Most people who read this newsletter are probably aware that two new medications are now funded to treat Crohn’s disease and ulcerative colitis.

These new medications are in a class of drugs we call “biologics” or “biologicals” and they are among the most effective medications to treat IBD.

What are biologicals and how do they work?

Medical researchers have identified certain proteins called "cytokines" that are produced by white blood cells which trigger the inflammation in people with Crohn’s and colitis. Biologicals are antibodies against these proteins. They bind to them and inactivate them. They are called biologicals because they are made by living cell cultures in the laboratory. They currently need to be either injected or given intravenously, but oral forms may be available in the future.

What were the first biologicals available in New Zealand?

The first biologics available in NZ were infliximab (Remicade) and adalimumab (Humira and Amgevita). They were first funded almost 15 years ago. Both medications are antibodies against the cytokine called “tumour necrosis factor”, one of the proteins that triggers inflammation in people with IBD. They are therefore referred to as “anti-TNF” medications. They are often very effective in bringing people into remission and are frequently used together with other medications such as azathioprine and 6-mercaptopurine.

Why do we need newer biologicals if we already have infliximab and adalimumab?

For three reasons. The first is that infliximab and adalimumab do not work for everyone. Some people simply do not improve with them. The second reason is side effects. All medications have side effects and some people do not tolerate anti-TNFs for a variety of reasons. The third reason is more complicated. Over time, usually after a few years, but sometimes sooner, some people lose response to these medications. This is because their bodies start seeing the medications as “foreign" molecules make antibodies against them. When people make antibodies to the drugs, the levels of the drugs drop in the body and they become less effective. This is why doctors will do blood tests to check the levels of these drugs when people stop responding or have a flare. Blood tests can also check for the presence of antibodies to the drugs. As noted above, anti-TNF medications are often used with azathioprine or 6-mercaptopurine which may help delay or prevent the body from developing antibodies to these medications.

What do people do when their biological stops working?

Before we had the newer biologicals, we did not have many options. Switching from one anti-TNF medication to another (from infliximab to Humira or vice versa) usually does not work. Sometimes increasing the dosage or shortening the interval between doses helps to raise the drug level to keep people in remission. For several years, we had no other options, other than surgery or treating people with brief courses of steroids to keep their disease under control. In short, we needed new biologicals that worked differently.

How do the newer biologicals work?

This February, two new biologicals were approved for funding by Pharmac. They are called vedolizumab and ustekinumab. They go under the brand names Entyvio and Stelara.

Vedolizumab (or Entyvio) is an antibody that binds to a protein called “α4β7 integrin” that interferes with the ability of inflammation-causing white blood cells to enter the gut. It is given intravenously like infliximab.

Ustekinumab (Stelara) is an antibody that interferes with the inflammation-causing proteins, “interleukins 12 and 23”. The first dose is given intravenously. After that, the medication is self-injected every 8 weeks.

How does my doctor decide which biological to start?

There are several factors that might affect that decision: Do you have fistulae? Have you been on another biological previously? Do you have Crohn’s disease or ulcerative colitis? Your preference of administration (IV or by injection)? Are you prone to getting infections? These and other factors go into the decision-making process which should be made jointly by you and your gastro team.