A multicenter phase II trial of paclitaxel, carboplatin, and cetuximab followed by chemoradiotherapy in patients with unresectable locally advanced squamous cell carcinoma of the head and neck

Background: Induction chemotherapy (IC) in locally advanced squamous cell carcinoma of the head and neck (LA-SCCHN) often compromises compliance with subsequent chemoradiotherapy (CRT), which negatively affects outcomes. Here, we assessed the combination of paclitaxel (PTX), carboplatin (CBDCA), and cetuximab (Cmab) as IC for unresectable LA-SCCHN. Methods: Induction chemotherapy consisted of weekly CBDCA area under the plasma concentration-time curve = 1.5, PTX 80 mg/m² and Cmab with an initial dose of 400 mg/m² followed by 250 mg/m² for 8 weeks. Following IC, CDDP (20 mg/m², 4 days × 3 cycles) and concurrent radiotherapy (70 Gy/35 fr) were started. Primary endpoint was the proportion of CRT completion (%CRT completion). PCE was planned to be deemed effective if the Bayesian posterior probability (PP), defined as the probability that %CRT completion was larger than the threshold value of 65%, exceeded 84%. Results: Thirty-five patients were enrolled. Cases were hypopharynx/oropharynx/larynx in 17/17/1 patients, all at Stage IV. Of 35 patients, 34 (97%) completed IC and 32 received CRT and met the criteria of full analysis set (FAS). In FAS, the %CRT completion was 96.9%, and PP was 99.9%, exceeding the prespecified boundary of 84%. Mean cumulative dose and relative to dose intensity of CDDP in CRT was 232.5 mg/m² and 100%, respectively. Response rate was 88.6% by IC and 93.8% in the CRT phase. Three year overall survival was 83.5%. Main grade 3 toxicities included neutropenia (11.4%) and skin rash (5.7%) during IC; and oral mucositis (31.3%) and neutropenia (12.5%) during CRT. No grade 4 toxicity or treatment-related death was seen. Conclusions: PCE as IC was feasible, with promising efficacy and no effect on compliance with subsequent CRT in unresectable LA-SCCHN.