Thursday, January 21, 2010

Why You Should Care About Treatment with Monoclonal Antibodies against Clostridium difficile Toxins

The New England Journal of Medicine just published an article regarding using monoclonal antibodies to treat clostridium difficile toxins (called C.diff). This is a very small study regarding a condition that most people are not familiar with. However, it is very representative of the future of medicine and findings like this have major implications for the cost and delivery of health care.

Monoclonal antibodies are engineered versions of the body's own defense system. They are usually given by injection or infusion. Currently, there are only a few that are used in clinical practice. Remicade (infliximab) is probably the best example, and treats a variety of conditions including psoriasis, arthritis and Crohn's disease. Xolair (omalizumab) is another for asthma. These drugs are not extensively used because of cost, side effects (Remicade can cause serious, life threatening illness) and convenience (Xolair injections are as frequent as allergy shots and no more effective or safer).

C.diff is an intestinal infection that people get after taking antibiotics. Your intestines have normal bacteria that help with digestion (like the Activia adds) and prevent other bacteria, like C.diff from taking over and causing problems. When taking antibiotics you not only kill the bacteria from the infection that is making you sick, you are also killing some of the bacteria that keep you healthy. The stronger the antibiotic(s) and the longer you take them, the more likely you are to get C.diff, which is why we see this in the hospital so often. C.diff is a common complication of a hospitalization, especially if a patient was on antibiotics. In addition, though older, cheaper medications can treat C. diff infections, recurrence of C. diff is not uncommon.
The study in the New England Journal studies 200 patients with a C.diff infection. Half got two monoclonal antibodies to the disease causing toxins made by the C.diff bacteria. The researchers found that the patients who got the antibodies has a much lower rate of recurrence (7% vs. 25%) and re-hospitalization (9% vs. 20%).

The reason you should care about this is because biologics are the wave of the future. Biologics are agents like monoclonal antibodies, blood products, vaccines and gene therapy; that are produced by biologic processes as opposed to chemical processes like most pills that people take today. The days of the blockbuster pills are over. Most pills are generic or will be generic soon. There are very few agents in the drug companies' pipeline. This is why so many drug companies are buying up smaller biotech companies. But more importantly, this is why pharma is so supportive of health care reform and even happy to cover the cost of seniors' medications when they fall into the "donut hole." Pharma realizes that their profits are no longer going to come from single pills that are taken daily by millions of people, but biologics that are taken by a few, really sick people. In addition to potential side effects (often way worse than pills), biologics are very, very expensive. Xolair and Remicade are both about $700 a dose. This does not cover the cost of infusion or injection, which can be quite pricey. Xolair is given every other week for a few years. In the current study, where both groups of patients were already taking the older, cheaper drugs; would it be worth say $1500 extra to reduce the rate of a recurrence by 18%? There are probably about 200,000 cases of hospital associated C.diff infections a year. That's a cost of $300 million! With the rising cost of health care, and efforts to control these costs, be on the look out for biologics.


Brad F said...

Thoughts on durable efficacy given the drug is aimed not at the bug, but at the toxin? Perhaps at 60, 90, 120 days, etc., there would be a diminution in effect in treatment arm? Attendant costs as well for readministration, etc., etc.

Perhaps of benefit in real sickies, but commentary does point out that finding the appropriate sub group is work in progress.


Unknown said...

What about people that have contracted c.Diff that have not been on antibiotics nor have they been hospitalized? I am one of those people and I am having a heck of a time getting rid of it. I have been reading that patients with c.diff should avoid OTC's such as Imodium, because it interfers with the gastric process. What about Byetta? I am a diabetic that takes Metformin and Byetta. Which we know Byetta slows the emptying process of the stomach. Wouldn't that also be considered and "interferene" of the gastric process?

Dr. Matthew Mintz said...

Community acquired C diff is pretty rare and if you are having a hard time getting rid of it, you certainly need to be seeing a physician who is an expert in this, such as an infectious disease specialist.
Immodium is not recommended for C diff and other forms of infectious diarrhea as it can prolong the course. Byetta works differently such that it should not be a problem. Metformin has GI side effects which could be made worse if you have C diff, but would not be necessarily contraindicated.