Quite a few scientists at Amgen could breathe sighs of relief over the weekend—that years of their work didn’t go down the drain. The world’s biggest biotech company, which has scientific operations in Seattle and Cambridge, MA, scored a victory in its quest to make cancer drugs tailored to specific genetic subgroups, when the idea passed muster in a major, rigorous clinical trial.
Amgen (NASDAQ: [[ticker:AMGN]]) said its lone marketed anti-tumor drug, panitumumab (Vectibix), kept tumors in check for a significantly longer time for colon cancer patients with a normal form of a gene called KRAS, compared with patients who have a more aggressive, mutated form of the gene. Results were from a study of more than 1,100 patients who were newly diagnosed.
Most drug companies try to market their products to the broadest possible group of patients who might benefit, but Amgen is taking the opposite tack. Last month, the company persuaded the FDA to incorporate new language into the prescribing information of Vectibix, first approved in September 2006. The updated wording essentially says that instead of prescribing it broadly among colon cancer patients who have failed prior therapy, the drug appears beneficial only for patients with a normal KRAS gene, and doesn’t work at all for those with a mutated form. Amgen is hopeful that by targeting about 40 percent of colon cancer patients with the normal gene, who are much more likely to benefit, it will increase the confidence of doctors and patients (and insurers) to try its drug, which sells for about $8,000 a month.
The drug isn’t a huge seller in the Amgen portfolio, but the finding is sending a ripple effect through the organization nonetheless. Mounting evidence for its genetic stratification strategy gives it greater confidence to push ahead with tests of other genes that might boost the odds of success with its other eight cancer drugs in clinical development. About 240 people inside Amgen—including computational biologists and immunologists in Seattle, and molecular biologists in Cambridge—have been working for five years to show that identifying these genetic biomarkers is the best way to increase the odds of success in cancer drug development, and help patients avoid needless side effects when the treatments are bound to fail.
“This really underscores the value of using KRAS as a predictive biomarker,” says David Reese, executive director for oncology. “We’re very pleased with the results.”
A little bit of statistics is required to understand why this latest trial is a watershed. Amgen has been making its case, to the FDA and others, for well more than a year that Vectibix works better
