Purpose: Combining cytotoxic agents with bevacizumab has yielded significant benefits in a number of solid tumors. Combining small-molecule kinase inhibitors of VEGFR with chemotherapy has yet to demonstrate clinical benefit. The dose, schedule and agents used may be critical to the development of this combinatorial therapy.
Methods: We performed a phase I trial of sunitinib and gemcitabine in patients with advanced solid tumor malignancies based on strong preclinical rationale.
Results: Two different MTDs were determined. The schedule of gemcitabine 800 mg/m(2) on days 1, 8, 15 and sunitinib 25 mg daily was considered to be a MTD. However, omission of day 15 gemcitabine was common, and thus, a second MTD of gemcitabine of 675 mg/m(2) on days 1 and 8 with sunitinib 25 mg daily was determined to be the recommended phase II dose. Grade 4 neutropenia and thrombocytopenia occurred in 33 and 6 %, respectively. Grade 3/4 non-hematological toxicities were uncommon. Four of 33 patients had a partial response. Another 11 patients had stable disease ranging from 3 to 36 months. Thus, the recommended phase II dose of this combination is gemcitabine 675 mg/m(2) on days 1 and 8 on an every 21-day schedule along with sunitinib 25 mg continuous daily.
Conclusions: This combination is well-tolerated and has significant clinical activity.