Following this success, treat to target has also been proposed for other rheumatic diseases, such as axial and peripheral spondyloarthritis (especially psoriatic arthritis), gout and systemic lupus erythematosus.5 Other medical specialties, including neurology and gastroenterology, are also starting to consider treat to target.6,7
One issue of contention in treat to target is how strict one must be in pursuing the treatment target. EULAR recommendations state that if “the target has not been reached by six months, therapy should be adjusted.”
The only nuance to this recommendation is: “One should consider the desired treatment target as well as various patient factors, including comorbidities, when making treatment adaptations.”
No specific exceptions to the rule of adapting medication in the case of failing to reach the target are offered.2
In a recent paper celebrating the anniversary of 10 years of the treat-to-target strategy, Josef Smolen, MD, PhD, its most prominent advocate, stated,5 “Treat to target is not an idée fixe, a strategy that has to be adhered to under all circumstances, but rather should be applied with prudency and several caveats in mind. … In clinical practice … being close to that threshold (even if slightly above the LDA/MDA threshold) should be seen as a success of the therapeutic intervention and not necessarily elicit a change of the treatment regimen.”
These nuances make no specific reference to the different parameters being used to assess disease activity and define the target. However, among the objections raised to treat to target are uncertainties regarding whether standard disease activity scores truly reflect disease activity or could be unduly influenced by patient-specific factors or comorbidities, such as fibromyalgia; the most appropriate definition of remission; and other patient-related limitations, such as drug intolerance and toxicity, which can limit therapeutic choices.8
In fact, the concerns regarding patient-specific factors, including comorbidities, have been repeatedly voiced as a reason for concern, especially regarding patients’ input into the metrics of disease activity and the definition of the target through the patient global assessment (PGA) of disease activity.
Back to the Scenario
Following treatment recommendations, Dr. Snow is inclined to change the bDMARD, despite the nuances described above. After all, Linda has always been a positive and reliable patient, and the SDAI is now above target. Another targeted agent or reinforced immunosuppressive therapy will certainly improve her condition.
Remission Definitions & Impact of PGA
The provisional definitions of remission jointly proposed by the ACR and EULAR in 2010 recommend the use of either a Boolean definition or an SDAI score of 3.3 or less in clinical trials.9 The use of a Clinical Disease Activity Index (CDAI) score of 2.8 or less is also used for clinical practice in the absence of CRP levels.