Evaluation of a discontinuous treatment protocol (VELCAP-S) for canine lymphoma.

Eighty-two dogs with lymphoma received a single 15-week course of chemotherapy, after which treatment was ceased until relapse. Fifty-six dogs (68%) achieved complete remission for a median 1st remission duration of 20 weeks. Forty-eight dogs relapsed, of which 30 repeated the induction cycle. In 22 of these dogs, 1st remission had been short, and they received maintenance chemotherapy; the other 8 dogs received 2 or 3 cycles of induction chemotherapy. Second remission rate for these 30 dogs was 87% (26 dogs). Overall disease control for the 38 dogs that remained on protocol was 44 weeks, which was not markedly shorter than for dogs treated with a previously reported protocol in which maintenance chemotherapy was instituted in all dogs after an identical 1st induction (VELCAP-L). Dogs that were febrile and dogs that were dyspneic were less likely to achieve a complete remission to induction chemotherapy. Of dogs that achieved a complete remission, those that were thrombocytopenic at entry had a shorter 1st remission, and dogs that were anorexic at entry had shorter overall disease control. There was a correlation between 1st remission duration and length of any subsequent remission obtained. The incidence of toxicity was high, particularly after the combination of doxorubicin and vincristine. Dose reductions because of toxicity did not markedly reduce remission duration. We conclude that discontinuous chemotherapy may reduce patient visits in a small number of patients because of long-term disease control. Delaying maintenance chemotherapy until after 2nd remission is achieved does not markedly affect overall disease control.

Lomustine (CCNU) for the treatment of resistant lymphoma in dogs.

Forty-three dogs with lymphoma that had relapsed or had failed to achieve complete remission to previous chemotherapy were treated with lomustine (1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea [CCNU]) at a dosage of 90-100 mg/m2 body surface area p.o. every 3 weeks. Durable complete or partial responses occurred in 11 dogs for a median of 86 days. The acutely dose-limiting toxicosis was neutropenia 7 days after administration, resulting in a recommended dosage of 90 mg/m2. Cumulative thrombocytopenia occurred in dogs receiving continued CCNU treatment, and a dose interval of 3 weeks may be too short for continued administration of this drug. Toxicoses evident as fever or central nervous system signs or renal damage were uncommon or rare. CCNU is effective in the treatment of relapsed lymphoma.

A combination chemotherapy protocol (VELCAP-L) for dogs with lymphoma.

Ninety-eight dogs with lymphoma treated with a 5-drug combination chemotherapy regimen (vincristine, L-asparaginase, cyclophosphamide, doxorubicin, prednisone [VELCAP-L]) were evaluated for pretreatment characteristics predictive for response and remission duration. The complete remission rate was 69%, with a median remission duration of 55 weeks. Dogs with advanced stage of disease, constitutional signs, dogs that were older, and dogs that were dyspneic were less likely to achieve remission. Once in remission, small dogs and dogs without pretreatment thrombocytopenia were likely to have longer remission duration. Toxicoses were frequent, but rarely fatal, and no predictitive factors were found for a dog developing toxicoses. VELCAP-L is an effective treatment for dogs in stage I-III lymphoma, particularly in young, small animals.

A comparison of doxorubicin and COP for maintenance of remission in cats with lymphoma.

Thirty-eight cats with lymphoma were treated with vincristine, cyclophosphamide, and prednisone (COP). They were randomized at entry to receive maintenance chemotherapy consisting of either single-agent doxorubicin or continued COP therapy, starting on week 4 of treatment and continuing for 6 months or until relapse. Eighteen cats achieved complete clinical remission after COP induction chemotherapy. The median remission duration for 11 cats continuing to receive COP was 83 days, which was significantly shorter than for 7 cats that received doxorubicin (281 days). Thus, doxorubicin should be considered a well-tolerated and efficacious agent for the maintenance of remission in cats with lymphoma.

Efficacy of, and toxicoses associated with, oral idarubicin administration in cats with neoplasia.

Idarubicin, a new synthetic anthracycline analogue, was administered orally to 34 cats with spontaneous tumors. The maximum tolerated dosage was determined to be 2 mg/cat/d given for 3 consecutive days every 3 weeks. Anorexia and leukopenia were found to be dose limiting in cats receiving the drug at a higher dosage. The most common toxicoses seen at the maximum tolerated dosage were leukopenia, anorexia, and vomiting; however, development of toxicoses was not found to be associated with sex, FeLV test result, tumor type, dosage, age, or weight. Idarubicin (2 mg/cat/d for 3 days, q 3 wks) was used to treat 18 cats with lymphoma in which complete remission had been achieved by administration of other chemotherapeutic agents. Median remission duration for these cats was comparable to that reported for cats treated with other protocols. We concluded that orally administered idarubicin would be useful in the treatment of cats with lymphoma.

Evaluation of butorphanol and cyproheptadine for prevention of cisplatin-induced vomiting in dogs.

Cisplatin was administered at a dosage of 50 mg/m2 of body surface to 69 dogs with various neoplasms. Dogs were randomly assigned to receive antiemetics according to 1 of the following 5 protocols: group 1, no antiemetic (control, n = 45 treatments); group 2, 0.4 mg of butorphanol/kg of body weight (n = 52 treatments); group 3, 0.2 mg of butorphanol/kg (n = 19 treatments); group 4, 2 mg of cyproheptadine/kg (n = 48 treatments); and group 5, 1 mg of cyproheptadine/kg (n = 10 treatments). Randomization was performed for each dog prior to each treatment. Butorphanol was administered IM immediately after completion of cisplatin infusion. Cyproheptadine was given orally 12 to 14 hours before and again immediately before cisplatin administration. The proportion of dogs that vomited in group 1 was 40 of 45 (89%). Butorphanol at a dosage of 0.4 mg/kg proved highly effective in preventing cisplatin-induced vomiting, reducing the proportion of dogs that vomited (10/52, 19%) compared with the control group.

Evaluation of mitoxantrone for the treatment of lymphoma in dogs.

Mitoxantrone was administered to 74 dogs with lymphoma at a dosage of 5.0 mg/m2 of body surface, IV, every 3 weeks. Thirty-four dogs had failed to respond to prior treatment with chemotherapeutic agents, which included doxorubicin (33 dogs). The remaining 40 dogs had not received prior treatment. Complete remission was determined in 19 of 74 dogs (26%), 10 of which had not received prior treatment. The median duration of remission for these 10 dogs was 94 days (range, 49 to 440 days, with 2 dogs still alive at 370 and 440 days, respectively). Nine dogs that had received prior treatment had complete remission that lasted for a median of 126 days (range, 42 to 792 days, with 1 dog still alive at 792 days). The combined remission rate (complete remission plus partial remission) was 41%. Toxicosis was minimal, developing in only 9 dogs and requiring hospitalization of 2 dogs. We concluded that the complete remission rate ascertained when mitoxantrone was the only treatment administered was low, compared with treatments that involved other chemotherapeutic agents; however, the combined remission rate of 41% indicated that mitoxantrone may be beneficial in the treatment of lymphoma in dogs.