GlaxoSmithKline (NYSE: GSK) and Pfizer (NYSE: PFE), global drug giants and competitors, are also expanding their relationship as partners.

The two drug giants who created a joint venture together targeting AIDS are going to collaborate on a possible anti-cancer treatment involving two of their own products.

Pfizer and GSK said Thursday that they will study the anti-cancer efficacy and safety of a combination of drugs – GSK’s Trametinib and Pfizer’s Palbociclib.

The combination of drugs will be tested in a Phase 1 and 2 clinical trial. It will target pateitns with advanced/metastatic melanoma.

Financial terms were not disclosed.

GSK will conduct the study.

gy is committed to maximizing the value of our portfolio for patients through the study of novel combinations. This includes combining our own cancer medicines with each other, as well as with those of other companies where there is strong scientific rationale,” said Garry Nicholson, general manager of Pfizer Oncology Business Unit. “Emerging data suggest the potential for trametinib and palbociclib to work together to treat melanoma. We look forward to collaborating with GSK to explore this potential and evaluate the clinical activity of this combination in melanoma.”

More Good News for HIV Joint Venture

On Friday, the two companies received more good news about their ViiV Healthcare joint venture.

Its HIV drug Tivicay was recommended for approval by the European Union’s drug regulator.

Tivicay won the backing of the Committee for Medicinal Products for Human Use in combination with other antiretroviral medicines for the treatment of HIV patients over the age of 12, the European Medicines Agency said in a statement.

The treatment, which was approved by the U.S. Food and Drug Administration in August, reduced the HIV virus to undetectable levels in more people than Gilead Sciences Inc.’s Atripla, the world’s best-selling AIDS drug, in a clinical trial released last year. The medicine, also known as dolutegravir, is an integrase strand transfer inhibitor that interferes with the enzymes necessary for HIV to multiply.

Merckmakes the first and only other approved integrase strand transfer inhibitor, Isentress, which was cleared in 2007 and had sales of $1.5 billion last year.

ViiV is an independent company that is a venture of Glaxo, Pfizer Inc. and Osaka, Japan-based drugmaker Shionogi & Co. Glaxo owns 76.5 percent of ViiV while Pfizer has a 13.5 percent stake and Shionogi holds 10 percent, according to Glaxo.

The EMA’s recommendations are the final stage before the European Commission, the EU’s executive arm, approves or rejects a drug for sale to patients in the 28-nation region. The EC usually follows the committee’s advice.

GSK operates its North American headquarters in RTP.

(Bloomberg contributed to this report.)

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