Comparison of outcomes in feline intermediate- to large-cell lymphoma treated with CMOP (cyclophosphamide, mitoxantrone, vincristine and prednisolone) instead of CHOP (cyclophosphamide, doxorubicin, vincristine and prednisolone)

ObjectivesThis study aimed to compare the response rate, progression-free interval (PFI), survival time (ST) and adverse events in cats treated with cyclophosphamide, mitoxantrone, vincristine and prednisolone (CMOP) vs cyclophosphamide, doxorubicin, vincristine and prednisolone (CHOP) for intermediate- to large-cell feline lymphoma.MethodsMedical records of cats treated for intermediate- to large-cell lymphoma between 2015 and 2023 from three referral institutions within the larger Sydney metropolitan area were retrospectively reviewed. Cats were included if they had a confirmed diagnosis of intermediate- to large-cell lymphoma and had received either a CMOP or CHOP protocol as a first-line treatment. Statistical analysis was conducted to determine if PFI or ST differed significantly between treatment groups. A multivariate analysis was also conducted to determine whether differences in prognostic factors between the groups may have biased outcomes.ResultsA total of 123 cats were enrolled, with 41 cats in the CMOP group and 82 cats in the CHOP group. No significant differences were identified between the response rates (66% in both groups), median PFI (CMOP 69 days, CHOP 59 days) and median ST (CMOP 103 days, CHOP 80 days) of cats treated with CMOP instead of CHOP.Conclusions and relevanceCMOP is a well-tolerated and suitable substitute for CHOP for feline intermediate- to large-cell lymphoma. It is logistically easier to administer as it can be given as an intravenous bolus and carries less risk of catastrophic extravasation injuries.