Phase II study of sunitinib malate in head and neck squamous cell carcinoma.

BACKGROUND: Sunitinib is an orally administered multitargeted tyrosine kinase inhibitor of RET, VEGFR, PDGFR, and c-KIT. We conducted a phase II trial to evaluate the tolerability and efficacy of sunitinib in metastatic and/or recurrent SCCHN patients.
METHODS: Patients who had received no more than two prior chemotherapy regimens were eligible and, depending on ECOG performance status (PS), were entered into either Cohort A (PS 0-1) or Cohort B (PS 2). Sunitinib was administered in 6-week cycles at 50 mg daily for 4 weeks followed by 2 weeks off. Primary endpoint for Cohort A was objective tumor response. A Simon two-stage design required twelve patients to be enrolled in the first stage and if 1 or fewer responses were observed, further study of this cohort would be terminated due to lack of treatment efficacy. Primary endpoint of Cohort B was to determine the feasibility of sunitinib in patients with ECOG performance status 2.
RESULTS: Twenty-two patients were accrued (Cohort A - 15 patients, Cohort B - 7 patients). Median age in cohort A and B was 56 and 61 years, respectively. Grade 3 hematologic toxicities encountered were lymphopenia (18%), neutropenia (14%) and thrombocytopenia (5%). There was only one incidence of grade 4 hematologic toxicity which was thrombocytopenia. Fatigue and anorexia were the most common non-hematologic toxicities. Grade 3 fatigue occurred in 23% of patients. The only grade 4 non-hematologic toxicity was one incidence of gastrointestinal hemorrhage. Non-fatal hemorrhagic complications occurred in 8 patients: epistaxis (3 patients), pulmonary hemorrhage (2 patients), gastrointestinal hemorrhage (2 patients) and tumor hemorrhage (1 patient). Four patients were not evaluable for tumor response (Cohort A - 3patients, Cohort B - 1 pt). One partial response was observed in the entire study. Dose reduction was required in 5 patients (Cohort A - 3 patients for grd 3 fatigue, grd 3 mucositis and recurrent grd 3 neutropenia; Cohort B - 2 patients for grd 3 fatigue and grd 3 nausea). Median time to progression for cohort A and B were 8.4 and 10.5 weeks, respectively. Median overall survival for cohort A and B was 21 and 19 weeks, respectively.
CONCLUSIONS: Sunitinib had low single agent activity in SCCHN necessitating early closure of cohort A at interim analysis. Sunitinib was well tolerated in PS 2 patients. Further evaluation of single agent sunitinib in head and neck is not supported by the results of this trial.