Efficacy of C/B‐OPP rescue for the treatment of relapsed canine lymphoma (1998–2004)

Introduction:  MOPP chemotherapy is useful for relapsed canine lymphoma. This study evaluates the efficacy of this protocol after substitution of CCNU (lomustine) or BiCNU (carmustine) for mechlorethamine (C/B‐OPP).
Methods:  Patient signalment, response to chemotherapy, toxicity and survival data were abstracted from medical records of dogs from receiving C/B‐OPP between 1998 and 2004.
Results:  Fifty‐eight dogs received C/B‐OPP rescue chemotherapy during the study period. The median remission duration after initial chemotherapy, consisting of CHOP‐based therapy in 91% of dogs, was 133 days (range, 10 to 932 days). Thirty‐eight of fifty‐eight dogs (66%) responded to C/B‐OPP rescue after relapse (22 CR, 16 PR), for a median of 48 days (range, 2 to 359 days). Overall, C/B‐OPP extended survival by a median of 90 days (range, 2 to 426 days). Twenty‐four dogs (41%) experienced one or more episodes of Grade II or higher gastrointestinal toxicity. Forty‐one dogs (71%) experienced one or more episodes of Grade II or higher hematologic toxicity. Twelve dogs (20%) developed regenerative anemia with diarrhea consistent with gastrointestinal hemorrhage. Treatment delays due to hematologic toxicity occurred in 37 dogs (63%). There were 16 nonfatal treatment‐related episodes of sepsis requiring hospitalization. 5 dogs died due to sepsis and/or chemotherapy‐related complications.
Conclusions:  C/B‐OPP chemotherapy has activity against relapsed canine lymphoma which is similar to that of traditional MOPP rescue therapy. Moderate to severe hematologic toxicity was observed. Further work is warranted to optimize drug doses and scheduling.