Phase 2 Study of AGA2115 in Adults with Osteogenesis Imperfecta (COL1A1/COL1A2 Variants) Evaluating Bone Density

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What is this study about?

Osteogenesis Imperfecta is a rare genetic condition that makes bones break easily because of abnormal collagen, a protein that gives bone strength. Most adults with this condition have changes in the genes COL1A1 or COL1A2. The study investigates a new medicine called AGA2115, which is a human‑engineered antibody designed to bind to two proteins, sclerostin and dickkopf‑related protein 1, that normally limit bone growth. By blocking these proteins, the drug aims to help the body build stronger bone. Participants will receive the medicine as a subcutaneous injection (a shot under the skin) or a matching placebo that looks the same but does not contain the active drug.

The main goal of the trial is to see whether AGA2115 can increase bone mineral density (BMD) in the lumbar spine after one year of treatment. Adults with the condition will be randomly assigned to either the active drug or the placebo group and will be followed for about 12 months, with regular visits to check safety and measure bone density. The study will collect information on any side effects and overall health while participants continue their usual care.

1 baseline assessments

baseline assessments are performed shortly after joining the trial. these include measurements of bone density at the lumbar spine, collection of medical history, and laboratory tests to establish starting values.

2 first medication administration

the first dose of the study medication is given after baseline assessments are completed.

if assigned to the active group, the participant receives AGA2115 as a subcutaneous injection (injection under the skin) of 2000 mg. the injection is delivered in a solution for injection.

if assigned to the control group, a matching placebo injection is given in the same manner.

3 regular follow‑up visits

the participant returns to the study site for scheduled visits. during each visit, safety checks, blood tests, and assessments of bone health are performed.

the study medication or placebo is administered at each visit according to the schedule defined by the trial protocol.

the visits continue for the duration of the trial, which includes a total period of 12 months of treatment.

4 month 12 evaluation

at month 12, a detailed measurement of lumbar spine bone mineral density (lumbar spine BMD) is performed.

the primary outcome is the percent change from the baseline value measured at the start of the trial.

5 study completion

after the month 12 evaluation, the participant completes the trial.

final safety assessments and study documentation are completed before the study ends.

Who Can Join the Study?

Be a man or a woman between 18 and 75 years old who has been diagnosed with osteogenesis imperfecta type I, III, or IV, and who has had genetic testing that shows changes in the COL1A1 or COL1A2 genes (these are the genes that help make strong bone protein).
Be able to sign an informed consent form, meaning you understand the study and agree to follow the rules and requirements written in the consent document and study plan.
Have a bone density measurement called a BMD (bone mineral density) with a T-score of –1.0 or lower at one of the following places: the lower back (lumbar spine), the upper part of the thigh bone (total hip), or the upper part of the thigh bone near the hip (femoral neck). A lower T-score means weaker bones.

Who Cannot Join the Study?

Having a low level of Vitamin D, which means the body does not have enough of this vitamin for healthy bones.
Having had cancer (also called malignancy) diagnosed or treated within the last 5 years.
Being pregnant, breastfeeding, or planning to become pregnant at any time during the study.
Having taken part in another clinical trial that gave a study drug within the past 12 months, or being enrolled in another trial at the same time.
Having uncontrolled diseases that affect bone health, such as abnormal parathyroid or thyroid function, or other hormone disorders.
Having a high or low level of blood calcium (hypercalcemia or hypocalcemia).
Having a history of rickets, osteomalacia, or any bone condition other than osteogenesis imperfecta that causes long‑bone deformities or a higher risk of fractures.
Having taken bisphosphonate medicines (drugs used to treat bone loss) within the past 6 months.
Having taken teriparatide, abaloparatide, strontium ranelate, or hormone replacement therapy within the past 12 months.
Having taken denosumab (or similar drugs) within the past 2 years.
Having ever taken anti‑sclerostin antibody medicines such as romosozumab, setrusumab, or blosozumab.
Having had a heart attack, stroke, or other major cardiovascular event within the past 12 months.

Where you can join this trial?

Verified and Recommended Sites

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Verified Sites

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Other Sites

Site Name	City	Country
Odense University Hospital	Odense	Denmark
Region Midtjylland	Aarhus	Denmark
Isala Klinieken Stichting	Zwolle	The Netherlands
Centre Hospitalier Lyon Sud	Pierre Benite	France
Hopital Beaujon	Clichy	France
Efqmcqr Unlbmsexeelr Mynnifm Cfpyxyv Riidkivde (exzygns Mgp	Rotterdam	The Netherlands
Lwqwu Usypajoqrxjp Mlarqsx Cupstqn (pqzbf	Leiden	The Netherlands

Trial status

Country	Status	Recruitment Start
Denmark	Not yet recruiting	27.02.2026
France	Not yet recruiting	27.02.2026
The Netherlands	Not yet recruiting	27.02.2026

Trial locations

AGA2115 is an experimental medicine that uses a specially designed antibody to block two proteins, sclerostin and dickkopf‑related protein 1, which normally stop bone from forming. By inhibiting these proteins, the drug aims to help the body build stronger bone. It is given as a liquid that is injected under the skin. In this study, the medicine is being tested to see if it can increase bone density in adults with osteogenesis imperfecta, a condition that makes bones fragile.

Investigated diseases:

Osteogenesis imperfecta

Osteogenesis Imperfecta – Osteogenesis Imperfecta is a genetic disorder that makes bones unusually weak and prone to breaking. People with the condition often experience fractures with little or no injury, especially during childhood. As they grow, the bones may become curved or misshapen, leading to a shorter stature. The disorder can also cause teeth that break easily and a tendency to develop joint stiffness. Over time, repeated fractures and bone changes can affect mobility and daily activities.

Trial ID:

2025-522951-24-00

Protocol code:

ACT24-001

NCT ID:

NCT07062588

Trial Phase:

Therapeutic exploratory (Phase II)

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Phase 2 Study of AGA2115 in Adults with Osteogenesis Imperfecta (COL1A1/COL1A2 Variants) Evaluating Bone Density

What is this study about?

Who Can Join the Study?

Who Cannot Join the Study?