Phase II study of 3-AP Triapine in patients with recurrent or metastatic head and neck squamous cell carcinoma.

Treatment options for recurrent or metastatic head and neck squamous cell carcinoma (HNSCC) are limited with response rates to cytotoxic chemotherapy of approximately 30% and median survival of 6 months. In a multicentre phase II study, 32 patients with recurrent or metastatic HNSCC received 3-AP Triapine (3-aminopyridine-2-carboxaldehyde thiosemicarbazone), an inhibitor of ribonucleotide reductase, 96 mg/m2, daily for 4 days every 14 days (one cycle). Eligibility criteria required Eastern Cooperative Oncology Group performance status (ECOG PS) of zero to two with a life expectancy of >3 months; one prior chemotherapy regimen was allowed. Thirty patients were assessable for response and toxicity. Median age was 57 years (range 36-79) and median ECOG PS was one (range 0-2). Thirteen patients had previously been treated with chemotherapy. A total of 130 cycles were administered with a median number of cycles of 3.5 (range 1-8). Mild anaemia (40%), nausea (22%) and fatigue (22%) were commonly reported with G3 and G4 neutropenia documented in 22% and 22%, respectively. Overall response rate was 5.9% (95% confidence interval 0.2% to 28.7%). One patient achieved a partial response, eight had stable disease and 21 progressive disease. Median time to disease progression was 3.9 months. 3-AP Triapine as a single agent, at this dose and schedule, is well tolerated but has only minor activity in the treatment of advanced HNSCC.