Elaine Husni, MD, MPH: I think the management, and what therapy to choose, is really a big question now, especially because we have so many to choose from. I think one of the things that strikes me the most of what's going on is that as we're getting more and more treatment, the skin psoriasis is actually getting cleared. And it's getting cleared for a long period of time—sometimes up to 52 weeks. Unfortunately, when you look at the joint side, we don't have as great of a response, so we're really not hitting 100% clearance of all the joints. And that leaves a lot of room for clinical judgment and for treatment options. So, despite having all the successes in skin psoriasis, we're not seeing the same success in joint manifestations. We really need to look at other options. There are many that are still on the horizon that are in early phase 1 and 2 trials. But for the ones that are FDA-approved already, I'm really grateful that we have more than 2-3 to go to. So we do look for what we call domain strategies. This is following the graph of treatment domains, for example, where they look at whatever your prominent domain is for psoriatic arthritis. Is it the skin that's driving the discomfort? Is it the joints that are driving it? Is it the axial skeleton? Is it the enthesitis? Depending on the domain, we actually become a little bit more specific about the types of treatment that we use.
For instance, I would say that the IL-17s and the up-and-coming IL-23s probably have a stronger and more robust response for the skin. So, if somebody is having more skin than joint discomfort, then we could see how reaching out to one of those agents makes sense. If the joints are much more problematic than skin, then you could see where a TNF inhibitor, for example, might be good in combination with methotrexate, which is one of our anchor drugs. Whether or not we do combination or monotherapy, those are all choices that we can make with shared, informed decision making with our patients.