Updated: Apr 17
In the 1890's, Dr. William Coley realized cancer cures might be possible - even for late-stage patients - if they experienced a bacterial infection.
He wasn’t the first person to notice this; other physicians in Germany had recorded similar occurrences.
But Dr. Coley was the first to create a new therapy using a mixture of weakened bacteria and began treating hundreds of patients.
The result was remarkably successful. He also shared his technique and so-called “Coley’s toxin” formulation with other doctors, many of who were actually able to cure their patients.
It wasn’t known at the time, but Coley had created a form of cancer immunotherapy – a way of fighting cancer by stimulating the patient’s immune system to kill tumor cells.
But unfortunately, due to the introduction of radiation therapy and chemotherapy, Coley’s toxin fell by the wayside. Today, Coley’s toxin is no longer available in the US or Canada. (Although there have been several attempts to revive its production, getting the regulatory approval has been impossibly hard).
The nearest thing to Coley’s toxin that is currently clinically used is called BCG (Bacillus Calmette-Guerin), to treat bladder cancer patients. For roughly 70% of patients with early stage bladder cancer, BCG treatment can effectively stop cancer recurrence.
But because BCG consists of living bovine tuberculosis bacteria, there is a finite possibility of harming the patient with an unwanted infection and also causing serious complications. BCT also tends to be poorly tolerated by some patients.
Is there a safer alternative?
Yes, there is. For both people and for pets.
Since the 1960s, researchers have been studying cell walls of bacteria that contain many different compounds that stimulate our immune system.
One of these technologies, called Mycobacterium Cell Wall Fraction (MCWF), has been developed into an anticancer immunotherapy - Immunocidin - for veterinary use.
The same technology was developed into a human bladder cancer formulation that progressed to Phase III clinical testing.
In the 1990s, Immunocidin was approved by the regulators in the US and Canada for treating mixed mammary tumors and mammary adenocarcinoma in dogs.
A small Canadian company, NovaVive Inc., produces Immunocidin, today (at a manufacturing site in Athens, GA).
If Immunocidin is licensed for treating mammary tumors, can it still help fight other cancer types?
MCWF is a strong immunostimulant, with potential to treat different cancer types, regardless of the location or origin.
(Coley’s toxin was also used to treat many types of cancer)
According to Graeme McRae, the president of NovaVive and one of the inventors of Immunocidin, the product was first tested to treat mammary tumors, even though there were indications that the formulation could be effective for other cancer types. In order to obtain regulatory approval for an anticancer therapy, the product must be tested for safety and show some efficacy in a certain tumor type.
New studies are evaluating how Immunocidin might help canine patients with osteosarcoma, bladder cancer and other tumor types (see below).
It's important to note that veterinarians are permitted to use regulator-approved therapies to treat other types of cancer (“off-label”) if they are comfortable doing so and believe it may help their patients.
What’s in Immunocidin and how does it work?
The active ingredient of Immunocidin is the purified fragments of cell walls from a soilborne bacterium called Mycobacterium phlei. This bacterium is non-pathogenic (does not cause disease) and is commonly found in the environment, including in soil and on the leaves of plants.
The cell walls naturally contain a high concentration compounds that stimulate the immune system, including muramyl dipeptides, trehalose dimycolate, mycolic acid and glycolipid lipoarabinomannan.
These compounds activate macrophages and other white blood cells, and produce cytokines such as IL-6, IL-8, IL-12, IL-18 and TNF-α that help turn on the immune system to fight disease.
The formulation also contains bacterial nucleic acids (e.g. DNA) that have anti-cancer effect, according to Miriam Cervantes DVM Ph.D., a research scientist at NovaVive.
How is it administered?
Immunocidin was initially approved as an intra-tumoral injection treatment.
Newer protocols involve administering the product by IV infusion and orally in different studies.
What kind of side-effects might there be?
Some dogs might experience mild and transient lethargy, fever, or vomiting, depending on how the product is administered and their level of sensitivity. If Immunocidin is injected into the tumor, there may be some injection site pain and there may be discharge from the tumor as it breaks down.
In what ways might Immunocidin help dogs with cancer?
-help a dog who is not a candidate for receiving surgery or other standard-of-care treatment
-help a dog who has relapsed or did not respond to a prior therapy,
-help recurrence of cancer.
What does its anti-cancer efficacy depend on?
How well it works depends on many factors, including:
-the dog’s overall health especially his or her immune system
-the tumor and tumor microenvironment
-the dosage, how it’s administered, and the frequency of administration.
-whether it is administered before the surgery as a neoadjuvant or after surgery
-whether it is combined with chemotherapy or other therapies
Researchers are trying to answer these and other questions.
Because Immunocidin is not a toxic agent like chemotherapy, it can be administered at a regular veterinary clinic (and not just at a specialty referral center that for some patients might be hours away). If the oral administration route selected, the dog can receive the therapy at home.
Another advantage is that it is relatively inexpensive compared to chemotherapy.
Are there studies enrolling patients?
In several case studies, Immunocidin has been shown to help extend survival times for dogs with osteosarcoma. In some o