A Phase 2/3 Study of Efgartigimod PH20 SC in Adult Participants with Bullous Pemphigoid

Inclusion Criteria:

• The participant is willing and able to do the following:

1. understand the requirements of the study

2. provide written informed consent

3. comply with the study protocol procedures.

• The participant is male or female and has reached the age of consent at the time ofsigning the informed consent form (ICF).

• Participants have clinical signs of BP.

• Contraceptive use should be consistent with local regulations regarding the methodsof contraception for those participating in clinical studies and: Women ofchildbearing potential must have a negative serum pregnancy test at screening and anegative urine pregnancy test at baseline before study intervention can beadministered.

The full list of inclusion criteria can be found in the protocol.

Exclusion Criteria:

• Other forms of pemphigoid or other autoimmune bullous diseases (AIBDs).

• Received unstable dose of treatments known to cause or exacerbate BP for at least 4weeks prior to the baseline visit

• Use of BP treatments other than oral corticosteroids (OCS), topical corticosteroids (TCS), conventional immunosuppressants or dapsone.

• Known contraindication to OCS therapy

• Active, chronic or latent infection at screening

• Positive COVID-19 test result at screening (testing performed if required per localregulations).

• History of malignancy unless deemed cured by adequate treatment with no evidence ofrecurrence for ≥3 years before the first administration of the IMP. Participantswith the following cancers can be included at any time, provided they are adequatelytreated prior to their participation in the study: Basal cell or squamous cell skincancer, Carcinoma in situ of the cervix, Carcinoma in situ of the breast, Incidentalhistological finding of prostate cancer

• Clinical evidence of other significant serious diseases, have had a recent surgery,or who have any other condition that, in the opinion of the investigator, couldconfound the results of the study or put the patient at undue risk or preventparticipants from complying with protocol requirements

• Use of an investigational product within 3 months before the first dose of IMP

• Previously participated in a clinical study with efgartigimod or currentlyparticipating in another interventional clinical study

• Known hypersensitivity to any of the components of the administered treatments

• Positive serum test at screening for an active infection: HBV, HCV, HIV

• Current or history (ie, within 12 months of screening) of alcohol, drug, ormedication abuse as assessed by the investigator

• Pregnant or lactating females and those who intend to become pregnant during thestudy

• Live or live-attenuated vaccine received <4 weeks before baseline visit

The full list of exclusion criteria can be found in the protocol.