Sunitinib, also known as Sutent®, is a new type of drug called a tyrosine kinase inhibitor. It is a capsule that is taken by mouth. The capsule works by interfering with special proteins, called kinases. Kinases are important in regulating how cells work and grow.

Gastrointestinal stromal tumours (GIST) are a rare type of cancer of the digestive system. The main treatment for a GIST, that can't be taken away by an operation or that comes back, is a tablet called imatinib (Glivec). But, sometimes GIST is no longer controlled by imatinib and begins to grow again. So, doctors are looking for new treatments that are effective at controlling the cancer when this happens.

Sunitinib has been tested as a treatment for GIST that no longer responds to imatinib.

A clinical trial of 312 people looked at whether sunitinib was better than a placebo (sugar pill) in treating people with GIST that was no longer responding to imatinib. Each person in the trial was given either sunitinib or a sugar pill (placebo).

Each person took, either a capsule containing sunitinib or a placebo pill, once a day for four weeks followed by a two week break. This treatment was repeated for as long as the cancer was being controlled.

The study found that the cancer stopped growing for longer in people taking sunitinib than people taking the placebo. When cancer isn't growing this is called stable disease. On average people taking sunitinib had stable disease for about 6 months compared to about 6 weeks for people taking the placebo.

Sunitinib was not so good at making the cancer shrink. Very few people, about 7 out of 100 (7%) taking sunitinib had their cancer get smaller. The cancer didn't shrink in anyone taking the placebo.

Overall, these are encouraging results. They show that sunitinib may be helpful in controlling GIST in people for whom imatinib is no longer working.

Sunitinib may cause side-effects. The main ones that have been reported include diarrhoea, sickness, mouth soreness, soreness of the palms of the hands and soles of the feet, high blood pressure, nose bleeds, skin changes (most often a yellowish tinge developing the skin) and changes in hair colour.

Based on these results sunitinib has recently been licensed for treating GIST that is no longer responding to imatinib. Your specialist will be able to tell you whether sunitinib may be a helpful treatment for you.

Reference

• Motzer RJ et al . Activity of SU11248, a Multitargeted Inhibitor of Vascular Endothelial Growth Factor Receptor and Platelet-Derived Growth Factor Receptor, in Patients With Metastatic Renal Cell Carcinoma. Journal of Clinical Oncology, 2006; 24: 16-24