Interleukin-2 (MIROCALS)

The Phase 2 trial (IMODALS) enrolled 36 participants into 2 different dosing regimens or placebo over 3 months. The trial showed that the number of circulating Tregs was increased with improved ability to control other immune cell responses that contribute to nerve cell death. This results are promising but the results need to be validated across a longer and larger trial. You can find out more about the trial here.

The Phase 2 trial (MIROCALS) evaluated the efficacy of IL-2 over 18 months in 304 participants. This phase 2 trial looked at a larger cohort of participants over a longer time period compared to IMODALS. You can find out more about the trial here.

The top-line results were announced at the 33rd International Symposium on ALS/MND on 6 December 2022. IL-2 was found to be safe and well tolerated, side effects were minimal across both treatment and placebo. When the whole trial population was analysed, treatment with IL-2 showed a modest decrease in risk of death for those on the treatment during the study, but this was found not to be statistically significant. However, when the survival analysis was adjusted - as planned in advance - by subgrouping people using a particular biomarker (a biological signal of damage to neurons) they found a larger and statistically significant effect on survival for those who received the treatment. This effect equated to an over 40% decrease in the risk of death for a large proportion (80%) of the overall trial population who received IL-2.

Following these top-line results, further analysis was conducted and the full results were published. These results showed that the trial failed to meet it’s primary aim of showing that IL-2 is an effective treatment for MND for the whole trial population. When the whole trial population was analysed, treatment with IL-2 showed a modest increase in survival for those on the treatment during the study, but this was found not to be statistically significant. However, when people on the trial were sub grouped, using a marker of disease activity called neurofilament, a statistically significant effect was found for 70% of the trial population. Those with low neurofilament levels, suggesting that they had slower disease progression, were found to be most likely to benefit from IL-2 treatment. It was found that those with low neurofilament and taking IL-2 were 18% more likely to be alive at the end of the trial compared to those with slow progression who were on placebo. There was also shown to be a 23% decrease in the rate of change in ALSFRS-R score between those with low neurofilament and on IL-2 and those with low neurofilament on placebo.

May 2025- The full results of the MIROCALS trial have been published in the Lancet. You can read more about these results on our blog.

Sept 2023 - The trial data is now being collated and analysed and we are awaiting publication of the full results. The MND Association has submitted an application for the repurposing of aldesleukin (also known as interleukin-2 or by its brand name Proleukin) to NHS England's Medicines Repurposing Programme. 

Dec 2022 - Topline results were announced at the 33rd International Symposium on ALS/MND. You can find out more here.

Jan 2022  - Topline results are expected in 2022.

June 2021  - MIROCALS completed recruitment.

• MIROCALS: breaking down the trial results - MND Research Blog
• Breaking down the MIROCALS clinical trial results
• MIROCALS: Episode MND
• Targeting Tregs: IMODALS study paves the way for MIROCALS

• Efficacy and safety of low-dose IL-2 as an add-on therapy to riluzole (MIROCALS): a phase 2b, double-blind, randomised, placebo-controlled trial - The Lancet
• Examining the evidence for IL-2 in amyotrophic lateral sclerosis - The Lancet

• MIROCALS trial results published | MND Association
• MIROCALS: what’s next? | MND Association