Using Lab Tests to Guide Anti-TNF Treatment in RA
Using Lab Tests to Guide Anti-TNF Treatment in RA
My name is Dr Stephen Paget. I'm the physician-in-chief emeritus at Hospital for Special Surgery in the Division of Rheumatology. I'd like to talk today about a few issues related to rheumatoid arthritis (RA).
We all know that with anti–tumor necrosis factor (TNF) medications, it is pretty much hit-or-miss. We have our own ways of starting them and then changing them. Unlike with an infection, there is no antibiogram to determine the preferred medication. Usually we give a 3-month course, and if it doesn't work we switch to another one. Because it is so hit-or-miss, it may be 2 years before you come upon the right medication for a patient, way outside of their window of opportunity. That's pretty frustrating.
Recently I've been involved in some lectures with people from the gastroenterology community who are knowledgeable about inflammatory bowel disease (IBD). They have similar kinds of issues as us rheumatologists. To get more specificity in regard to the response to anti-TNF medications in IBD, they use serum anti-TNF drug levels. For example, therapeutic levels can be defined with infliximab and adalimumab. The other information that you can get from specialty labs is antibodies against anti-TNF medications. If somebody is not responding to an anti-TNF medication and you get a trough level that is too low, then it may very well be that you need to increase the dose or the frequency. If you have neutralizing antibodies, you may have to switch to a different medication or add some other medication that will stop the development of the neutralizing antibodies. For example, in RA, methotrexate can be used with infliximab.
I think we should use these laboratory tests more. The anti-TNF business is a $45 billion-a-year industry. Because using these agents is so hit-or-miss, it can be very frustrating. If we had another method by which we could really define whether somebody is responding or not, and why they may not be responding, I think that would be important. The reason I bring up the money part of this is because these tests (eg, the levels of adalimumab and infliximab or detecting neutralizing antibodies) are expensive. I think we really need to consider this more in our daily treatment of our patients with RA. Thank you.
My name is Dr Stephen Paget. I'm the physician-in-chief emeritus at Hospital for Special Surgery in the Division of Rheumatology. I'd like to talk today about a few issues related to rheumatoid arthritis (RA).
We all know that with anti–tumor necrosis factor (TNF) medications, it is pretty much hit-or-miss. We have our own ways of starting them and then changing them. Unlike with an infection, there is no antibiogram to determine the preferred medication. Usually we give a 3-month course, and if it doesn't work we switch to another one. Because it is so hit-or-miss, it may be 2 years before you come upon the right medication for a patient, way outside of their window of opportunity. That's pretty frustrating.
Recently I've been involved in some lectures with people from the gastroenterology community who are knowledgeable about inflammatory bowel disease (IBD). They have similar kinds of issues as us rheumatologists. To get more specificity in regard to the response to anti-TNF medications in IBD, they use serum anti-TNF drug levels. For example, therapeutic levels can be defined with infliximab and adalimumab. The other information that you can get from specialty labs is antibodies against anti-TNF medications. If somebody is not responding to an anti-TNF medication and you get a trough level that is too low, then it may very well be that you need to increase the dose or the frequency. If you have neutralizing antibodies, you may have to switch to a different medication or add some other medication that will stop the development of the neutralizing antibodies. For example, in RA, methotrexate can be used with infliximab.
I think we should use these laboratory tests more. The anti-TNF business is a $45 billion-a-year industry. Because using these agents is so hit-or-miss, it can be very frustrating. If we had another method by which we could really define whether somebody is responding or not, and why they may not be responding, I think that would be important. The reason I bring up the money part of this is because these tests (eg, the levels of adalimumab and infliximab or detecting neutralizing antibodies) are expensive. I think we really need to consider this more in our daily treatment of our patients with RA. Thank you.
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