Tocilizumab for severe and refractory mucous membrane pemphigoid

BACKGROUND: Mucous membrane pemphigoid (MMP) is a rare autoimmune blistering disease involving mucous membranes with a potentially devastating fibrosing course. Laryngotracheal and/or oesophageal involvement may lead to life-threatening complications, while corneal involvement may lead to blindness. OBJECTIVES: To characterize the serum cytokine profile of MMP and to evaluate the efficacy of tocilizumab in nine cases of severe MMP according to the serum levels of IL-6. METHODS: Sera from MMP patients were compared to sex- and age-matched healthy donors (HD) and patients with bullous pemphigoid (BP), using two proteomic assays (Olink and Luminex). The Olink assay included 40 MMP, 40 BP and 40 HD sera, and the Luminex assay included 63 MMP, 31 BP and 24 HD sera. Based on these findings, nine patients with severe and refractory MMP received tocilizumab on a compassionate use basis after failure of standard therapies. RESULTS: Proteomic analyses revealed high serum levels of IL-6, IL-8, MIP-1α/CCL3 and MIP-1β/CCL4 in MMP compared to BP and HD. Patients with MMP who achieved complete remission during follow-up had lower baseline serum levels of IL-6 (p < 0.0001), IL-8 (p = 0.0382), MIP-1α/CCL3 (p = 0.0005) and MIP-1β/CCL4 (p = 0.0009) than those with persistent disease activity. Nine patients with severe and refractory MMP were treated with tocilizumab. Their mean MMPDAI score decreased from 14.8 ± 6.6 to 4.2 ± 3.2 (p = 0.009). At the last evaluation, seven patients (78%) were in partial remission, one (11%) in complete remission and one (11%) recently treated achieved control of disease activity. Baseline IL-6 was elevated in five of eight tested patients; all three with normal IL-6 levels improved clinically. Four non-severe adverse events were observed (two neutropenias, one thrombocytopenia, one hepatic cytolysis). CONCLUSIONS: Proteomic analyses identified a distinct MMP cytokine profile with increased IL-6, IL-8, MIP-1α/CCL3 and MIP-1β/CCL4, supporting IL-6 targeting, with tocilizumab as a potential option in severe refractory MMP.