title: Efficacy of vinblastine for treatment of canine mast cell tumors.
abstract: BACKGROUND
  The optimal dosage and clinical efficacy of vinblastine (VBL) for treatment of mast cell tumors (MCTs) in dogs has not been established.
  
  
  OBJECTIVE
  Single-agent VBL has antitumor activity against MCTs in dogs.
  
  
  METHODS
  Fifty-one dogs with nonresectable grade II or III cutaneous MCTs.
  
  
  METHODS
  Prospective, open clinical trial. Dogs were systematically allocated (by hospital record number) to receive IV treatment with VBL at a dosage of 2.0 mg/m2 (weekly for 4 treatments then biweekly for 4 treatments; VBL 2.0) or treatment with VBL at a dosage of 3.5 mg/m2 (biweekly for 5 treatments; VBL 3.5). The primary outcome measure was reduction in tumor size.
  
  
  RESULTS
  Twenty-five dogs were allocated to the VBL 2.0 group and 26 were allocated to the VBL 3.5 group. In the VBL 2.0 group, 3 (12%) had a partial response (PR) for a median of 77 days (range, 48-229 days). Overall response rate in the VBL 3.5 group was 27%. One dog (4%) had a complete response for 63 days and 6 dogs (23%) had a PR for a median of 28 days (range, 28-78 days). Toxicoses were uncommon in the VBL 2.0 group. Twelve (46%) dogs in the VBL 3.5 group had < 500 neutrophils/microL 7 days after treatment; 2 dogs with neutropenia developed concurrent fevers.
  
  
  CONCLUSIONS
  VBL, when used as a single-agent, has activity against MCTs in dogs although the response rate is lower than those reported for VBL-containing combination protocols. Further, findings suggest VBL at a dosage of 3.5 mg/m2 should be considered for use in future phase II/III trials.
authors.affiliation: Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA. kmr32@cornell.edu
authors.forename: K M
authors.initials: KM
authors.lastname: Rassnick
authors.forename: D B
authors.initials: DB
authors.lastname: Bailey
authors.forename: A B
authors.initials: AB
authors.lastname: Flory
authors.forename: C E
authors.initials: CE
authors.lastname: Balkman
authors.forename: M A
authors.initials: MA
authors.lastname: Kiselow
authors.forename: J L
authors.initials: JL
authors.lastname: Intile
authors.forename: K
authors.initials: K
authors.lastname: Autio
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D004283:Dog Diseases / Q000188:drug therapy*; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D005260:Female; D008297:Male; D008415:Mastocytosis / Q000188:drug therapy*; D014747:Vinblastine / Q000008:administration & dosage / Q000627:therapeutic use*
chemical_list: D000970:Antineoplastic Agents; D014747:Vinblastine