A prospective, multi-centre, Veterinary Radiation Therapy Oncology Group study reveals potential efficacy of toceranib phosphate (Palladia) as a primary or adjuvant agent in the treatment of canine nasal carcinoma.

Radiation is the standard of care for dogs with nasal tumours. The addition of another therapy that could improve outcome without increasing toxicity is attractive. Medical therapy that could offer better outcome than maximally tolerated dose chemotherapy when radiation therapy (RT) is not possible or is declined is also attractive. This article reports the findings from a prospective, multi-centre, non-randomized, Veterinary Radiation Therapy Oncology Group clinical trial designed to evaluate whether toceranib phosphate (toceranib) has primary activity and if the addition of toceranib to RT could positively impact outcome. Owner's discretion determined enrolment in toceranib alone or toceranib + RT arm. Historical controls for radiation alone were selected from patients treated with identical RT and imaging protocols. Responses were evaluated with pre-treatment and week-16 CT scans. RT total dose of 42 Gy was completed in 10 fractions. Sixty-three dogs enrolled from 10 study sites. Overall response rates (CR + PR) were significantly improved in the toceranib + RT (79.4%) and RT alone (68.9%) arms over toceranib alone (22%) (p = .011). Clinical benefit rates (CR + PR + SD) were significantly improved in the toceranib + RT arm over the RT alone arm at 97.3% and 79.2% respectively (p = .036). Treatment with toceranib alone, toceranib + RT and RT alone resulted in median survival times of 298, 615 and 368 days respectively, but were not statistically significantly different (p = .0502). Adverse events associated with toceranib administration did not potentiate the RT side effect profile. Toceranib appears to have primary activity against nasal carcinoma.

Long-term outcome following surgical and radiation treatment of vertebral angiomatosis in a cat.

CASE DESCRIPTION A 2-year-old 5.2-kg (11.4-lb) neutered male domestic shorthair cat was referred because of a 6-week history of progressive paraparesis. CLINICAL FINDINGS Neurologic examination revealed moderate ambulatory paraparesis with marked spinal hyperesthesia at the thoracolumbar junction. The lesion was localized to the T3-L3 spinal cord segment. Clinicopathologic testing, thoracic radiography, and abdominal ultrasonography revealed no abnormalities to explain the observed clinical signs. Advanced spinal imaging with MRI revealed an extradural right-lateralized mass originating from the L2 vertebral pedicle and causing severe spinal cord compression. TREATMENT AND OUTCOME Surgical decompression was achieved by performance of a right-sided hemilaminectomy at L2. Histologic examination of biopsy samples obtained from the mass revealed an ill-defined zone of mature vascular proliferation extending through the preexisting vertebral bone, consistent with vertebral angiomatosis. After surgical recovery, adjuvant radiation therapy was initiated with a total dose of 48 Gy administered in 16 fractions of 3 Gy each over a 3-week period. Neurologic function rapidly improved to full ambulation with only minimal monoparesis of the right pelvic limb. Results of neurologic and MRI examination performed 26 months after surgery indicated no change in neurologic status or evidence of recurrence. CLINICAL RELEVANCE To the authors' knowledge, this report was the first to describe the long-term outcome for vertebral angiomatosis in a cat. Surgical decompression and radiation therapy provided an excellent outcome in this case. Vertebral angiomatosis should be considered as a differential diagnosis for any young cat with thoracolumbar myelopathy secondary to a mass associated with the vertebral pedicle.

Evaluation of 12- and 24-month survival rates after treatment with masitinib in dogs with nonresectable mast cell tumors.

OBJECTIVE: To evaluate the effectiveness of masitinib for the treatment of nonresectable mast cell tumors (MCTs) in dogs at 12 and 24 months after onset of treatment. ANIMALS: 132 dogs with nonresectable grade 2 or 3 MCTs. PROCEDURES: Dogs received masitinib (12.5 mg/kg/d, PO; n = 106) or a placebo (26). After 6 months, treatment was extended with tumor assessments at 3-month intervals until detection of disease progression. Endpoints were tumor response and overall survival rate and time. RESULTS: In dogs with nonresectable MCTs, masitinib significantly improved survival rate, compared with results for the placebo, with 59 of 95 (62.1%) and 9 of 25 (36.0%) dogs alive at 12 months and 33 of 83 (39.8%) and 3 of 20 (15.0%) dogs alive at 24 months, respectively. Median overall survival time was 617 and 322 days, respectively. Tumor control at 6 months had a high predictive value for 24-month survival, with high specificity (88%) and sensitivity (76%), whereas short-term tumor response (within 6 weeks) had a poor predictive value. Complete responses at 24 months were observed in 6 of 67 (9.0%) dogs with nonresectable MCTs treated with masitinib. CONCLUSIONS AND CLINICAL RELEVANCE: Masitinib significantly increased survival rates at 12 and 24 months in dogs with nonresectable MCTs. Control of disease at 6 months, but not best response at 6 weeks, was predictive of long-term survival in dogs treated with masitinib, which suggested that short-term response may be irrelevant for assessing clinical efficacy of tyrosine kinase inhibitors for treatment of MCTs.