title: The correlation between plasma aprepitant concentration and antiemetic effect in Japanese gastric or esophageal cancer patients.
abstract: BACKGROUND
  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.
  
  
  METHODS
  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.
  
  
  RESULTS
  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).
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Pharmacy, Toho University Omori Medical Center, 6-11-1, Omori-nishi, Ota-ku, Tokyo, 143-8541, Japan, k-nishizawa@med.toho-u.ac.jp.
authors.forename: Kosuke
authors.initials: K
authors.lastname: Nishizawa
authors.forename: Hideaki
authors.initials: H
authors.lastname: Shimada
authors.forename: Masaaki
authors.initials: M
authors.lastname: Ito
authors.forename: Yoko
authors.initials: Y
authors.lastname: Oshima
authors.forename: Satoshi
authors.initials: S
authors.lastname: Yajima
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Kikuchi
authors.forename: Yasukiyo
authors.initials: Y
authors.lastname: Sumino
authors.forename: Hironori
authors.initials: H
authors.lastname: Kaneko
authors.forename: Kenji
authors.initials: K
authors.lastname: Nishizawa
authors.forename: Masahiko
authors.initials: M
authors.lastname: Obayashi
mesh_terms: D000368:Aged; D000932:Antiemetics / Q000097:blood*; D000970:Antineoplastic Agents / Q000009:adverse effects* / Q000627:therapeutic use; D000077608:Aprepitant; D002945:Cisplatin / Q000009:adverse effects* / Q000627:therapeutic use; D016903:Drug Monitoring; D004938:Esophageal Neoplasms / Q000097:blood / Q000188:drug therapy; D005260:Female; D005770:Gastrointestinal Neoplasms / Q000097:blood / Q000188:drug therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009025:Morpholines / Q000097:blood*; D009325:Nausea / Q000097:blood / Q000139:chemically induced / Q000188:drug therapy; D013274:Stomach Neoplasms / Q000097:blood / Q000188:drug therapy; D014839:Vomiting / Q000097:blood / Q000139:chemically induced / Q000188:drug therapy*
chemical_list: D000932:Antiemetics; D000970:Antineoplastic Agents; D009025:Morpholines; D000077608:Aprepitant; D002945:Cisplatin