Addex Parkinson's product progressing in early clinical trials

Addex Pharmaceuticals has announced that it has completed the first part of a two-part Phase I clinical trial to evaluate the newly developed modified release formulation of ADX48621. ADX48621 is scheduled to start a Phase IIa proof of concept study for the treatment of levodopa associated dyskinesia in Parkinson's disease during the first half of 2009.

Chief Medical Officer Charlotte Keywood said: "we are pleased by the progress of ADX48621 and are preparing to start the Phase IIa proof of concept trial to study its utility in Parkinson's disease dyskinesia next year."

Part One was a randomized two-way crossover comparison study in 12 healthy subjects to test the pharmacokinetics, safety and tolerability of the original active pharmaceutical ingredient (API) in capsule with the modified release capsule. The modified release formulation achieved the predefined pharmacokinetic criteria required to continue into Part Two. Tolerability and safety monitoring parameters also supported continuing the trial.

Part Two is a double-blind, placebo-controlled, multiple ascending, repeat dose study in 24 healthy subjects to test the safety, tolerability and pharmacokinetics of three different doses of the modified release formulation.

Addex also has initiated a separate Phase I crossover trial to study ADX48621 interactions with gender and food in about 15 older healthy male and female subjects.

Top-line data from both trials are expected by year-end.

ADX48621 is a metabotropic glutamate receptor 5 (mGluR5) negative allosteric modulator (NAM). Published studies by others using mGluR5 inhibitors have shown that this mechanism has efficacy in rodent and primate models of Parkinson's disease - both to reduce Parkinson's disease dyskinesia and as a levodopa sparing agent.

Dyskinesias in Parkinson's disease patients are motor fluctuations that often result from chronic levodopa therapy. Although levodopa is widely regarded as the best available treatment for Parkinson's disease, dyskinesias occur in more than half of patients after 5 to 10 years of levodopa therapy, with the percentage of affected patients increasing over time*. To date attempts to moderate dyskinesias via pharmaceutical treatments have been largely unsuccessful.

* Obeso JA, et al. The evolution and origin of motor complications in Parkinson's disease. Neurology. 2000;55 (suppl 4):S13-S20.

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