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This page contains information on Regressin-V for veterinary use.
The information provided typically includes the following:
  • Regressin-V Indications
  • Warnings and cautions for Regressin-V
  • Direction and dosage information for Regressin-V


This treatment applies to the following species:
Manufacturer: Bioniche Animal Health

Mycobacterium Cell Wall Fraction Immunostimulant

U.S. Vet. Lic. No.: 289

Active Ingredient(s): The mycobacteriaceae have been known for many years to have antitumor activity. REGRESSIN®-V is an emulsion of cell wall fractions which have been modified to reduce their toxic and allergic effect, but retain their antitumor activity. REGRESSIN®-V stimulates the activation of macrophages and thymic lymphocytes which kill tumor cells. REGRESSIN®-V contains procaine hydrochloride 0.2% w/v (which exhibits local analgesic properties) and green tracking dye solution 0.1% w/v (which helps indicate the infiltration of the injected tumor mass or area).

Regressin-V Indications

REGRESSIN®-V is recommended for the immunotherapy of mixed mammary tumor and mammary adenocarcinoma in dogs and equine sarcoid in horses. Although REGRESSIN®-V is administered by intratumoral injection, the response is generalized, and untreated sites frequently undergo regression. Prognosis should be guarded in advanced malignant disease with metastases, as remissions will be less frequent. Remissions cannot be guaranteed as each tumor will vary in its response.

Dosage and Administration

REGRESSIN®-V is administered only by intratumoral injection. The entire tumor and a small region of adjacent and underyling tissue must be thoroughly infiltrated using no larger than a 20 gauge needle. Injection without careful infiltration of the tumor may not be effective. It is important to mix the emulsion thoroughly and inject the tumor as quickly as possible because the emulsion may begin to separate soon after mixing. The tumor tissue may be very firm and excessive pressure on the syringe plunger may be required to infiltrate the tumor. The injection may produce pain in some animals; anesthetics or additional analgesics may be used. Dosage varies with tumor size, but 1 mL should be considered a minimum dose.

Dogs: REGRESSIN®-V proved to be effective against mixed mammary tumors and mammary adenocaricinomas in dogs, but was not effective against liposarcomas in dogs. Canine mammary tumors may be treated once, two (2) to four (4) weeks prior to surgery. Whereas surgical removal of mammary tumors produces a desireable cosmetic result, tumor-free survivals is not significantly improved. On the other hand, dogs treated with mycobacterium cell wall fractions, prior to surgery, experience significantly extended mean tumor-free survival time, and a significantly greater number of dogs survive free of tumor.4 REGRESSIN®-V is well-tolerated by aged dogs with chronic cardiovascular and renal disease. This makes immunotherapy without surgery an attractive method of treatment for those patients who are poor surgical risks. Treatment should be repeated every one (1) to three (3) weeks. Tumors that fail to respond after four (4) treatments should be considered refractory and therapy discontinued. Eighty-eight percent of dogs treated with immunotherapy only were free of tumor two (2) years later. Individual doses range from 1 to 30 mL (average about 2.5 mL). The average cumulative dose is about 10 mL.

Horses: Equine sarcoid is very responsive to immunotherapy with mycobacterium cell wall fractions.5 Large, pedunculated sarcoids should be debulked by partial excision prior to therapy. REGRESSIN®-V is safe for use in pregnant mares. Treatment should be repeated every one (1) to three (3) weeks. Tumors that fail to respond after four (4) treatments should be considered refractory and therapy discontinued. Ninety-four (94) percent of horses treated were free of tumor two (2) years later. Individual doses range from 1 to 60 mL (average about 10 mL). The average cumulative dose is about 10 mL.

Contraindication(s): Immunotherapy may not be effective in animals receiving concurrent immunosuppressive therapies. Avoid the use of corticosteroids or ACTH where possible.

Precaution(s): Store at 2-7°C in a refrigerator, but do not freeze. The emulsion separates on standing. Resuspend by shaking or rotating the vial between the hands until the emulsion has a homogeneous “milky” appearance. If necessary, REGRESSIN®-V may be heated to 65°C to facilitate suspension.

Caution(s): The inflammatory response with edema and malaise occasionally is severe after the initial treatment. Therapy should be discontinued until the reaction has subsided. This product contains procaine hydrochloride and should not be used in performance horses within 96 hours of the event.

Warning(s): Do not use in food producing animals.

Side Effects

Mild fever, drowsiness and an increased metabolic rate leading to decreased appetite may occur for one to two days following a REGRESSIN®-V injection. These are all normal responses to the release of cytokines.1,2,3 An elevated body temperature enhances the immune function by stimulating lymphocyte activity,2 and thus should not be considered an adverse side effect. Local inflammation which is sensitive to the touch occurs fairly often, but it usually is not bothersome to the patient. Necrosis with suppuration may occur in regressing tumors and clients should be informed that the tumor may drain for several weeks. Tumors may be aspirated with a sterile syringe and needle to help prevent drainage. If drainage develops, it often may be stopped by application of astringents such as silver nitrate and styptic powders.


Available upon request.

Presentation: 10 mL vials.

NAC No.: 11070051

Telephone:   706-549-4503
Order Desk:   888-549-4503
Fax:   706-548-0659
Every effort has been made to ensure the accuracy of the Regressin-V information published above. However, it remains the responsibility of the readers to familiarize themselves with the product information contained on the US product label or package insert.

Copyright © 2017 North American Compendiums. Updated: 2017-11-28