IMM 308 – Clostridium difficile infection

Clostridium difficile is the most serious cause of antibiotic-associated diarrhoea (AAD) and can lead to pseudomembranous colitis, a severe infection of the colon, often resulting from eradication of the normal gut flora by antibiotics. In antibiotic-associated diarrhoea, the antibiotics commonly used to treat infection cause an imbalance in the normal healthy bacteria present in the gut allowing bacteria such as Clostridium difficile to multiply exponentially.  This is harmful because the bacterium releases toxins that can cause bloating, constipation, and diarrhoea with abdominal pain, which may become severe. Latent symptoms often mimic some flu-like symptoms. People are most often infected in hospitals and nursing homes and C. difficile infection is increasing in the outpatient setting. Relapses of C. difficile infection can range in severity from asymptomatic to severe and life-threatening, especially among the elderly.

Early intervention and aggressive management are key factors to recovery. Repeated C. difficile infection is estimated to occur in perhaps 15-30% of those infected. C. difficile infection accounts for considerable increases in the length of hospital stays and more than US$3.2 billion in health care costs each year in the United States. In Australia the cost was estimated in 1995 to around $1.25 million dollars per hospital, per year in 1995. The cost of managing C.difficile infections in hospitals is greater than the treatment needed to control Staphylococcus aureus (golden staph).

The emergence of a new, highly toxic strain of C. difficile, resistant to fluoroquinolone antibiotics and hyper virulent was identified in 2005. This is often referred to as the Quebec strain. A theory for explaining the increased virulence of this strain is that it is a hyper producer of both toxins A and B, and that certain antibiotics may actually stimulate the bacteria to hyper produce.

There is a significant need for alternative therapies that are not reliant on antibiotics to treat, prevent or stop recurrence after primary treatment. It has been demonstrated that Immuron’s product neutralizes the necrotic toxin (Toxin B) of Clostridium difficile in cell culture.

Clinical proof of principle has already been established for this method of treatment and prevention in a Phase II clinical study in the USA undertaken by ImmuCell Corporation which licensed to Immuron a patent and certain know-how related to C. difficile. This gives us confidence that our development program will be successful.

Immuron is continuing the preclinical work and has produced the proprietary vaccine used in the production of the antibodies for both the more common strain of C.difficile and the Quebec strain. Studies in animal models are underway and Immuron has approval for a Phase 2 clinical trial to commence in Israel subject to successful results in animal models.