(Corrects second paragraph to show that the recommendation is to approve the relapsing forms, not the relapsing-remitting form of MS)

FRANKFURT, June 23 (Reuters) - Germany's Merck KGaA has won a key recommendation to become a late entrant to the market for oral multiple sclerosis (MS) drugs in Europe, six years after its first attempt to launch the cladribine pill failed.

The European Medicines Agency, the EU's drugs regulator, said on Friday its experts had come out in favour of approving cladribine, branded as Mavenclad, for the treatment of the relapsing forms of MS.

The European Commission, which has the final word, typically adopts the experts' view.

In 2011, U.S. drug regulators' concerns about whether cladribine could cause cancer put an end to Merck's development and marketing plans for the drug.

Since then, other drugmakers have pulled ahead with oral MS treatments, gradually replacing standard injection therapies and reaching a share of the overall MS market of more than 40 percent.

The main contenders are Biogen's Tecfidera, with about $4 billion in global sales, as well as Gilenya from Novartis and Sanofi's Aubagio.

But Merck, a diversified chemicals and healthcare group, further analysed the trials it conducted at the time and the insight encouraged it last year to seek approval in Europe without conducting further studies.

Merck has said it might file for regulatory approval in the United States, depending on ongoing discussions with the U.S. Food and Drug Administration.

Oral drugs are taking market share from established injectable MS drugs such as Merck KGaA's Rebif, Teva's Copaxone and Bayer's Betaferon/Betaseron.

The existing distribution network for Rebif would allow Merck to launch cladribine at relatively low costs. (Reporting by Ludwig Burger; Editing by Mark Potter)