title: A double-blind, randomized, multiple-dose, parallel-group study to characterize the occurrence of diarrhea following two different dosing regimens of neratinib, an irreversible pan-ErbB receptor tyrosine kinase inhibitor.
abstract: OBJECTIVE
  Neratinib, a potent, low-molecular-weight, orally administered, irreversible, pan-ErbB receptor tyrosine kinase inhibitor has antitumor activity in ErbB2 + breast cancer. The objective of this study was to characterize the onset, severity, and duration of diarrhea after administration of neratinib 240 mg once daily (QD) and 120 mg twice daily (BID) for ≤14 days in healthy subjects.
  
  
  METHODS
  A randomized, double-blind, parallel-group, inpatient study was conducted in 50 subjects given oral neratinib either 240 mg QD or 120 mg BID with food for ≤14 days. The primary endpoint was the proportion of subjects with diarrhea of at least moderate severity (grade 2; 5-7 loose stools/day). In subjects with grade 2 diarrhea, fecal analytes were determined. Pharmacokinetic profiles were characterized for neratinib on Days 1 and 7.
  
  
  RESULTS
  No severe (grade 3) diarrhea was reported. By Day 4, all subjects had grade 1 diarrhea. Grade 2 diarrhea occurred in 11/22 evaluable subjects (50 % [90 % confidence interval (CI): 28-72 %]) in the QD group and 17/23 evaluable subjects (74 % [90 % CI: 52-90 %]) in the BID group (P = 0.130). In fecal analyses, 18 % tested positive for hemoglobin and 46 % revealed fecal lactoferrin. Specimen pH was neutral to slightly alkaline. In pharmacokinetic analyses, Day 1 peak plasma concentration and Day 7 steady-state exposure were higher with the QD regimen than the BID regimen. In an exploratory analysis, ABCG2 genotype showed no correlation with severity or onset of diarrhea.
  
  
  CONCLUSIONS
  Incidences and onsets of at least grade 1 and at least grade 2 diarrhea were not improved on BID dosing compared with QD dosing.
authors.affiliation: Pfizer Inc, 500 Arcola Road, Collegeville, PA 19426, USA. Richat.Abbas-Borhan@pfizer.com
authors.forename: Richat
authors.initials: R
authors.lastname: Abbas
authors.forename: Bruce A
authors.initials: BA
authors.lastname: Hug
authors.forename: Cathie
authors.initials: C
authors.lastname: Leister
authors.forename: Daryl
authors.initials: D
authors.lastname: Sonnichsen
mesh_terms: D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters / Q000235:genetics; D000284:Administration, Oral; D019540:Area Under Curve; D003967:Diarrhea / Q000139:chemically induced* / Q000235:genetics / Q000473:pathology; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005243:Feces / Q000737:chemistry; D005838:Genotype; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007781:Lactoferrin / Q000032:analysis; D008657:Metabolic Clearance Rate; D009363:Neoplasm Proteins / Q000235:genetics; D011804:Quinolines / Q000008:administration & dosage / Q000009:adverse effects* / Q000493:pharmacokinetics; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000037:antagonists & inhibitors*; D012720:Severity of Illness Index; D013997:Time Factors
chemical_list: D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters; D007781:Lactoferrin; D009363:Neoplasm Proteins; D011804:Quinolines; D018719:Erb-b2 Receptor Tyrosine Kinases; C116614:ABCG2 protein, human; C487932:neratinib