title: Corifollitropin alfa or rFSH treatment flexibility options for controlled ovarian stimulation: a post hoc analysis of the Engage trial.
abstract: BACKGROUND
  We sought to determine the impact of treatment flexibility on clinical outcomes in either a corifollitropin alfa or recombinant follicle-stimulating hormone (rFSH) protocol.
  
  
  METHODS
  Post hoc analysis of a prospective, multicenter, randomized, double-blind, double-dummy non-inferiority clinical trial (Engage). Efficacy outcomes were assessed on patients from the Engage trial who started treatment on menstrual cycle day 2 versus menstrual cycle day 3, patients who received rFSH step-down or fixed-dose rFSH, patients who received rFSH on the day of human chorionic gonadotropin (hCG) compared with those who did not, and patients who received hCG when the criterion was reached versus those with a 1-day delay.
  
  
  RESULTS
  The effect of each of the treatment flexibility options on ongoing pregnancy rate was not significant. The estimated difference (95% confidence interval) in ongoing pregnancy rate was -4.3% (-9.4%, 0.8%) for patients who started ovarian stimulation on cycle day 2 versus day 3, 1.8% (-4.1%, 7.6%) for patients who received hCG on the day the hCG criterion was met versus 1 day after, 3.2% (-2.1%, 8.6%) for patients who received rFSH on the day of hCG administration versus those who did not, and -5.8% (-13.0%, 1.4%) for patients who received a reduced versus fixed-dose of rFSH from day 8.
  
  
  CONCLUSIONS
  Treatment flexibility of ovarian stimulation does not substantially affect the clinical outcome in patients' treatment following initiation of ovarian stimulation with either corifollitropin alfa or with daily rFSH in a gonadotropin-releasing hormone antagonist protocol.
  
  
  BACKGROUND
  Trial was registered under ClinicalTrials.gov identifier NCT00696800.
authors.forename: Arthur
authors.initials: A
authors.lastname: Leader
authors.forename: Paul
authors.initials: P
authors.lastname: Devroey
authors.forename: Han
authors.initials: H
authors.lastname: Witjes
authors.forename: Keith
authors.initials: K
authors.lastname: Gordon
mesh_terms: D000293:Adolescent; D000328:Adult; D006063:Chorionic Gonadotropin / Q000627:therapeutic use; D004311:Double-Blind Method; D005260:Female; D005640:Follicle Stimulating Hormone / Q000627:therapeutic use*; D043373:Follicle Stimulating Hormone, Human / Q000627:therapeutic use*; D006801:Humans; D007247:Infertility, Female / Q000188:drug therapy*; D009865:Oocytes / Q000187:drug effects; D010062:Ovulation Induction / Q000379:methods*; D011446:Prospective Studies; D011994:Recombinant Proteins / Q000627:therapeutic use; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D006063:Chorionic Gonadotropin; D043373:Follicle Stimulating Hormone, Human; D011994:Recombinant Proteins; C437186:follicle stimulating hormone, human, with HCG C-terminal peptide; D005640:Follicle Stimulating Hormone