Objective: To evaluate potential drug-drug interactions between polyethylene glycol loxenatide (PEX-168) and warfarin.
Materials and methods: This was an open-label, single-arm, two-treatment, sequential study. 16 healthy male subjects were administered warfarin (5 mg) alone on day 1 and received PEX-168 subcutaneously 200 µg once a week during days 14 - 42, with warfarin (5 mg) on day 44. Pharmacokinetics of R- and S-warfarin, as well as pharmacodynamics of warfarin, as measured by prothrombin time (PT) and international normalized ratio (INR), were assessed.
Results: The geometric mean ratios (GMRs) of area under the curve from time zero to the time of the last quantifiable concentration (AUC0-t) for PEX-168 + warfarin vs. warfarin were 0.950 (90% CI: 0.898, 1.006) for R-warfarin and 0.989 (90% CI: 0.946, 1.033) for S-warfarin. The GMRs of maximum observed plasma concentration (Cmax) values were 0.965 (90% CI: 0.893, 1.043) for R-warfarin and 0.983 (90% CI: 0.899, 1.075) for S-warfarin, both of which were contained in the interval 0.80 - 1.25. PEX-168 had no effect on the area under the effect-time curve from time 0 to 168 hours of INR and PT, as demonstrated by the GMRs of 0.987 (90% CI: 0.974, 1.000) and 0.990 (90% CI: 0.979, 1.002), respectively.
Conclusion: Concomitant administration of PEX-168 and single-dose warfarin was well tolerated. PEX-168 had no effect on the pharmacokinetics or pharmacodynamics of warfarin.