As promised, we’re going to talk today about a relatively new type of treatment for IBD: Biologic Therapies. What are they? How are they used? Why are they so exciting?
Biologic therapies are unique in that, rather than being synthetically derived like most drugs, they are genetically modified medications derived from organisms and/or their products (such as genes, proteins, antibodies, etc). Until the advent of these biologics, the only medications available are ones, as previously discussed, that have significant effects on the patient’s entire body. But biologics offer the opportunity to very specifically target treatment, so as to limit side effects. The role of biologics in the treatment of autoimmune disorders is to block the production of cytokines, a specialized protein molecule used by the immune system to control inflammation. More cytokines means more inflammation. There are different types of cytokines. Most biologics target the production of TNF-alpha, or Tumor Necrosis Factor Alpha. There are 3 of these:
- Infliximab (Remicade®)
- Adalimumab (Humira®)
- Certolizumab pegol (Cimzia®)
All three of these medications are genetically engineered monoclonal antibodies that suppress the production of TNF-alpha.
Remicade is the most popular choice right now. It’s a chimeric antibody, meaning that it’s derived from more than one species. Remicade is a fusion of human and mouse proteins (75% and 25%, respectively). It was the first FDA-approved biologic therapy for Crohn’s disease and ulcerative colitis. It’s administered by IV drip infusion, and has proven very effective in achieving and maintaining remission in many patients. Some patients have developed hypersensitivity to the drug over time, and are no longer able to tolerate it. Other patients can develop resistance or non-response to Remicade, as their immune system begins to develop other antibodies against it.
Humira is also a synthetic antibody that blocks production of TNF-alpha, but it is composed of all human proteins. It is administered by injection. It is effective in treating moderate to severe Crohn’s disease cases that have not responded well to other treatments and who have lost response to, or become hypersensitive to Remicaid.
Certolizumab pegol, or Cimzia, is a relative newcomer. It is the only anti-TNF medication that includes both an antibody as well as a special chemical, polyethylene glycol, which postpones the excretion of the drug, allowing it to stay in the patient’s system longer.
Anti-TNF-alpha medications are not the only type of biologic drug available. Recent advances have brought the development of Natalizumab, or Tysabri®. Tysabri is a synthetic human antibody, and is an integrin receptor antagonist. Rather than blocking the production of TNF-alpha, Tysabri works by binding to and inhibiting the function of certain types of white blood cells thought to be involved in inflammation. It is administered by IV infusion to patients who have not responded well to anti-TNF therapies.
And that’s not all! Other biologic therapies are under active development and research right now. Much effort is being poured into developing new ways of selectively and specifically disabling or enabling certain functions within the immune system, and it will be exciting to watch over the next decade as new research comes to fruition.
Possible side effects with these therapies are relatively rare, but include reaction at the IV site, upper respiratory infection, headaches, nausea and rash. Some patients have experienced anaphylactic allergic reactions, and patients who carry latent tuberculosis can sometimes experience worsening or newly active infection. Both of these very serious side effects can be easily treated with other medications. Also, patients who have a history of infliximab use tend to show a greater probability of developing multiple sclerosis and/or lymphoma.
Overall, I’m pretty encouraged by the success seen by the use of these drugs. I think it’s pretty miraculous that we’ve been able to come up with such amazing medicines. Having said that, it is my sincere hope that I can find some way to achieve and maintain remission that is based in diet and natural medicine. I’m open to using these therapies if it should turn out that I need them, but I’m going to try my darndest to avoid them if at all possible. The immune system is far more complex than we fully understand right now, and I am ambivalent about the benefits of mucking about with it any more than absolutely necessary.
I’ve now talked about the 5 types of medications used by Western medicine to treat Crohn’s disease. As I’ve mentioned before, I’m planning to work with 2 different gastroenterologists: One is a Western-trained MD, the other is a Naturopath. Next up: A series on some of the potential therapies I’ve discussed with my Naturopath, including the somewhat controversial use of low-dose Naltrexone.