Phase I study of two different schedules of bortezomib (BORT) and pemetrexed (PEM) in advanced solid tumors

Abstract

17051 Background: BORT(PS-341) is a small molecule proteasome inhibitor while PEM, a multi-targeted antifolate, inhibits multiple enzymes involved in purine/pyrimidine formation. Both are approved anti-cancer agents. We examined the safety and tolerability of two different schedules of BORT and PEM in patients with advanced solid tumors. Methods: Two dose escalation trials (Arm A and Arm B) were conducted simultaneously. PEM was given every 21 days in both arms (500–600 mg/m2 IV). Arm A: BORT was given D1,4,8 &11 (0.7–1.3 mg/m2). Arm B: BORT was given D1 & 8 (1.0–1.6 mg/m2). All patients received vitamin B12, folic acid and decadron. Dose limiting toxicity (DLT) was defined as: grade (GR) 4 platelets (plts) (≤25K); GR 3 plts (25K-49,999K) with bleeding, requirement for transfusion, or lasting > 7 days; febrile neutropenia; GR3 ANC (ANC ≤1.0 × 109) with documented infection, or any ≥ GR3 non-heme toxicity. Results: 18 patients have been treated on 3 of the 4 planned dose levels. Tumor types included lung (12), prostate (2), breast (1), thymus (1), head & neck (1) and adenoid cystic carcinoma (1). Pt. characteristics: Median age 65 years; Sex M/F = 7/11; Performance Status ≤1/2 = 18/0. There have been no DLTs in either arm (Dose level 3-Arm A: PEM 500 mg/m2, BORT 1.3 mg/m2; Arm B:PEM 500 mg/m2, BORT 1.6 mg/m2). Most common GR3/4 toxicities were: neutropenia 27% and lymphopenia 11%. Of 17 evaluable patients: 1 had partial response, 11 had stable disease, 5 had progressive disease. Mean number of cycles: 4. Arm A had more doses held during the first cycle than Arm B (6 doses held vs. 1 dose held). Accrual to the final dose level in both arms is ongoing. Conclusions: 1) PEM in combination with BORT is feasible and tolerable. 2) Thus far, there are no differences in toxicity between the arms. 3) A randomized, multi-institutional phase II study will examine the efficacy of these two schedules in patients with NSCLC. No significant financial relationships to disclose.