Cisplatin, raltitrexed, levofolinic acid and 5-fluorouracil in locally advanced or metastatic squamous cell carcinoma of the head and neck: a phase I-II trial of the Southern Italy Cooperative Oncology Group (SICOG).

BACKGROUND

The combination of cisplatin (CDDP) and 5-fluorouracil (5-FU) can be regarded as a reference regimen in squamous cell carcinoma of the head and neck (SCCHN). Raltitrexed (Tomudex) is a direct and specific thymidilate synthase (TS) inhibitor, which has shown clinical activity against SCCHN in a previous phase I study, when combined with 5-FU and levo-folinic acid (LFA). Preclinical data support the combination of CDDP and raltitrexed. The aim of the present study was to evaluate the combination of cisplatin, raltitrexed. LFA and 5-FU in a phase I-II study.

PATIENTS AND METHODS

Patients with locally advanced or metastatic SCCHN were treated with a combination of cisplatin at the starting dose of 40 mg/m2. followed by raltitrexed at the starting dose of 2.5 mg/m2 on day 1; levo-folinic acid at fixed dose of 250 mg/m2, followed by 5-fluorouracil at the starting dose of 750 mg/m2 on day 2. Doses of the three cytotoxic agents were alternately escalated up to dose-limiting toxicity (DLT). Treatment was recycled every two weeks and given up to a maximum of eight courses; after chemotherapy, patients with locally advanced disease received a locoregional treatment.

RESULTS

Forty-five patients were entered into the study. Six dose levels were tested. At CDDP 50 mg/m2, raltitrexed 3 mg/m2, 5-FU 900 mg/m2, four out of six patients showed DLT, which was in all cases grade 4 neutropenia. Therefore, this dose level was defined as maximum tolerated dose (MTD). CDDP 60 mg/m2, raltitrexed 2.5 mg/m2, LFA 250 mg/m2, 5-FU 900 mg/m2 was the dose level recommended for phase II. CDDP, Raltitrexed and 5-FU mean actually delivered dose intensities at the selected dose level were 26, 1.05, and 378 mg/m2/week, respectively. Neutropenia was the main side effect and was observed even at the lowest dose levels. Nonhematologic side effects were mild. Nine complete responses (20%) and twenty-one partial responses (47%) were observed, for an overall response rate of 67% (95% confidence interval (95% CI): 51%-80%), according to intention to treat analysis. Fifteen of fifteen patients (100%) treated at the dose level selected for phase II had an objective response (5 complete responses, 10 partial responses).

CONCLUSIONS

The results of our dose escalation clearly demonstrate that it is possible to combine CDDP, raltitrexed, and modulated 5-FU at effective doses, without unexpected toxicities. The response data point to an impressive clinical activity, which will be better defined by an ongoing large phase II study.