Evaluation of mechlorethamine, vinblastine, procarbazine, and prednisone for the treatment of resistant multicentric canine lymphoma

Abstract

Multi-agent chemotherapy successfully induces remission in most naïve, high-grade canine lymphoma patients; however, disease recurrence is common. MOPP (mechlorethamine, vincristine, procarbazine, and prednisone) is an effective rescue protocol used to re-induce remission, but is associated with gastrointestinal toxicity and can be a less desirable option for patients that previously failed vincristine-containing protocols. Therefore, alternative members of the vinca alkaloid family, such as vinblastine, could be potentially advantageous as substitutes for vincristine to reduce gastrointestinal toxicity and chemoresistance. The objective of this study was to report the clinical outcomes and toxicity of 36 dogs with relapsed or refractory multicentric lymphoma treated with a modified MOPP protocol whereby vincristine was replaced with vinblastine (MVPP). The overall response rate to MVPP was 25% with a median progression free survival of 15 days and a median overall survival of 45 days. MVPP at the prescribed doses resulted in modest and transient clinical benefit, but was well tolerated with no treatment delays or hospitalizations secondary to side effects. Given the minimal toxicity, dose intensification could be considered to improve clinical responses.