By Sophie Sassard and Freya Berry
LONDON (Reuters) - Apollo Global Management (APO.N) is planning to bid for all GlaxoSmithKline's (GSK.L) mature drugs, joining an auction expected to value the business at more than $3 billion, according to four people familiar with the process.
The private equity firm, run by Leon Black, could change the dynamic of the auction because it is ready to buy all the products on offer, while other potential buyers are looking to acquire only certain regional businesses.
GSK, which the sources said had asked for final bids by early next week, might find it simpler to deal with a single buyer, although the company has made clear that maximising shareholder value is the top priority of the divestment.
Other potential bidders include private equity firm KKR (KKR.N), which has teamed up with private Dutch-based specialty drugmaker Norgine, and Denmark's Lundbeck (LUN.CO).
It is unclear whether Indian drugmaker Lupin (LUPN.NS) or other private equity firms are still in the running.
GSK, Britain's biggest drugmaker, is looking to divest its mature prescription medicine products sold in North America and western Europe in a bid to improve its growth profile.
The drugs on the block, known as established products, are expected to have combined 2014 sales of around 1 billion pounds ($1.6 billion), although their sales are declining due to competition from cheaper generics.
The sources said GSK was looking for a multiple of more than two times sales, suggesting a price of at least $3.2 billion.
GSK is being advised by Lazard and aims to find buyers by the end of the year.
Acquiring GSK's older drugs would be more complicated for private equity funds than other drug manufacturers as GSK is not planning to sell the factories, which means the funds would need to outsource manufacturing and distribution operations.
GSK Chief Executive Andrew Witty said last month that the sale of the established products was proceeding as planned. A company spokesman declined further comment.
Apollo, Norgine and Lundbeck declined to comment while KKR didn't respond to request for comment.
The GSK brands up for sale include antidepressant Paxil, migraine treatment Imitrex, Zantac for stomach acid and Zofran for nausea. The company intends to retain the rights to such products in emerging markets, where they are still growing.
($1 = 0.6351 British pound)
(Writing by Ben Hirschler; Editing by Alex Smith and David Evans)