Cells (Feb 2022)

Imatinib Mesylate for the Treatment of Canine Mast Cell Tumors: Assessment of the Response and Adverse Events in Comparison with the Conventional Therapy with Vinblastine and Prednisone

  • Thais Rodrigues Macedo,
  • Genilson Fernandes de Queiroz,
  • Thaís Andrade Costa Casagrande,
  • Pâmela Almeida Alexandre,
  • Paulo Eduardo Brandão,
  • Heidge Fukumasu,
  • Samanta Rios Melo,
  • Maria Lucia Zaidan Dagli,
  • Ana Carolina B. C. Fonseca Pinto,
  • Julia Maria Matera

DOI
https://doi.org/10.3390/cells11030571
Journal volume & issue
Vol. 11, no. 3
p. 571

Abstract

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Mast cell tumors (MCTs) are common neoplasms in dogs, and treatments for these diseases include surgery, polychemotherapy and targeted therapy with tyrosine kinase inhibitors. This study aimed to evaluate the response and the adverse events of treatment with imatinib mesylate (IM) compared to conventional therapy using vinblastine and prednisolone (VP) in canine cutaneous MCTs. Twenty-four dogs were included in the study; 13 animals were treated with IM and 11 with VP. Tumor tissue samples were submitted for histological diagnosis, grading and KIT immunostaining. The response to treatment was assessed by tomographic measurements according to VCOG criteria. Adverse events were classified according to VCOG-CTCAE criteria. The IM and VP groups had dogs with similar breeds, gender, ages, MCT localization, WHO stages and lymph node metastasis profiles. Most MCTs were grade 2/low and had KIT- patterns 2 and 3. The objective response rate (ORR) was significantly higher (30.79%) in the IM group then in VP group (9.09%). Adverse events (AE) in IM group were all grade 1, significantly different from VP. In conclusion, IM presented better ORR and less severe adverse events when compared to VP, representing a suitable option for the treatment of low-grade canine MCTs.

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