Neostim and Neostim Plus - Animal Immuno Solutions

Information For Veterinarians

Our intratumoural adjuvant therapy is a locally delivered immunotherapy designed to stimulate a powerful anti-cancer immune response from within the tumour itself. By injecting a small volume of a immune-activating formulation directly into the tumour, this therapy aims to convert the tumour from an immune-silent site into an immune target. The tumour tissue serves as a source of cancer antigens specific to the individual patient, while the Neostim serves as a danger signal to boost immune response.

This approach is grounded in extensive veterinary and comparative oncology research and has demonstrated meaningful clinical responses and excellent tolerability in dogs with naturally occurring cancers in research trials.

How It Works

Many tumours actively suppress local immune responses, allowing cancer cells to persist and progress. Intratumoural adjuvant therapy introduces carefully selected powerful immune stimulants directly into the tumour microenvironment, triggering innate immune activation, improved antigen presentation, and downstream adaptive anti-tumour immunity.

Importantly, treating the tumour locally can also generate durable systemic immune effects, meaning responses may extend beyond the injected lesion. In clinical trials, dogs with multicentric mast cell tumour showed immune activation in non-injected and de novo tumours.

Intratumoral CFA — Neostim can generate systemic immune responses in non injected and *de novo* tumours Immunohistochemistry for T cells and B lymphocytes in a high grade Mast Cell Tumour Pretreatment B and T cell levels are very low but increase after Neostim therapy in the primary tumour In this case the Neostim injected mass showed full durable remission A *de novo* Mast cell tumour arising four months later in the same dog showed abundant intratumoral B and T lymphocytes despite not being treated with Neostim The neck mass did not recur despite incomplete surgical resection
_{Reference Carroll CSE Andrew ER Malik L Elliott KF Brennan M Meyer J Hintze A Almonte AA Lappin C MacPherson P Schulte KM Dahlstrom JE Tamhane R Neeman T Herbert EW Orange M Yip D Allavena R Fahrer AM Simple and effective bacterial based intratumoral cancer immunotherapy J Immunother Cancer 2021 Sep99e002688 doi 101136jitc 2021 002688}

Key Features

Direct tumour targeting: immune activation begins exactly where it is needed
Non-systemic delivery: avoids many of the side effects associated with traditional chemotherapy
Rapid immune engagement: immune responses may be seen within weeks
Cost-effective and practical: designed for use in real-world general veterinary practice
Combinable: can be used alone or alongside surgery, radiation, or other immunotherapies
Safe for the patient’s family and veterinary care team: being immune based the vaccine does not produce any toxic residues or metabolites
Suitable for use in primary care practice and specialist settings.

Mast Cell Tumours Intratumoral — Neostim therapy Response of three dogs with Mast Cell tumour to intratumoral adjuvant Neostim Panel A shows the clinical findings pretreatment histopathology and post treatment histopathology after mass remission
_{Source Carroll CSE Andrew ER Malik L Elliott KF Brennan M Meyer J Hintze A Almonte AA Lappin C MacPherson P Schulte KM Dahlstrom JE Tamhane R Neeman T Herbert EW Orange M Yip D Allavena R Fahrer AM Simple and effective bacterial based intratumoral cancer immunotherapy J Immunother Cancer 2021 Sep99e002688 doi 101136jitc 2021 002688}

Which Patients May Benefit?

Intratumoural adjuvant therapy is best suited for dogs with:

Accessible solid tumours (cutaneous, subcutaneous, oral, or superficial lesions)
Cancers such as mast cell tumours, melanoma, soft tissue sarcomas, and other solid tumours
Tumours that are inoperable, recurrent, or where surgery is not immediately feasible
Owners seeking an immune-based alternative or complement to standard of care treatments

Pipi — Neostim Plus therapy dog with an oral melanoma which was metastatic to the draining lymph node The dog received Neostim Plus Gross and histologic appearance at 3 weeks and 6 weeks post treatment
_{Images courtesy of Dr Matthew Weston and Dr Rachel Allavena}

Safety And Tolerability

Clinical experience has shown this therapy to be well tolerated, with side effects typically limited to transient local inflammation consistent with immune activation. Dogs may get increased swelling in the injected tumour. Local ulceration may occur if the treatment is injected superficially. The risk of ulceration is higher in dogs with mast cell tumour, as these tumours are inherently prone to ulceration. Because the treatment is delivered directly into the tumour, systemic toxicity is minimal, making it suitable for patients who may not tolerate aggressive systemic therapies.

A Practical Immunotherapy For Today’s Veterinary Patients

Intratumoural adjuvant therapy represents a new pillar of veterinary cancer care—one that harnesses the immune system rather than relying solely on cytotoxic approaches. Designed to be accessible, combinable, and effective, it offers veterinarians a powerful new tool for managing solid tumours in dogs. It is safe for the dog, veterinary care team and the patient’s family, and can be easily administered in general practice settings.

This therapy is can only be administered under veterinary supervision, either as a standalone treatment or as part of a broader, integrated oncology plan.

Our intratumoral therapy (Neostim and Neostim Plus) is not a registered veterinary product and must therefore be used off label. Its administration is restricted to registered veterinarians, who must exercise independent clinical judgment, ensure appropriate case selection, and obtain informed owner consent in accordance with relevant state and territory veterinary legislation and professional standards. As with all off-label therapies, responsibility for safe use, monitoring, and adverse event management rests with the treating veterinarian.

Considerations For Administration

The intratumoral adjuvant injection (Neostim and Neostim Plus) is suitable for patients with superficial tumours that are directly injectable but –

can’t be removed surgically,
where there is residual disease after attempted excision,
or where the owner has declined surgery.

For example, recurrent or multicentric mast cell tumours, and tumours on limbs where amputation is declined. It is well suited to dermal and oral cancers such as mast cell tumour or melanoma, with both cancers showing complete remission with Neostim and Neostim Plus as a sole treatment in a subset of patients.

Theoretically this treatment could be applied with ultrasound guided injection for deeper cancers, however this approach has not been trialled, and should be applied with caution. Avoiding sensitive or critical tissues, such as the eye, perineural tissues or larynx, is essential as the treatment is designed to trigger inflammation and will result in swelling and a granulomatous inflammatory response.

This therapy contains a potent oil-based adjuvant (Neostim) or combination of adjuvants (Neostim Plus) which acts as a depot, providing immune stimulation at the site of the cancer for weeks. Because of its potency and depot action, only a single treatment is required and recommended. Repeat injections are likely to result in significant swelling, increased pain and inflammation and are not recommended.

Reported beneficial clinical responses include tumour remissions, tumour shrinkage, tumour growth stasis, reduced recurrence with incomplete exision, reduction in metastatic or multicentric cancer burden, and extensions in survival times. In clinical trials positive clinical benefits are seen on average in 30% of patients.

Dogs with tumours that are amenable to injection, with:

Confirmed diagnosis (biopsy or cytology) and grading/staging as appropriate to confirm a neoplastic process.
Tumours that are non-resectable or where the owner has declined surgical removal.
A predicted minimum survival of ≥12 weeks as it takes 3-5 weeks for maximum immune response to occur within the tumour.
Pets who are on any standard of care therapy, or pets where the owners have elected immunotherapy as a stand-alone therapy.
Whilst immunosuppressive therapy, like corticosteroids, may theoretically reduce the effectiveness of the immunotherapy, we have had success with patients on these drugs. Non-steroidal anti-inflammatory drugs are preferred compared to steroids when managing pain and inflammation in patients receiving immunotherapy due to reduced immunosuppression.
Best responding cancers include mast cell tumour and oral melanoma (however other solid tumours may benefit from immunotherapy).