The correlation between plasma aprepitant concentration and antiemetic effect in Japanese gastric or esophageal cancer patients.

Abstract

Chemotherapy-induced nausea and vomiting (CINV) are significant problems in cancer patients, but a correlation between plasma aprepitant concentration and antiemetic effect has not been reported. This study aimed to characterize the correlation between plasma aprepitant concentration and clinical antiemetic effect in a limited group of Japanese gastric or esophageal cancer patients. Thirty-three Japanese cancer patients receiving cisplatin-based chemotherapy for the first time following oral aprepitant (125 mg on day 1 and 80 mg on days 2 and 3) were enrolled. The plasma aprepitant concentrations 48 h after the first administration were determined using liquid chromatography-mass spectrometry. Patients were allocated to the high-concentration group (plasma aprepitant concentration was >331.1 ng/ml) or the low-concentration group (plasma aprepitant concentration was ≤ 331.1 ng/ml) to investigate the relationship between plasma aprepitant concentration and antiemetic effects. No significant differences were found between the two groups in terms of percentage of CINV prevention. Of 13 patients who experienced CINV [MASCC Antiemesis Tool (MAT) score >3], those in the high-concentration group showed a significant improvement in CINV following aprepitant administration (days 1-3). The present study suggests that the antiemetic effect of aprepitant is associated with plasma aprepitant concentration. A plasma aprepitant concentration of 331.1 ng/ml may be a valid threshold for identifying its optimal antiemetic effects in Japanese gastric or esophageal cancer patients.