title: Targeting of rifamycin SV to the colon for treatment of travelers' diarrhea: a randomized, double-blind, placebo-controlled phase 3 study.
abstract: BACKGROUND
  Rifamycin SV is under development for treatment of travelers' diarrhea (TD) in a new oral formulation, Rifamycin SV MMX (RIF-MMX; Santarus Inc., San Diego, CA, USA), which targets its delivery to the colon, making it a unique rifamycin drug.
  
  
  METHODS
  This was a randomized, double-blind, phase 3 study of adult travelers to Mexico or Guatemala experiencing acute diarrhea. A total of 264 patients received RIF-MMX (2 × 200 mg twice daily for 3 days, n = 199) or placebo (n = 65) in a 3 : 1 ratio. The primary endpoint was the length of time between the administration of first dose of study drug and passage of the last unformed stool (TLUS; after which clinical cure was declared). Other endpoints included eradication of pathogens from the stools, pathogen minimum inhibitory concentration (MIC), and adverse events (AEs).
  
  
  RESULTS
  TLUS was significantly shorter in the RIF-MMX group (median: 46.0 hours) compared with placebo (median: 68.0 hours; p = 0.0008) and a larger percentage of RIF-MMX treated patients (81.4%) achieved clinical cure compared with placebo patients (56.9%). TLUS was significantly shorter in the subgroups of patients with enteroaggregative, enterotoxigenic, or diffusely adherent Escherichia coli infections (p = 0.0035) with nonsignificant activity against invasive bacteria (p = 0.3804). Overall pathogen eradication rates were numerically higher in the RIF-MMX group (67.0%) compared with placebo (54.8%) but the difference did not reach significance (p = 0.0836). In vitro resistance to rifamycin SV was observed in some bacteria remaining after treatment of patients with RIF-MMX but was not associated with lower efficacy in them. AEs appeared to be more frequent with placebo (38.5%) than with RIF-MMX (29.6%).
  
  
  CONCLUSIONS
  RIF-MMX shortened the duration of TD in patients with a broad range of pathogens and was well tolerated. The unique pharmacokinetic properties of the drug offer evidence that TD pathogens work at the level of the colon.
authors.affiliation: Center for Infectious Diseases, University of Texas School of Public Health, Houston, TX, USA.
authors.forename: Herbert L
authors.initials: HL
authors.lastname: DuPont
authors.forename: AnnKatrin
authors.initials: A
authors.lastname: Petersen
authors.forename: Jeff
authors.initials: J
authors.lastname: Zhao
authors.forename: Arley
authors.initials: A
authors.lastname: Mundt
authors.forename: Zhi-Dong
authors.initials: ZD
authors.lastname: Jiang
authors.forename: Stephan
authors.initials: S
authors.lastname: Miller
authors.forename: Jose
authors.initials: J
authors.lastname: Flores
authors.forename: Reshma
authors.initials: R
authors.lastname: Shringarpure
authors.forename: Luigi
authors.initials: L
authors.lastname: Moro
authors.forename: Robert G
authors.initials: RG
authors.lastname: Bagin
authors.forename: E David
authors.initials: ED
authors.lastname: Ballard
authors.forename: Mark C
authors.initials: MC
authors.lastname: Totoritis
mesh_terms: D000284:Administration, Oral; D000328:Adult; D003967:Diarrhea / Q000188:drug therapy* / Q000382:microbiology / Q000517:prevention & control; D004311:Double-Blind Method; D004926:Escherichia coli / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000188:drug therapy* / Q000517:prevention & control; D005260:Female; D005765:Gastrointestinal Agents / Q000008:administration & dosage*; D006166:Guatemala; D006801:Humans; D008297:Male; D008800:Mexico; D012294:Rifamycins / Q000008:administration & dosage*; D000078262:Rifaximin; D014195:Travel; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D005765:Gastrointestinal Agents; D012294:Rifamycins; D000078262:Rifaximin