Mucous Membrane Pemphigoid After Anti‐ <scp>PD</scp> ‐1 Therapy: Risk‐Stratified Management and Treatment Outcomes

Mucous membrane pemphigoid (MMP) following anti-programmed cell death-1 (PD-1) therapy is rare but increasingly reported. Management of high- and low-risk MMP in this setting and the potential oncologic trade-offs remain poorly defined. We performed a narrative synthesis of all published cases of anti-PD-1-associated MMP, following MEDLINE, Embase, and PubMed Central searches from January 2014 to June 2025. Fifteen cases from thirteen reports met the inclusion criteria, with a median MMP latency period of 12.5 weeks. The oral mucosa was frequently involved and was the index site in 84.6% (11/13). Ocular involvement was observed in only one patient and resolved with topical corticosteroids (TCS). Anti-PD-1 therapy was successfully continued in three low-risk cases with systemic steroid treatment. Overall, doxycycline plus TCS produced the best low-risk response: 5/10 low-risk patients were treated with doxycycline plus TCS; all five achieved complete remission (CR) at least at one anatomic site (3/5 CR at all sites, 2/5 CR with partial response (PR) at different sites). High-risk MMP required escalation with methotrexate, rituximab, and/or intravenous immunoglobulin (IVIg). Of the patients, 86.7% (13/15) experienced CR or PR of MMP, and a single recurrence was reported. Tumor control (CR or PR) was maintained in 72.7%, with one relapse following anti-PD-1 therapy cessation. Anti-PD-1-associated MMP is typically oral-predominant and, unlike classic MMP, has infrequent ocular involvement. Management and therapeutic responses differed by site of involvement. Discontinuation of anti-PD-1 is not always required. When anti-PD-1 therapy continuation is clinically prioritized, a systemic steroid-based regimen can stabilize MMP and facilitate completion of immunotherapy.