Laryngeal involvement in mucous membrane pemphigoid predicts poor response to rituximab: IJDVL

Mucous membrane pemphigoid (MMP) is an autoimmune subepidermal bullous disease with a tendency to scar and may progress to blindness or airway obstruction. When it involves the eyes or larynx, Mucous membrane pemphigoid (MMP) tends to be refractory to conventional treatments and rituximab (RTX) has emerged as a potential therapeutic solution for MMP in the past few years. Recently a case series with a review describing the use of rituximab in MMP was described in the Clinical and Experimental Dermatology journal.

It was a case series of 4 patients of MMP who were diagnosed on the basis of typical clinical features, histology and direct immunofluorescence study.

All patients were women (mean age 72 years at the initiation of RTX treatment). Three patients had oral and laryngeal disease. Ocular and oesophageal disease were seen in one patient each. The mean duration of disease before RTX therapy was 40.75 months (range 7– 84 months). All patients had failure with at least one systemic treatment. All the patients were treated with two infusions of RTX (1 g each, given on Days 1 and 15).

In the series all 3 patients had commenced treatment with inflammatory erosive laryngeal lesions without evidence of significant scarring. 2/3 patients with laryngeal involvement had no response to RTX treatment. The third patient achieved complete remission (CR) for 2 years with subsequent relapses every 2 years which responded well to an additional RTX cycle each time.. Patient 4, who did not have laryngeal involvement achieved CR and was lost to follow-up.

A literature search was done which revealed 30 articles including 167 patients of MMP treated with RTX. Late observation endpoints (defined as outcome after at least 2 months of therapy) were noted for 144 patients, of whom 100 (69.4%) achieved CR, 26 (18%) achieved partial remission (PR) and 18 (12.5%) had no remission (NR). In total CR or PR were achieved with RTX treatment in 87.5% of patients with MMP.

Different outcomes were noted in the same patient, as certain anatomical sites responded differently to RTX treatment. Of all sites, the larynx seemed to be the most refractory to RTX treatment. In total only 40% of patients with laryngeal involvement achieved CR, whereas other sites achieved CR rates of 67%–80% (P = 0.014).

Of the 7 laryngeal MMP cases recalcitrant to RTX, 2 did not respond to additional cycles of RTX, and one remained unresponsive despite therapy with intravenous immunoglobulins (IVIG). Of the six patients with laryngeal disease who achieved CR, four were taking concomitant immunosuppressive therapy making it difficult to draw conclusions about RTX efficiency.

In conclusion rituximab is a potent therapy for MMP and relapses after RTX are frequent so maintenance therapy should be considered. Laryngeal involvement in patients with MMP may predict poor response to rituximab and in view of its serious consequences of local scarring, prompt combination therapy should be considered for these MMP cases.

Source- Baniel A, Oestreicher-Kedem Y, Peled A, Bar-Ilan E, Geller S, Sprecher E, Baum S. Laryngeal mucous membrane pemphigoid serves as a prognostic factor for poor response to treatment with rituximab. Clin Exp Dermatol. 2021 Jul;46(5):915-919. doi: 10.1111/ced.14662. Epub 2021 May 27. PMID: 33811681