In this prospective clinical study, a novel immunomodulator, LDI-100, which comprises low concentrations of bacillus Calmette-Guérin (BCG) and human chorionic gonadotropin (hCG), was evaluated for safety and efficacy in dogs with naturally occurring mast cell tumors (MCTs). Ninety-five dogs with grade II or III MCT were randomly assigned to 2 groups. One group (n = 49) received IV vinblastine (2 mg/m2) once weekly for 6 weeks. The second group (n = 46) received 0.2 ml LDI-100 (containing 0.05 ml BCG [27 ng/ml] and 2 units hCG) SC once daily for 6 weeks. Dogs were rechecked at weeks 2, 4, and 6. Clinical performance scores were reassessed at each visit; complete physical examination, complete blood count, serum biochemical profile, and urinalysis were done at weeks 2 and 4. The study found no significant difference between the 2 groups with regard to host factors (sex, weight, and age) or clinical performance scores. Both treatment groups had similar tumor response rates of > 50% volume reduction (28.6% in the LDI-100 group and 11.8% in the vinblastine group). Adverse events (gastrointestinal tract signs, signs of depression, and increased rectal temperature) were not significantly different between the 2 groups. However, 11 of 49 dogs in the vinblastine group (22.4%) had at least 1 episode of neutropenia, while no dogs in the LDI-100 group had any episodes of neutropenia. It was concluded that LDI-100 provides a clinical response similar to that of vinblastine but without myelosuppression, warranting further prospective clinical studies.
COMMENTARY: Treating cancer effectively while minimizing side effects can be tricky. Thus, when treatments are developed that help achieve this goal, it is exciting news for clinicians. Biological-response modifiers, which alter the relationship between the tumor and host by modifying the host's response to tumor cells, have been studied for years. BCG has been used widely for treatment of certain cancers in horses and cattle, and hCG has been studied as an immunomodulator for treating inflammatory and neoplastic conditions in humans. Although both are FDA approved, this is the first report of the 2 compounds used in combination for cancer treatment. The results look promising, and it will be interesting to see how LDI-100 performs in combination treatment for MCT and other cancers in future clinical studies.
Evaluation of a novel immunomodulator composed of human chorionic gonadotropin and bacillus Calmette-Guérin for treatment of canine mast cell tumors in clinically affected dogs. Henry CJ, Downing S, Rosenthal RC, et al.
AM J VET RES 68:1246-1251, 2007.