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

ARGX-113-2009 is an operationally seamless 2-part, phase 2/3, prospective, global, multicenter, randomized, double-blinded, placebo-controlled study to investigate the efficacy, safety, tolerability, immunogenicity, participant-reported outcome measures (including those assessing participant QoL), PK, and PD of efgartigimod PH20 SC administered via subcutaneous (SC) injection in adult participants with moderate to severe BP. This study intends to demonstrate that efgartigimod is an effective and safe treatment for BP, providing participants with control of disease activity (CDA) and eventually remission while reducing their cumulative exposure to OCS.

study will consist of 2 parts:

* Part A of the study is a phase 2 evaluation that intends to provide proof of concept for the therapeutic activity of efgartigimod PH20 SC in participants with BP.
* Part B of the study is a phase 3 evaluation that intends to confirm the results obtained from part A in a separate, larger group of participants with BP.

An interim analysis will be performed during part A (on data obtained through week 26 for all Part A participants) to assess the primary endpoint and several secondary endpoints, confirm the appropriate sample size for part B of the study, and determine whether the efficacy results observed through week 26 of part A warrant continued study of efgartigimod PH20 SC for the treatment of participants with BP (futility analysis).

Other than differences in main goals, endpoints, and statistical analyses, parts A and B are identical in schedule, structure, assessments, and conduct.


Eligibility Criteria:
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 of signing the informed consent form (ICF).
* Participants have clinical signs of BP.
* Contraceptive use should be consistent with local regulations regarding the methods of contraception for those participating in clinical studies and: Women of childbearing potential must have a negative serum pregnancy test at screening and a negative urine pregnancy test at baseline before study intervention can be administered.

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 4 weeks 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 local regulations).
* History of malignancy unless deemed cured by adequate treatment with no evidence of recurrence for ≥3 years before the first administration of the IMP. Participants with the following cancers can be included at any time, provided they are adequately treated prior to their participation in the study: Basal cell or squamous cell skin cancer, Carcinoma in situ of the cervix, Carcinoma in situ of the breast, Incidental histological 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, could confound the results of the study or put the patient at undue risk or prevent participants 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 currently participating 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, or medication abuse as assessed by the investigator
* Pregnant or lactating females and those who intend to become pregnant during the study
* Live or live-attenuated vaccine received \<4 weeks before baseline visit

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