Phase I and pharmacokinetic study of LY293111, an orally bioavailable LTB4 receptor antagonist, in patients with advanced solid tumors.

ABSTRACT

PURPOSE: LY293111, a novel diaryl ether carboxylic acid derivative, is a potent and selective inhibitor of the lipoxygenase pathway either directly through 5'-lipoxygenase or via antagonism of the leukotriene B4 (LTB4) receptor. More recently it has been determined to have peroxisome proliferator activated receptor-gamma agonist (PPARgamma) activity. LY293111 has antineoplastic activity in a variety of preclinical models. The tolerability and pharmacokinetics of LY293111 administered continuously, by mouth, BID for repeat cycles of 21 days was evaluated. PATIENTS AND METHODS: Thirty-eight patients with advanced solid tumors were treated at five dose levels (200 to 800 mg BID) for a total of 102 cycles. RESULTS: The most common toxicity was diarrhea (76%). One patient at 600 mg BID (n = 11) and two at 800 mg BID (n = 8), experienced dose-limiting grade 3 diarrhea. Dose reductions and/or delays were infrequent. Increases in steady-state maximum plasma concentration (Cmax,ss) and area under the steady-state plasma concentration time curve 0 to 12 hours (AUCtau,ss) on day 8 could be considered to be dose-proportional over the four-fold-dose range. Interpatient variability in Cmax,ss and AUCtau,ss was estimated to be 65% and 71% respectively. There was a small increase in AUC (1.37; 90% CI, 0.85 to 2.21) between single and multiple doses. Two patients with progressive chondrosarcoma and melanoma had stable disease lasting approximately 336 and 168 days, respectively. CONCLUSION: LY293111 can be administered safely by continuous oral therapy with mild toxicities. Diarrhea is dose-limiting. The recommended phase II dose will be 600 mg BID. The steady-state concentrations in humans exceed relevant levels observed in preclinical models.