Phase I trial of escalating doses of ABI-007 (nanoparticle albumin-bound paclitaxel) and gemcitabine in patients (pts) with thoracic malignancies

Abstract

18094 Background: ABI-007, nanoparticle albumin-bound paclitaxel, has a different toxicity profile than solvent-based paclitaxel including a lower rate of severe neutropenia. This trial was designed to determine the maximum tolerated dose (MTD) of ABI-007 in combination with gemcitabine (G) in patients with thoracic malignancies. Methods: Patients were required to have a performance status of 0–1, =3 cytotoxic chemotherapy regimens, and preserved renal, hepatic, and bone marrow function. Patients received G 1,000 mg/m2 on days 1, 8 in all cohorts and ABI-007 on day 1 at doses of 260, 300, 340 mg/m2 depending on the treatment cohort every 21 days (1 cycle = 21 days). Day 8 G dose modifications were: G held for ANC < 500 x 109/L or platelets (plts) < 50,000 x 109/L, and 75% of the G dose was given if the ANC 500–999 x 109/L or plts 50,000–99,000 x 109/L. Dose limiting toxicities (DLT) were assessed after the first cycle and were defined as: grade 3 non-hematologic toxicity, febrile neutropenia, grade 4 anemia or thrombocytopenia, ANC = 500 for = 7 days, 2-week delay in initiating the second cycle, or omission of the day 8 G. Doses were escalated in cohorts of 3–6 pts. Results: Thirteen patients were consented and 12 pts were treated (median age 62.5 years (range 35–75); median number of prior treatments 2.5 (range 1–4); tumor types: 6 non-small cell lung cancer (NSCLC), 5 small cell lung cancer (SCLC), and 1 esophageal. At an ABI-007 dose of 300 mg/m2, 1 of 6 pts experienced a DLT (omission of day 8 G due to ANC < 500), and at an ABI-007 dose of 340 mg/m2 2 of 3 patients experienced a DLT (1 pt grade 3 rash and pruritus; 1 pt grade 3 fatigue and anorexia). Additional grade 3 or 4 toxicities observed over all cycles were: neutropenia (n=2), sensory neuropathy (n=1), febrile neutropenia (n=1). G was given at full dose in 38 of the 39 cycles. Eight pts were evaluable for response by RECIST: 4 partial responses (SCLC, n=2; NSCLC, n=2), 4 stable disease (NSCLC, n=3; esophageal, n=1). Conclusions: The MTD of ABI-007 is 300 mg/m2 day 1 in combination with G 1,000 mg/m2 on days 1, 8 every 21 days. This combination was well tolerated and demonstrated activity in previously treated NSCLC and SCLC patients. No significant financial relationships to disclose.