Analyst: GlaxoSmithKline's Tykerb dead in the water after breast cancer failure

GlaxoSmithKline's ($GSK) cancer treatment Tykerb took a blow last month when it failed a major late-stage trial in breast cancer. Now, at least one analyst figures the drug is crippled by that data--and that marketing it for breast cancer would be a waste of money.

The study that torpedoed Tykerb compared Roche's Herceptin--the gold standard in HER2-positive breast cancer--against the combination of Herceptin and the GSK drug in patients who had undergone surgery. Obviously, the hope was that adding Tykerb to Herceptin would be a boost for those patients. But it wasn't; the dual therapy failed to show statistical superiority over Herceptin alone at staving off the disease.

Based on response data from another study, hopes were high for Tykerb in post-surgery patients. Now, with the new trial failure on the one hand--and Roche's new line-up of HER2-positive cancer therapies, Perjeta and Kadcyla, on the other--Tykerb's chances look slim, GlobalData analyst Jamie Mallinson figures.

Adding to the uncertainty about Tykerb's future is the fact that it will go to Novartis as part of Glaxo's oncology portfolio sale to the Swiss drugmaker in a $16 billion deal. "Tykerb has failed to establish itself as a strong competitor in the HER2-positive market, and its use in the adjuvant setting was the only way it could gain a decent share of the breast cancer therapeutics market after Roche launched Perjeta and Kadcyla," Mallinson said in a recent report.

Coming on top of last year's Tykerb failure in HER2-positive gastric cancer, the loss in breast cancer is a big disappointment. The upshot? GlobalData figures there is "little more to expect" from the drug. So, the firm says, neither Glaxo nor Novartis is likely to expend much effort--or money--marketing Tykerb.

But after Novartis inked its deal for the GSK cancer portfolio in April, analysts said that the Swiss drugmaker could easily add Tykerb to its marketing lineup. Sales reps working on the Novartis treatment Afinitor, which is approved for breast cancer as well as other forms of the disease, could also tout Tykerb with little additional effort or expense. Whether Novartis can prove the Tykerb naysayers wrong? We'll have some time to wait and see.

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