Phase I dose-escalating study of raltitrexed ('Tomudex') and cisplatin in metastatic non-small cell lung cancer

The aim of this Phase I, dose-escalation study was to determine the maximum tolerated dose (MTD), recommended dose (RD), and dose-limiting toxicity (DLT) of a raltitrexed ('Tomudex') and cisplatin combination in patients with previously untreated, metastatic non-small cell lung cancer (NSCLC).

Patients received raltitrexed (15-min intravenous infusion), followed by cisplatin (1-h intravenous infusion), every 3 weeks at escalating dose levels.

In total, 21 patients entered the study. No DLT was observed up to dose level 4 (raltitrexed 3.0 mg/m(2) plus cisplatin 80 mg/m(2)), or in the first 3 patients who received dose level 5 (raltitrexed 3.5 mg/m(2) plus cisplatin 80 mg/m(2)). However, 1 patient, entered at dose level 6 (raltitrexed 4.0 mg/m(2) plus cisplatin 80 mg/m(2)) experienced severe toxicity (including grade 3 diarrhea), and no further patients were recruited at this level. Of 4 additional patients who received raltitrexed 3.5 mg/m(2) plus cisplatin 80 mg/m(2), 3 also experienced DLTs. The most common adverse events included nausea/vomiting, asthenia, diarrhea, and hematologic toxicities. Of 19 patients evaluated for response, 3 achieved a partial response, 13 had stable disease, and 3 progressed.

The MTD is raltitrexed 3.5 mg/m(2) plus cisplatin 80 mg/m(2), and the RD for future studies is raltitrexed 3.0 mg/m(2) plus cisplatin 80 mg/m(2); DLTs were diarrhea and asthenia. The combination of raltitrexed and cisplatin shows clinical activity in patients with metastatic NSCLC.