The purpose of this study was to provide an initial assessment of the potential biologic activity of toceranib phosphate (Palladia®) in select solid tumors in dogs. Cases in which toceranib was used to treat dogs with anal sac anal gland adenocarcinoma, metastatic osteosarcoma, thyroid carcinoma, head and neck carcinoma, and nasal carcinoma were included. Clinical benefit (CB) was observed in 63/85 (74%) dogs including 28/32 anal sac tumors (8PR, 20SD), 11/23 osteosarcomas (1PR, 10SD), 12/15 thyroid carcinomas (4PR, 8SD), 7/8 head and neck carcinomas (1CR, 5PR, 1SD) and 5/7 (1CR, 4SD) nasal carcinomas. For dogs experiencing CB, the median dose of toceranib was 2.8 mg/kg, 36/63 (58.7%) were dosed on a Monday/Wednesday/Friday basis, and 47/63 (74.6%) were treated 4 months or longer. While these data povide preliminary evidence that toceranib exhibits CB in dogs with certain solid tumors, future prospective studies are necessary to define its true activity.

Combining drugs with known single-agent activity that lack overlapping dose-limiting toxicities and exert antitumor activity through different mechanisms could improve clinical outcome. As toceranib and vinblastine meet these requisites, a phase I trial was performed on the combination in dogs with mast cell tumors. The dose-limiting toxicity for the simultaneous combination was neutropenia and the maximally tolerated dose was vinblastine (1.6 mg/m2 every other week) concurrent with toceranib (3.25 mg/kg PO, every other day). This represents greater than a 50% reduction in dose-intensity for vinblastine (compared to single-agent use) and as such does not support this combination based on current drug combination paradigms. While a strict adherence to dose paradigms speaks against the combination, evidence of significant activity (71% objective response) and enhanced myelosuppression suggest additive or synergistic activity. A prospective randomized evaluation comparing this combination with standard single-agent treatments would seem prudent to interrogate this potential.

BackgroundWe hypothesized that the addition of toceranib to metronomic cyclophosphamide/piroxicam therapy would significantly improve disease-free interval (DFI) and overall survival (OS) in dogs with appendicular osteosarcoma (OSA) following amputation and carboplatin chemotherapy.Methods and FindingsThis was a randomized, prospective clinical trial in which dogs with OSA free of gross metastatic disease (n = 126) received carboplatin chemotherapy (4 doses) following amputation. On study entry, dogs were randomized to receive piroxicam/cyclophosphamide with or without toceranib (n = 63 each) after completing chemotherapy. Patient demographics were not significantly different between both groups. During or immediately following carboplatin chemotherapy, 32 dogs (n = 13 toceranib; n = 19 control) developed metastatic disease, and 13 dogs left the study due to other medical conditions or owner preference. Following carboplatin chemotherapy, 81 dogs (n = 46 toceranib; n = 35 control) received the metronomic treatment; 35 dogs (n = 20 toceranib; n = 15 control) developed metastatic disease during the maintenance therapy, and 26 dogs left the study due to other medical conditions or owner preference. Nine toceranib-treated and 11 control dogs completed the study without evidence of metastatic disease 1-year following amputation. Toceranib-treated dogs experienced more episodes of diarrhea, neutropenia and weight loss than control dogs, although these toxicities were low-grade and typically resolved with supportive care. More toceranib-treated dogs (n = 8) were removed from the study for therapy-associated adverse events compared to control dogs (n = 1). The median DFI for control and toceranib treated dogs was 215 and 233 days, respectively (p = 0.274); the median OS for control and toceranib treated dogs was 242 and 318 days, respectively (p = 0.08). The one year survival rate for control dogs was 35% compared to 38% for dogs receiving toceranib.ConclusionsThe addition of toceranib to metronomic piroxicam/cyclophosphamide therapy following amputation and carboplatin chemotherapy did not improve median DFI, OS or the 1-year survival rate in dogs with OSA.

Citrated recalcified (nonactivated) TEG demonstrated changes consistent with hypocoagulability in horses with colitis that had preidentified coagulation abnormalities. This technique has high interindividual variability and low intra-assay variability. TEG may be useful for detecting hypocoagulable states in horses with colitis and suspected coagulopathies.