Conclusions
While the combination of cixutumumab and sorafenib had a toxicity profile similar to that of sorafenib monotherapy, it manifested limited clinical efficacy in unselected patients with HCC.
Methods
Eligible patients with no prior systemic therapy for advanced HCC and Child-Pugh A to B7 were treated with sorafenib 400 mg BID and escalating doses of cixutumumab (2, 4, or 6 mg/kg IV weekly) in a 3 + 3 design. Dose limiting toxicity (DLT) was defined as treatment-related grade 3 or 4 non-hematologic toxicity (except for a subset of manageable toxicities) or any grade 4 hematologic toxicities.
Purpose
The insulin-like growth factor (IGF) pathway is activated in hepatocarcinogenesis. Cixutumumab is a monoclonal antibody against human insulin-like growth factor-1 receptor (IGF-1R). Given the cross-talk between the IGF and VEGF pathways, we performed a phase I study of the combination of cixutumumab and sorafenib in hepatocellular cancer (HCC).
Results
In 21 patients enrolled, there were 3 DLTs; grade 3 hyperglycemia, grade 3 hypophosphatemia, and grade 5 peritonitis. The maximum tolerated dose of cixutumumab was 4 mg/kg IV weekly with standard dose sorafenib. Eighteen of 21 (86%) patients had grade 3 or above toxicities attributed to treatment. One patient also experienced grade 4 colonic perforation and grade 5 peritonitis. The median number of cycles completed was 4 (0-26). Of 16 patients evaluable for response, 81% achieved stable disease. The median progression free survival was 6.0 months (95% CI 3.6-undefined) and the median overall survival was 10.5 months (95% CI 7.1-undefined). Conclusions: While the combination of cixutumumab and sorafenib had a toxicity profile similar to that of sorafenib monotherapy, it manifested limited clinical efficacy in unselected patients with HCC.