A phase II study of AT-101 (Gossypol) in chemotherapy-sensitive recurrent extensive-stage small cell lung cancer.

Background: AT-101 is an oral inhibitor of the antiapoptotic Bcl proteins (Bcl-2, Bcl-XL, Bcl-W, and Mcl-1) and an inducer of the pro-apoptotic proteins noxa and puma. We studied the efficacy of AT-101 in patients with recurrent chemosensitive extensive-stage small cell lung cancer (SCLC).

Methods: Patients with recurrent "sensitive" SCLC (defined as no progression during and no disease recurrence <2 months after completion of first-line platinum-based chemotherapy) were eligible. AT-101 was administered 20 mg orally daily for 21 of 28 days each cycle for up to six cycles. The primary end point was the objective response rate.

Results: At the time of planned interim evaluation, none of the 14 evaluable patients enrolled in the first stage had any response to therapy, and the study was closed permanently for further accrual. Three patients (21%) achieved stable disease after two cycles of therapy. Grade 3 toxicities included anorexia, fatigue, and nausea/vomiting.

Conclusions: AT-101 is not active in patients with recurrent chemosensitive SCLC.