UPDATE 1-EU backs Glaxo's breast cancer drug with warnings

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LONDON, April 24 (Reuters) - European drug regulators on Thursday recommended approval of GlaxoSmithKline Plc's (GSK.L) new breast cancer pill Tykerb, or Tyverb, but with additional warnings about potential liver toxicity.

A European Medicines Agency's expert committee was asked to look again at the product by the European Commission last month after clinical data showed hepatotoxicity -- predominantly elevated liver enzymes -- could occur during treatment.

After reviewing the new data, the agency said it had concluded the benefit-risk-balance for using Tykerb to treat patients with advanced or metastatic breast cancer was positive.

"The committee recommended that the product information should be amended to add special warnings about the risk of hepatotoxicity," it said in a statement.

Recommendations for marketing approval by the agency's Committee for Medicinal Products for Human Use (CHMP) are normally endorsed by the European Commission within a couple of months.

Tykerb is one of Glaxo's big new drug hopes, and the first of several cancer medicines that it hopes to have approved by 2010. Studies of the product are also underway to treat early-stage and inflammatory breast cancers, as well as head and neck, gastric and lung cancers.

It is designed to be given in combination with Roche's (ROG.VX) Xeloda for treating breast cancer patients whose tumours overexpress the HER2 protein.

Because Tykerb, known generically as lapatinib, is given as a pill it is more convenient than Roche and Genentech Inc's DNA.N blockbuster Herceptin, which works in a similar way but must be injected.

Unlike Herceptin, which aims to block cancer from outside the cell, Tykerb works within cells by blocking two enzymes thought to promote cancer. (Reporting by Ben Hirschler)