Is PASI 90 becoming the new PASI 75?

ISTANBUL – With the majority of psoriasis patients now achieving PASI 90 responses in randomized trials of the latest-generation biologic agents, a push is on to replace PASI 75 with PASI 90 as the new goal defining treatment success. But some dermatologists have misgivings about raising the bar.

"More and more, editorialists are promoting the idea of silencing psoriasis in all patients. This is a tricky and challenging goal," Dr. Hervé Bachelez said at the annual congress of the European Academy of Dermatology and Venereology.

Dr. Bruce E. Strober

"You’ve probably noticed that PASI 90 and even PASI 100 are becoming important as secondary endpoints in virtually all clinical trials. It’s good, it’s legitimate, and the PASI 90 probably better reflects the wishes of the patient and the physician than the PASI 75. But we have to wait and see what the caveats of this are. You can say, ‘Let’s push the response rate up to PASI 100 in all patients,’ but the danger is that if you cross a line, you may be unable to precisely regulate the level of immunosuppression in some patients. Basically you can expect some safety issues in real life that you would not see in clinical trials," cautioned Dr. Bachelez, professor of dermatology and head of the inflammatory skin diseases unit at Saint Louis University Hospital, Paris.

Not so many years ago the notion of PASI 90 responses in high double figures seemed a pipedream, he observed. For example, the week-12 PASI 90 rate in published randomized trials of methotrexate was only 9%, while for the first-generation tumor necrosis factor inhibitor etanercept, the rates were 19%-23%. In contrast, among the highlights of this year’s EADV congress were the presentation of results from clinical trials of two investigational interleukin-17 inhibitors: In the pivotal Phase III FIXTURE trial, secukinumab-treated patients had a PASI 90 response rate of 72% at week 16, while the week-16 PASI 90 rate in the Phase II OLE trial was 87% in patients on brodalimab, and even out to week 96, it was 78%.

Underscoring Dr. Bachelez’ concern that the randomized trial experience likely underestimates the true extent of safety hazards posed by potent therapies in daily clinical practice was a report by a consortium of 13 Spanish dermatology departments responsible for the BIOBADADERM registry. The Spanish registry is focused on safety and includes only psoriasis patients on systemic therapy, whether biologics or classic drugs. Among the first 1,042 enrollees receiving systemic therapy, fully 30% would not have been eligible for participation in randomized controlled trials for various reasons, including age greater than 70 years, having chronic kidney or liver disease, a history of hepatitis B or C, HIV infection, or cancer, or having psoriasis of a type other than chronic plaque disease.

The disturbing finding was that during 2,179 person-years of prospective follow-up, the large group of patients ineligible for randomized trials had a 2.7-fold increased risk of serious adverse events compared with patients on systemic therapy who were eligible for study participation.

The number needed to harm was calculated as follows: For every 40 patients treated with systemic therapy for 2.1 years despite not being eligible for randomized trials, one additional serious adverse event can be expected compared with similar treatment in randomized trial-eligible patients, according to the investigators (Arch. Dermatol. 2012;148:463-70). And that’s without pushing the envelope by trying to aim for a PASI 90 response, Dr. Bachelez noted.

A contrary view regarding PASI 90 as an emerging standard of treatment excellence was put forth elsewhere at the meeting by Dr. Peter van de Kerkhof, professor and head of the department of dermatology at Radboud University in Nijmegen, the Netherlands.

He cited multiple studies demonstrating that substantial PASI reductions may not translate into tangible improvements in patients’ quality of life. For example, among psoriasis patients who achieved a PASI 75 response in one European study, 65% still had a Dermatology Life Quality Index (DLQI) score of 2 or more (Eur. J. Dermatol. 2010;20:62-7).

"This implies that there is something more to be wished for by patients, even when PASI 75 is reached," according to Dr. van de Kerkhof.

Moreover, in another trial, even among patients with a PASI score of 0 at week 24, only 70% had an optimal DLQI of 0, not 100% as most dermatologists might expect (Br. J. Dermatol. 2006;154:1161-8).

^{Bruce Jancin/IMNG Medical News}

Dr. Peter van de Kerkhof

A recent survey of 2,151 European psoriasis patients and their dermatologists highlighted a substantial degree of dissatisfaction with current therapies. Patients on biologics had higher rates of improvement from severe to moderate or mild disease than did those on any other forms of psoriasis therapy, yet 41% of patients on biologics were dissatisfied with their treatment (J. Dermatolog. Treat. 2013;24:193-8).