Over a decade ago, Curt Freed and his team came to focus on a class of existing drugs called HDAC inhibitors after research identified a gene mutation that in rare cases triggers Parkinson’s….“I think phenylbutyrate has a good chance of stopping the progression of Parkinson’s disease in humans,” said Freed, who heads the Division of Clinical Pharmacology and Toxicology at CU Health Sciences Center at Anschutz in Aurora.