Ditekiren is a relatively large renin inhibitor incorporating the hydroxyethylene isostere as well as both the P4 proline and P2’ isoleucine of angiotensinogen. Methylation of the P2-site histidine backbone nitrogen stabilizes the P2-P3 peptide bond towards degradation by chymotrypsin. Even though oral bioavailability was low, serum ditekiren levels were equivalent to 4–8 times the in vitro IC50 for renin inhibition for this peptide throughout the 2.5 h after oral administration that blood levels were monitored. In Na-depleted cynomolgus monkeys, oral dose elicited a hypotensive response that had not returned to baseline by 5 h. Ditekiren had been in phase II clinical trials for the treatment of heart failure and hypertension. However, these studies were discontinued.