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

Trial details

Who runs it

Biogen

Trial code

NCT07722546EU 2026-526482-19-00

Record updated

12 November 2026

Original 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.Read full original descriptionShow less

A Placebo-Controlled, Multicenter, Randomized Phase 2 Trial Evaluating the Efficacy and Safety of Felzartamab Compared to Placebo in Adult Participants With Graves' Disease

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).

Inclusion: 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.

Exclusion: ATD dose change within 12 weeks prior to Day1, or anticipated need for dose adjustment prior to randomization (except for protocol-defined safety management); Use of immunosuppressive therapy within 5 half-lives/12 weeks of Screening; 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; History of thyroidectomy or radioactive iodine therapy; 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; Known or suspected history of hypersensitivity to felzartamab or its excipients; Co-existing autoimmune diseases that require systemic immunosuppressants (e.g., cyclosporine, methotrexate, biologics, monoclonals); Any condition that requires chronic use of high-dose steroids; NOTE: Other protocol-defined Inclusion/Exclusion criteria may apply; Type 1 diabetes and type 2 diabetes mellitus with hemoglobin A1c (HbA1c) > 8%.

ClinicalTrials.gov NCT07722546 · EU CTIS 2026-526482-19-00