LY500307
Although schizophrenia is equally common in men and women, the disease has a later onset and more benign course in women. This suggests a possible protective effect of estrogen, and indeed, extensive literature supports the use of exogenous estrogen in schizophrenia, where it reduces relapses and improves cognitive impairment and negative symptoms.
“We have no other agents that do that,” noted Dr. Breier, also chief of the psychotic disorders program and director of the Prevention and Recovery Center at Indiana University.
What he considers the best-executed clinical trial of estradiol in schizophrenia, an 8-week, double-blind, randomized study of a 200-mcg estradiol patch or placebo in 200 women aged 19-46 on antipsychotics, was published last year (JAMA Psychiatry. 2019 Jul 31;76[10]:1-9).
The results were impressive. However, estrogen may not be a viable treatment for men and premenopausal women because of its side effects, including feminization, and increased thrombotic and malignancy risks.
This was the impetus for the placebo-controlled randomized trial of LY500307, a highly selective estrogen receptor beta agonist originally developed by Eli Lilly as a potential treatment for benign prostatic hypertrophy, for which it proved ineffective. In animal models, estrogen receptor beta is responsible for a range of effects, including enhanced cognition, social behavior, and an anxiolytic action, whereas the alpha receptor affects the sex organs, skeletal and metabolic homeostasis, and is responsible for estrogen’s problematic side effects.
All three doses studied in the phase 2 randomized trial, which included 94 men with schizophrenia, proved safe, well-tolerated – and ineffective.
“I think one potential conclusion one could consider from these data is that estrogen receptor alpha engagement may be necessary for the estrogenic therapeutics in schizophrenia,” Dr. Breier said.
He reported having no financial conflicts regarding the trial, funded by Indiana University. Outside the scope of the study, he serves as a consultant to Karuna Therapeutics, BioXcel, and Perception Neuroscience.
Dr. Fleischhacker serves as a consultant to Boehringer Ingelheim, which sponsored the phase 2 study of BI 425809, as well as to Angelini, Richter, and Recordati.
SOURCE: ECNP 2020, Session S.12.