NCT07722546 · Biogen
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
(GRAVITATE)
What this study is about
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.
View original scientific description
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).
Interventions
DRUG
Felzartamab
Administered IV
DRUG
Placebo
Administered IV
Primary outcome measures
Percentage of Participants who are Euthyroid and off Anti-Thyroid Drugs (ATD) at Week 24
Time frame: At Week 24
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- 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. Key
Exclusion criteria
- 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. NOTE: Other protocol-defined Inclusion/Exclusion criteria may apply.
Where
- Los Angeles, California
- Asheville, North Carolina
- Dallas, Texas
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Aug 21, 2026 · Source of record for eligibility and locations