Stelfonta
Active substance
ATC code
Species
Dogs.
Indications
For the treatment of non-resectable, non-metastatic (WHO staging) mast cell tumours of the following types in dogs:
- Cutaneous mast cell tumours (located anywhere on the dog) and
- Subcutaneous mast cell tumours located at or distal to the elbow or the hock.
Tumours must be less than or equal to 8 cm3 in volume, and must be accessible to intratumoral injection.
Dose to be administered and administration route
Intratumoral use.
STELFONTA is provided as a single use vial for intratumoral (IT) injection.
The surface of the mast cell tumour (MCT) to be treated must be intact, in order to minimize the leakage of the product after IT injection.
Before administering this veterinary medicinal product, it is essential that concomitant treatments (corticosteroids, H1 and H2 receptor blocking agents) are initiated to address the risk of mast cell degranulation (see also section 5.1).
• Corticosteroid (e.g. oral prednisone or prednisolone at anti-inflammatory dose): Start medication 2 days prior to STELFONTA treatment, administered at 0.5 mg/kg orally, twice a day (PO BID) daily until 4 days post-treatment (i.e. for 7 days in total) and continue by reducing the corticosteroid dose to a single dose of 0.5 mg/kg orally, once a day (PO OID) for a further 3 days (10 days total).
• H1 receptor blocking agent (e.g. oral diphenhydramine): Start medication on the day of STELFONTA treatment and continue for a total of 8 days.
• H2 receptor blocking agent (e.g. oral famotidine): Start medication on the day of STELFONTA treatment and continue for a total of 8 days.
Administer the veterinary medicinal product as a single dose of 0.5 ml per cm3 of tumour volume, as determined on the day of dosing by the following calculations:
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STEP 1 – Calculate the tumour size: Tumour Volume (cm3) = length (cm) x width (cm) x height (cm) x 0.5 |
Confirm the Tumour Volume does not exceed 8 cm3 (Please also refer to section 5.1).
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STEP 2 – Calculate the dose: |
Confirm the dose of STELFONTA does not exceed 0.15 ml/kg body weight with a maximal volume of 4mL per dog (Please also refer to section 5.1).
The minimum dose of STELFONTA is 0.1 ml, regardless of tumour volume. If the calculated dose is <0.1 ml, administer 0.1 ml.
Appropriate hygienic measures (such as clipping of the treated area) should be performed prior to treatment.
Once the correct dose of the veterinary medicinal product has been determined, draw up the required volume into a sterile Luer lock syringe with a 23-27 gauge needle.
Caution should be used to avoid manipulation of the tumour to minimise the risk of degranulation. To inject, insert the needle into the tumour mass through a single injection site. Whilst applying even pressure on the syringe plunger, move the needle back and forth in a fanning manner to inject the veterinary medicinal product into different locations within the tumour. Care should be taken to restrict injections to the tumour mass only (no injection into the margins or beyond the periphery of the tumour).
When the total dose of the veterinary medicinal product has been administered, pause for up to 5 seconds to allow tissue dispersion before removing the needle from the tumour.
The site of application should be covered for the first 48h after treatment to prevent direct contact with the product’s residual or the leaking product. Handle the cover with gloves to avoid contact with the product. In case of severe leakage of wound debris, which may occur in the first weeks following administration of the product, the wound should be covered.
If tumour tissue remains 4 weeks after the initial treatment and the surface of the residual mass is intact, a second dose may be administered. The size of the residual tumour should be measured and the new dose calculated before the second dose is administered.
Adverse reactions
The following adverse reactions can be observed in dogs:
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Very common (>1 animal / 10 animals treated): |
Pain upon injection/Injection site pain 2, 3, Wound at injection site/Injection site reaction NOS1, 2, 3, Injection site swelling 2, 6 Lameness 2, 3, Vomiting3, Tachycardia3 |
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Common (1 to 10 animals / 100 animals treated): |
Injection site pain 2, 4, Wound at injection site/Injection site reaction NOS 1, 2, 4, Injection site infection 3, Injection site erythema 2, 3, 6, Injection site bruising 2,3, Injection site oedema 2,3, Scar contraction at injection ite/Application site scar 4, Injection site ulcer 3 Behavioural disorder NOS 3, Enlarged lymph node (localised) 5, Diarrhoea 3, Stomach ulceration 4, 6, Haemorrhagic gastritis 4, 6, Anaemia 3, Neutrophilia 3, Increased band neutrophils 3, Hypoalbuminemia3, Leucocytosis 3, Monocytosis 3, Elevated creatine kinase 3 Lameness[1], 2, 4, New neoplastic mass/Neoplasia NOS 3, Tremor 3, Cystitis 3, Tachypnoea 3, Pruritus 3, Lethargy 3,4, Anorexia 3, Decreased appetite 3, Weight loss 3, Pyrexia 3, Malaise 6 |
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Uncommon (1 to 10 animals / 1,000 animals treated): |
Injection site nodule 3, Loss of essential tissue/Digit amputation, Limb amputation, Tail amputation 4, Inappropriate Defecation 3, Haemorrhage 3, Compromised circulation/ Circulatory disorder NOS 4, Tachycardia 4, Regurgitation 3, Flatulence 3, Melaena3, Cholestasis/Cholecystitis 3, Hyperkalaemia 3, Proteinuria 3, Leucocytosis 4, Increased band neutrophils 4, Thrombocytopenia 4, Thrombocytosis 3, Elevated alanine aminotransferase (ALT) 3,4, Elevated serum alkaline phosphatase (SAP) 3, Elevated total bilirubin 3, Elevated gamma-glutamyl transferase (GGT) 3, Elevated triglyceride 3, Elevated blood urea nitrogen (BUN) 3, Somnolence, Neuropathy NOS 4, Seizure 4, Polyuria 3, Urinary incontinence 3, Cellulitis 4, Skin slough 4, Dermatitis 3, Licking 3, Macular rash 3, Pruritus 4, Anorexia 3, Abrasion 3, Decreased appetite 3, Dehydration 3, Polydipsia 3 |
NOS: not otherwise specified
1Formation of wounds is an intended reaction to treatment and is expected following the use of this veterinary medicinal product in all cases. In the pivotal field study, a maximum wound surface area was observed at 7 days after treatment for most patients, although in a small number of cases wound size increased up to 14 days post treatment. Most wounds were completely reepithelised within 28 to 42 days of treatment (with individual cases that healed by day 84. In most cases, the wound area will increase with increasing tumour size. However, this is not a reliable predictor for wound size or severity, and duration of healing. These wounds resolve by second intention healing with minimal intervention. Wound management measures may be required as deemed necessary by the responsible veterinarian. The speed of healing is related to the size of the wound.
2Very commonly and/or commonly reported local adverse events, such as pain upon injection, pain at injection site, injection site bruising/erythema/oedema, lameness in a treated limb and wound formation, are related to localised pathology. The wounds may evolve to cover significantly larger areas than the original size of the tumour.
3 Reaction of mild to moderate intensity
4 Reaction of severe intensity
5 Enlargement of the draining lymph node of mild to moderate intensity can be observed.
6 Manipulation of mast cell tumours may cause the tumour cells to degranulate. Degranulation can result in swelling and redness at and around the tumour site as well as systemic clinical signs, including stomach ulceration and bleeding and potentially life-threatening complications, including hypovolemic shock and/or a systemic inflammatory response. In order to reduce the occurrence of local and systemic adverse events related to mast cell degranulation and histamine release, all treated dogs must be provided with concomitant supportive therapies, consisting of corticosteroids and H1 and H2 receptor blocking agents, both before and after treatment.
The frequency of adverse reactions is defined using the following convention:
- very common (more than 1 in 10 animals treated displaying adverse reaction(s))
- common (more than 1 but less than 10 animals in 100 animals treated)
- uncommon (more than 1 but less than 10 animals in 1,000 animals treated)
- rare (more than 1 but less than 10 animals in 10,000 animals treated)
- very rare (less than 1 animal in 10,000 animals treated, including isolated reports).
Reporting adverse events is important. It allows continuous safety monitoring of a veterinary medicinal product. Reports should be sent, preferably via a veterinarian, to either the marketing authorisation holder or its local representative, or the national competent authority via the national reporting system. See also the last section of the package leaflet for contact details.
