NEW YORK (Reuters Health) - Fixed-dose rituximab therapy can produce durable remission of pemphigus, a retrospective study suggests.
"I believe rituximab could well be the first line therapy of choice because it works well, is well tolerated, and it avoids the huge number of side effects of systemic steroids (like prednisone)," Dr. Neil H. Shear from the University of Toronto told Reuters Health by email. "It is ultimately about giving the best overall quality of life and economic benefit of the right therapy for the right disease."
Rituximab appears to be effective in a number of autoimmune diseases, but the optimal way to use it in pemphigus is unknown.
Dr. Shear and colleagues review their experience using a fixed-dose protocol of rituximab (1 g IV on days 1 and 15 followed by 500 mg IV at six-month intervals if needed) in 92 patients: 84 with pemphigus vulgaris and 8 with pemphigus foliaceus.
The median disease duration before rituximab therapy was 24 months, and 83% of patients were receiving systemic corticosteroids or immunosuppressive therapies at the time of their first rituximab infusion.
All patients showed improvement after rituximab treatment: 74 (80%) had complete remission after the first cycle, and all patients had complete remission by the 4th cycle.
There were 56 relapses (61%) after the first cycle, with a median time to relapse of 15 months, the authors reported online February 5th in JAMA Dermatology. Average time to relapse was significantly shorter for patients receiving adjuvant treatment (12 months) than among those who did not receive adjuvant therapy (40.6 months).
At the time of last follow-up (a median 24 months after the first treatment cycle), 56 patients (61%) were in complete remission, 26 (28%) were in complete remission on therapy, two (2%) had partial remission, three (3%) had partial remission on therapy, and five (5%) experienced relapse/flare.
In the 15 patients with at least 45 months of follow-up, all had achieved complete remission at some point during follow-up.
Two deaths, neither of them related to rituximab therapy, occurred during follow-up, and there were no serious infectious adverse events. Fifteen patients had infusion reactions, but only one had to stop treatment.
"Confirm the diagnosis when an autoimmune blistering disease is suspected," Dr. Shear advised. "If it is pemphigus vulgaris, then rituximab should be considered at the start or near the start for patients who have access to it."
"As we learn more about rituximab, its efficacy and its safety, it is clear that it is a paradigm shift in the treatment of a very serious and challenging disease," Dr. Shear concluded.
Dr. Farah Sameem from Government Medical College Srinagar, Kashmir, India has studied various regimens for pemphigus. Dr. Sameem told Reuters Health by email, "Taking into consideration the reshaping of B cell milieu that (rituximab) causes, theoretically it should be the first treatment option offered to naive B cells without any confounding factors."
"As it is, antibody mediated autoimmune disorders are difficult to manage with conventional options," Dr. Sameem said. "Taking our resource strapped setting into consideration, however, I would use rituximab in cases of pemphigus recalcitrant to a conventional and affordable regimen of dexamethasone-cyclophosphamide pulse therapy."
Dr. Sameem added, "It would be my humble suggestion that as rituximab is an upcoming drug, many of its side effects may be noticed during its increasing use. Hence, I would suggest monitored therapy in a few research centers to start with only."
Dr. Shear noted that Roche did not provide support for the study or the writing of the paper.
JAMA Dermatol 2014.
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