FRIDAY, Sept. 24, 2004 (HealthDayNews) -- Twice daily doses of 400 milligrams of the drug imatinib (Gleevec) can slightly improve progression-free survival for people with gastrointestinal stromal tumors (GIST), says a European study in this week's issue of The Lancet.
Imatinib is approved worldwide for treating patients with GIST, tumors that don't respond to conventional chemotherapy, the researchers said. This study found that a single daily dose of the drug is sufficient to induce a therapeutic response and that a doubling of the daily dose may slightly improve patients' progression-free survival.
The study included 946 people with metastatic GIST. They were randomly assigned to receive a 400 milligram dose of imatinib either once or twice a day.
After two years, 50 percent of those taking the double dose, and 56 percent of those taking the single dose, were alive and free of disease progression. About four months after the start of treatment was the optimum time for therapeutic effect in both groups, the scientists said.
"If the aim of treatment is response induction, a daily dose of 400 mg. given for 4-6 months seems to be sufficient," researcher Dr. Jaap Verweij, Erasmus University Medical Center, the Netherlands, said in a prepared statement.
"However, in patients with widespread metastatic disease, the prolonged progression-free survival achieved with 400 mg twice daily might lead one to favor this regimen. Whether a similar outcome could be achieved with fewer side effects by making use of the reduction in drug clearance over time -- e.g. with a starting dose of 400 mg. daily followed by stepwise dose escalation to 400 mg. twice a day -- is still a matter for further clinical investigations," Verweij said.
The American Cancer Society has more about GIST.