Toceranib
Toceranib is a pioneering veterinary-specific oral targeted therapy, classified as a small molecule tyrosine kinase inhibitor (TKI). **Key Indications:** * FDA-approved for the treatment of Patnaik grade II or III, recurrent, cutaneous **mast cell tumors (MCTs)** with or without regional lymph node involvement in dogs. **Off-label / Investigational Uses:** * May be useful for treating a variety of other tumors in dogs, including sarcomas, carcinomas, melanomas, and multiple myeloma. * Increasingly utilized as part of **metronomic chemotherapy** protocols (using low, continuous doses of anticancer agents to inhibit tumor angiogenesis and growth). **Clinical Pearls:** * Calcitriol may synergistically enhance the antiproliferative activity of toceranib in dogs with mast cell tumors. * Due to its mechanism, it can cause significant vascular dysfunction; surgical interventions require careful timing around toceranib administration.
Mecanismo: Toceranib competitively inhibits **ATP** binding at the intracellular kinase domain of several split kinase receptor tyrosine kinases (RTKs). **Key Targets:** * **VEGFR-2** (Vascular Endothelial Growth Factor Receptor-2) * **PDGFR-β** (Platelet-Derived Growth Factor Receptor-Beta) * **c-Kit** (Stem Cell Growth Factor Receptor) **Pathway:** Inhibition of RTKs → prevents receptor phosphorylation → blocks downstream signal transduction → exerts an antiproliferative effect on endothelial cells and induces cell cycle arrest and apoptosis in tumor cells. Because canine mast cell tumor growth is frequently driven by activating mutations in **c-Kit**, toceranib directly targets the neoplastic cells while simultaneously reducing tumor angiogenesis via **VEGFR-2** and **PDGFR-β** inhibition.
Dosificación por especie
- Malignancies (Off-label) · 2.5 mg/kg (range 1.5-3.25 mg/kg) · PO · Monday, Wednesday, Friday basis (or less frequently q48h) · Ongoing based on response and toxicity · Limited information available. Off-label use.
- Patnaik grade II or III, recurrent, cutaneous mast cell tumors (Label Dose) · 3.25 mg/kg PO every other day (q48h) · PO · q48h · Ongoing as tolerated · Dose reductions of 0.5 mg/kg (to a minimum dose of 2.2 mg/kg every other day) and dose interruptions for up to two weeks may be utilized to manage adverse reactions. Do not split tablets.
- Patnaik grade II or III, recurrent, cutaneous mast cell tumors (Clinical Experience Dose) · 2.5-2.75 mg/kg PO every other day · PO · q48h · Ongoing as tolerated · Often better tolerated than the label dose, resulting in less toxicity and fewer drug holidays. Alternatively, a Monday/Wednesday/Friday schedule may be used, especially when combined with other drugs in metronomic protocols.
- Mast cell tumours and other malignancies · 2.5-3.25 mg/kg · PO · q48h or on a Monday, Wednesday, Friday basis · Ongoing based on response and toxicity · Monitor closely. See Appendix for specific chemotherapy protocols.
Las dosis son una referencia clínica para médicos veterinarios. Confirme siempre con la información vigente del producto y el paciente individual.
Vías de administración
Contraindicaciones
- Breeding, pregnant, or lactating bitches
- Dogs less than 24 months of age or weighing less than 5 kg (safe use not evaluated)
- Pregnant or lactating bitches
- Dogs < 2 years old
- Dogs < 5 kg
- Patients with any signs of gastrointestinal haemorrhage
- Known hypersensitivity to toceranib
Efectos adversos
- Diarrhea (can be severe)
- Decreased or loss of appetite
- Lameness
- Weight loss
- Gastrointestinal bleeding (blood in stool, melena)
- Muscle cramping
- Neutropenia
- Hypoalbuminemia
- Thromboembolic disease (including pulmonary emboli)
- Vasculitis
- Pancreatitis
- Nasal depigmentation
- Change in coat or skin color
- Epistaxis
- Seizures
- Pruritus
- Diarrhoea
Interacciones farmacológicas
- NSAIDs (e.g., piroxicam, carprofen) · Increased risk of gastrointestinal ulceration or perforation. Use with extreme caution; never give on the same day as toceranib to avoid exacerbating GI toxicity.
- CYP3A4 Inhibitors (e.g., ketoconazole, fluconazole, itraconazole, clarithromycin, verapamil, grapefruit juice) · May theoretically increase toceranib plasma concentrations and toxicity. Use with caution.
- Corticosteroids · Increased risk of severe gastrointestinal toxicity and ulceration. · major
- NSAIDs · Increased risk of severe gastrointestinal toxicity and ulceration. · major
- Other chemotherapeutic agents · Potential for additive myelosuppression and systemic toxicity. Use with caution. · moderate
Monitoreo
- CBC (monitor for neutropenia and anemia)
- Hematocrit
- Serum Albumin
- Creatinine
- Serum Phosphate
- Urinalysis
- Full chemistry panels
- Clinical signs of GI toxicity (diarrhea, fresh blood in stool, melena)
- Tumor size and response to therapy
- Blood pressure (baseline and monthly)
- Urinalysis (baseline and monthly, monitor for proteinuria)
- Haematology (baseline and monthly)
- Biochemistry (baseline and monthly, monitor albumin and ALT)
- Coagulation profiles (if adverse signs occur)
- Faecal occult blood tests (if adverse signs occur)
- Weekly owner check-ins for the first 6 weeks to monitor for GI signs
Sobredosis
Toceranib has a **narrow margin of safety**. While specific acute toxicity data is limited, overdoses are likely to cause severe gastrointestinal distress, myelosuppression, and vascular events. > **Action:** In the event of an acute overdose, consider immediate gut decontamination (emesis/activated charcoal) if caught early. Contact an animal poison control center for further guidance and provide aggressive supportive care.
La referencia de fármacos de VetSheet está destinada a médicos veterinarios como apoyo a la decisión clínica; no sustituye el juicio profesional ni la información vigente del fabricante.