Shionogi increases stake in ViiV Healthcare as Pfizer exits HIV venture in USD2.13B deal

JAPAN—Japanese pharmaceutical company Shionogi & Co is strengthening its position in the global fight against HIV by acquiring a larger stake in ViiV Healthcare, the specialist HIV medicines developer, through a USD2.13 billion investment.

The deal comes as Pfizer completes its exit from the joint venture it helped establish more than 15 years ago.

ViiV Healthcare will issue new shares to Shionogi worth USD2.13 billion, which will boost the Japanese drugmaker’s economic interest in the company to 21.7%.

Shionogi first joined ViiV Healthcare as a shareholder in 2012, and this latest move significantly expands its commitment to developing treatments for people living with HIV.

The transaction marks the end of Pfizer’s involvement with ViiV Healthcare, as the American pharmaceutical giant sells its entire 11.7% stake in the company.

Pfizer will receive USD1.89 billion from the deal, while GSK, which maintains its controlling 78.3% majority stake in ViiV Healthcare, will collect a special dividend payment of USD250 million.

Investors responded positively to the news in Tokyo, where Shionogi’s shares climbed 2.8% to ¥2,925 (USD18.53) when trading opened on January 20.

This represented a notable increase from the previous day’s closing price of ¥2,840.50.

GSK and Pfizer originally created ViiV Healthcare in 2009 as a strategic collaboration to pool their resources and expertise to combat the global HIV pandemic.

Both companies transferred their HIV-related assets to the newly formed venture at that time.

These assets included important medications such as Epzicom/Kivexa, which combines abacavir sulfate and lamivudine, along with Selzentry/Celsentri, which contains maraviroc.

Today, ViiV Healthcare manages a portfolio of 15 prescription HIV medicines and maintains four experimental candidates currently undergoing clinical trials.

The company focuses particularly on developing ultra-long-acting therapies for both treatment and prevention, including long-acting injectable medications that patients could potentially administer themselves.

This research direction mirrors recent innovations in the field, such as Gilead’s Yeztugo, which contains lenacapavir.

Regulators in the United States and Europe approved Yeztugo in 2025 as the first and only biannual pre-exposure prophylaxis (PrEP) medication.

David Redfern, who chairs ViiV Healthcare, welcomed the agreement by noting that it streamlines the company’s shareholder structure.

He expressed enthusiasm about continuing the productive partnership with Shionogi to advance ViiV’s pipeline of long-acting injectable HIV medicines for both treatment and prevention.

Gilead Sciences currently dominates the HIV treatment landscape, particularly following its announcement of Phase III trial data for Yeztugo, the twice-yearly PrEP medication.

The Phase III trials demonstrated remarkable effectiveness, with the biannual drug preventing nearly 100% of HIV cases among study participants who received the treatment.

Market analysts at GlobalData project steady growth for the HIV pharmaceutical market across the seven major markets, which include the United States, France, Germany, Italy, Spain, the United Kingdom, and Japan.

The market is forecast to expand from USD26.5 billion in 2023 to USD32.1 billion by 2033, representing a compound annual growth rate of 1.9%.

The global HIV treatment landscape faced significant challenges in 2025 when the World Health Organization called for expanded access to newly approved HIV medications amid widespread funding reductions.

President Donald Trump’s administration cut substantial foreign aid funding that year, which severely affected HIV, malaria, and tuberculosis treatment services in low-income countries that relied on support from the United States Agency for International Development.