Long‑Term Safety and Efficacy Study of ENTR‑601‑45 and ENTR‑601‑44 in Participants with Duchenne Muscular Dystrophy

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What is this study about?

The study focuses on Duchenne Muscular Dystrophy, a rare genetic condition that leads to progressive muscle weakness and loss of function. Participants who can benefit from a technique called exon skipping—a method that allows cells to produce a shorter but still useful form of the missing protein—will receive one of two investigational medicines, ENTR-601-45 or ENTR-601-44. Both drugs are delivered by intravenous infusion, meaning they are given slowly through a needle placed in a vein, and they belong to a phosphorodiamidate morpholino oligomer platform designed to help the therapeutic molecules reach muscle cells.

The purpose of the trial is to evaluate the long‑term safety and tolerability of the study drug in this patient population. After an initial screening, participants will receive the assigned medication at regular intervals over an extended period while undergoing routine health checks, including measurements of vital signs, blood laboratory tests, and a heart test known as an electrocardiogram. Physical examinations will assess walking ability, standing up from the floor, climbing stairs, and upper‑limb function, and blood samples will be taken to monitor drug levels and any immune response. The study is open‑label, so all participants know they are receiving the investigational therapy, and it continues beyond the earlier phase of the research.

1 baseline assessments

after you join the study, you will undergo initial assessments to record your current health status.

these assessments include a physical examination, measurement of vital signs such as blood pressure and heart rate, laboratory tests of blood and urine, an electrocardiogram (ecg) to check heart rhythm, and a review of any current symptoms.

2 first intravenous infusion of entr-601-45

you will receive an intravenous infusion of entr-601-45, a solution prepared for infusion into a vein.

the dose is calculated as 20 milligrams per kilogram of your body weight.

the infusion is administered by a trained health professional over a period of time determined by the study protocol.

3 scheduled follow‑up visits

regular clinic visits are scheduled throughout the study to monitor your safety and tolerability.

at each visit you will have vital signs checked, laboratory tests performed, an ecg recorded, and a brief physical examination.

these visits also allow the study team to record any adverse events you may experience.

4 additional intravenous infusion of entr-601-44

at designated visits you may receive an intravenous infusion of entr-601-44, another solution for infusion.

the dose is 18 milligrams per kilogram of your body weight.

the infusion is given in the same manner as the first infusion, under the supervision of study staff.

5 functional and performance assessments

periodically you will be asked to perform simple tests that measure your ability to walk, rise from the floor, climb stairs, and use your upper limbs.

examples of these tests are the 10‑meter walk/run, timed rise from floor, timed 4‑stair climb, stride velocity, north star ambulatory assessment, and performance of the upper limb version 2.0.

the results help evaluate any changes in your muscle function over time.

6 final end‑of‑study evaluation

at the end of the study period you will undergo a final set of assessments similar to the baseline visit.

these include vital signs, laboratory tests, ecg, physical examination, and the functional performance tests.

the final data are used to determine the long‑term safety and tolerability of the study drugs.

Who Can Join the Study?

  • Must be willing and able to give consent (an agreement to join the study if you are an adult) or assent (a child’s agreement to join the study) after understanding what it involves.
  • Must have already completed one of the earlier clinical studies named ENTR-601-44-201 or ENTR-601-45-201.
  • Must be male.
  • Must be within the age range specified by the study (generally children and adolescents).
  • If you are a male who is sexually active with a female partner who could become pregnant, you must agree to use condoms during sexual intercourse.

Who Cannot Join the Study?

  • If the investigator (the study doctor) together with the medical monitor or a sponsor designee decides that any change from the original parent study eligibility criteria, including any safety events (health problems) that occurred during the earlier study, would make the drug’s safe use impossible, you cannot participate.

Where you can join this trial?

Verified and Recommended Sites

No sites found in this category

Verified Sites

Site Name City Country Status
Katholieke Universiteit te Leuven Leuven Belgium
Fondazione Policlinico Universitario Agostino Gemelli IRCCS Rome Italy

Other Sites

Site Name City Country Status
Ospedale San Raffaele S.r.l. Milan Italy
Stichting Radboud University Medical Center Nijmegen The Netherlands
Universitair Ziekenhuis Gent Gent Belgium
Hospital Sant Joan De Deu Barcelona Esplugues De Llobregat Spain
Centre Hospitalier Regional De La Citadelle Liege Belgium
Ospedale Pediatrico Bambino Gesu’ Rome Italy
Hgvdvxum Vhww djesfufr Barcelona Spain
Cikpsu Cbzioso Nbkx Milan Italy
Lbqnv Uqsmgvxroenk Mykuenw Cnlqfhn (pasem Leiden The Netherlands

Want to learn more about this study or check if you can participate? Contact us.

Trial status

Country Status Recruitment Start
Belgium Belgium
Not yet recruiting
26.08.2026
Italy Italy
Not yet recruiting
26.08.2026
Spain Spain
Not yet recruiting
26.08.2026
The Netherlands The Netherlands
Not yet recruiting
26.08.2026

Trial locations

ENTR-601-45 is an experimental medication being tested in this study. It is given through a vein as a liquid that is slowly infused. The drug uses a new technology that helps deliver a small piece of genetic material into muscle cells. In Duchenne muscular dystrophy, this approach aims to let the cells skip a faulty part of the gene, which can produce a shorter but still working muscle protein. The trial is checking how safe and well‑tolerated the medication is when used for a long time.

ENTR-601-44 is another experimental medication evaluated in the same study. Like the other product, it is administered by intravenous infusion as a solution. It also belongs to the same platform that helps a genetic molecule enter muscle cells to skip a problematic gene segment. By doing this, it hopes to improve the production of a functional muscle protein in people with Duchenne muscular dystrophy. The study monitors its long‑term safety, how well patients can tolerate it, and its overall effect on the disease.

Duchenne muscular dystrophy – Duchenne muscular dystrophy is a genetic disorder that causes muscles to become weak and thin. Symptoms usually appear in early childhood, often before age five, with difficulty running, climbing stairs, and rising from the floor. As the condition progresses, the weakness spreads to the hips, shoulders and arms, leading to loss of the ability to walk and the need for a wheelchair. Over time the muscles that control breathing and other daily activities become affected, making everyday tasks increasingly difficult.

Trial ID:
2025-525124-10-00
Protocol code:
ENTR-601-DMD-202
Trial Phase:
Therapeutic exploratory (Phase II)

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