Phase I study of intermittent oral dosing of the insulin-like growth factor-1 and insulin receptors inhibitor OSI-906 in patients with advanced solid tumors.

PURPOSE: We determined the maximum tolerated dose (MTD), safety, pharmacokinetics, pharmacodynamics, and preliminary activity of OSI-906, a potent, oral, dual inhibitor of insulin-like growth factor-1 receptor (IGF1R) and insulin receptor (IR), in patients with advanced solid tumors. EXPERIMENTAL DESIGN: This was a multicenter, open-label, dose escalation phase I study evaluating three intermittent dosing schedules of once-daily OSI-906 [schedule (S) 1, days 1-3 every 14 days; S2, days 1-5 every 14 days; S3, days 1-7 every 14 days]. A fed-fasting expansion cohort was included in the study. RESULTS: Seventy-nine patients were enrolled: 62 in S1, 4 in S2, and 13 in S3. S2 was discontinued. Dose-limiting toxicity comprised grade 3-4 hyperglycemia, vomiting, fatigue, and prolonged QTc interval. The MTD and recommended phase II dose of OSI-906 was 600 mg for both S1 and S3 schedules. Other common adverse events were grade 1-2 nausea, vomiting, fatigue, and diarrhea. The pharmacokinetics of OSI-906 was dose linear, and the terminal half-life ranged between 2 and 6 hours. High-fat meals had a moderate effect on the pharmacokinetics of OSI-906. At the MTD, inhibition of IGF1R and IR was observed in peripheral blood mononuclear cells. An increase in plasma IGF1 concentrations, an indirect measure of IGF1R signaling inhibition, was seen at doses ≥ 450 mg. Two patients with adrenocortical carcinoma achieved partial responses. CONCLUSION: The MTD of 600 mg was well tolerated and associated with preliminary antitumor activity. These data support further evaluation of OSI-906 in solid tumors.

A phase I study of continuous oral dosing of OSI-906, a dual inhibitor of insulin-like growth factor-1 and insulin receptors, in patients with advanced solid tumors.

PURPOSE: OSI-906 is a potent inhibitor of insulin-like growth factor-1 receptor (IGF1R) and insulin receptor (IR). The purpose of this study was to determine the MTD, safety, pharmacokinetics, pharmacodynamics, and preliminary activity of OSI-906 in patients with advanced solid tumors. PATIENTS AND METHODS: This was a nonrandomized, open-label, phase I, dose-escalation study in patients with advanced solid tumors. The study also included a diabetic expansion cohort and a biomarker expansion cohort of patients with colorectal cancer. Patients were treated with OSI-906 by once- or twice-daily continuous dosing schedules. RESULTS: Of 95 patients enrolled in the study, 86 received at least one dose of OSI-906. Dose-limiting toxicities included QTc prolongation, grade 2 abdominal pain and nausea, hyperglycemia, and elevation of aspartate aminotransferase and alanine aminotransferase (all grade 3). The MTDs were established to be 400 mg once daily and 150 mg twice daily. The recommended phase II dose was determined as 150 mg twice daily. OSI-906 was rapidly absorbed with a half-life of 5 hours, and steady-state plasma concentrations were achieved by day 8. Pharmacodynamic effects on IGF1R and IR phosphorylation were levels observed and correlated with plasma concentrations of OSI-906. Thirty-one patients had stable disease as their best response. One patient with melanoma had a radiographic partial response and underwent resection, during which only melanocytic debris but no viable tumor tissue was identified. CONCLUSIONS: At the established MTD, OSI-906 was well tolerated and antitumor activity was observed. These results support further evaluation of OSI-906 in solid tumors.

BAY 43-9006 exhibits broad spectrum oral antitumor activity and targets the RAF/MEK/ERK pathway and receptor tyrosine kinases involved in tumor progression and angiogenesis.

The RAS/RAF signaling pathway is an important mediator of tumor cell proliferation and angiogenesis. The novel bi-aryl urea BAY 43-9006 is a potent inhibitor of Raf-1, a member of the RAF/MEK/ERK signaling pathway. Additional characterization showed that BAY 43-9006 suppresses both wild-type and V599E mutant BRAF activity in vitro. In addition, BAY 43-9006 demonstrated significant activity against several receptor tyrosine kinases involved in neovascularization and tumor progression, including vascular endothelial growth factor receptor (VEGFR)-2, VEGFR-3, platelet-derived growth factor receptor beta, Flt-3, and c-KIT. In cellular mechanistic assays, BAY 43-9006 demonstrated inhibition of the mitogen-activated protein kinase pathway in colon, pancreatic, and breast tumor cell lines expressing mutant KRAS or wild-type or mutant BRAF, whereas non-small-cell lung cancer cell lines expressing mutant KRAS were insensitive to inhibition of the mitogen-activated protein kinase pathway by BAY 43-9006. Potent inhibition of VEGFR-2, platelet-derived growth factor receptor beta, and VEGFR-3 cellular receptor autophosphorylation was also observed for BAY 43-9006. Once daily oral dosing of BAY 43-9006 demonstrated broad-spectrum antitumor activity in colon, breast, and non-small-cell lung cancer xenograft models. Immunohistochemistry demonstrated a close association between inhibition of tumor growth and inhibition of the extracellular signal-regulated kinases (ERKs) 1/2 phosphorylation in two of three xenograft models examined, consistent with inhibition of the RAF/MEK/ERK pathway in some but not all models. Additional analyses of microvessel density and microvessel area in the same tumor sections using antimurine CD31 antibodies demonstrated significant inhibition of neovascularization in all three of the xenograft models. These data demonstrate that BAY 43-9006 is a novel dual action RAF kinase and VEGFR inhibitor that targets tumor cell proliferation and tumor angiogenesis.