NIL-A is a neuroimmunophilin that was developed by Guilford and Amgen for Parkinson's disease [1]. A second generation product, NIL-A succeeds an earlier immunophilin product called GPI-1046. Preclinical development of GPI-1046 itself appears to have been suspended [2]. Data from efficacy and pharmacokinetic studies with NIL-A were presented at the Acute Neuronal Injury: New Therapeutic Opportunities meeting in August of 1998, Las Vegas, USA. The compound apparently possesses 50% oral bioavailability, and approximately 25 fold greater efficacy compared with GPI 1046, as well as a superior half life and absorption profile.

The investment community has been enthusiastic about NIL-A, suggesting that the drug may be a potential blockbuster with the potnetial for $1 billion in annual sales [3]. Details concerning the structure of NIL-A is not yet available. According to www.biospace.com [4], NIL-A is a modified form of GPI-1046 that is more potent, is longer lasting, and can be taken orally. In the meanwhile serious questions have been raised concerning the efficacy of GPI-1046