This clinical study will evaluate the effectiveness, safety, and tolerability of the investigational study drug efgartigimod in adults with moderate to severe pemphigus vulgaris (PV) or pemphigus foliaceus (PF)


You may be eligible to participate in the study if you are at least 18 years of age or older and have been diagnosed with pemphigus vulgaris or pemphigus foliaceus. Additional eligibility requirements apply.


Find a participating site location near you and complete a questionnaire to determine your potential eligibility for this global study.

See if you qualify for this study.




Fill out the form to determine if you may be eligible.

Your personal information will be kept confidential, and will not be shared without your permission except as required by law, and will only be used for the purpose of this study. Our full privacy policy can be viewed here: Privacy Policy.

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Additional eligibility criteria apply.

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Am I Eligible?

These are some of the requirements to be able to participate in the study.

Are at least 18 years of age or older.

Have a clinical diagnosis of pemphigus vulgaris (mucosal, cutaneous, mucocutaneous) or pemphigus foliaceus.

Have no known negative reactions to oral prednisone.

Have not been diagnosed with another significant serious disease.

Have not recently undergone or have planned a major surgery during the period of the trial.

Are not pregnant or lactating and are not actively trying to become pregnant.

There are additional study requirements that participants must meet in order to take part in the study. A study representative will discuss them with you.

More about the ADDRESS Study

ADDRESS Study Goals


The ADDRESS study is designed to assess how effective and safe the investigational study drug efgartigimod SC (subcutaneous, means under the skin) is compared to a placebo (drug with no active ingredient) given with prednisone as a possible treatment for adults living with pemphigus vulgaris (PV) or pemphigus foliaceus (PF).

What to expect during the ADDRESS study


To participate in this study, participants will be asked to read and sign an Informed Consent Form (ICF). The form explains:

  • The purpose of the study
  • Study visits and procedures
  • Potential risks and benefits
  • Confidentiality
  • Information on how to withdraw from the study


During screening, participants will be evaluated to see if they meet the study criteria. The screening period can last up to 3 weeks.


Approximately 150 adults will take part in the ADDRESS study in countries around the world. Participants enrolled in the study will be randomly assigned by a computer (by chance) to either the efgartigimod SC group or the placebo group. 2 out of every 3 participants will receive the investigational study drug while the remainder will receive the placebo. All participants regardless of study treatment assignment (receiving either the investigational study drug or placebo) will additionally receive oral prednisone, or equivalent such as prednisolone. The study is blinded, meaning that neither you nor the study team will know which study treatment you are receiving.


As safety is our top priority, all enrolled participants will be monitored and supported by the study team. Procedures to make sure participants are doing well will be required in this study, some of them include:

  • Health questions
  • Physical examinations
  • Blood and urine tests


Participants will be enrolled in the ADDRESS study for up to 41 weeks (it may be shorter). If all criteria are met, at the conclusion of the study, you will be given the opportunity to join an open-label extension study (ADDRESS+ study) where everyone participating may receive efgartigimod SC for an additional year in accordance to his/her clinical status.

More About Pemphigus

Pemphigus Vulgaris (PV) or Foliaceus (PF) are rare and severe autoimmune diseases where antibodies in the body attack skin proteins and cause blistering of the skin.(b)

Normally, the immune system within your body produces antibodies to fight off harmful invaders (i.e. bacteria and viruses), however in pemphigus, the body produces antibodies that damage cells in your skin and mucous membranes. (a)

Pemphigus vulgaris typically presents with blisters on the skin and/or in the mouth and is the most common type of pemphigus. (a)

With pemphigus foliaceus, blisters may appear on the scalp, face, or torso. It does not affect mucous membranes, so pemphigus foliaceus blisters will not appear in the mouth or eyes. (a)

Pemphigus vulgaris typically causes weight loss as a result from difficulty in swallowing.

(a) https://mayocl.in/32LRZ9R

(b) https://rarediseases.org/rare-diseases/pemphigus/

Frequently Asked Questions

What is a clinical study?

Clinical studies are research studies that evaluate the effect of an intervention on specified outcomes. In a clinical trial, volunteer participants receive specific interventions according to the research plan or protocol. These interventions may be medical products, such as drugs or devices; procedures; or changes to participants’ behavior, such as diet.[1]


Clinical trials used in drug development are sometimes described by phase. These phases are defined by the Food and Drug Administration (FDA). Each phase has a different purpose and helps researchers answer different questions.[2]

  • Phase 1: Researchers test a drug or treatment in a small group of people for the first time. The purpose is to study the drug or treatment to learn about safety and identify side effects.
  • Phase 2: The new drug or treatment is given to a larger group of people to determine its effectiveness and to further study its safety.
  • Phase 3: The new drug or treatment is given to large groups of people to confirm its effectiveness, monitor side effects, compare it with standard or similar treatments, and collect information that will allow the new drug or treatment to be used safely.
  • Phase 4: After a drug is approved by the FDA and made available to the public, researchers track its safety in the general population, seeking more information about a drug or treatment’s benefits, and optimal use.

What is an investigational study drug?

An investigational study drug has not been approved by the U.S. Food and Drug Administration (FDA) or other regulating body but is allowed to be administered to people for research purposes.

What is Efgartigimod?

Efgartigimod is the investigational study drug that is being tested in this clinical research study. Efgartigimod is being evaluated for the treatment of participants with severe autoimmune diseases with confirmed presence of pathogenic immunoglobulin G, IgG autoantibodies, where a severe unmet medical need exists such as pemphigus.


Refer to the argenx website for more information.

What is a placebo?

A placebo has no active ingredient and is used to compare the effects of the investigational study drug. The placebo will look like the investigational study drug and will be administered the same way to make sure that no one, not even the study doctor, will know which drug has been assigned to whom.

How is COVID-19 expected to affect the trial?

During the COVID-19 pandemic, it may not be possible to perform all assessments as planned for this trial. With this possibility in mind, processes and procedures have been developed to provide participants with pemphigus the opportunity to continue the study during the COVID-19 pandemic. All sites are equipped with personal protective equipment (PPE) and are practicing social distancing when relevant. If you have any additional questions or concerns as related to the COVID-19 pandemic, please speak with your study doctor.

Can participants withdraw from the clinical trial after they’ve started?

Taking part in a clinical research study is entirely voluntary. Participants can withdraw at any time for any reason. Your standard care by your primary doctor will not change.

What are my responsibilities while participating in this study?

You are asked to follow, without exception, the rules and instructions listed within the Informed Consent for the study. If you do not follow these rules and instructions, you may be withdrawn from the study.


In order to provide maximum protection for your health, the study is conducted under the direct supervision of the study doctor, who is assisted by trained healthcare personnel.  You will need to provide all information about your current and past health (medical history) at the Screening Visit and at each Follow-Up Visit, including your participation in any other research studies. This information is to protect your health.


If you have a primary doctor, it is strongly recommended that you inform them of your interest to participate in this research study.

Will compensation be provided?

There will be no cost to you for taking part in this study. You will receive all investigational study drugs, tests, examinations, and medical care related to this study at no cost. You will not be paid to take part in this study, but you may be compensated for any reasonable travel expenses (bus/train/taxi fares) incurred as a result of taking part in this study if you provide a receipt. A study representative can answer any questions you may have about compensation and travel concierge services.

How can I learn more about the investigational drug and this study?

More information on this clinical trial can be found through the links below:

ADDRESS: Clinicaltrials.gov NCT04598451  

ADDRESS+: Clinicaltrials.gov NCT04598477




More information about argenx (the company conducting this trial) : https://www.argenx.com/

Study Locations

GREEN=ACTIVE Location is currently enrolling participants for the study.

RED = PLANNED Location is planned, but not currently enrolling participants at this time.

If you don’t see an activated site near you, please come back at a later time, activated sites will be updated in real time. If you see an activated site near you and are interested in participating in the ADDRESS study, complete the form to speak with a study representative regarding your eligibility and available study locations.

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      Please contact a study representative at (844) 576-0114 for more information.



      Interested participants should fill out the above form.

      For additional information, contact a study representative at (844) 576-0101.

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