Pandemic Dictates Reconsideration of Pemphigus Therapy

Bruce Jancin

July 17, 2020

Editor's note: Find the latest COVID-19 news and guidance in Medscape's Coronavirus Resource Center.

The conventional treatment mainstays for pemphigus are problematic during the COVID-19 pandemic, and a shift in disease management strategy is in order, Dedee F. Murrell, MD, said at the virtual annual meeting of the American Academy of Dermatology.

Together with physicians from the Mayo Clinic, Alexandria (Egypt) University, and Tehran (Iran) University, she recently published updated expert guidance for treatment of this severe, potentially fatal mucocutaneous autoimmune blistering disease, in a letter to the editor in the Journal of the American Academy of Dermatology. She presented some of the key recommendations at AAD 2020.

First off, rituximab (Rituxan), the only Food and Drug Administration–approved medication for moderate to severe pemphigus vulgaris and a biologic considered first-line therapy prepandemic, is ill-advised during the COVID-19 era. Its mechanism of benefit is through B-cell depletion. This is an irreversible effect, and reconstitution of B-cell immunity takes 6-12 months. The absence of this immunologic protection for such a long time poses potentially serious problems for pemphigus patients who become infected with SARS-CoV-2.

Also, the opportunity to administer intravenous infusions of the biologic becomes unpredictable during pandemic surges, when limitations on nonemergent medical care may be necessary, noted Dr. Murrell, professor of dermatology at the University of New South Wales and head of dermatology at St. George University Hospital, both in Sydney.

"We have taken the approach of postponing rituximab infusions temporarily, with the aim of delaying peak patient immunosuppression during peak COVID-19 incidence to reduce the risk of adverse outcomes," Dr. Murrell and coauthors wrote in the letter (J Am Acad Dermatol. 2020 Jun;82[6]:e235-6).

The other traditional go-to therapy for pemphigus is corticosteroids. They're effective, fast acting, and relatively inexpensive. But their nonselective immunosuppressive action boosts infection risk in general, and more specifically it increases the risk of developing severe forms of COVID-19 should a patient become infected with SARS-CoV-2.

"A basic therapeutic principle with particular importance during the pandemic is that glucocorticoids and steroid-sparing immunosuppressive agents, such as azathioprine and mycophenolate mofetil, should be tapered to the lowest effective dose. In active COVID-19 infection, immunosuppressive steroid-sparing medications should be discontinued when possible, although glucocorticoid cessation often cannot be considered due to risk for adrenal insufficiency," the authors continued.

"Effective as adjuvant treatment in both pemphigus and COVID-19,intravenous immunoglobulin supports immunity and therefore may be useful in this setting," they wrote. It's not immunosuppressive, and, they noted, there's good-quality evidence from a Japanese randomized, double-blind, controlled trial that a 5-day course of intravenous immunoglobulin is effective therapy for pemphigus (J Am Acad Dermatol. 2009 Apr;60[4]:595-603).

Moreover, intravenous immunoglobulin is also reportedly effective in severe COVID-19 (Open Forum Infect Dis. 2020 Mar 21. doi: 10.1093/ofid/ofaa102.).

Another option is to consider enrolling a patient with moderate or severe pemphigus vulgaris or foliaceus in the ongoing pivotal phase 3, international, double-blind, placebo-controlled PEGASUS trial of rilzabrutinib, a promising oral reversible Bruton tyrosine kinase inhibitor. The medication has a short half-life and a self-limited immunomodulatory effect. Moreover, the trial is set up for remote patient visits on an outpatient basis via teledermatology, so the 65-week study can continue despite the pandemic. Both newly diagnosed and relapsing patients are eligible for the trial, headed by Dr. Murrell. At AAD 2020 she reported encouraging results from a phase 2b trial of rilzabrutinib.

She is a consultant to Principia Biopharma, sponsor of the PEGASUS trial, and has received institutional research grants from numerous pharmaceutical companies.

This story originally appeared on MDedge.com.

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