Pfizer and GlaxoSmithKline will combine their HIV products and pipelines to form a specialty company, according to an announcement today.

The business, focused solely on research, development and commercialization of HIV medicines, will capture 19% of the category’s global market share, the statement said. Initially, GSK will hold an 85% interest in the company, with Pfizer at 15%.

“At the core of this specialist business is a broad portfolio of products and pipeline assets, which can be more effectively leveraged through the new company’s strong revenue base and dedicated research capability,” said Andrew Witty, GSK’s CEO, in the statement.

Jeff Kindler, CEO at Pfizer, said: “With the strength of the companies’ current HIV products, as well as the complementary fit of Pfizer’s HIV pipeline and GSK’s global distribution capabilities, the new company is well positioned to bring new and improved medicines to patients with more speed and efficiency.”

The combined company portfolio contains 11 marketed products – including top GSK sellers Combivir and Epzicom, and Pfizer’s Selzentry – with an additional six products in the early phases of development. Combivir is the fifth best-selling drug in the US, with $409.4 million in sales for 2008, according to IMS Health data. Bristol-Myers Squibb and Gilead’s combination therapy Atripla leads the category at $1.4 billion in US sales for 2008, with Gilead’s Truvada ($1.1 billion) in second and Bristol-Myers Squibb’s Reyataz ($777.4 million) in third. The total US market for HIV drugs grew by 13% from 2007 ($6.4 billion) to 2008 ($7.2 billion).

Dominique Limet, currently SVP and head of GSK’s personalized medicine strategy, has been appointed as CEO designate of the new company, and will become a member of the board. According to a Wall Street Journal report, the company could be worth as much as $7.5 billion.