title: Phase II open-label study of single-agent hydroxyurea for treatment of mast cell tumours in dogs.
abstract: This prospective study evaluated the efficacy and safety of hydroxyurea (HU) in dogs with measurable mast cell tumours (MCTs). Dogs were treated with HU at 60 mg kg(-1)per os q24h for 14 days then 30 mg kg(-1) q24h thereafter or until MCT recurrence. Forty-six dogs were enrolled. The overall response rate was 28%. Two dogs had a complete response (CR) for 256 and 448 days, respectively. Eleven dogs had a partial response for a median duration of 46 days (range, 28-189 days). Grade 2 to 4 neutropenia occurred in eight dogs and grade 4 thrombocytopenia in two. Grade 3-4 anaemia occurred in seven dogs; overall, there was a significant decrease in haematocrit after treatment with HU. The median drop in haematocrit was 10%. This study demonstrated that HU has activity in the treatment of MCTs with mild anaemia being the primary adverse event.
authors.affiliation: Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA. kmr32@cornell.edu
authors.forename: K M
authors.initials: KM
authors.lastname: Rassnick
authors.forename: R
authors.initials: R
authors.lastname: Al-Sarraf
authors.forename: D B
authors.initials: DB
authors.lastname: Bailey
authors.forename: J D
authors.initials: JD
authors.lastname: Chretin
authors.forename: B
authors.initials: B
authors.lastname: Phillips
authors.forename: C H
authors.initials: CH
authors.lastname: Zwhalen
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D004283:Dog Diseases / Q000188:drug therapy*; D004285:Dogs; D004334:Drug Administration Schedule / Q000662:veterinary; D005260:Female; D006918:Hydroxyurea / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D007958:Leukocyte Count / Q000662:veterinary; D008297:Male; D054705:Mastocytoma, Skin / Q000188:drug therapy / Q000662:veterinary*; D011446:Prospective Studies; D013921:Thrombocytopenia / Q000139:chemically induced / Q000662:veterinary; D016896:Treatment Outcome
chemical_list: D000970:Antineoplastic Agents; D006918:Hydroxyurea