DAPTA (D-ala-peptide T-amide) is a synthetic peptide that prevents HIV entry by blocking binding of HIV gp120 protein with CCR5 receptor. In a small clinical study of internasal formulation of DAPTA in long-term infected HIV patients, administration of DAPTA led to decrease in the amount of virus isolated from white blood cells, an increase in gamma-interferon secreting T-cells in the absense of drug-related toxicity. In another clinical study DAPTA in combination with antiretroviral therapy reduced the peripheral (plasma and serum) viral load, but did not reduce the CSF viral load.

Merrion Pharmaceuticals was developing an oral tablet formulation of acyline, a gonadotropin-releasing hormone (GnRH) antagonist, referred to as MER 104. MER-104 effectively suppresses luteinizing hormone (LH) and follicle-stimulating hormone (FSH) secretion in man. Acyline has been investigated for the prevention and treatment of hypogonadism and contraception. Injectable forms have been administered successfully in man in Phase II studies as part of a potential contraceptive regimen. MER-104 is an enteric coated acyline tablet developed by Merrion Pharmaceuticals using GIPET™ I technology to enable the oral administration of this decapeptide. The development of acyline appears to have been discontinued.

Ramorelix is a glycosylated gonadoliberin antagonist patented by Hoechst A.-G. as an anticancer agent. In preclinical studies, a single injection of ramorelix microparticles inhibited tumor progression for only 14 days. This short action is due to a different release profile of the ramorelix microparticles and the different specific activities of peptides incorporated. In the preventive experiments, animals were treated 17 days after DMBA induction before tumor development. Treatment with buserelin implants every 56 days or with buserelin microparticles every 28 days and the treatment with ramorelix microparticles every 7 days prevented the development of tumors. Six weeks after the last injection of ramorelix microparticles a strong tumor progression was seen. There was a clear correlation between peptide release and tumor inhibition. The implants and the microparticles were well tolerated, no tissue reaction or side-effects of ramorelix were seen.

SER-100 (previously known as ZP120, Ac-RYYRWKKKKKKK-NH2) is a peripherally acting orphanin FQ/nociceptin (ORL-1) receptor agonist that is in development with Serodus Pharmaceuticals for the treatment of Isolated systolic hypertension. SER-100 is a peripherally acting, highly potent and selective NOP receptor partial agonist, which was developed by coupling a chain of six lysine residues to an existing NOP receptor partial agonist hexapeptide, Ac-RYYRWK-NH2 to improve meta-bolic stability. SER-100 has sodium-potassium-sparing aquaretic and anti-natriuretic activity. SER-100 exerts a chronic hypotensive and bradycardic effects in rodents, including models of systemic and pulmonary hypertension. SER-100 produces its cardiovascular effects, at least in part, by inhibition of cardiac and vascular sympathetic activity. In terms of clinical evaluation, SER-100 was originally assessed in a randomized, double-blind, placebo controlled Phase II trial as add-on therapy in patients with sub-acute decompensated chronic heart failure (NCT00283361); how-ever, the clinical development of the peptide for this indication was terminated prematurely due to significant hypotensive activity, primarily on systolic blood pressure (SBP). Nonetheless, as a result of this profound drop in SBP, SER-100 (10 mg, s.c., bid) was investigated in a randomized, placebo-controlled study in patients with treatment-resistant isolated systolic hypertension (NCT01987284) and found to produce a meaningful and long lasting drop in SBP(~7 mmHg) and diastolic (~4 mmHg) blood pressure (DBP),as well as being safe and well-tolerated. FDA has granted an Orphan Drug Designation for SER-100 in pulmonary arterial hypertension (PAH).