The selective neurokinin 3 antagonist AZD2624 does not improve symptoms or cognition in schizophrenia: a proof-of-principle study.

Problems with the efficacy of second-generation antipsychotics on negative symptoms and cognition have highlighted the need for further development of drugs targeting central nervous system neurotransmitter systems other than dopamine. One target in development is neurokinin 3 (NK(3)) tachykinin receptors, which are coreleased and interact with dopamine. This study investigates the efficacy, tolerability, and cognitive effects of AZD2624, a selective, orally active NK(3) receptor antagonist, in symptomatic patients with schizophrenia. Patients were randomly assigned to 1 of 3 treatment groups: AZD2624 40 mg, placebo, or olanzapine 15 mg. Treatment lasted for 28 days, and the Positive and Negative Syndrome Scale, the Clinical Global Impression Severity Scale and Improvement Scales, and cognition as assessed by CogState were used as primary outcome measures. There were no significant differences in patients treated with AZD2624 versus placebo on change in Positive and Negative Syndrome Scale total score and Clinical Global Impression Severity Scale; in addition, no change in CogState measures was found. Results of the trial do not support a role for the NK(3) antagonist AZD2624 as a therapeutic treatment for acute schizophrenia when used as monotherapy.