A new 'personalised' drug has been found to decrease the size of tumours in patients with advanced melanoma by 30 per cent. Results of an initial trial were presented at the meeting of the American Society of Clinical Oncology in Orlando, US. The results showed that the experimental treatment, a 'personalised' oral drug known as PLX4032, kept the melanoma at bay for six months. Pharmaceutical giant Roche and a privately owned company called Plexxikon Inc will carry out larger trials later this year and undertake testing to select suitable patients as candidates for further trials and later for treatment with the drug.
'Malignant melanoma', or simply 'melanoma', is a skin tumour that involves pigment-producing skin cells. It is the most serious form of skin cancer, and one of the deadliest of all cancers. Each year in the UK some 2,000 people die from melanomas and around 10,400 people are diagnosed with the condition - roughly fourfold the number diagnosed in the 1970s - making it the most rapidly increasing cancer in the UK. Melanomas start as a blemish or change to a mole on the skin and are treatable if caught early enough.
However, once patients develop metastatic disease (where the cancer spreads to other organs such as the lungs or liver) there are few treatment options and only five per cent of patients live five years beyond diagnosis - most die within a matter of months. In the trial nine of the 16 cancer patients saw their tumours shrink by at least 30 per cent and survival without disease progression was extended. When asked what difference the drug made, one doctor involved in the trial commented that it was the first time he had 'time to get to know my patients'.
A genetic mutation in the 'BRAF' cellular pathway, an important mediator of cell growth and division, occurs in 60 per cent of melanomas and about eight per cent of all solid tumours. The new drug (and its competitors, including XL281 from Exelixis Inc and RAF265 from Novartis AG) works by selectively targeting and destroying tumour cells that carry this BRAF mutation. PLX4032 is also being developed to help fight other cancers, such as bowel cancer, but has no effect against cancers that lack the BRAF mutation. New drugs such as these are seen by many to signal the end of 'blockbuster' drugs that treat everybody or every cancer, in favour of treatments that are tailored to the genetic makeup of specific cancers or groups of individuals.
The trial's lead investigator Dr Keith Flaherty, an assistant professor at the Abramson Cancer Centre of the University of Pennsylvania, said: 'Seven years after BRAF mutations were first identified, we have validation that this mutation is a cancer driver and therapeutic target. In addition to a new and important chapter in the story of targeted therapy development in cancer, we are especially excited for our melanoma patients for whom there are few treatment options.'