Phase I evaluation of telatinib, a VEGF receptor tyrosine kinase inhibitor, in combination with bevacizumab in subjects with advanced solid tumors.

BACKGROUND

Blocking both receptor and ligand of the vascular endothelial growth factor (receptor) VEGF(R) pathway might be feasible and increase antitumor activity. This phase I study investigated telatinib, an oral tyrosine kinase inhibitor targeting VEGFR-2, combined with bevacizumab, in adults with solid tumors.

METHODS

Twenty-six patients were treated in successive cohorts with telatinib (twice-daily continuously, 450-900 mg) or bevacizumab (bi-weekly, starting dose 5 mg/kg). Safety, pharmacokinetics, endothelial (progenitor) cell (E(P)C)/growth factor kinetics and efficacy were assessed.

RESULTS

Most frequent adverse events were pain, nausea, voice changes and fatigue. Five dose-limiting toxicities (DLTs) occurred: hypertension (cohort I and II), bowel perforation, lipase increase and atrial flutter (cohort III). Cumulative toxicity resulted in a bevacizumab dose reduction to 1 mg/kg (cohort III). Due to three DLTs (n = 14), this cohort represented the best-tolerated dose level. Bevacizumab effectively neutralized plasma VEGF even at 1 mg/kg. Twelve patients had stable disease (clinical benefit 46%). EPC and SDF-1α levels increased during monotherapy telatinib.

CONCLUSIONS

Telatinib (450 mg b.i.d.) combined with bevacizumab (1 mg/kg bi-weekly) shows antitumor activity, but accumulating constitutional toxicity impedes long-term treatment of patients. Therefore, this combination will not be pursued in a phase II setting.