Bullous pemphigoid (BP) is an autoimmune subepidermal blistering disease, primarily affecting older adults. Estimating its exact global incidence and prevalence is challenging due to variations in study methodologies, diagnostic criteria, and data collection across different populations. While a single definitive global estimate is unavailable, several studies provide valuable insights into the disease burden:

• A 2023 systematic review and meta-analysis aimed to provide updated global estimates for Huntington's disease, but also included data on other neurological conditions. This review did not specifically provide updated global incidence or prevalence estimates for BP.

• A 2019 meta-analysis investigated the association between BP and malignancy. While not its primary focus, the study mentioned a malignancy rate of 11% in BP patients, but did not provide overall incidence or prevalence figures for BP.

• A 2017 review article on BP described it as the most common autoimmune subepidermal blistering disease in Western countries, typically affecting the elderly. It stated that BP is immunologically characterized by autoantibodies against BP180 and BP230. However, this review did not provide specific incidence or prevalence data.

• A 2017 study examined the incidence and prevalence of inherited epidermolysis bullosa (EB) in the United States. While providing valuable data on EB, this study did not address the incidence or prevalence of BP.

• A 2014 study estimated the standardized prevalence of pemphigoid (a group of diseases including BP) among adults in the United States using electronic health records. The overall prevalence was found to be 0.012%, or 12 cases per 100,000 adults. The prevalence increased with age, reaching 0.038% (37.7 cases per 100,000 adults) in those aged 60 years and older.

• A 2011 study determined the incidence and mortality from bullous pemphigoid in the United Kingdom using a general practice database. The incidence of BP was found to be 4.3 per 100,000 person-years and was observed to be increasing over time.

• A 2008 review article on pemphigoid diseases stated that the most common type is bullous pemphigoid, mainly affecting older people. The reported incidence in Europe had more than doubled in the past decade at the time of publication. However, precise figures were not provided.

It's important to note that BP incidence and prevalence vary by geographical region, age, and potentially other factors. Studies conducted in specific populations or regions may not be generalizable to the global population. Further research with standardized methodologies and broader data collection is needed to obtain more accurate and comprehensive global estimates of BP incidence and prevalence.

Dupilumab Trials Beyond Bullous Pemphigoid:

Dupilumab, a monoclonal antibody targeting the IL-4 receptor alpha subunit (blocking IL-4 and IL-13 signaling), is being investigated for various conditions beyond Bullous Pemphigoid. These include:

• Skin Diseases:

• Prurigo nodularis: Studies show promising results with significant itch reduction and lesion improvement.

• Nummular eczema: Dupilumab's efficacy is being explored in this chronic inflammatory skin condition.

• Allergic contact dermatitis: Trials are underway to assess dupilumab's potential in managing allergic contact dermatitis.

• Chronic hand eczema: Dupilumab is being studied as a potential treatment for chronic hand eczema.

• Spontaneous chronic urticaria: Research is exploring dupilumab's role in managing chronic urticaria, particularly in cases where standard treatments are inadequate.

• Alopecia areata: Dupilumab's efficacy in promoting hair regrowth in alopecia areata is under investigation.

• Netherton syndrome: Dupilumab's potential to alleviate symptoms in this rare genetic skin disorder is being explored.

• Eczematous eruption of aging: Case reports suggest potential benefits of dupilumab in this condition.

• Papuloerythroderma of Ofuji: Case reports indicate possible efficacy of dupilumab in this rare skin disease.

• Epidermolysis bullosa pruriginosa: Case reports suggest dupilumab may reduce pruritus and improve skin findings in this condition.

• Chronic prurigo and chronic idiopathic pruritus: Studies indicate dupilumab's potential in managing these pruritic conditions, with early improvement in itch as a predictor of response.

• Respiratory Diseases:

• Allergic bronchopulmonary aspergillosis: Dupilumab's efficacy in managing this allergic lung condition is being investigated.

• Chronic eosinophilic pneumonia: Dupilumab's potential in treating this rare lung disease is being explored.

• Allergic rhinitis: Studies are underway to assess dupilumab's role in managing allergic rhinitis.

• Asthma: Dupilumab is approved for moderate-to-severe asthma with an eosinophilic phenotype or oral corticosteroid dependence. Studies show it reduces exacerbations and improves lung function.

• Chronic rhinosinusitis with nasal polyps: Dupilumab is approved for this condition and shows significant improvement in polyp size, symptoms, and need for surgery. Head-to-head trials with other biologics are ongoing.

• Gastrointestinal Disorders:

• Eosinophilic gastrointestinal disorders: Particularly eosinophilic esophagitis (EoE), are a research focus for dupilumab. Case reports suggest potential benefits in EoG and accompanying severe asthma.

• Food allergy: Dupilumab's potential role in managing food allergies is being investigated.

Intervention Models:

The intervention models in these trials vary depending on the specific condition. They typically involve:

• Monotherapy: Dupilumab is administered alone without other systemic treatments.
• Add-on therapy: Dupilumab is added to existing standard treatments, such as topical corticosteroids in atopic dermatitis or triple therapy in COPD.
• Combination therapy: Dupilumab is used in combination with other biologics, particularly in cases of anti-TNF-induced dermatitis.

Dosage regimens also vary depending on the condition and patient characteristics, such as age and weight. Clinical trials are crucial for determining the optimal intervention models and dosage regimens for each indication.