Cancer Research Lab

Imatinib interruption results in rapid progression in most patients with advanced gastrointestinal stromal tumors and cannot be recommended unless patients experience significant toxicity, French researchers report in the March 20th issue of the Journal of Clinical Oncology.

“This trial shows that it is not possible to interrupt a targeted treatment — here imatinib– of cancer in the advanced phase, without exposing a patient to a high risk of rapid relapse,” lead investigator Dr. Jean-Yves Blay said.

To investigate whether imatinib might be safely stopped in patients in whom disease were controlled, the researchers randomized 58 patients with advanced gastrointestinal stromal tumors who had responded or who had stable disease following a year of treatment, to continue with imatinib or to have their treatment interrupted.

After follow-up for as long as 2 years, 8 of 26 patients in the continuation group had disease progression. This was the case in 26 of 32 patients in the interruption group. However, 24 of these patients responded when imatinib was reintroduced.

“When efficacious, the standard strategy remains to give the treatment without stopping unless there is progression or intolerance,” Dr. Blay said.

A second randomization, this time at 3 years, is being performed and the results will be presented later this year at the annual meeting of the American Society of Clinical Oncology, he said.