A Study to Learn About The Effects of Felzartamab on Thyroid Function and Its Safety in Adults With Graves' Disease Ages 18 to 75 Years Old

NCT07722546 | Not Yet Recruiting Phase 2 FDA Drug

• 2 other identifiers: 299GD2012026-526482-19-00
• Study Type: interventional
• Target: 60
• Locations: 0 countries
• Sites: N/A

Brief Summary

In this study, researchers will learn more about the use of felzartamab in participants with Graves' Disease, also known as GD. GD is an autoimmune disease, which means the body's immune system attacks its own healthy cells. In people with GD, the immune system produces abnormal antibodies, called thyroid-stimulating hormone receptor antibodies (TRAb), that attack the thyroid gland. This causes the thyroid to become too active and produce too much hormone, a condition called hyperthyroidism. Participants with GD are often treated with anti-thyroid drugs, or ATDs, which are medicines that help bring thyroid hormone levels back to normal. Felzartamab is designed to target certain immune cells that produce the abnormal TRAb antibodies. The main goal of the study is to learn whether felzartamab can help bring thyroid hormone levels back to normal and allow participants to stop taking ATDs. Participants will receive either felzartamab or placebo during the study. A placebo looks like the study drug but contains no real medicine. The main question that researchers want to answer is:

• How many participants have normal thyroid levels without receiving any ATD medicine at Week 24? Researchers will also learn more about the safety of felzartamab and how the body processes the drug. The study will be done as follows:
• Participants will be screened to check if they can join the study.
• This is a double-blind study, which means neither the participants, study doctor, or site staff will know if participants are receiving felzartamab or a placebo.
• Participants will be placed into 1 of 3 groups. Two groups will receive felzartamab while the other receives placebo.
• Participants will receive felzartamab or placebo as intravenous (IV) infusions, which are slow injections into a vein using a needle. The Treatment Period will last 20 weeks.
• During the Treatment Period, the study doctor may gradually lower the dose of the ATD if a participant's thyroid levels become normal.
• Afterwards, participants will enter a follow-up period which will last 12 weeks.
• In total, participants will have 22 study visits. Participants will stay in the study for about 9 months (up to 36 weeks).

Conditions

Graves' Disease

Keywords

Hyperthyroidism

Outcome Measures

Primary Outcomes (1)

• Percentage of Participants who are Euthyroid and off Anti-Thyroid Drugs (ATD) at Week 24

  At Week 24

Secondary Outcomes (9)

• Percentage of Participants who Have Down-Titrated to ≤ 50% of Their Baseline ATD and are Euthyroid at Week 12 and Week 24

  At Weeks 12 and 24

• Percentage of Participants who are Euthyroid at Week 12 and Week 24

  At Weeks 12 and 24

• Change From Baseline in Free Triiodothyronine (FT3)

  Baseline up to Week 32

• Change From Baseline in Free Thyroxine (FT4)

  Baseline up to Week 32

• Change From Baseline in Thyroid-Stimulating Hormone (TSH)

  Baseline up to Week 32

Study Arms (3)

Placebo

PLACEBO COMPARATOR

Participants will receive multiple IV doses of placebo.

Drug: Placebo

Felzartamab or Placebo

EXPERIMENTAL

Participants will receive multiple IV doses of felzartamab or placebo.

Drug: Felzartamab; Drug: Placebo

Felzartamab

EXPERIMENTAL

Participants will receive multiple IV doses of felzartamab.

Drug: Felzartamab

Interventions

Felzartamab DRUG

Administered IV

Also known as: BIIB148, MOR202, MOR03087, TJ202

Felzartamab; Felzartamab or Placebo

Placebo DRUG

Administered IV

Felzartamab or Placebo; Placebo

Eligibility Criteria

• Age: 18 Years - 75 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Have active disease and are thyroid-stimulating hormone receptor antibodies (TRAb) positive, defined as:
• Free thyroxine (FT4) and free triiodothyronine (FT3), within the reference range,
• suppressed thyroid-stimulating hormone (TSH)
• TRAb levels \> upper limit of normal (ULN)
• Participants must be receiving stable dose of anti-thyroid drugs (ATD) for at least 12 weeks prior to randomization.
• Must agree to refrain from blood product donation from Screening through end of study. If a participant terminates early from the study, they must refrain from blood product donation for 90 days following the last dose of study drug.

You may not qualify if:

• History of thyroidectomy or radioactive iodine therapy.
• ATD dose change within 12 weeks prior to Day1, or anticipated need for dose adjustment prior to randomization (except for protocol-defined safety management).
• Active, moderate-to-severe, or sight threatening thyroid eye disease (TED) (as assessed by the clinical activity score \[CAS\]), or requirement for imminent or ongoing TED-directed therapy (e.g., systemic glucocorticoids, biologic therapy, orbital radiation, surgery).
• Any history of malignancy within 5 years prior to Screening except for adequately treated in situ carcinoma of the cervix uteri, basal or squamous cell carcinoma or non-melanomatous skin cancer.
• History of hyperthyroidism not caused by GD (e.g. toxic multinodular goiter, autonomous thyroid nodule, acute inflammatory thyroiditis) and/or history or presence of thyroid storm.
• Type 1 diabetes and type 2 diabetes mellitus with hemoglobin A1c (HbA1c) \> 8%.
• Known or suspected history of hypersensitivity to felzartamab or its excipients.
• Use of immunosuppressive therapy within 5 half-lives/12 weeks of Screening.
• Co-existing autoimmune diseases that require systemic immunosuppressants (e.g., cyclosporine, methotrexate, biologics, monoclonals).
• Prior use of an anti-Neonatal Fragment Crystallizable Receptor (FcRn) therapy or intravenous immunoglobulin (IVIg) within 6 months of the last dose prior to Screening.
• Any condition that requires chronic use of high-dose steroids.

Sponsors & Collaborators

• Biogen: lead

MeSH Terms

Conditions

Graves Disease; Hyperthyroidism

Interventions

felzartamab

Condition Hierarchy (Ancestors)

Exophthalmos; Orbital Diseases; Eye Diseases; Goiter; Thyroid Diseases; Endocrine System Diseases; Autoimmune Diseases; Immune System Diseases

Study Officials

• Medical Director

  Biogen

  STUDY DIRECTOR

Central Study Contacts

US Biogen Clinical Trial Center

CONTACT

866-633-4636; clinicaltrials@biogen.com

Global Biogen Clinical Trial Center

CONTACT

clinicaltrials@biogen.com

Study Design

• Study Type: interventional
• Phase: phase 2
• Allocation: RANDOMIZED
• Masking: QUADRUPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: July 20, 2026
• First Posted: July 23, 2026
• Study Start (Estimated): August 15, 2026
• Primary Completion (Estimated): January 31, 2028
• Study Completion (Estimated): March 31, 2028
• Last Updated: July 23, 2026

Record last verified: 2026-07

Data Sharing

• IPD Sharing: Will share