Sensational Observation: Modified Amino Acid May Halt Disease Onset in Early Stage

An international team of researchers led by the Department of Neurology at Philipps University Marburg, in collaboration with LMU Munich, has published two remarkable case reports that could represent a turning point in Parkinson’s disease treatment. The research, appearing today in Nature Communications, describes how treatment with a modified amino acid—acetyl-DL-leucine (ADLL)—appears to stop the progression of Parkinson’s disease in its early, pre-symptomatic stage, and in some respects, even reverses the associated changes in the brain. These early results come from two patients—one man and one woman—who both had isolated REM sleep behaviour disorder (iRBD), a recognised early warning sign of Parkinson’s. People with iRBD have more than an 85% chance of developing Parkinson’s disease or Lewy body dementia within 10 to 15 years. Only around 15% remain unaffected. Both patients were treated with 5 grams of ADLL per day for 22 months. Before starting the treatment, they showed multiple early signs of Parkinson’s, including: Abnormal dopamine transporter scans (DAT-SPECT), indicating reduced dopamine activity in the brain. Loss of smell (anosmia), another well-known early symptom of Parkinson’s. According to Professor Dr Wolfgang Oertel, lead investigator of the study and a senior neurologist at Marburg, the results were astonishing: “In all my years of research and clinical practice, I have never seen anything like this.” Key Findings The study focused on three measurable indicators of Parkinson’s progression: Severity of REM sleep behaviour disorder (RBD-SS-3 score) Dopamine transporter activity (via DAT-SPECT scans) Parkinson’s disease-specific brain metabolism pattern (PDRP-z score) measured by FDG-PET imaging In both patients: The RBD symptoms reduced significantly within three weeks and remained low throughout the treatment period. Their DAT-SPECT scans showed improved dopamine transporter function, suggesting that brain degeneration had not only stopped but had partially reversed. Brain metabolism patterns associated with Parkinson’s either stabilised or improved. For instance, in one patient, the putaminal binding ratio (a marker of dopamine loss) improved from 1.22 to 1.67 after treatment. At the same time, their brain metabolism (PDRP-z score) slightly improved, from 3.28 to 3.18. The second patient showed even more marked improvements. How Does Acetyl-DL-Leucine Work? ADLL appears to support two critical systems within brain cells: The lysosomal system, which is responsible for waste removal and recycling within cells. Cellular energy production (ATP), which powers all cell activity and is often impaired in Parkinson’s. Preclinical studies have shown that acetyl-L-leucine (one of the components of ADLL) increases ATP production. Animal studies also show that in early Parkinson’s, both energy metabolism and lysosomal function are severely disrupted. This makes ADLL, with its dual mechanism of action, a logical candidate for early intervention. ADLL is a combination of two forms of the same molecule—acetyl-D-leucine and acetyl-L-leucine. The treatment used in these two patients included both forms. However, emerging evidence from animal studies suggests that the L-form alone (acetyl-L-leucine) is likely the active component. Future trials will therefore focus specifically on this version. What’s Next? While these results are based on just two patients and should be interpreted cautiously—due to the absence of a placebo group or blinding—they are sufficiently compelling to justify immediate further investigation. Randomised, placebo-controlled trials are already being planned. Professor Oertel concluded: “We have observed a stabilisation, and even reversal, of Parkinson’s disease indicators in two people who were at very high risk of developing the disease. The improvement in brain imaging cannot be explained by a placebo effect. Although more data are needed, this could be the start of a major shift in how we approach early Parkinson’s.” Professor Dr Peter Berlit, Secretary General of the German Neurological Society, added: “Many major medical breakthroughs have started with individual, unexpected observations. If further research confirms that acetyl-L-leucine can halt or delay Parkinson’s disease, this could become a historic milestone in neurology. For now, we must remain cautious, but we are optimistic and committed to rigorous, fast-tracked trials to follow up this discovery.”