Practical Application of Clinical Trial Measures in Atopic Dermatitis

Peter L. Salgo, MD: Cheryl, we have some scores and endpoints when you’re trying to measure AD in clinical trials, like the IGA score. You were talking about that. Which ones do you like? Do you like the IGA score?

Cheryl Allen, BS Pharm, MBA: Well, we heard from the doctor that while it’s great for the FDA to use in their very controlled clinical trials, it’s not something that’s used in the practice setting. And, unfortunately, as specialty pharmacies working with the physician, prescriber community, working with the payers, we deal with criteria for use that can be different across the different payers. We are trying to make the case for the individual patient for appropriate use of that therapy.

Peter L. Salgo, MD: I’m talking about in the clinical trials. Clearly, we’re going to try to morph this into clinical medicine, but when you’re trying to measure this for a trial, for a paper, you’ve got these various markers, right? There’s the IGA, the BSA, you said the EASI score, and the 5-D pruritus scale.

Cheryl Allen, BS Pharm, MBA: Yes.

Peter L. Salgo, MD: What is the utility of the meaningfulness, at least in terms of research, on these things?

Cheryl Allen, BS Pharm, MBA: I think in the research, we heard the FDA is very heavily depending on the IGA and the outcomes of that—I think 70% was the SOLO scores. Some were greater than 75%.

Peter L. Salgo, MD: That’s the IGA?

Cheryl Allen, BS Pharm, MBA: Right.

Jeffrey D. Dunn, PharmD, MBA: I personally struggle with that a little bit. I agree. I think that’s realistically what’s going to be used because it’s something you can actually apply to clinical practice. But when I look at a 4- or 5-point scale, I don’t know how specific that is. I don’t know where you go from a 2 to a 3. What does that mean to a payer or somebody who’s paying for this drug? So, I prefer things like the EASI, just like I do with PASI. But the challenge is, those are used in clinical trials, they’re not used in clinical practice.

Peter L. Salgo, MD: Which brings us back to Jonathan. Out in the real world, we have all of these studies. The studies are using some marker they’ve got to judge these drugs by and the efficacy by. But in the real world, can you use any of these to treat patients?

Jonathan Silverberg, MD, PhD, MPH: Yes and no. I want to double back, just for one second, to the trials outcomes. It’s been the Wild West for decades in terms of which assessment should be used, and there are a ton of different pseudo-objective assessments out there. There’s an attempt to really harmonize things intentionally. There’s this Harmonizing Outcome Measures and Eczema Home Group, and they’ve picked two winners. One is the Eczema Area and Severity Index (the EASI) and then Scoring Atopic Dermatitis, or SCORAD. The EASI was developed in the United States; SCORAD was developed in Europe. They’re both good because they account for both the severity of the lesion, as well as the extent of it, so just how diffuse the disease is. They’re hard to do, but they’re now accepted standards. You’re going to start to see all future systemic studies or studies of systemic agents using these. And that will hopefully help for comparative efficacy research.

In the real world, it’s hard. The EASI score is analogous to the PASI in psoriasis. No practitioner wants to use these. They’re hard to do. It’s hard to do the math, it’s cumbersome, and they’re not always reliable outside the trial setting because it takes a certain amount of training. We do this all the time, so we get it right, we think, but in the clinical setting, where you’re seeing one or two of these a year, how reliable is that assessment?

I think when you look at body surface area, this is a reasonable one that some patients could rely on, certainly even if the lesions were mild but were absolutely everywhere. And then, you’re talking about patients who haven’t responded well to topical agents. I think that’s one that probably most of us would be able to agree on. What that cut-off is, I think you could have a discussion on. But then, at the same time, there are some patients who may have more localized disease that’s so refractory, so intense, it may cover 5% or 10% body surface here, but nothing else touches it.

Peter L. Salgo, MD: This sounds really complicated. What is a reimburser going to do? Are you going to be able to give a reimburser a score based on a 10? Either it’s small but bad or mild but big. How can you do that in the real world? Does it work?

Jeffrey D. Dunn, PharmD, MBA: I was going to say we like yes and no. We’re not going to get it, we generally don’t have it, but we would love it.

Jonathan Silverberg, MD, PhD, MPH: And I guess I throw that back at you. What would you be comfortable with? Something like a combination of body surface area and the fact that they’ve responded or not responded to existing treatments?

Jeffrey D. Dunn, PharmD, MBA: I think that’s where we’re going to shake out, yes.

Ed Pezalla, MD, MPH: I think you’re going to need to make sure that the pruritus and other things are included in that because the intensity of that is part of what really distresses patients the most.