Assessing the Severity of Plaque: The Need for Topical vs Systemic Therapy

Linda F Stein Gold, MD: Leon, I’m going to turn it over to you now. We have a good overview of the pathogenesis of the disease, we have a nice overview of the comorbidity of the disease, but when we look at patients, in clinical trials we always divide them into mild, moderate, and severe psoriasis. But in actual practice, we don’t necessarily say, “Oh, you’re a moderate patient, you’re a mild patient.” It’s more that we look at them and we decide, “Are you a topical candidate, are you a systemic candidate?” Leon, can you give us insight, when you’re seeing patients, how do you assess disease severity? How do you decide?

Leon H. Kircik, MD: That’s a great question, Linda. But what I’d like to do first for those of us who are not involved in clinical trials, let me explain how we do it in the clinical trial business, and then I’ll come to the real-life situation. As you know, when we do clinical trials, we do pick moderate to severe patients, especially for biologics and systemic treatments, and the way we do that is with a scale of what we call IGA [Investigator’s Global Assessment] or PGA [Physician’s Global Assessment], the investigative global assessment. We do have that scale: clear, almost clear, mild, moderate, and severe. Now that scale is totally independent of the affected body surface area [BSA]. So we can have 2% body surface area, but that patient can be, depending on the plaque, moderate or severe. On the other hand, when we do it in real life, in clinical practice, I absolutely don’t think like that. I look at the body surface area; in my mind, body surface area has a lot to do with where am I going to go? Am I going to stay with topicals, or am I going to go with systemic treatment? Because it’s almost impossible to smear a cream all over the place if you have more than 10% body surface area.

The other thing is, as you know, all the third-party payers require at least 10% body surface area for biologic coverage, so it only makes sense that we do that. Now, when you look at the history of how we decided what is mild, moderate, severe, we can look at the NPF [National Psoriasis Foundation], we can look at European Union regulatory bodies, or the FDA, everybody has different criteria. I remember years ago, the NPF wanted at least 3% to 10% BSA to be considered to be moderate. There are all kinds of different calculations or measurements, even when it comes to body surface area and what’s considered moderate or severe. But in my mind, I do separate the patients into systemic or topical treatment, and depending on their body surface area, also depending on what they want to do. Some people can have 2% to 3% body surface area and they don’t want to use a cream. It all depends on the patient, but mostly, that systemic versus topical patient, in my mind, depends on the body surface area.

Linda F Stein Gold, MD: Thank you, Mark, Jerry, and Leon for this rich and informative discussion. Thank you for watching this HCPLive® Peer Exchange. If you enjoyed the content, please subscribe to our e-newsletters to receive upcoming Peer Exchanges and other great content right in your inbox.

This transcript has been edited for clarity.