Piroxicam as Anti-Angiogenic Cancer Therapy

Uses/Indications: Piroxicam’s primary use is in dogs as adjunctive therapy for bladder transitional cell carcinoma. It may also be of benefit in squamous cell carcinoma, mammary adenocarcinoma, and transmissible venereal tumor (TVT). It also offers additional benefit as an NSAID reducing pain and inflammation.

Anti-angiogenic therapy which is designed to cut off blood supply to a tumor may prevent a cancer from progressing. Unlike chemotherapy, anti-angiogenic treatments are well-tolerated, have few side effects, and may control the cancer over the course of an animal’s lifetime.

Studies:

1. Knapp et al. first reported the use of piroxicam for transitional cell carcinoma (TCC) of the bladder in dogs.
2. Schmidt et al .studied 17 dogs with measurable oral squamous cell carcinoma which were treated with piroxicam at a dosage of 0.3mg/kg of body weight PO every 24 hours until progressive disease or unacceptable signs of toxicosis developed or the dog died. One dog had complete remission (maxilarry tumor), and 2 dogs had partial remissions (lingual tumor and tonsillar tumor). An additional 5 dogs had stable disease, including 1 with maxillary tumor, 2 with mandibular tumors, and 2 with tonsillar tumors. One dog had a mild adverse GI tract effects that resolved with misoprostol treatment. Response rate was similar to that reported for cytotoxic treatments.

Adverse Effects:  **Very Narrow Therapeutic Window**

Canines: Potential for causing significant GI ulceration and bleeding, CNS effects: headache, dizziness, tinnitus, pruritus and rash, peripheral edema, renal papillary necrosis

Dosing:  Dogs: 0.3mg/kg PO Daily or every other day, given with food

**Oil Suspension stable up to 180 days**

Contraindication/Warnings:

1. Patients who are hypersensitive or are severely allergic to aspirin/NSAIDS
2. Use only when potential benefits outweigh the risks in patients with active or history of GI ulcer disease or bleeding disorders
3. Use with caution in animals with severely compromised cardiac function

Monitoring Parameters:

1. Adverse effects (particularly GI bleeding)
2. Liver function and renal function tests (BUN and creatinine) should be monitored occasionally with chronic use