It is becoming increasingly clear that a substantial proportion of RA patients fail to respond to the more common treatment regimens including combinations of DMARDs (methotrexate, Arava, etc.) and TNF inhibitors (Enbrel, Humira, Remicade, etc). As recently noted by researchers,
“However, about 20% to 40% of patients treated with a TNF inhibitor fail to achieve a 20% improvement in American College of Rheumatology criteria, and more lose response over time (secondary failure or acquired therapeutic resistance) or experience adverse events following treatment with a TNF inhibitor.” (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2669237/)
The television advertisements in the United States for these drugs show happy, active people. It is heartening that many RA patients receive excellent results from DMARDs and anti-TNF medications. But I seem to have found myself in the 20-40% group of non-responders. Apparently there is a name for this…Refractory RA.
Refractory in the medical sense means “resistant to treatment or cure” (http://www.merriam-webster.com/dictionary/refractory). According to the National Institutes of Health,
“Refractory disease is defined as failure to attain a predefined target, which is now accepted to be remission or, at least, a low disease activity state.” (http://www.ncbi.nlm.nih.gov/pubmed/21570496)
Since remission is embedded within this definition, it must be clearly operationalized. The predefined target for remission of RA is from the recently revised ACR-EULAR criteria. In order to be technically in remission,
At any time point, patient must satisfy all of the following:
Tender joint count – equal or less than 1
Swollen joint count – equal or less than1
C-reactive protein – equal or less than 1 mg/dl
Patient global assessment – equal or less than 1 (on a 0–10 scale) (p. 581)
These are the stringent criteria applied for clinical trials of newly developed drugs. But applied to currently approved drugs, do patients on these drugs reach remission status? In a review of several studies, the use of traditional DMARDs like methotrexate result in between 35-65% of patients reaching remission. Other comparison studies demonstrated remission rates within a range of 24% with methotrexate alone to 64% with Humira. In one recently published study in China, only 25% of patients achieved remission status using the ACR-EULAR criteria. Many of the remission rate studies were conducted using the old criteria before 2010. Whatever standard is used, it is clear that there are a considerable number of patients who are not in remission.
Biological medicines that are not in the TNF inhibitor class like Xeljanz, Rituxan, and Actemra, are commonly recommended for refractory RA (see studies linked to each medicine above). In the United Kingdom, failure of TNF inhibitors leads to a recommendation to use Rituxan (see http://guidance.nice.org.uk/TA195). But these “second tier” biologicals don’t always result in patients reaching remission status. All one needs to do is read the prescribing information for each of these drugs to quickly realize that many patients in the clinical trials did not reach ACR-EULAR remission status. This is actually the case for all approved RA drugs.
Rheumatology researchers in Portugal recently stated,
“During the last decade we have experienced exciting developments regarding the approval of new treatment options but few patients are reaching sustained remission and refractory patients continue to be a problem. Thus, it is critical to understand how clinicians can decrease the risk of refractoriness by closely monitoring disease activity, using well defined and accepted composite measures, and by early and optimized use of DMARDs, including biologics.” (http://www.ncbi.nlm.nih.gov/pubmed/21570496)
This quote sums up the problem which remains. A large proportion of RA patients who are currently on biological and DMARD medication combinations do not achieve remission status – they have Refractory RA. This evidence lends credence to the fact that more work needs to be done in order to develop treatments that result in true remission. Ultimately, a cure should be the goal for this insidious disease.