Imatinib demonstrated activity and appeared well tolerated in patients with AIDS-related Kaposi’s sarcoma, according to results of a phase 2 study.
The study included 30 patients who received 400 mg imatinib (Gleevec, Novartis) — a stem cell factor and platelet-derived growth factor receptor inhibitor — daily for up to 12 months. The doses escalated up to 600 mg a day at 3 months in patients with stable disease.
Median treatment duration was 22.5 weeks (range, 0.3-52.7). Nine patients (30%) completed 52 weeks of treatment. Seven patients (23%) discontinued treatment due to disease progression, and five (17%) discontinued due to adverse events.
Overall, 10 patients (33%) achieved partial response and six patients (20%) demonstrated stable disease. Median time to response was 21 weeks and the median duration of response was 36 weeks.
Seven patients (23%) experienced progression of Kaposi’s sarcoma. The median time to progression among patients who achieved a partial response or stable disease was 48 weeks.
Seventy percent of patients experienced an adverse event of any grade, and there were 11 instances of grade 3 or grade 4 adverse events.
Researchers did not observe stem cell factor and platelet-derived growth factor mutations or any changes in the candidate cytokines correlated with response. They noted that antiretroviral therapy did not interfere with imatinib metabolism.
“This regimen may be useful as an alternative for patients who do not require cytotoxic chemotherapy or whose disease has progressed on conventional therapy,” the researchers wrote. “Exploration in classic Kaposi’s sarcoma may also be warranted, particularly because this is a disease of the elderly who may benefit from noncytotoxic therapies.”
Disclosure: The researchers report research funding from Novartis.