Conference Coverage

Is PASI 100 the new benchmark in psoriasis?



The current high-performance biologic agents for psoriasis are so unprecedentedly effective that it’s finally come to this: “Is PASI 90 good enough? I think we should just do away with PASI 90 [90% improvement in Psoriasis Area and Severity Index score] and look at how well our drugs do against the metric of PASI 100. The whole ball of wax. Let’s just go for complete clearance,” Craig L. Leonardi, MD, declared in a provocative presentation at the Hawaii Dermatology Seminar provided by Skin Disease Education Foundation/Global Academy for Medical Education.

He advocates using number needed to treat (NNT) as a performance yardstick. He finds it helpful in translating sometimes-arcane clinical trial results into useful information to guide everyday practice. The NNT is the average number of patients who need to be treated with a drug or procedure in order to achieve one additional good outcome, compared with a control intervention or placebo. It’s the inverse of the absolute risk reduction. The lower the NNT, the better an intervention is performing.

Dr. Craig Leonardi of Saint Louis University Bruce Jancin/Frontline Medical News

Dr. Craig Leonardi

“I think this gives you a different view on how these drugs perform. It kind of gives a feel for what you might have reasonable expectations of seeing when you pick one of these drugs. Another reason to be aware of this type of analysis is that I can assure you every pharmacy benefits manager and insurance industry insider uses NNT all the time,” said to Dr. Leonardi, a dermatologist and clinical trialist at Saint Louis University.

He presented a chart that summarized the NNTs to achieve a PASI 100 response for various systemic agents commonly used in treating moderate to severe psoriasis. He obtained the data from Food and Drug Administration–regulated product labeling and phase 3 clinical trials.

Dr. Leonardi drew attention to the worst performers on the list: methotrexate, with an NNT of 25 to achieve a PASI 100 response, and etanercept, with an NNT of 23.3.

“Methotrexate is a drug that the insurance industry says we have to flow through on our way to biologic drugs. But if complete clearance is your goal, this is an exercise in futility. These patients will never, ever get to complete clearance – or it’s at least very unlikely. We shouldn’t be asked to go through methotrexate on our way to anything. We shouldn’t be asked to use methotrexate at all. We should be bypassing it. And some of us are working on this,” he said.

Ustekinumab and adalimumab are the current market leaders in biologic therapy for psoriasis, but they don’t stack up so well when viewed through the filter of PASI 100 response, with NNTs of 9.2 and 5.3, respectively.

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