A phase I dose escalation study of pemetrexed in patients with advanced head and neck squamous cell cancer (HNSCC)

Abstract

6055 Background: Despite recent advances in therapy, patients (pts) with recurrent or metastatic HNSCC continue to demonstrate a poor median survival. In these pts, early trials with pemetrexed, a novel antimetabolite that acts upon several enzymes involved in pyrimidine and purine synthesis, have demonstrated promising efficacy and tolerability. Prior studies found that the administration of oral dexamethasone with pemetrexed reduced the incidence of skin rash. Later, vitamin supplementation (B12 and folic acid), given in addition to the dexamethasone, further diminished side effects. However, no trial has yet evaluated the appropriate steroid dose and its relation to the dosing of pemetrexed, in the setting of vitamin supplementation. We conducted a phase I trial to determine the maximum tolerated dose, toxicity, and preliminary efficacy of pemetrexed when given with different schedules of, or in the absence of, dexamethasone in pts with advanced HNSCC who had been treated with at least one or more chemotherapy regimens. Methods: Eligible pts had metastatic or recurrent HNSCC, prior treatment with one or more chemotherapy regimens, ECOG PS =2, and life expectancy >3 months. A conventional algorithm-based dose escalation design was applied, with three predefined dose levels (DL) of pemetrexed (500 mg/m2, 600 mg/m2, and 700 mg/m2) within each schedule of dexamethasone (none, 20 mg IV on day 1, and 4 mg orally bid for 3 days). Results: A total of 23 pts have been enrolled; 18 pts were evaluable. Median age was 57 years (range 47–82). Median ECOG PS was 1 (range 0–2), and 75% of pts were male. Number of prior chemotherapy regimens were as follows: 1 (40%), 2 (35%), 3 (15%), and 4 (10%). Preliminary data demonstrated only 2 treatment-related adverse events that were grade 3 or greater: anemia (DL1) and pneumonia (DL 1). In all, 13 pts have received pemetrexed with less than standard recommended dexamethasone dosing (none or IV), including 7 pts who received no dexamethasone. Of the 18 evaluable pts, 1 pt had a partial response and 2 pts had stable disease. Conclusions: This represents the first study that demonstrates that steroids may not be required as premedication with pemetrexed. Due to the limited toxicity observed, trial enrollment continues with dose escalation. [Table: see text]