Lomustine for treatment of canine transmissible venereal tumor

ABSTRACT: Canine transmissible venereal tumor (TVTC) is a highly casuistic transmissible neoplasm in Brazil. Chemotherapy with vincristine sulfate is considered the treatment of choice, but the need for weekly applications and hematological monitoring, in addition to costs, are obstacles to owners’ adhesion to the treatment. Lomustine is an alkylating class antineoplastic agent, and because it is administered orally, it is a more practical and less costly treatment option for the owners of animals with neoplasms sensitive to the drug. This study evaluated the therapeutic efficacy of lomustine in dogs affected by TVTC. Twelve dogs with cytopathological diagnosis of natural genital TVTC were selected. The dogs were submitted to the experimental protocol with lomustine administration at doses of 70 to 85 mg/m2 orally every 21 days, totaling a maximum of two administration cycles. The animals were reevaluated every 7 days until a maximum of +49 days after the first dose of lomustine, to monitor the regression of neoplastic lesions through measurements. Among the 12 dogs submitted to the lomustine protocol, 8/12 achieved complete remission of the neoplasm and were considered cured (66.6%), 1/12 had partial response to treatment (8.33%) and 3/12 had stable disease (25%). Important adverse effects such as severe neutrophilic leukopenia were detected in 3/12 dogs (25%). The clinical study indicated that lomustine may be a treatment option for TVTC.

摘要：犬传染性生殖道肿瘤（Canine Transmissible Venereal Tumor, TVTC）在巴西属于高发传染性肿瘤。硫酸长春新碱化疗被视为该病的首选治疗方案，但每周给药与血液学监测的需求，加之治疗成本，均成为宠物主人依从治疗的阻碍因素。洛莫司汀（Lomustine）属于烷基化类抗肿瘤药物，且可口服给药，因此对于对该药物敏感的肿瘤患犬主人而言，是一种更实用且成本更低的治疗选择。本研究评估了洛莫司汀对罹患TVTC的患犬的治疗效果。本研究选取了12只经细胞病理学诊断为自然感染生殖道TVTC的患犬，受试犬按照实验方案接受洛莫司汀给药：剂量为70~85 mg/m²，口服给药，每21天一次，总给药周期最多为2个。在首次给予洛莫司汀后，每7天对受试动物进行一次复查，最长复查周期至给药后49天，通过测量肿瘤病灶以监测其消退情况。在接受洛莫司汀治疗方案的12只患犬中，8只（66.6%）实现肿瘤完全缓解并被视为治愈，1只（8.33%）出现部分治疗应答，3只（25%）病情稳定。在3只患犬（25%）中检测到严重中性粒细胞减少症（neutrophilic leukopenia）等重要不良反应。本临床研究表明，洛莫司汀可作为TVTC的潜在治疗选择。