LOPH: a novel chemotherapeutic protocol for feline high-grade multicentric or mediastinal lymphoma, developed in an area endemic for feline leukemia virus

Abstract

Objectives: The aim of this study was to establish the safety and efficacy of a novel multidrug lomustine-based chemotherapeutic protocol for cats with high-grade multicentric or mediastinal lymphoma, in an area endemic for feline leukemia virus (FeLV).

Methods: This prospective study included owned cats, diagnosed (cytologically) with multicentric or mediastinal lymphoma and treated with the LOPH (lomustine, vincristine [Oncovin; Antibióticos do Brasil], prednisolone and hydroxydaunorubicin [doxorubicin]) protocol. A complete blood count was performed before every chemotherapy session and any significant abnormalities recorded as possible related toxicities. Median survival time (MST) and disease-free interval were estimated by Kaplan-Meier curves.

Results: Twenty-one cats were included in this study. Nineteen (90.5%) tested positive for FeLV and were therefore considered to have persistent viremia. Complete response was reported in 81% (n = 17/21), while three had partial remission and one had no response. Seven cats finished the induction protocol within 20-31 weeks (23.1 ± 4.5; median 20) and all seven received a maintenance protocol. The MST (lymphoma-related survival) for the 21 cats was 214 days. The MST was 214 days for cats with mediastinal lymphoma (n = 13), but it was not reached for multicentric lymphoma (n = 8; P = 0.9). The MST of cats with persistent FeLV antigenemia was 171 days. Grade I anorexia and vomiting occurred in 19% of the cats (n = 4/21). Hematologic toxicity was found in 100% of the cats at some point during their treatment, but it was mostly grade I or II. Neutropenia, thrombocytopenia and anemia occurred in 16/21, 21/21 and 15/21 cats, respectively.

Conclusions and relevance: The LOPH protocol was well tolerated by cats with lymphoma and persistent FeLV viremia, and resulted in a better MST than similar studies with other protocols. Novel studies and controlled trials are necessary in order to evaluate the efficacy of different protocols according to the lymphoma subtype, anatomic form and FeLV status.

Keywords: Cancer; doxorubicin; intraperitoneal; lomustine; lymphoid neoplasia; prednisolone; vincristine.

Figure 1

Kaplan–Meier curves. (a) Survival (%) of cats with mediastinal (n = 14; median 214 days) or multicentric (n = 7; median not reached) lymphoma. (b) Disease-free-interval (%) of cats with mediastinal (n = 14; median 165 days) or multicentric (n = 7; median not reached) lymphoma. Cox–Mantel log-rank did not differ (P >0.05)