Expansion for Glaxo's Tykerb

GlaxoSmithKline (GSK) recently announced that it has received accelerated approval from the U.S. Food and Drug Administration (FDA) for the use of Tykerb (lapatinib) as a first-line treatment for women with metastatic breast cancer in a new combination regimen.

With this approval, Tykerb can now be used in combination with Novartis’ (NVS) Femara (letrozole) for the treatment of postmenopausal women with hormone receptor positive metastatic breast cancer, which overexpresses the HER2 receptor and requires treatment of hormonal therapy. Approval in the EU -- where Tykerb is available under the trade name Tyverb -- for this indication has yet to come. Tykerb is an oral intracellular dual (ErbB-2/EGRF) tyrosine kinase inhibitor.

Phase III trials in combination with letrozole showed that the combination therapy was associated with a 5.2 month increase in progression-free survival versus letrozole alone as a first-line treatment in ErbB2 positive breast cancer patients. 

Glaxo initially gained approval for Tykerb for use in combination with Roche’s Xeloda in cases where patients with advanced or metastatic breast cancer whose tumors overexpress HER2 have received prior therapy including an anthracycline, a taxane and trastuzumab. 

The recent approval should help boost Tykerb sales, which came in at $186 million in the first nine months of 2009. Glaxo has Tykerb in studies for head & neck squamous cell carcinoma, refractory inflammatory breast cancer and gastric cancer. Tykerb is also being studied in combination with Votrient, which is approved for the treatment of patients with advanced renal cell carcinoma, for breast cancer.

We currently have an Underperform recommendation on Glaxo. While Glaxo’s diversified base and presence in different geographical areas should help support revenues, we remain concerned about future growth prospects given the patent challenges being faced by several of Glaxo’s products. With several products expected to lose exclusivity and the swine flu opportunity likely to miss expectations, we expect Glaxo’s top-line to remain under pressure in the coming quarters.

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