Research gaps persist in psoriasis, psoriatic arthritis

Orlando – The advent of increasingly effective – and still costly – biologic drugs for psoriasis and psoriatic arthritis (PsA) has highlighted the fact that dermatologists do not know which patients would benefit most from preventative measures.

A key unanswered question in psoriasis is whether physicians can predict – and therefore prevent – progression to PsA, said Mark Lebwohl, M.D. He is Sol and Clara Kest Professor and Chairman, Department of Dermatology, Icahn School of Medicine at Mount Sinai.

Before biologics, "The drugs that we had helped the pain of arthritis but were not dramatically effective at preventing joint destruction. Methotrexate is a classic example – patients still benefit from it today, but the joints continue to deteriorate as evidenced by x-rays."

Tumor necrosis factor (TNF) alpha inhibitors were the first drug class allowed to claim that they prevent radiographic progression of PsA. "Etanercept was the first, followed by infliximab and adalimumab. Then came golimumab and certolizumab. These 5 drugs are dramatically effective for psoriatic arthritis – they don't just get rid of the pain, but they also prevent x-ray progression."

More recently, the interleukin (IL) 17 blockers secukinumab and ixekizumab have shown similar abilities. "We have quite a few tools now to prevent joint damage. If we knew in advance which patients with psoriasis were going to develop psoriatic arthritis, it would help us help our patients. We could put them on those drugs early to prevent joint damage."

Among patients with psoriasis and PsA, he said, 72% present with psoriasis first. MRIs can show bone marrow edema (a sign of impending joint damage), "But we need better tests to predict which patients will get psoriatic arthritis." To that end, said Dr. Lebwohl, several companies are investigating genetic markers, while physicians continue to explore use of imaging modalities. "A genetic or serologic marker would be most helpful."

Similarly, researchers are attempting to predict which patients will develop other comorbidities such as cardiovascular disease. "When the biologics came out, patients were put into registries. And we've been finding, particularly with the TNF blockers, that there's a dramatic reduction in heart attacks in people who take these drugs."

A third knowledge gap, Dr. Lebwohl said, is which patients will respond to which treatments. "The new treatments that are coming out are dramatically effective in almost everybody. The problem is, they all cost a fortune." Knowing which patients would likely respond best – and which ones would do just as well with cheaper treatments – will help dermatologists and their patients immensely, he said.

Disclosures: Dr. Lebwohl has been a clinical investigator for most manufacturers of drugs for psoriasis and psoriatic arthritis. All payments from these companies go not to him but to Mount Sinai.