Biologic activity and safety of temozolomide in dogs with naturally-occurring apocrine gland anal sac adenocarcinoma (AGASACA): a pilot study

Purpose and Brief Study Description:

The primary purpose of this study is to evaluate the clinical impact of temozolomide in dogs diagnosed with apocrine gland anal sac adenocarcinoma (AGASACA). Temozolomide is a chemotherapy drug used in human oncology to treat brain tumors, malignant melanoma, and more recently several different neuroendocrine tumors. Whilst AGASACA in dogs is not embryologically of neuroendocrine origin, it does share many characteristics with those tumor types, and can also respond to similar medications. The use of temozolomide in dogs has been previously reported for brain tumors, lymphoma, and malignant melanoma. Given that there is not a standard-of-care chemotherapy protocol for AGASACA, the investigators hope that temozolomide will demonstrate significant biologic activity for this tumor type, and become part of this disease’s clinical management.

All enrolled dogs will ideally receive 4 cycles (1 cycle = 5 days) of temozolomide, administered by mouth, at home, on study days 0/1 through 5, days 28 through 32, days 56 through 60, and days 84 through 88 (i.e. 1 cycle every month). Hospital visits will be scheduled immediately prior to each 5 day cycle of temozolomide, on study days 0/1, 28, 56, and 84. Appropriate chemotherapy recheck visits will also be scheduled for monitoring purposes 1 week after each 5 day cycle of temozolomide, on study days 12, 39, 67, and 95. A final study recheck will be scheduled on study day 112. Blood samples +/- urine samples, will be collected at most of these recheck visits. Re-staging imaging, including thoracic radiographs (chest x-rays) and abdominal ultrasound, will be undertaken on study days 56 and 112.


  • Dogs diagnosed with apocrine gland anal sac adenocarcinoma (AGASACA), for which surgery is not deemed a reasonable option for whatever reason, will be considered for enrollment.
  • Dogs of any breed, age, gender and weight, with satisfactory health scores will be considered for enrollment.
  • Dogs receiving additional concurrent radiation therapy and/or chemotherapy will be excluded from this study.
  • Dogs having received prior surgery, radiation therapy and/or chemotherapy will be considered for enrollment, with adherence to certain washout times.

Client Compensation:
There are some funds to support client and pet involvement in this study. These funds will not cover the initial appointment and tests required to determine study eligibility, including the initial blood work, initial urinalysis, initial thoracic radiographs (chest x-rays) and initial abdominal ultrasound. The study funds will cover the cost of the temozolomide in the form of a Veterinary Health Center credit, which could be applied to the initial visit and eligibility costs. The funds will also cover the subsequent study specified visits, on study days 12, 28, 39, 56, 67, 84, 95, and 112, including only the visit fee, blood work, urinalysis, thoracic radiographs (chest x-rays) and ultrasound. A set allowance is also allocated for potential chemotherapy side effects. Any additional hospital visits, laboratory tests, imaging, and treatments, outside of those specified by the study protocol, will not be covered.

Contact Information:
For more information, please contact Kris Richardson, Clinical Trials Coordinator:
Phone: (785) 532-3046; Email: