SYN118 is a potent and selective inhibitor of 4-hydroxyphenylpyruvate dioxygenase (HPPD), which is an enzyme in the primary pathway responsible for the breakdown of tyrosine, the precursor of the neurotransmitter dopamine.
According to Biotie, the Phase 2a study of SYN118 did not show significant improvement in measures of PD motor function when compared to placebo.
The UCB collaboration also includes Biotie’s adenosine A2a receptor antagonist tozadenant (SYN115), which is in phase 2b development for Parkinson’s disease, and the SYN118 decision has no impact on it.