Clinigen Limited announced the top-line results from MIROCALS (Modifying Immune Response & OutComes in Amyotrophic Lateral Sclerosis) a phase 2b randomised placebo-controlled trial investigating the efficacy and safety of low dose interleukin-2 (ld IL-2) for controlling neuro-inflammation in newly-diagnosed patients with amyotrophic lateral sclerosis (ALS). The MIROCALS trial, conducted in 220 patients from 17 clinics across the UK and France, in collaboration with eight leading research groups in the UK, France, Italy and Sweden, investigated whether low dose IL-2 can modify aspects of neuro- inflammation, which is believed to play a central role in ALS disease progression. Dr. Gilbert Bensimon presented the top-line results at the International Symposium on ALS /Motor Neuron Diseases.

The unadjusted analysis of the primary endpoint showed a 19% reduction in risk of death in IL2 treated patients compared with placebo, which was not statistically significant. However, analysis adjusting for a pre-specified primary core biomarker, cerebrospinal fluid phosphorylated neurofilament heavy chain (CSF-pNFH), demonstrated a statistically significant decrease (73%) in the risk of death for the IL2 group over the 21-month trial period. Interaction by CSF-pNFH levels was found to be selective.

The interaction on survival was not present in patients with high CSF-pNFH (21% of study participants), which corresponded with aggressive, fast progressing disease. However, patients with low to moderate CSF-pNFH levels (79% of study participants), correlating with less aggressive disease progression, demonstrated a significant decrease in the risk of death (43%) for the IL2 group. Similarly, a slowing of decline in ALSFRS-R (ALS Functional Rating Scale – Revised, a key metric in functional capability in patients with ALS) was found in the IL2 group of patients with low CSF-pNFH levels (c. 70% of study participants).

The treatment was well tolerated, with adverse events recorded as mostly mild to moderate, occurring across both active treatment and placebo arms.