Negative symptoms represent an attractive target for drug development

A half-day workshop on issues in the design of clinical trials to evaluate treatments for negative symptoms of schizophrenia, chaired by Stephen Marder, MD, UCLA Department of Psychiatry and David Daniel, M.D., United BioSource Corporation was held 5 October 2009, as part of the International Society for CNS Clinical Trials and Methodology (ISCTM) Autumn Conference in San Diego, CA.

Negative symptoms, characterized by reduced motivation, reduced emotional experience, social withdrawal and slowing of psychomotor functions, remain a key unmet treatment need for persons with schizophrenia. Questions addressed at this workshop centered on the optimal designs of clinical studies that might be developed to achieve regulatory approval for monotherapy and adjunctive therapy indications for the treatment of negative symptoms.

Discussion centered on whether a functional co-primary is necessary to gain approval from regulatory authorities and how to differentiate negative symptoms from other conditions with similar phenotypes like depression, extrapyramidal symptoms, paranoia, cognitive dysfunction, side effects of medication, etc. A representative from the FDA, Dr. Robert Levin, indicated that a co-primary functional endpoint would not be necessary to gain approval for this indication in the US. Nevertheless, measures of potentially confounding symptoms would have to be included in such trials to demonstrate that the effect identified in these trials is specific to the treatment of negative symptoms.

Additional discussion focused on the need for negative symptoms to be stable and persistent in clinical trials aimed at demonstrating efficacy of a therapeutic agent. Dr. Marder concluded “Representatives from academia, industry, and government agreed that negative symptoms represent an attractive target for drug development.”