Title : Efficacy and safety of rituximab versus pulse therapy in Immunobullous disorders: A retrospective study
Abstract:
The immunobullous disorders represents a group of conditions characterized by antibody-mediated autoimmune responses. Antibody target includes proteins in the hemidesmosomes and the basement membrane zone (pemphigoid group), desmosomes (pemphigus group).
The mainstay of treatment for these conditions are systemic corticosteroids. However, due to serious adverse events associated with long term corticosteroids therapy, dexamethasone cyclophosphamide pulse therapy was introduced by Pasricha and Gupta in 1982 in India. It consists of the administration of suprapharmacological doses of steroids in an intermittent manner to achieve rapid therapeutic effect while minimising the adverse effects of long-term steroids.
With the introduction of rituximab, the monoclonal antibody, a favorable and durable response to autoimmune bullous disorders was noted. US FDA approved its use in these conditions in 2017.
A study conducted at Karnataka Medical College and Research Institute from 2019 enrolled 87 patients with immunobullous disorders, including 64 with pemphigus vulgaris (PV), 15 with pemphigus foliaceus (PF), 7 with bullous pemphigoid (BP), and 1 with pemphigus erythematosus (PE). Treatment regimens included dexamethasone cyclophosphamide pulse (DCP), dexamethasone azathioprine pulse (DAP), dexamethasone methotrexate pulse (DMP), and rituximab.
Among 64 PV patients, 44 were started on DCP, of which 12 completed all phases (11 achieved complete remissio, 1 relapsed and responded to rituximab) and 31 discontinued treatment (22 in Phase I, 9 in Phase II), with only 1 continuing in phase II. 14 PV patients received DAP; only 1 completed all phases but relapsed and responded to rituximab. 9 discontinued treatment (4 in Phase I, 5 in Phase II), with 1 is continuing in phase I. 3 patients on DAP started on rituximab because of disease relapse. 1 PV patient on DMP completed all phases and achieved remission. 5 PV patients were directly started on rituximab.
Among 15 PF patients, 12 were on DCP, 1 on DAP, and 2 on rituximab. Most DCP patients failed to complete treatment (5 in phase I, 6 in phase II) with only 1 continuing in Phase I. The single DAP patient was in Phase III. All BP patients (n=7) on DCP failed to follow up. The single PE patient on DCP completed treatment and achieved remission.
Of 12 patients on rituximab, 7 were directly initiated without prior DCP or DAP therapy and 5 shifted to rituximab due to treatment failure or side effects associated with DCP or DAP therapy 9 responded, 2 were lost to follow-up, and 1 died.
This study proves that rituximab therapy for immunobullous disorders is superior to DCP or DAP therapy However, the high cost associated with rituximab therapy prevents its usage as first line of treatment in developing and resource limited countries.
