GlaxoSmithKline said yesterday it expects to advance four new cancer drugs into Phase III testing next year, as part of an ambitious strategy to become one of the biggest companies in oncology.

These four would join three other drugs to treat cancer patients that are already in Phase III trials at GSK. If they reach the market, GSK has a chance to capture a significant slice of the market for oncology drugs, expected to almost double in size to $70 million dollars by 2009, according to Tachi Yamada, the firm’s head of R&D.

He told a seminar held yesterday to review GSK's cancer and supportive care pipeline that the new treatments could quadruple oncology sales at GSK, currently running at around $1 billion.

The latest drugs to progress to the pivotal trial stage are: Tykerb (lapatinib), a once-daily oral treatment for breast cancer; eltrombopag to prevent uncontrolled bleeding among patients suffering cancer or liver disease; casopitant to prevent chemotherapy-associated nausea; and pazopanib for renal cancer and other malignancies.

They will join GSK’s cervical cancer vaccine Cervarix, Avodart (dutasteride) for prostate cancer and Entereg (alvimopan), a gastrointestinal drug which also has applications in the management of cancer patients.

Tykerb is a dual-kinase inhibitor, blocking the ErbB1 (EGFR) and ErbB2 receptors, which are associated with cancer-cell proliferation and tumour growth. In trials conducted to date 40% of breast cancer patients experienced either tumour reduction or stable disease after treatment with the drug for at least 24 weeks. Three new Phase III trials are being initiated by January 2006, two in first-line therapy and one in refractory breast cancer. An update on this clinical programme will be presented at the San Antonio Breast Cancer Symposium on December 8.

GSK has high hopes for Tykerb, which could be used alongside other breast cancer drugs including Roche/Genentech's big-selling Herceptin (trastuzumab) product.

Eltrombopag is a small-molecule drug that stimulates the receptor for thrombopoietin, a growth factor that boost production of blood platelets. The drug could become the first oral treatment for thrombocytopenia, a condition which can lead to uncontrolled bleeding, significantly reduced life expectancy and compromised treatment for cancer or liver disease. Analysts have predicted this drug will easily achieve blockbuster status – and could be a multibillion dollar product - if it reaches the market.

Casopitant, a neurokinin-1 antagonist, could extend GSK’s antinauseant franchise now the firm’s Zofran (ondansetron) product is facing generic competition. Most patients receiving chemotherapies known to cause nausea are treated with a 5-HT3 antagonist such as Zofran, but 40% still suffer symptoms. Casopitant has a higher response rate as a monotherapy than Zofran and can also be used in combination with the latter drug, said GSK.

Finally, pazopanib is a once-daily, oral inhibitor of vascular endothelial growth factor (VEGF) and has been shown to inhibit tumour growth in early-stage clinical trials by blocking the formation of new blood vessels. It has shown particular efficacy in renal cell carcinoma, with a 100% response rate in a Phase I study, and could also be used for other cancer types, including gastrointestinal, neuroendocrine, lung and thyroid cancers, as well as sarcomas.