Vinblastine as a second rescue for the treatment of canine multicentric lymphoma in 39 cases (2005 to 2014)

OBJECTIVES The objective of this study was to retrospectively evaluate response and outcome of dogs with multicentric lymphoma treated with single-agent vinblastine as a second rescue. METHODS Medical records from 39 client-owned dogs receiving vinblastine rescue treatment (having relapsed on or following completion of UW-Madison and CCNU/L-asparaginase protocols), between 2005 and 2014, were reviewed for information regarding clinical presentation, diagnostic testing, drug dosage, number of treatments, side effects, response and outcome. RESULTS The median starting dose of vinblastine was 2·6 mg/m2 (1·7 to 2·8 mg/m2), administered weekly until disease progression. Of the 39 dogs treated, 3 dogs (7·7%) achieved a complete remission, 7 dogs (17·9%) achieved a partial response, 18 dogs (46·2%) maintained stable disease and 11 (28·2%) had progressive disease. Ten dogs (25·6%) developed a grade III or IV neutropenia, and 4 dogs (10·3%) developed grade III or IV thrombocytopenia (one dog in both categories). After starting vinblastine, the median progression-free survival was 29·5 days (0 to 77 days) and overall median survival time was 46 days (4 to 250 days). Duration of first remission was identified as a positive predictor of outcome. CLINICAL SIGNIFICANCE Single-agent vinblastine is well tolerated in dogs with relapsed or refractory lymphoma. Responses were incomplete and short-lasting.