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Target Indication: Anxiety and Depression

On March 20, 2008, EPIX announced that the company has discontinued the clinical development of PRX-00023 due to lack of significant efficacy shown in the recently completed Phase 2b trial in patients with major depressive disorder (MDD).

For more than 20 million Americans, even the brightest days can be tinged by unwarranted worry and sadness. They suffer from generalized anxiety disorder (GAD) and depression, two of the most prevalent forms of mental illness.

GAD and depression are likely the result of abnormal regulation of neurotransmitters in the brain, including serotonin (5-HT). Both disorders are often present together, and most patients are treated with the same drugs -primarily selective serotonin reuptake inhibitors (SSRIs) and, more recently, serotonin noradrenaline reuptake inhibitors (SNRIs). These treatments, while often very helpful, have deficiencies that range from a slow onset of action to a variety of unpleasant side effects (e.g., sexual dysfunction, sleep disorders). Regardless, more than $20 billion is spent worldwide each year on drug therapies to treat GAD and depression.

With PRX-00023, we are targeting a significant unmet medical need and commercial opportunity for a selective, once-daily, agonist of a specific GPCR known as 5-HT1A that avoids the sexual dysfunction and sleep disorders associated with SSRIs, lacks the addictive and sedative effects of the benzodiazepines, and does not have the slow onset, short half-life, and side effects of a chemical class of 5-HT1A agonists called azapirones (most of which have failed in clinical development due to poor tolerability at effective doses).