Safety and Tolerability of Intrathecal TRCN-1023 in Adults with Amyotrophic Lateral Sclerosis (ALS) – Randomized Placebo‑Controlled Phase 1/2 Trial

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What is this study about?

The study focuses on adults with Amyotrophic lateral sclerosis, a rare condition that leads to gradual loss of muscle strength and control. The experimental medicine being tested is TRCN-1023, which is delivered as a small amount injected directly into the fluid surrounding the spinal cord, a technique called intrathecal administration. For comparison, a matching placebo containing only artificial cerebral spinal fluid is also used.

The purpose is to evaluate the safety and tolerability of single doses of the study drug. After receiving one injection, participants are monitored for several weeks to track any side effects and to assess how the drug moves through the body (pharmacokinetics) and how it influences bodily functions (pharmacodynamics). The trial uses a randomized, double‑blind design, meaning neither the participants nor the study staff know which injection is the active drug or the placebo, and it includes a short series of visits for screening, dosing, and follow‑up assessments.

1 enrollment

after agreeing to participate, you become a trial participant and receive a study identification number.

2 baseline evaluation

a series of assessments are performed before any study medication is given. these include a review of medical history, a physical examination, and collection of blood and cerebrospinal fluid (csf) samples for laboratory testing.

the results establish your health status at the start of the trial.

3 randomization

you are assigned, by a computer system, to receive either trcn-1023 or the placebo (artificial csf). the assignment is concealed from you and the study staff.

4 study drug administration

a single dose of the assigned product is given by intrathecal injection, which means the medication is injected into the space surrounding the spinal cord.

the exact amount of trcn-1023 varies according to the dose level being tested; the placebo is an identical‑appearing solution of artificial csf.

5 immediate post‑injection monitoring

after the injection you remain in the clinic for several hours while staff observe you for any signs of adverse events such as changes in breathing, blood pressure, or discomfort.

additional blood and csf samples may be taken during this period to begin assessing the medication’s behavior in the body.

6 follow‑up visits

you return to the clinic at scheduled times over the observation period (typically a number of weeks defined by the study).

each visit includes a safety check, recording of any new adverse events, and collection of blood and csf samples to measure the levels of trcn-1023 and evaluate its pharmacokinetics (how the body processes the drug) and pharmacodynamics (the drug’s effects).

7 final assessment

at the end of the defined follow‑up period, a final set of safety examinations and laboratory tests are performed.

the information gathered is used to determine the overall safety and tolerability of the single dose of trcn-1023.

Who Can Join the Study?

Be able to fully understand why the study is being done, the possible risks, and sign a written consent form that follows Good Clinical Practice (GCP) and allows the use of your protected health information.
If you are male, you must agree to use at least one highly effective birth‑control method from the day you sign the consent until at least 24 weeks after the last study dose, and you must not donate sperm for the same 24‑week period. Your female partner must also use a highly effective method (such as a condom plus diaphragm with spermicide or condom plus spermicide) from the first screening visit until 24 weeks after the last dose.
You must agree not to share any details about your trial experience, safety information, or results on social media or other public places.
You must be at least 18 years old and not older than 75 years at the time of the first screening visit.
You must have a diagnosis of ALS that is classified as clinically definite, probable, or probable laboratory‑supported according to the revised EI Escorial criteria (a set of guidelines used by doctors to confirm ALS).
You must have had ALS‑related symptoms (such as muscle weakness or loss of function in the upper motor neuron) within the past 24 months; occasional twitching (fasciculations) or cramps alone are not enough.
You need to be able to complete the required lung function tests (such as measuring breathing capacity) with results that fall within the normal range for your age, sex, and height.
You must be willing and able to follow all study procedures, which include traveling to the study site, undergoing a brain magnetic resonance imaging (MRI) scan, a lumbar puncture (spinal tap), an intrathecal (IT) injection (a medication given into the fluid around the spinal cord), blood draws, and any home‑based assessments.
You must be on a stable dose of an approved ALS medication for at least 4 weeks before the first screening visit:
- If you take riluzole, the dose must stay the same (for example, 50 mg twice daily) throughout the study.
- If you take edaravone, you must have completed at least two treatment cycles before screening and keep the same dose during the study; if edaravone is given by IV, it must be given at least 1 week apart from the study drug.
Your blood tests that check clotting ability (including platelet count, International Normalized Ratio (INR), prothrombin time (PT), and activated partial thromboplastin time (aPTT)) must be within normal limits, or any abnormal result must be cleared by the investigator.
If you are female, you must meet one of the following:
- Use at least one highly effective birth‑control method from the time you sign the consent until at least 112 days after the last study dose.
- Be postmenopausal, meaning you have had no periods for at least 12 months without another medical reason, confirmed by a hormone test (follicle‑stimulating hormone, FSH).
- Be surgically sterile (have had a hysterectomy, removal of both fallopian tubes, or removal of both ovaries) at least 1 month before screening.
- If not surgically sterile, have a negative pregnancy test (highly sensitive serum β‑human chorionic gonadotropin (β‑HCG)) at the first screening visit.

Who Cannot Join the Study?

Receiving any vaccine within four weeks before the planned study drug injection.
Having significant heart test (electrocardiogram or ECG) problems, such as a prolonged QT interval (over 450 ms for men or 470 ms for women), abnormal heart‑wave shapes that make the QT measurement unreliable, a history of irregular heartbeats, symptoms of long QT syndrome, or risk factors for a dangerous rhythm called torsade de pointes, low heart rate, low potassium or magnesium levels, or a known congenital long QT condition.
Being currently enrolled in another clinical trial or having taken another investigational drug within four weeks (or five drug half‑lives, whichever is longer) before the first screening visit.
Having previously received small interfering RNA (siRNA), antisense oligonucleotides (ASOs), stem‑cell therapy, or gene therapy.
Using off‑label ALS disease‑modifying drugs before the first screening visit.
Having an active infection that requires antiviral or antimicrobial medication and that will not be finished at least seven days before the first study visit.
Having a recent history of drug or alcohol abuse (within the past six months) or a positive urine test for illegal drugs, unprescribed opiates, barbiturates, or benzodiazepines.
Having a significant risk of suicide, such as suicidal thoughts or behaviors in the past year or a clinical assessment indicating high risk.
Having another serious medical or psychiatric condition that could prevent completing the trial.
Having a known allergy or intolerance to antisense oligonucleotides (ASOs).
Any condition that the investigator believes would make participation unsafe or would interfere with the study.
Having a tracheostomy or needing continuous assisted ventilation for more than 22 hours per day during the three months before the first screening visit.
Being unable to avoid alcohol for 24 hours before and after each study drug administration.
Being an employee, contractor, or immediate family member (spouse, parent, child, or sibling) of the sponsor, investigator, or site staff.
Having a serious lung disease not caused by ALS that could affect breathing assessments (intermittent non‑invasive ventilation is allowed).
Having another neuromuscular or neurodegenerative disease that could confuse study results, except frontotemporal dementia is allowed if ALS is the main diagnosis.
Being pregnant, breastfeeding, or, if of child‑bearing potential, not using effective birth‑control measures.
Having any reason that prevents a brain MRI, such as a pacemaker, aneurysm clip, artificial heart valve, metal implants, or metal fragments in the eyes, skin, or body.
Having any reason that prevents a lumbar puncture or intrathecal injection, including a platelet count below 100,000/mm³, clotting disorders, use of blood‑thinners that cannot be safely stopped, signs of increased pressure inside the skull, or previous spinal surgery that would make the procedure difficult.
Having certain abnormal laboratory results, such as liver enzymes (ALT, AST) or gamma‑glutamyl transferase > 3 times the normal limit, total bilirubin > 2 times normal (unless Gilbert’s syndrome is documented), serum creatinine > 2 times normal, estimated kidney function (eGFR) below 60 mL/min/1.73 m², hemoglobin below 9 g/dL, or neutrophil count below 1,000 cells/µL.
Having a known infection with HIV, hepatitis C, or chronic hepatitis B.

Where you can join this trial?

Verified and Recommended Sites

No sites found in this category

Verified Sites

Site Name	City	Country	Status
Rostock University Medical Center	Rostock	Germany

Other Sites

Site Name	City	Country
Universitair Medisch Centrum Utrecht	Utrecht	The Netherlands
Klinikum der Technischen Universitaet Muenchen (TUM Klinikum)	Munich	Germany
Institut fuer Klinische Transfusionsmedizin und Immungenetik Ulm gGmbH	Ulm	Germany
Universitaetsklinikum Schleswig-Holstein AöR	Kiel	Germany

Trial status

Country	Status	Recruitment Start
Germany	Not yet recruiting	01.06.2026
The Netherlands	Recruiting	01.06.2026

Trial locations

TRCN-1023 is an experimental drug being tested for the first time in people with amyotrophic lateral sclerosis (ALS). In this study, it is given as a small amount of liquid that is injected directly into the space around the spinal cord (intrathecal injection). The trial is looking at how safe the drug is, how well people can tolerate it, and how the body processes it after a single dose. Researchers are also checking whether the drug shows any early signs that it might help slow the disease or improve symptoms.

Investigated diseases:

Amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis – Amyotrophic lateral sclerosis is a progressive disorder that affects the nerves controlling muscle movement. It leads to gradual weakening of the muscles, starting often with the hands, feet, or speech. Over time, more muscles become involved, making everyday tasks increasingly difficult. The disease continues to advance as the nerve cells that control muscles slowly deteriorate.

Trial ID:

2025-523111-11-00

Protocol code:

TRCN-1023-ALS-101

Trial Phase:

Human Pharmacology (Phase I) – Other

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Safety and Tolerability of Intrathecal TRCN-1023 in Adults with Amyotrophic Lateral Sclerosis (ALS) – Randomized Placebo‑Controlled Phase 1/2 Trial

What is this study about?

Who Can Join the Study?

Who Cannot Join the Study?