title: Subcutaneous 5-azacitidine treatment of naturally occurring canine urothelial carcinoma: a novel epigenetic approach to human urothelial carcinoma drug development.
abstract: OBJECTIVE
  We determined the efficacy, biological activity, pharmacokinetics and safety of the hypomethylating agent 5-azacitidine (Celgene Corp., Summit, New Jersey) in dogs with naturally occurring invasive urothelial carcinoma.
  
  
  METHODS
  We performed a preclinical phase I trial in dogs with naturally occurring invasive urothelial carcinoma to examine once daily subcutaneous administration of 5-azacitidine in 28-day cycles at doses of 0.10 to 0.30 mg/kg per day according to 2 dose schedules, including days 1 to 5 (28-day cohort) or days 1 to 5 and 15 to 19 (14-day cohort). Clinical efficacy was assessed by serial cystosonography, radiography and cystoscopy. Urinary 5-azacitidine pharmacokinetic analysis was also done. Pretreatment and posttreatment peripheral blood mononuclear cell and invasive urothelial carcinoma DNA, respectively, was analyzed for global and gene specific [CDKN2A (p14ARF)] methylation changes.
  
  
  RESULTS
  Enrolled in the study were 19 dogs with naturally occurring invasive urothelial carcinoma. In the 28-day cohort the maximum tolerated dose was 0.20 mg/kg per day with higher doses resulting in grade 3 or 4 neutropenia in 4 of 6 dogs. In the 14-day cohort the maximum tolerated dose was 0.10 mg/kg per day with grade 3 or 4 neutropenia seen in 2 of 3 dogs treated at higher doses. No grade 3 or 4 nonhematological toxicity was observed during either dosing schedule. Of 18 dogs evaluable for tumor response partial remission, stable disease and progressive disease were observed in 4 (22.2%), 9 (50.0%) and 4 (22.2%), respectively. Consistent 5-azacitidine levels (205 to 857 ng/ml) were detected in urine. Pretreatment and posttreatment methylation analysis revealed no significant correlation with clinical response.
  
  
  CONCLUSIONS
  Subcutaneous 5-azacitidine showed promising clinical activity in a canine invasive urothelial carcinoma model, thus meriting further development in humans with urothelial carcinoma.
authors.affiliation: Indiana University Melvin and Bren Simon Cancer Center, Indianapolis, Indiana 46202, USA. nhahn@iupui.edu
authors.forename: Noah M
authors.initials: NM
authors.lastname: Hahn
authors.forename: Patty L
authors.initials: PL
authors.lastname: Bonney
authors.forename: Deepika
authors.initials: D
authors.lastname: Dhawan
authors.forename: David R
authors.initials: DR
authors.lastname: Jones
authors.forename: Curtis
authors.initials: C
authors.lastname: Balch
authors.forename: Zhongmin
authors.initials: Z
authors.lastname: Guo
authors.forename: Corie
authors.initials: C
authors.lastname: Hartman-Frey
authors.forename: Fang
authors.initials: F
authors.lastname: Fang
authors.forename: Heidi G
authors.initials: HG
authors.lastname: Parker
authors.forename: Erika M
authors.initials: EM
authors.lastname: Kwon
authors.forename: Elaine A
authors.initials: EA
authors.lastname: Ostrander
authors.forename: Kenneth P
authors.initials: KP
authors.lastname: Nephew
authors.forename: Deborah W
authors.initials: DW
authors.lastname: Knapp
mesh_terms: D000818:Animals; D000964:Antimetabolites, Antineoplastic / Q000008:administration & dosage*; D001374:Azacitidine / Q000008:administration & dosage*; D002295:Carcinoma, Transitional Cell / Q000188:drug therapy* / Q000235:genetics*; D004285:Dogs; D004354:Drug Screening Assays, Antitumor; D057890:Epigenomics; D006801:Humans; D007279:Injections, Subcutaneous
chemical_list: D000964:Antimetabolites, Antineoplastic; D001374:Azacitidine
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