since 2017 has been real but partial. The vaccines business, the HIV franchise and the respiratory portfolio are genuinely strong, the separation of Haleon clarified what the company is, and the rate at which assets have entered late-stage development has improved substantially. Against that, it remains smaller than the American and Swiss leaders, its shares trade at a discount to them, and its dependence on dolutegravir creates a defined cliff in the late 2020s that the acquisitions of the mid-2020s are intended to bridge.

Its historical contribution is not in doubt. The medicines that its predecessor companies produced, from salbutamol and chlorpromazine to the semi-synthetic penicillins, the H2 antagonists, the first HIV treatment and the first malaria vaccine, constitute one of the more substantial records of any industrial organisation, and the Wellcome Trust, created by the proceeds of one of them, has become among the largest funders of medical research in the world.

Controversies

The 2012 criminal and civil settlement

On 2 July 2012 GlaxoSmithKline pleaded guilty to criminal charges and agreed to pay US$3 billion to resolve claims brought by the United States Department of Justice, at the time the largest healthcare fraud settlement in American history and the largest payment ever made by a pharmaceutical company.

The settlement covered three principal matters. The company pleaded guilty to promoting paroxetine, sold as Paxil in the United States and Seroxat in Britain, for use in patients under eighteen, for which it was not approved; to promoting bupropion, sold as Wellbutrin, for weight loss, sexual dysfunction, substance addiction and attention deficit hyperactivity disorder, none of which were approved uses; and to failing to report safety data on rosiglitazone, sold as Avandia, to the Food and Drug Administration between 2001 and 2007.

The conduct described in the settlement documents extended beyond promotion. The company had paid for physicians to attend meetings at resorts in Jamaica, Bermuda and California, sponsored speaker programmes whose purpose was remuneration rather than education, and funded continuing medical education and journal articles that presented its products favourably. A sales campaign for Paxil had been named Diamonds and Pearls. Physicians who prescribed in volume received hunting trips, spa treatments and tickets to sporting events.

Study 329

The paroxetine matter rested substantially on a clinical trial in adolescents, known as Study 329, whose results were published in 2001 in the Journal of the American Academy of Child and Adolescent Psychiatry under the names of academic authors, concluding that the drug was generally well tolerated and effective. The paper was written by a medical communications agency engaged by the company, and internal documents disclosed in litigation showed that the trial had not met its primary outcome measures and that adverse events including suicidal behaviour had been reclassified in ways that reduced their apparent frequency.

A reanalysis of the original data published in The BMJ in 2015 under the Restoring Invisible and Abandoned Trials initiative concluded that paroxetine was neither effective nor safe in the population studied. The episode became the principal case study in arguments for compulsory registration and full reporting of clinical trials, and contributed directly to the reforms subsequently adopted by regulators, journals and, from 2013, by GSK itself, which became the first large company to commit to publishing detailed clinical study reports and to allow independent researchers access to patient-level data.

Avandia

Rosiglitazone was approved in 1999 for type 2 diabetes and became a very large product. In May 2007 a meta-analysis by Steven Nissen and Kathy Wolski published in the New England Journal of Medicine found a 43 per cent increase in the risk of myocardial infarction among patients taking it. Internal documents showed that the company had conducted its own analyses several years earlier reaching comparable conclusions and had not disclosed them.

The Food and Drug Administration restricted the drug's availability in 2010, requiring prescribers and patients to enrol in a restricted access programme, and European regulators withdrew it entirely. The restrictions were lifted in the United States in 2013 after a re-adjudication of the principal cardiovascular outcome trial did not confirm the risk, by which time the product had effectively ceased to be prescribed. The affair was among the principal reasons regulators now require cardiovascular outcome trials for diabetes medicines before approval.

Bribery in China

In September 2014 a court in Changsha convicted GlaxoSmithKline China Investment Co. of bribery and imposed a fine of ¥3 billion, approximately £297 million, the largest corporate penalty ever imposed in China. Mark Reilly, the British head of the Chinese business, received a suspended three-year sentence and was deported, and four Chinese executives received suspended sentences.

The scheme involved payments to doctors, hospital administrators and government officials, routed through travel agencies that invoiced for conferences that did not take place, in order to increase prescribing. The investigation began after an anonymous whistleblower sent material to the company's headquarters and to Chinese authorities, and it was accompanied by an unusual sequence of events including the detention of corporate investigators hired by the company and a televised confession.

The case was significant beyond GSK. It signalled a change in Chinese enforcement against multinational companies, prompted comparable investigations across the pharmaceutical industry, and led the company to abandon the practice of paying sales representatives according to prescription volume, first in China and then worldwide, a change no competitor had made.

SB Pharmco Puerto Rico

In October 2010 the company paid US$750 million and its subsidiary SB Pharmco Puerto Rico pleaded guilty to distributing adulterated drugs manufactured at a plant in Cidra between 2001 and 2005, including products with incorrect doses, contaminated with other medicines or of the wrong strength. The affected products included Kytril, Bactroban, Paxil CR and Avandamet.

The case originated with Cheryl Eckard, the company's global quality assurance manager, who had reported the problems internally, been told to make the findings disappear, and was dismissed. She brought a whistleblower action under the False Claims Act and received US$96 million, at the time the largest such award to an individual.

Pandemrix and narcolepsy

Pandemrix, an influenza vaccine produced for the 2009 H1N1 pandemic and given to several million people in Europe, was subsequently associated with an increased incidence of narcolepsy in children and adolescents, particularly in Finland, Sweden, Ireland and the United Kingdom. Epidemiological studies indicated an approximately twelvefold increase in risk in vaccinated children in some populations, and the mechanism is believed to involve molecular mimicry between a vaccine component and a receptor involved in the regulation of sleep, in genetically susceptible individuals.

Several governments accepted liability under indemnities they had granted manufacturers as a condition of emergency supply, and compensation schemes were established. The episode is frequently cited by opponents of vaccination and is regarded by public health authorities as a genuine and serious adverse outcome that was identified by surveillance systems working as intended, affecting a vaccine used in one pandemic and not used since.

Zantac and ranitidine

In 2019 an independent laboratory reported that ranitidine could degrade into N-nitrosodimethylamine, a probable human carcinogen, particularly at elevated temperatures, and the Food and Drug Administration requested withdrawal of all ranitidine products from the American market in April 2020.

Tens of thousands of claims were brought in the United States against GSK, which had originated the drug, and against subsequent manufacturers and distributors. A federal court excluded the plaintiffs' scientific evidence in December 2022 and dismissed approximately 50,000 federal claims, but state court proceedings continued, notably in Delaware, where a judge permitted expert testimony in 2024. In October 2024 GSK agreed to pay up to US$2.2 billion to settle about 93 per cent of the state court cases without admitting liability, together with a further US$70 million to resolve a whistleblower claim in California.

Competition and pricing

In February 2016 the Competition and Markets Authority fined GSK £37.6 million for agreements under which it paid potential generic competitors to delay entering the British market for paroxetine, a practice known as pay for delay, alongside fines on the generic companies involved. The decision was partly upheld on appeal after a reference to the Court of Justice of the European Union.

An earlier antitrust case in 1973 concerned the pricing of griseofulvin, an antifungal, and the company has been the subject of competition proceedings in several jurisdictions over patent strategies and over the pricing of medicines in developing countries.

Other matters

In March 2007 the company was fined NZ$217,000 in New Zealand after two schoolgirls' science project established that Ribena, then a GSK product, contained negligible vitamin C despite advertising claims to the contrary, an episode that attracted attention disproportionate to its financial consequence.

The company has faced criticism for continuing to supply medicines in Russia after the 2022 invasion of Ukraine, a position it shares with most pharmaceutical companies and which it defends on the ground that withholding medicines from patients is not a legitimate instrument of policy. It has suspended advertising and new clinical trials there.

Its pricing of medicines in developing countries has been contested throughout its history, from the zidovudine campaigns of the late 1980s through the South African litigation over HIV treatment in 2001, in which GSK was among 39 companies that sued the South African government over legislation permitting parallel importation and compulsory licensing and withdrew the action under international pressure. The company has since adopted tiered pricing, patent pool participation and, from 2016, a policy of not filing patents in the poorest countries at all, measures that have been welcomed while the underlying question of how research is financed remains unresolved.

Corporate affairs

Structure and listing

GSK plc is incorporated in England and Wales, listed on the London Stock Exchange as a constituent of the FTSE 100 and on the New York Stock Exchange through American depositary receipts. Its shareholder register is dominated by institutional investors, principally the large index managers, and it has no controlling shareholder.

The question of where the company should be listed has become live. British-listed pharmaceutical companies have traded at persistently lower valuations than American ones with comparable pipelines, which the industry attributes to the composition of the British investor base, to the absence of a large domestic market paying American prices, and to the decline of the London market generally. GSK's executives have denied any intention to move the primary listing while acknowledging the disparity.

Leadership

Chief executives of the merged company have been Jean-Pierre Garnier from 2000 to 2008, Andrew Witty from 2008 to 2017, Emma Walmsley from 2017 to 2025 and Luke Miels from 2026. Chairmen have included Sir Christopher Gent, Sir Philip Hampton and Sir Jonathan Symonds.

Walmsley's tenure is assessed differently according to the measure applied. The pipeline she inherited was widely regarded as the weakest of any large pharmaceutical company, and the number of assets in late-stage development increased substantially under her; the vaccines business produced two of the most successful launches of the period; and the separation of Haleon was executed cleanly. Against that, the share price underperformed the sector and the company's largest products face patent expiry in the late 2020s, including dolutegravir, on which a substantial proportion of profit depends.

Employees

GSK employs approximately 65,000 people in more than 70 countries, a figure reduced from more than 100,000 before the Haleon separation and successive restructurings. Its largest concentrations are in the United Kingdom, the United States, Belgium and India.

Venture investment

SR One, the company's venture capital arm established in 1985, was among the earliest corporate venture funds in the life sciences and was separated as an independent firm in 2020. Action Potential Venture Capital invests in bioelectronic medicine, a field GSK pursued through a joint venture with Verily, the Alphabet life sciences company, called Galvani Bioelectronics, which develops implantable devices that modulate nerve signals to treat chronic disease.

Philanthropy and access

GSK has for two decades ranked at or near the top of the Access to Medicine Index, which assesses how far the largest pharmaceutical companies make their products available in low and middle income countries. Its measures have included tiered pricing under which the poorest countries pay a fraction of developed-market prices; the reinvestment of 20 per cent of profits made in least developed countries in health infrastructure in those countries; participation in the Medicines Patent Pool for HIV medicines through ViiV; a commitment not to file patents in low-income and least developed countries; and open innovation arrangements including the deposit of compound libraries and data on neglected tropical diseases in the public domain.

It has supplied albendazole free of charge for the elimination of lymphatic filariasis since 1998, donating more than nine billion tablets, one of the largest sustained medicine donations by any company, and the disease has been eliminated as a public health problem in a number of countries as a result. It supports the Global Fund, Gavi and the Global Polio Eradication Initiative.

These measures have attracted criticism from two directions: from campaigners who argue that they are marginal relative to the pricing of medicines in wealthy countries and that the underlying patent system remains the obstacle, and from investors who question whether a company should forgo revenue in this way. The company's position, set out most fully by Andrew Witty, is that the industry's licence to operate depends on being seen to behave reasonably and that pricing which excludes most of the world's population is unsustainable in the long term.

Science and recognition

Researchers working for GSK and its predecessors have received four Nobel Prizes: Gertrude Elion and George Hitchings of Burroughs Wellcome and James Black of Smith Kline and French shared the prize in Physiology or Medicine in 1988, and John Vane, who worked at Wellcome, shared it in 1982 for his work on prostaglandins and the mechanism of aspirin. The Wellcome laboratories were unusual in permitting and expecting their scientists to publish, and the resulting body of work is among the most substantial produced by any industrial research organisation.

The company's historical contributions include salbutamol, chlorpromazine, cimetidine, ranitidine, amoxicillin, co-amoxiclav, zidovudine, acyclovir, allopurinol, azathioprine, lamotrigine, sumatriptan, dolutegravir, the first malaria vaccine and the first broadly protective vaccine against meningococcal B disease.

Competition

GSK competes with Pfizer, Merck and Co., Sanofi and Moderna in vaccines, where the four largest companies supply the majority of the world's doses; with AstraZeneca and Sanofi in respiratory medicine; with Gilead Sciences in HIV, where the two companies have been direct rivals for three decades and have litigated repeatedly; and with the full range of large pharmaceutical companies in oncology and immunology.

Its competitive position differs from that of its peers in that it is comparatively small in oncology, the field that has absorbed the greatest share of industry investment, and comparatively large in vaccines and infectious disease, which are less profitable per dose but which produce durable franchises and which proved during the pandemic to carry strategic significance beyond their financial contribution.

The principal risk identified by analysts is the expiry of exclusivity on dolutegravir from the late 2020s, which will expose a very large share of profit to generic competition, and the company's acquisitions since 2022 have been directed at assembling products to replace it.

Identity and branding

The name GlaxoSmithKline, adopted in 2000, combined three of the four predecessor names and was among the more unwieldy in British corporate life, generally shortened to GSK in speech from the outset. The formal change to GSK in May 2022 accompanied a new visual identity built around an orange device the company described as representing the union of science, technology and talent, and was intended to mark the separation from the consumer business and the concentration on medicines.

The predecessor brands survive in various forms. Glaxo persists in the names of subsidiaries in several countries, notably GlaxoSmithKline Pharmaceuticals Limited in India, which remains separately listed. Wellcome survives as the name of the trust, which has no connection with the company beyond its origin, and in the Wellcome Collection and the Wellcome Sanger Institute. Beecham survives in Beecham's cold remedies, which passed to Haleon. Allen and Hanburys, a company founded in 1715 and acquired by Glaxo in 1958, gives GSK the oldest documented ancestry of any pharmaceutical company, and its name remains on some inhaler products in Britain.

Timeline

Principal dates include the founding of Plough Court Pharmacy, the ancestor of Allen and Hanburys, in 1715; John K. Smith's Philadelphia drugstore in 1830; Thomas Beecham's pills in 1842; Joseph Nathan's trading company in 1873; the founding of Burroughs Wellcome in 1880; the first Glaxo dried milk in 1904; the establishment of the Wellcome Trust in 1936; the isolation of 6-aminopenicillanic acid at Beecham in 1957; salbutamol in 1968; chlorpromazine in 1954 and cimetidine in 1976 at Smith Kline and French; zidovudine at Burroughs Wellcome in 1987; ranitidine at Glaxo in 1981; the SmithKline Beecham merger in 1989; Glaxo's acquisition of Wellcome in 1995; the formation of GlaxoSmithKline in 2000; the 2012 settlement; the Chinese bribery conviction in 2014; the Novartis asset exchange in 2015; Shingrix in 2017; the Tesaro acquisition in 2019; the separation of Haleon and the change of name in 2022; Arexvy in 2023; the Zantac settlement in 2024; and the appointment of Luke Miels in 2026.