Monitoring of TNF blocker therapy

Today, patients living with chronic inflammation and inflammatory disease have newer treatment options available of more selective medicine that goes beyond broad immunosuppressive treatments, for example, TNFα blockers.

What is a TNF blocker?

TNF inhibitors or blockers are medicine that help stop inflammation.  TNFα blockers target a specific protein TNF (Tumor Necrosis Factor).  TNF plays an important role in the inflammation process.  Thus, by blocking TNF, TNF blockers help stop inflammation.

TNF blockers are used for the treatment of inflammatory diseases such as ulcerative colitis, Crohn’s disease and rheumatoid arthritis.

How does TNF blockers work?

TNF blockers are antibodies developed in a laboratory (biologic agent) to target TNF (Tumor Necrosis Factor).

The human body produces TNF as a cell signalling protein or cytokine.  It is a substance in the body that causes inflammation and can lead to immune system diseases.  Usually, your body keeps your TNF levels steady, but if you have for example an autoimmune disease, something goes wrong, and your body starts making too much TNF that leads to inflammation.  Inflammation that’s out of control can damage your body.

TNFα blockers suppress the immune system by blocking the activity of TNF.  Once they’re in your blood, they cause a reaction in your immune system that blocks inflammation.

Why would your doctor monitor the level of the TNFα blocker in your blood?

In order for TNFα blockers to work optimally it is important to check their levels in your blood on a regular basis.

Biologic agents have a narrow range of effectiveness.  They can easily be under- or over-dosed and there is variability among persons treated at the same dose level (bioavailability).  Monitoring of antibody levels of TNF blockers helps to optimally adjust the therapy to the individual needs of a specific person.

Therapeutic drug monitoring (TDM) of TNFα blockers

The goal of therapeutic drug monitoring (TDM) is to maximize the clinical benefits of a medication while minimizing its side effects.  If the dosage is too low, then the person will receive no clinical benefit and might build a tolerance to the medicine.  If the dosage is too high, then the person might be subject to toxicity.  At the right dosage for a particular person, the medicine works as designed, yielding the best benefits and the treatment becomes ‘just right.’

It is challenging to find the correct dosage to work for everyone, because how the medicine works in the body (pharmacokinetics) can differ significantly between individual patients receiving the same dosage.  Pharmacokinetics includes factors such as the rate at which a patient builds immunity against the medication (if at all), the rate of medication clearance from the body, how the medication is absorbed, how the medication is distributed and more.  Through TDM, doctors can better tailor that patient’s specific biologic dosage (for example, TNFα blocker) and treatment plan.