STELFONTA

Prepare for STELFONTA, mast cell tumor injection

MCT WAS HERE

Sammi
10 years, Pitt Bull

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Before your dog’s STELFONTA® treatment, it’s important to understand how the process works and what to expect and how to minimise side effects or adverse events.

The spot where your dog’s tumor is will likely look worse before it can get better. This is normal; and it’s part of the tumor removal and healing process. While uncommon, the wound may be extensive, requiring additional treatment and prolonged recovery times.

See how STELFONTA works
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Stelfonta spaniel

Most mast cell tumors treated with STELFONTA are fully healed within 4–6 weeks of the initial injection.  The healing process may take longer in some dogs.1,2

STELFONTA protocol: medications start 2 days before the injection

Before your dog‘s STELFONTA treatment, your veterinarian will prescribe essential oral medications to reduce the risk of mast cell degranulation. Any manipulation of a mast cell tumor can cause degranulation, releasing large amounts of chemicals and compounds like histamine that can pose a serious, potentially even fatal, risk to your dog’s health.

  • Corticosteroids are administered starting 2 days prior to the day of treatment, on treatment day, and given continuously through the 7th day post treatment (for a total of 10 days).
  • H1 and H2 receptor blocking agents are started on the day of treatment, continuing to Day 7 post-treatment (for a total of 8 days).

Experts recommend pre-emptive pain medication to keep patients comfortable.1 It is expected that the injection site may swell and bruise in the first few days, which may be painful and can be managed with analgesia prescribed by your veterinarian.

1. AAHA Pain Management Guidelines for Dogs and Cats, 2022

Reduce the risk of degranulation: commence medications 2 days before the STELFONTA injection and continue for 7 days after treatment. This is not the time to stop early – or skip doses. It is critical for your dog’s wellbeing to give these medications as prescribed. Your veterinarian may also prescribe pain medication to keep your dog comfortable in the first few days after their STELFONTA injection.

Your veterinarian will prescribe a corticosteroid, an H1 receptor blocking agent and an H2 receptor blocking agent when treating with STELFONTA to decrease the potential for severe systemic adverse reactions, including death, from mast cell degranulation

Download our helpful medication schedule to keep track of the days and times of administration
Medication schedule tracker

The day of the STELFONTA injection​

Checklist for treatment day:

  • Has my dog received the corticosteroid for the past 2 days? No meds, no treatment!
  • Have I discussed pain medication with my veterinarian? When will it commence?
  • Do I know how to contact my veterinarian if I have any concerns after the injection? What about after hours?
  • When is the re-check scheduled?

Your veterinarian will inject STELFONTA directly into the mast cell tumor.  Most dogs do not need to be sedated or put under anesthesia for this procedure.   Your veterinarian may recommend sedation if your dog is anxious or aggressive or if the tumor is located on a sensitive part of your dog’s body.

Within 4 hours of a STELFONTA treatment, the cells inside the tumor begin to break down.  At this point, you may notice the tumor area starting to change color or swell.

See STELFONTA start working within hours

Basset Hound mast cell tumor treatment

Ginger
BREED Bassett Hound
AGE  8 yrs
TUMOR 2.2cm³ cutaneous mast cell tumor on her chest

MCT before Stelfonta
pre-treatment
After Stelfonta mast cell tumor treatment
2 hours post injection

Benji
BREED Boxer
AGE  8 yrs
TUMOR 2.5cm³ cutaneous mast cell tumor on his shoulder

Stelfonta treatment
pre-treatment
2 hours after Stelfonta treatment
2 hours post injection

Learn how to care for your dog after STELFONTA treatment

Care after STELFONTA

FDA-CVM WARNING: SEVERE WOUND FORMATION IN HUMANS; EXTENSIVE WOUND FORMATION, MAST CELL DEGRANULATION, AND DEATH IN DOGS DUE TO MAST CELL DEGRANULATION

Human Safety

  • Accidental self-injection of STELFONTA® may cause severe wound formation. To decrease the risk of accidental self-injection, sedation of the dog may be necessary (see Dosage and Administration, Human Warnings and Adverse Reactions).

Dog Safety

  • Always administer a corticosteroid, an H1 receptor blocking agent (e.g. diphenhydramine), and an H2 receptor blocking agent (e.g. famotidine) when treating with STELFONTA to decrease the potential for severe systemic adverse reactions, including death, from mast cell degranulation (see Contraindications and Dosage and Administration).
  • Do not inject STELFONTA into subcutaneous mast cell tumors located above the elbow or hock (e.g. on the body, head, or neck). This may result in accumulation of necrotic debris in the subcutaneous space increasing the risk of systemic adverse reactions, including death, from mast cell degranulation (see Contraindications, Warnings and Adverse Events).
  • Treatment with STELFONTA has been associated with cellulitis and severe tissue sloughing extending away from the treated site resulting in extensive wounds that require additional treatment and prolonged recovery times (see Warnings, Precautions and Adverse Events).

IMPORTANT SAFETY INFORMATION
Formation of wounds, possibly extensive, is an intended and likely response to treatment with STELFONTA along with associated swelling, bruising and pain; these wounds are expected to heal. Appropriate pre- and post-treatment medications must be given, including a corticosteroid plus blocking agents for both H1 and H2 receptors, in order to decrease the potential for severe systemic adverse reactions, including death, from mast cell degranulation.

Full prescribing information