부산대학교 도서관

3504 Background: Bcl-2 is a rational target in SCLC since it is overexpressed in 60%-90% of tumors and may play a role in resistance of SCLC to chemotherapy. Obatoclax is a small molecule BH3 mimetic that blocks bcl-2 binding to proapoptotic family members. Obatoclax has growth inhibitory effects in several solid tumor cell lines and xenografts, with at least additive effects in combination with topotecan. The primary objective of this study was to evaluate the safety profile and maximum tolerated dose (MTD) of obatoclax plus topotecan in patients with relapsed SCLC and other solid tumors.Methods: We conducted a phase I dose escalation study using a standard "3+3" design. Obatoclax was administered at 14 or 20 mg/m2 over 3 hours on day 1 every 21 days. A subsequent cohort received obatoclax 14mg/m2 on days 1 and 3. Topotecan was given at 1.25 mg/m2 days 1-5. All patients received pegfilgrastim on day 8. Eligible patients were adults with solid tumors appropriate for treatment with topotecan. Patients with neurologically stable, treated brain mets were eligible.Results: 14 patients have been treated including 8 SCLC, 3 extrapulmonary small cell, 1 carcinoid, 1 Merkel cell and 1 melanoma previously treated with 1 or 2 lines of chemotherapy. Nearly all patients experienced neurologic toxicities during the obatoclax infusion which included ataxia, dysarthria, somnolence and/or mood alteration; these typically resolved 1-2 hours after completion of the infusion. The MTD of obatoclax was 20 mg/m2 on day 1 with Dose Limiting Toxicities (DLT) including grade 3 neurotoxicity (2 pts) and febrile neutropenia. Hematologic toxicity included grade 3/4 anemia (6 pts), thrombocytopenia (5 pts) and neutropenia (5 pts). Other toxicities included mild nausea/vomiting, fatigue, pruritus, and constipation. Clinical activity was seen in patients with SCLC including 1 PR and 4 SD out of 7 evaluable. The median TTP for these SCLC patients was 11 weeks.Conclusions: The recommended phase II dose is obatoclax 14 mg/m2 on days 1 and 3 with topotecan 1.25 mg/m2 on days 1-5 in 21 day cycles. A phase II study in second-line SCLC is open. Supported by NCI U01-CA69856. No significant financial relationships to disclose.