September 29, 2010

African-Americans equally likely to benefit from erlotinib and other targeted lung cancer therapy, SOM researcher finds

African-American patients with non-small cell lung cancer are just as likely to display an epidermal growth factor receptor mutation in tumors as whites, which suggests they are as likely to benefit from targeted therapies such as erlotinib, according to a study conducted by a Wayne State University School of Medicine researcher.

"This study has immediate implications for patient management. Patients with EGFR mutations have a much better prognosis and respond better to erlotinib than those who do not," said Ramsi Haddad, Ph.D., director of the Laboratory of Translational Oncogenomics at the Barbara Ann Karmanos Cancer Institute and assistant professor at the WSU School of Medicine.

Haddad's study, which he presented at the Fourth American Association for Cancer Research International Conference on Molecular Diagnostics in Cancer Therapeutic Development, also showed that African-Americans were more likely to have mutations on exon 19, rather than exon 21, which suggests they would be even more responsive to erlotinib.

Erlotinib, marketed as Tarceva by Genentech, has shown remarkable benefits in non-small cell lung cancer patients with EGFR mutations. Other therapies are in development and genetic testing is clinically available.

Previous studies had suggested that African-Americans had lower rates of EGFR mutation, which researchers had offered as a possible explanation for their generally poorer prognosis.

However, Dr. Haddad's study was larger than those conducted for previous reports. His research team observed 149 patients with non-small cell lung cancer, including 80 whites and 69 blacks.

Using state-of-the-art technology that allowed for simultaneous detection of hundreds of oncogene mutations in clinical samples, the team identified EGFR mutations in 20 of these patients, including 12 whites and eight blacks. The difference was not statistically significant.

One-hundred percent of the EGFR mutations in black patients were in exon 19, compared with only two-thirds of the mutations found in white patients.

"It is well-documented that the incidence of lung cancer is higher among African-Americans, particularly men, and that their survival is generally poorer compared to their white counterparts," Dr. Haddad said. "Our data suggest that African-Americans with NSCLC harbor mutations in EGFR at rates similar to whites. Thus, African ancestry should not be a factor when deciding whether to test a tumor for these mutations, as doing so could widen the disparity seen in survival. Physicians treating these patients may want to consider this new information in their treatment decisions."