EU to take another look at GSK breast cancer drug

Europe’s drugs regulators will take another look at GlaxoSmithKline Plc’s new breast cancer pill Tyverb after new data showed a small risk of higher liver enzymes during treatment with the drug.

GSK, Europe’s biggest drug maker, said on Tuesday that the European Commission had referred Tyverb, which is on sale in the United States under the name Tykerb, back to the EU’s Committee for Medicinal Products for Human Use (CHMP).

CHMP recommended conditional approval for Tyverb in December, meaning it could go on sale but that additional data were required.

GSK said it did not believe the new data changed the risk-benefit profile for Tyverb, and Nomura Code analyst Mike Ward agreed it was no more than a minor setback.

“It’s potentially a slight delay to the rubber-stamping of the official approval,” he said.

GSK said a review of clinical trial and post-marketing data showed that hepatotoxicity - predominately elevated liver enzymes - could occur during treatment with Tyverb, but that the overall incidence of this was only four in 1,000 patients.

“Severe hepatotoxicity has been uncommon. Elevated liver enzymes generally returned to normal when the patients stopped taking Tyverb,” it said in a statement.

“GSK has informed investigators in ongoing clinical trials, and healthcare providers in those countries where Tyverb is approved, to recommend increased frequency of blood tests to monitor liver function.”

GSK said it expected Tyverb would be discussed at the next meeting of the CHMP from April 21-24.

“It’ll have to go on the label for sure…but in the context of people dying of cancer I don’t think it’s a major issue,” Nomura Code’s Ward said.

At 1500 GMT, GSK shares were up 2.4 percent at 1,039 pence, versus a 2 percent rise on the DJ Stoxx European healthcare index.

Tyverb is one of GSK’s biggest 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.

Tyverb is designed to be given in combination with Roche’s Xeloda for treating patients with advanced or metastatic breast cancer 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 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.