Should we treat-to-target in psoriatic arthritis?

11 August 2016

Professor Christopher Ritchlin (USA) and Professor Eric Ruderman (USA) debate the pros and cons of treat-to-target treatment strategies in psoriatic arthritis.

Hello I'm Christopher Ritchlin, I am Professor and Chief of the Allergy, Immunology and Rheumatology division at the University of Rochester Medical Center. And I'm Eric Ruderman, I'm a Professor of Medicine and Rheumatology at the Northwestern University, Feinberg School of Medicine, and the Practice Director for the Rheumatology Clinic.

Psoriatic arthritis is my favourite for a treat-to-target strategy, largely because this is a disease that involves multiple different domains or areas of involvement; not only including the joints but also the skin, the entheses, the digits, and the dactylitis in the axial spine. This is a complex disease and I think it is important for us to understand how our patients are doing.  In order to carry that out, we have to look at these various domains and achieve targets. Now this is problematic because in the office it's very challenging to assess all these different domains in a timely fashion; we have major challenges ahead of us. However, there was one study performed called the TICOPA study, in which the eight treat-to-target approaches were applied and compared to a usual care treatment. In this study, carried out in the United Kingdom, a 48-week trial of patients with psoriatic arthritis early disease, split patients into two groups; one group was treated with a treat-to-target strategy where they were evaluated every month by a rheumatologist, and then they were treated, and then they looked at minimal disease activity, which looks at seven different domains versus usual treatment from their community rheumatologist who saw them every three months. The results are shown in the slide, and one can see from the perspective of the ACR20, 50, 70, and the skin response, that those that had a treat-to-target strategy, had almost twice the response in some cases as though they've got usual care. So based on these results I think we have preliminary information that suggests to us treat-to-target can actually be very beneficial. Although I should mention, before Eric answers me, that there was a higher side effect profile on the patients that had the treat-to-target strategy. So Chris, while this trial is very interesting and I think they showed some really exciting results, I’m not sure that the treat-to- target approach is ready for prime time and psoriatic arthritis. It has become the standard of rheumatoid arthritis over the last number of years and for a number of reasons: one, now we have a great deal of data that shows outcomes across the board, not just joint symptoms but functional outcomes, other outcomes are important and respond to this kind of treat-to-target approach. I'm not sure we can necessarily translate that strictly to psoriatic arthritis, as you mentioned, this is a disease that affects a number of different areas, it's not a monocentric disease like rheumatoid arthritis. We are really focused primarily on joint response here: we've got joints, we've got dactylitis, we've got enthesitis, we've got skin disease, we've got nail disease, and I think the challenge becomes picking the target, and in this study the target was largely driven by minimal disease activity, which is largely driven by joints, and in fact the primary outcomes of this study was joints- joint outcome.

On the other hand, I think we really need to talk to our patients, look at our patients, and try to understand what the outcomes that are most important to them are. I've certainly had plenty of patients whose joints are better but their skin is not responding and that's really an important outcome. I've had other patients with skin that is not doing very well and yet they're satisfied with that-if their joints are better. I think the challenge of a treat-to-target, and a tight control approach like that, is it puts everybody in the same bucket and looks at the same sort of groups of outcomes, and treats everybody the same, but I’m not sure were quite ready to do that.

The last thing I would comment on is that one of the things that drives treat-to-target rheumatoid arthritis has been the recognition that the vast majority of those patients are going to have progressive joint damage, progressive destruction and progressive functional loss over time if not treated aggressively. I don't know that we know that yet in psoriatic arthritis. In particular patients with mild disease or more enthesitis related disease, and I don't know that aggressive therapy necessarily leads to long-term better functional outcomes of those patients. Until we have that data, I'm not sure we're ready to institute that treat-to-target approach for everyone. So Eric, I would agree with you that we can't take the same approach with every patient and that we have to have a conversation with them to find out what seems to be working, and it may be different for one patient versus another. I think the important point is that we need to be evaluating these domains with our patients; we know where they're responding in some and not in others, whether or not we take the same tight control approach to all patients probably is not going to be the case, but we certainly need better data to determine, as you said, whether or not this improves long-term outcomes. I can agree with that.

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