Cancer treatments that attack tumors based on their individual genetic characteristics – not their location in the body – far surpbad traditional methods, extending survival to twice as many patients, a study said on Saturday.
The therapy involves examining tumors to look for clues about their genetic mutations and comparing them with new drugs designed to block cancer growth at the molecular level.
Researchers in Texas began studying the impact of these therapies in 2007, after seeing the success of Gleevec (imatinib): a revolutionary drug approved by US regulators in 2001 that proved very successful against chronic myeloid leukemia.
The results of the first and largest precision medicine trial to observe survival in a number of cancer types and many different targeted therapies released at the meeting of the American Society of Clinical Oncology in Chicago, the annual meeting on cancer plus biggest in the world.
Th The study, called IMPACT, enrolled 3,743 patients at the Texas MD Anderson Cancer Center from 2007 to 2013.
All patients had advanced cancers, or "terminal illness," which included cancers of the gastrointestinal tract, mammary or lung. Melanoma and cancer of the female reproductive tract were also included, along with rarer types of cancer.
Enrollees had typically tried at least four treatments, sometimes up to 16, which could not stop the growth of their cancer.
Patients receiving molecularly targeted therapies obtained an investigational drug that was then tested in a commercial trial or FDA-approved targeted therapy for another indication.
After three years, 15% of people treated with targeted cancer therapies were alive, compared to 7% in the non-target group.
After 10 years, 6% of the target group was alive, compared to only 1% in the other group.
In general, targeted therapies led to an average of four months of life without progression of cancer, known as progression-free survival, and an additional nine months of overall survival.
It is still far from a cure
Those who were treated with additional approaches lived less than three months without cancer and 7.3 months more in general.
Researchers say that the field has grown tremendously since 2007, and that further research will improve the range of therapies available for cancer patients.
"When IMPACT was first opened, we tested for no more than one or two genes," said lead researcher Apostolia Tsimberidou, professor of therapeutic cancer research at MD Anderson.
"Patients are now being evaluated for hundreds of genes, amplifications and mutations, as well as for immune markers," he added.
"Ideally, in the future, tumor testing of patients and badysis of cell-free DNA will become the standard of care at the time of diagnosis."