Gene test backs focused use of Amgen's Vectibix
Last Updated: 2007-09-25 10:01:10 -0400 (Reuters Health)
BARCELONA (Reuters) - New research showing Amgen Inc's colon cancer drug Vectibix only benefits a sub-group of patients may result in more focused use of such therapies for the disease in future, researchers said on Tuesday.
The world's largest biotech company said the finding showed the KRAS gene could be used as a clinical biomarker by doctors to select patients likely to respond to treatment with Vectibix, known generically as panitumumab.
Researchers told the European Cancer Conference the mutated KRAS gene was clearly associated with drug resistance. Of the 62 patients evaluated, 21 had the mutated or activated form of the gene and none responded to therapy.
The results come after European regulators last week changed tack and recommended approval of Vectibix -- but only for patients whose tumours do not have a mutation of KRAS.
Vectibix, which was approved last year in the United States, has been seen as a key medicine in the development pipeline of U.S.-based Amgen.
It competes with ImClone Systems's Erbitux, which is marketed in Europe by Germany's Merck KGaA. Both drugs target the epidermal growth factor receptor (EGFR), which promotes tumour growth through a set of intracellular proteins.
"In the future, physicians may select treatment options specifically for patients whose tumours harbour the non-mutated KRAS gene," Roger Perlmutter, Amgen's head of research, said in a statement.
Industry analysts at Morgan Stanley said in a note that KRAS dependent labelling or usage would limit the target patient population for EGFR treatments, since only 60 percent of the patient population have a non-mutated version of the gene.
But in the long term it could increase use of drugs like Vectibix and Erbitux within non-mutated KRAS tumour groups, in much the same way as Roche Holding AG's Herceptin has proved highly successful in a sub-group of breast cancer patients.
(Additional reporting by Ben Hirschler in London)
