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 proteins, called kinases. Kinases are important in regulating how cells work and grow.

Sunitinib has been licensed for use in people with kidney cancer that has spread to other parts of the body (called advanced or metastatic kidney cancer).

The main treatment for kidney cancer is surgery to remove the tumour. Unfortunately, if the cancer has spread outside the kidney, it is more difficult to treat and can't usually be cured. Advanced kidney cancer is most often treated, in the UK, with interferon alpha (IFN), a drug that boosts the immune system to help fight the cancer.

A clinical trial of 750 people was run to compare the effectiveness of sunitinib to interferon in people with advanced kidney cancer. Half the people in the trial took interferon and the other half took sunitinib.

People on sunitinib took a tablet once a day for four weeks followed by a two week break. The course was then repeated. This pattern was continued for as long as the treatment was helping.

The cancer shrank in 31 out of every 100 (31%) people taking sunitinib. The cancer shrank in 6 out of every 100 (6%) people taking interferon.

The study also found that the cancer stopped growing for longer in people taking sunitinib than in people taking interferon. When the cancer isn't growing this is called stable disease. On average people taking sunitinib had stable disease for 11 months compared to 5 months in the interferon group.

These results are encouraging but it is still too early to say if sunitinib helps people to live for longer.

Side effects caused by the treatments were different in each group.

Interferon was more likely to cause problems with weakness and tiredness (fatigue). While people taking sunitinib were more likely to have problems with diarrhoea, high blood pressure and soreness of the palms of their hands and soles of their feet (hand-foot syndrome).

But, overall people taking sunitinib reported having a better health related quality of life than people taking interferon.

Your specialist will be able to tell you whether sunitinib may be a possible treatment for you.

Unfortunately, sunitinib may not be widely available in the UK. In Scotland, the Scottish Medicines Consortium (SMC), who advise on the use of new medicines in Scotland, have ruled against sunitinib being made available on the NHS. The body that issues guidance on the use of new treatments in England and Wales, the National Institute for Clinical Excellence (NICE), and have not yet looked at its use. So, primary care trusts in England and Wales will look at each case individually.

Reference

• Motzer RJ et al Sunitinib versus Interferon-alfa in metastatic renal-cell carcinoma. The New England Journal of Medicine. Vol 356(2) 115-124