Phase II study of induction chemotherapy followed by concurrent chemoradiotherapy with raltitrexed and cisplatin in locally advanced nasopharyngeal carcinoma

Objective: For locally advanced nasopharyngeal carcinoma (LA-NPC) patients, high incidences of distant metastases and severe treatment related toxicities are the main obstacles needed to be overcome. Raltitrexed, a specific thymidylate synthase inhibitor with a convenient administration schedule, has an acceptable and manageable toxicity, and possesses radio-sensitizing properties. To investigate the efficacy and safety of raltitrexed and cisplatin induction chemotherapy and concurrent chemoradiotherapy (IC+CCRT) in patients with LA-NPC, a phase II clinical study was conducted.

Methods: Sixty eligible patients with LA-NPC were enrolled into this study. A raltitrexed-cisplatin combination was used as part of an IC+CCRT regimen. Raltitrexed-cisplatin IC was given once every 3 weeks (q3w) for two cycles, followed by raltitrexed-cisplatin based CCRT q3w for two cycles. Intensity-modulated radiotherapy (IMRT) was given for all enrolled patients.

Results: All patients were included in survival analysis according to the intent-to-treat principle. The objective response rate (ORR) 3 months after treatment was 98%. The 2-year overall survival (OS) rate was 92%. The median relapse-free survival (RFS) time was 30.5 [95% confidence interval (95% CI), 28.4-32.3] months. The 2-year RFS rate was 85%. The 2-year local failure-free survival (LFFS) rate was 97% and the 2-year distant metastasis-free survival (DMFS) rate was 88%. Acute toxicities were mostly grade 2 and 3 reactions in bone marrow suppression, gastrointestinal side effect and oropharyngeal mucositis. Only two patients occurred grade 4 acute toxicities, one was bone marrow suppression and the other was dermatitis radiation.

Conclusions: The combination of raltitrexed and cisplatin has a comparable efficacy to those in standard first-line therapy.