Table of contents

• Clinical trial overview
• Liver disease studies
• Neurology and eye studies
• Other conditions studied
• Trial design, phases, and participants
• Main endpoints and outcome measures
• Trial status and size

Clinical trial overview

The trial data show that Acetylcysteine is being studied in several very different settings, not just one disease. The trials include people with liver disease, ALS, retinitis pigmentosa, cannabis dependence, upper respiratory tract infections, severe acute infection, and healthy volunteers.^[1]

These studies are mainly designed to test whether Acetylcysteine helps as part of a treatment plan, whether it improves disease-related outcomes, and whether it is safe and well tolerated in the target group.^[1]

Liver disease studies

Two trials focus on severe forms of alcoholic hepatitis, which is a serious liver inflammation linked to alcohol use.^[1] One authorised Phase 3 study in 180 patients is testing methylprednisolone plus Acetylcysteine and measuring 1 month mortality, meaning death within one month after treatment begins.^[1]

Another authorised Phase 3 study, PROCORNAC, is testing Acetylcysteine with prednisolone in 477 patients with severe alcoholic hepatitis and comparing it with standard prednisolone treatment.^[1] Its main endpoint is the rate of patients alive with compensated liver disease, meaning the liver is still working well enough to avoid major complications, at 90 days.^[1]

A different authorised Phase 3 study in living donor renal transplantation is also listed, but the intervention shown in the source is a renal perfusion solution rather than Acetylcysteine.^[1] Because the trial data provided do not clearly link Acetylcysteine to that study, it should be viewed as background trial information rather than a direct Acetylcysteine trial.^[1]

Neurology and eye studies

One authorised study in ambulatory patients with amyotrophic lateral sclerosis (ALS) is a Phase 1 trial that combines Acetylcysteine with EH301 and riluzole, and compares the combination with placebo.^[1] The study measures changes in the ALSFRS-R scale, a functional rating scale for ALS, and the time until patients have a 20% drop in that score.^[1]

A large authorised Phase 3 trial in 498 people with retinitis pigmentosa, a group of inherited eye diseases that slowly damage vision, is testing oral Acetylcysteine against placebo.^[1] The main endpoint is the change in EZ width on eye scans, which is used to track loss of retinal structure over time.^[1] The study also aims to assess long-term safety and tolerability over 45 months.^[1]

Another authorised Phase 3 study in early psychosis does not list Acetylcysteine in the intervention text provided, so it is not counted here as a direct Acetylcysteine trial based on the source data alone.^[1]

Other conditions studied

One completed low-intervention study in 18 healthy subjects tested intravenous Acetylcysteine with fentanyl and naloxone to explore opioid-induced respiratory depression, which means slowed breathing caused by an opioid pain medicine.^[1] The primary outcome was minute ventilation, a measure of how much air a person breathes in one minute.^[1]

A completed Phase 3 study in 50 people with cannabis dependence tested oral Acetylcysteine versus placebo and aimed to learn about the working mechanisms of treatment.^[1] The primary outcome was listed as day 14 after study start.^[1]

A withdrawn Phase 3 study in 483 patients with upper respiratory tract infections and wet cough tested a fixed-dose combination that included Acetylcysteine against its individual components.^[1] The main outcome was time to clinically significant improvement in symptoms such as cough, fever, and cold symptoms.^[1]

Another withdrawn Phase 3 study in 300 patients with severe acute infection included intravenous Acetylcysteine as part of an individualized treatment strategy.^[1] Its primary outcome was days alive and out of hospital at 14 days after randomization, often shortened to DAOH-14.^[1]

Trial design, phases, and participants

Most of the listed Acetylcysteine studies are interventional, which means the research team gives a treatment and then measures the results.^[1] Several are randomized, placebo-controlled, and double-masked, meaning treatment assignment is by chance, placebo is used for comparison, and neither the participant nor the team knows the assignment during the study.^[1]

The participant groups are very specific. They include adults with severe liver disease, ambulatory patients with ALS, people with retinitis pigmentosa, people with cannabis dependence, people with severe acute infection, people with upper respiratory tract infection, and healthy volunteers in one breathing study.^[1]

The phases also vary. There is one Phase 1 study, one Phase 2 study, several Phase 3 studies, and one low-intervention study, showing that Acetylcysteine is being tested from early safety work to larger efficacy studies.^[1]

Main endpoints and outcome measures

The trials measure different outcomes depending on the disease being studied. In liver disease, the endpoints include mortality at 1 month and survival with compensated liver disease at 90 days.^[1]

In ALS, the key outcome is change in ALSFRS-R and the time to a 20% decline in that score, which helps show whether function is worsening more slowly.^[1]

In retinitis pigmentosa, the main endpoint is loss of EZ width on spectral domain optical coherence tomography, a scan that gives detailed pictures of the retina.^[1] In the breathing study, the outcome is minute ventilation, and in the cannabis dependence study, the main time point is day 14 after study start.^[1]

Some studies also focus on symptom improvement, safety, and tolerability, which are important because they show whether the treatment may help patients without causing unacceptable problems.^[1]

Trial status and size

The source data show a mix of trial statuses. Some studies are authorised, some are completed, and some are withdrawn, which means they did not continue as planned.^[1]

Enrollment sizes range from small studies with 18 or 50 participants to larger Phase 3 trials with nearly 500 participants.^[1] This range suggests that Acetylcysteine is being studied in both focused early research and larger confirmatory trials.^[1]