Gene Testing Predicts Response to Erbitux
Testing for KRAS Gene Pinpoints Which Patients Will Benefit From Targeted Therapy
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KRAS Predicts Response to Erbitux continued...
Among the results:
- People with normal KRAS genes were 32% less likely to have their cancer progress than those who had mutated KRAS genes.
- At one year, 43% of patients with normal KRAS genes given Erbitux and chemo were alive and free of cancer vs. 25% given chemotherapy alone.
"In KRAS-mutant patients, there was no difference [in response rates]," van Cutsem says.
- Tumors shrank by more than half in 59.3% of patients with the normal gene, compared with only 43.2% of those on chemo alone. Again, there was no difference in response rates among those with the KRAS mutation.
- The main side effect, as in other studies of Erbitux, was an acne-like rash. It developed in 16.2% of patients on combo therapy, but in none on chemo alone.
'An Exciting Era'
Julie Gralow, MD, chairwoman of ASCO's communications committee and a cancer specialist at the University of Washington, says, "This is an exciting area of targeted agents."
Noting that therapies like Erbitux typically cost upwards of $5,000, Gralow says, "A big question is, how are we going to be able to afford these drugs in our patients? With KRAS testing, we can predict the two-thirds of patients who will benefit. We don't need to give this drug to the other third now."
That, she says, will spare them both the cost and side effects of unnecessary treatment. Gralow moderated a news conference to discuss the findings.