A randomized controlled trial of the effect of prednisone omission from a multidrug chemotherapy protocol on treatment outcome in dogs with peripheral nodal lymphomas

OBJECTIVE To determine the effect of prednisone omission from a multidrug chemotherapy protocol on outcome in dogs with peripheral nodal lymphomas. DESIGN Single-center, nonblinded, parallel-group, randomized, controlled trial. ANIMALS 40 client-owned dogs with a histopathologically confirmed diagnosis of peripheral nodal lymphoma and an expected survival time of > 4 weeks with treatment. PROCEDURES Treatment consisted of a combination of l-asparaginase, cyclophosphamide, doxorubicin, vincristine, and prednisone (L-CHOP) or an identical protocol except for the omission of prednisone (L-CHO). The primary outcome of interest was progression-free survival time. Veterinary caregivers and assessors of outcome were not blinded to treatment assignment. Treatment assignment was concealed from the owners of study dogs prior to enrollment, but was revealed after written informed consent was provided. RESULTS The trial was terminated early because of slow enrollment. The 40 dogs successfully enrolled in the study were randomly assigned to the L-CHOP (n = 18) or L-CHO (22) group; results for all 40 dogs were analyzed with respect to the primary outcome. Median progression-free survival time was 142.5 days for dogs receiving L-CHO and 292 days for dogs receiving L-CHOP (hazard ratio, 1.79; 95% confidence interval, 0.85 to 3.75). Serious adverse events were more common among dogs receiving L-CHO. However, this difference was not significant. CONCLUSIONS AND CLINICAL RELEVANCE The exclusion of prednisone from the L-CHOP protocol did not appear to result in improved progression-free survival time for dogs with peripheral nodal lymphomas. However, the present trial was likely underpowered to detect a clinically meaningful difference in progression-free survival time between groups.