[Research on synthetic peptides of biological interest].

Research on synthetic peptides at the Institute for Drug Research (IDR) is exemplified by an overview of the projects that resulted in significant results. The first synthesis of oxytocin, a pituitary hormone, in 1953 launched the research on synthetic peptides all over the world. This synthesis was reproduced by Bodanszky at the IDR in 1954, then, after some improvements, the process was presented to Richter to produce synthetic oxytocin for therapeutic purposes. Significant result was the first synthesis of the 39-member whole molecule of human ACTH, another pituitary hormone. A short SAR study on luteinizing hormone-releasing hormone (LHRH) led to an interesting analog, Cit-8-LHRH, and somewhat later, to the D-Cit-6-LHRH analogues, of which SB-75 become marketed under the name Cetrorelix. Studies on the brain peptides, enkephalins, resulted in GYKI-14,238, the first analog that showed analgesic activity upon systemic administration and whose human efficacy could also be proven during clinical examination. Significant results were also achieved in the research on anticoagulant peptides. The first highly potent peptide aldehyde inhibitor of thrombin, GYKI-14,166, was identified at the IDR as well as its stable analog, GYKI-14,766. This compound was selected for detailed preclinical study, licensed to Eli Lilly Company, got the generic name efegatran, and entered clinical trials. The first non-covalent peptide inhibitor of thrombin, GYKI-14,525, was also identified at the IDR. Thus IDR really provided the prototype of original thrombin inhibitors in the mid 70's, and analogues were prepared in many laboratories through two decades. IDR's current research program's objective includes a quest for peptide originals that can inhibit both thrombin and factor Xa in solution and also within plasma clots in which these enzymes are entrapped. Structures with such inhibitory profile were identified among the efegatran-related alpha-hydroxy acid and ethoxycarbonyl-amino acid derivatives. The follow-up molecules are even more promising as antithrombotics, and may also be useful for treatment of disseminated intravascular coagulation, an often fatal syndrome, so we continue working on this project.