The Mayo Clinic has reported that patients taking a commonly prescribed treatment for colon cancer are dying at almost three times the rate of patients who took other medications for the same disease. The chemotherapy drug, irinotecan, has been shown to increase life expectancy by about two months for patients with advanced colorectal cancer. However, in the first two months of receiving the drug, 33 out of 1,199 patients died, among patients taking different drugs, only 10 out of 905 patients died within the same period.
The drug is manufactured by Pharmacia and marketed under the name Camptosar. Although the findings are preliminary and not statistically significant, the company has sent letters to doctors in the US advising them of the results. The finding is somewhat controversial, as this effect of the drug has not been seen previously. However, the research group at the Mayo Clinic explains that this may result from the fact that the deaths were spread out among different medical centres, and when data were pooled the effect was seen; it might not have been obvious to individual physicians. Doctors who are conducting the study will be giving the drug in lower doses and will be more aggressive about looking for warning signs of toxicity, including diarrhea, nausea, vomiting and a low white blood cell count.
The results of the study will be published in a letter in an upcoming issue of the New England Journal of Medicine.