Clinical impact of pharmacokinetically-guided dose adaptation of 5-fluorouracil: results from a multicentric randomized trial in patients with locally advanced head and neck carcinomas.

A significant link between 5-fluorouracil (5FU) plasma concentration and its therapeutic activity has been demonstrated in colon and head and neck cancer patients for 5FU used as a continuous infusion. Dose adjustment based on pharmacokinetic follow-up has been proposed to decrease hematological and digestive toxicities, but the clinical impact of this approach has not yet been demonstrated. A randomized multicentric study was conducted to evaluate the clinical interest of 5FU dose adaptation guided by pharmacokinetics. One hundred twenty-two head and neck cancer patients were randomly assigned to receive induction chemotherapy with cisplatin (100 mg/m2, day 1) and 5FU (96-h continuous infusion), either at standard dose (St-arm; 4 g/m2) or at a dose adjusted according to the 5FU area under the curve (AUC0-48h; PK-arm). In total, 106 patients were evaluable for toxicity and response. In the PK-arm (n = 49), 5FU doses and area under the curve were significantly reduced during cycle 2 and cycle 3 (P