Drug giants GlaxoSmithKline (NYSE: GSK) and Pfizer (NYSE: PFE) are joining forces to fight HIV by creating a new, jointly owned company.

The new company’s name will be announced when the deal closes, now set for the fourth quarter.

The new company will be based in London and run by longtime Glaxo executive Dominique Limet, who now leads its personalized medicine strategy. The company’s U.S. headquarters will be in Research Triangle Park, N.C., where Glaxo’s American headquarters are.

The partners Thursday morning before markets opened in New York.

The deal allows the two companies to merge their strengths in the HIV drugs business – GSK is a big seller of HIV treatments but its products are relatively old and its pipeline of future drugs is also relatively weak. Pfizer, on the other hand, has a significant store of drugs in development but few products on the market.

"The combination of a broad current revenue base and a new diverse pool of pipeline assets provides a significant platform to invest in developing and delivering new HIV medicines," Glaxo Chief Executive Andrew Witty said during a Thursday conference call with analysts.

London-based GSK, will initially hold an 85 percent equity interest in the new company, with New York-based Pfizer holding the remaining 15 percent. for information about the new firm, which won’t be named until later this year.

GSK has a long tradition of AIDS drug development in RTP, including AZT.

The new company will have a product portfolio of 11 marketed products including market-leading therapies such as Combivir, Kivexa and Selzentry/Celsentri. Based on 2008 results, the combined portfolio generates sales of around 1.6 billion pounds ($2.4 billion).

The companies said revenues at that level will provide the new company with financial stability and support investment in its pipeline.

"We’re going to just simply give it enough cash to support its working capital," Witty said. "It’s not going to have any debt."

Witty also told reporters he expects $90 million, or 60 million pounds, in savings — mostly next year — from cutting administration and marketing overlaps. He said research and development operations would be basically unchanged.

The two companies said that the new business "will be more sustainable and broader in scope than either company’s individually," adding that it will hold a 19 percent share of the growing market.

The new company will have a broad product portfolio of 11 marketed products including market-leading therapies such as Combivir, Kivexa and Selzentry/Celsentri. Based on 2008 results, the combined portfolio generates sales of around 1.6 billion pounds ($2.4 billion).

The companies said revenues at that level will provide the new company with financial stability and support investment in its pipeline.

"By combining Pfizer’s and GlaxoSmithKline’s complementary strengths and capabilities, we are creating a new global leader in HIV and reaffirming our ongoing commitment to the treatment of the disease," said Pfizer Chief Executive Officer Jeff Kindler in a joint statement issued to the London Stock Exchange.

"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," Kindler added.

The new company will contract research and development services directly from Glaxo and Pfizer to develop new medicines.

Limet currently is senior vice president and head of GSK’s Personalized Medicine Strategy.

Other board members of the new venture are:

• Julian Heslop, chief financial officer, GSK and chairman of the new HIV company
• Cees Heiman, regional president, Specialty Care Business Unit, Europe, Pfizer
• Zhi Hong, SVP and head of Infectious Diseases CEDD, GSK
• Abbas Hussain, president Emerging Markets, GSK
• Duncan Learmouth, SVP Corporate Communications & Community Partnerships, GSK
• Martin Mackay, president, Global Research & Development, Pfizer
• Ian McCubbin, SVP Strategy, Logistics and External Supply, GSK
• Ellen Strahlman, SVP and Chief Medical Officer, GSK