SYN-118 is a potent and selective inhibitor of hydroxyphenylpyruvate dioxygenase (HPPD), the primary enzyme responsible for the catabolism of tyrosine, the precursor of the neurotransmitter dopamine. Preclinical studies have shown that SYN-118 is active in animal models of Parkinson’s disease. Clinical studies and patient experience with SYN-118 have shown pronounced and predictable elevations in the circulating concentrations of tyrosine.

Synosia has completed an open label, proof-of-mechanism study with SYN-118 for Parkinson’s disease and a proof-of-concept trial in restless legs syndrome. The encouraging efficacy and safety results from these studies provide a strong rationale for moving this programme forward.  The company initiated a randomised, placebo controlled Phase IIa study in Parkinson’s disease patients in the final quarter of 2009.