Mechlorethamine (
Mustargen),
Oncovin) (
vincristine),
procarbazine and
prednisone (MOPP)
chemotherapy is useful for relapsed canine
lymphoma. This study evaluates the efficacy of MOPP after substitution of
CCNU (
lomustine, LOPP protocol) or
BCNU (
carmustine,
BOPP protocol) for
mechlorethamine in 60 dogs with relapsed
lymphoma. Seven of 14 (50%) dogs treated with BOPP responded, for a median of 129.5 days for complete responders (range 9-354 days) and a median of 140 days for partial responders (range 4-276 days). Twenty-three of 44 (52%) dogs treated with LOPP responded for a median of 112 days for complete responders (range 48-250 days) and a median of 84.5 days for partial responders (range 69-290 days). Two dogs receiving a combination of LOPP and BOPP partially responded for 28 and 163 days, respectively. With BOPP
chemotherapy, nine dogs (20.5%) and seven dogs (50%) had one or more episodes of Grade II or higher
neutropenia and
thrombocytopenia, respectively. Seven dogs (50%) had one or more episodes of Grade II or higher gastrointestinal toxicity. While receiving LOPP
chemotherapy, 28 dogs (63.6%) and 17 dogs (38.6%) had one or more episodes of Grade II or higher
neutropenia and
thrombocytopenia, respectively. Seventeen dogs (38.6%) had one or more episodes of Grade II or higher gastrointestinal toxicity. Overall, there were 17 non-fatal treatment-related episodes of
sepsis requiring hospitalization. Eight dogs (13%) died or were euthanized because of treatment-related
sepsis and/or
chemotherapy-related complications. Severe haematologic toxicity, coupled with the improved response duration observed in dogs receiving reduced doses during B/L-
OPP rescue, underscores the need for protocol optimization.