Objective—To determine the response rate after administration of a single dose of doxorubicin in dogs with B-cell or T-cell multicentric or thymic lymphoma.
Design—Retrospective case series.
Animals—41 client-owned dogs with lymphoma.
Procedures—Medical records of dogs in which lymphoma was diagnosed between February 2006 and October 2008 were reviewed. Entry criteria included that dogs had a confirmed lymphoma that was immunophenotyped to be of B-cell or T-cell origin. Only dogs that received doxorubicin alone as their first chemotherapy treatment and were evaluated 1 week later were included in the study. Dogs were excluded when they had received prior treatment with corticosteroids. Medical records were reviewed to obtain signalment, stage and substage of lymphoma, and immunophenotype and to determine whether the dog had hypercalcemia at the time of diagnosis.
Results—Dogs with T-cell lymphoma had a significantly lower response rate to doxorubicin than did dogs with B-cell lymphoma. Twenty-five of 29 (86.2%) dogs with B-cell lymphoma had a complete response, compared with 2 of 12 dogs in the T-cell group that had a complete response. The overall response rate of dogs with B-cell lymphoma was 100%, compared with a response rate of 50% in dogs with T-cell lymphoma.
Conclusions and Clinical Relevance—Standard-of-care chemotherapy protocols for the treatment of dogs with lymphoma include doxorubicin. Many dogs with T-cell lymphoma did not respond to doxorubicin; therefore, multiagent protocols containing doxorubicin may not be optimal. Alternative protocols should be considered for dogs with T-cell lymphoma that do not respond to doxorubicin.
Objective—To evaluate the safety and efficacy of a vaccine containing plasmid DNA with an insert encoding human tyrosinase (ie, huTyr vaccine) as adjunctive treatment for oral malignant melanoma (MM) in dogs.
Animals—111 dogs (58 prospectively enrolled in a multicenter clinical trial and 53 historical controls) with stage II or III oral MM (modified World Health Organization staging scale, I to IV) in which locoregional disease control was achieved.
Procedures—58 dogs received an initial series of 4 injections of huTyr vaccine (102 μg of DNA/injection) administered transdermally by use of a needle-free IM vaccination device. Dogs were monitored for adverse reactions. Surviving dogs received booster injections at 6-month intervals thereafter. Survival time for vaccinates was compared with that of historical control dogs via Kaplan-Meier survival analysis for the outcome of death.
Results—Kaplan-Meier analysis of survival time until death attributable to MM was determined to be significantly improved for dogs that received the huTyr vaccine, compared with that of historical controls. However, median survival time could not be determined for vaccinates because < 50% died of MM before the end of the observation period. No systemic reactions requiring veterinary intervention were associated with vaccination. Local reactions were primarily limited to acute wheal or hematoma formation, mild signs of pain at the injection site, and postvaccination bruising.
Conclusions and Clinical Relevance—Results support the safety and efficacy of the huTyr DNA vaccine in dogs as adjunctive treatment for oral MM.
Impact for Human Medicine—Response to DNA vaccination in dogs with oral MM may be useful in development of plasmid DNA vaccination protocols for human patients with similar disease.