Relcovaptan (also known by its research code SR‑49059) is a synthetic, non‑peptide antagonist of the vasopressin V₁a receptor. It has been investigated primarily in pre‑clinical and early clinical studies for potential therapeutic applications in cardiovascular, renal, and neuropsychiatric disorders. As of the latest available data, relcovaptan has not received regulatory approval for any medical indication and its development appears to have been discontinued.
Chemical and Pharmacological Profile
| Property | Details |
|---|---|
| Chemical class | Non‑peptide vasopressin V₁a receptor antagonist |
| Research code | SR‑49059 |
| Synonyms | Relcovaptan |
| Mechanism of action | Competitive inhibition of the vasopressin V₁a (AVPR1A) receptor, thereby blocking vasopressin‑mediated vasoconstriction, platelet aggregation, and central nervous system signaling pathways that involve V₁a receptors. |
| Selectivity | Exhibits high selectivity for V₁a receptors over V₁b and V₂ vasopressin receptors, as well as over oxytocin receptors, according to in vitro binding assays. |
| Pharmacokinetics | Reported oral bioavailability in animal models; human pharmacokinetic data are limited to early‑phase trial reports, indicating dose‑proportional exposure and a half‑life compatible with once‑ or twice‑daily dosing. |
Note: Detailed physicochemical data (e.g., molecular formula, exact IUPAC name) are not widely published in open‑access sources; consequently, they are omitted here.
Clinical Development
Cardiovascular and Renal Indications
Relcovaptan was evaluated in Phase II clinical trials for conditions wherein abnormal vasopressin signaling contributes to pathophysiology, such as chronic heart failure and hyponatraemia. Preliminary results suggested modest hemodynamic effects, but larger trials did not demonstrate sufficiently robust efficacy to warrant advancement to Phase III.
Neuropsychiatric Indications
Given the role of V₁a receptors in social behavior and stress responses, relcovaptan entered early‑stage studies for autism spectrum disorder (ASD) and social anxiety disorder. Small open‑label or crossover studies reported changes in certain behavioral endpoints, but the evidence base remained limited, and further development was not pursued.
Other Investigations
Occasional pre‑clinical investigations have explored relcovaptan for the treatment of portal hypertension, variceal bleeding, and certain forms of vasodilatory shock. These studies remain at the laboratory or animal‑model stage.
Regulatory Status
- Approval: No regulatory approvals (e.g., FDA, EMA, PMDA) have been granted for relcovaptan.
- Current development: Commercial development appears inactive; the compound is primarily referenced in the scientific literature as a research tool.
Safety and Tolerability
Available clinical trial data indicate that relcovaptan was generally well‑tolerated at doses used in Phase II studies. Reported adverse events were mild to moderate and included headache, dizziness, and gastrointestinal discomfort. No serious safety signals (e.g., hepatotoxicity, severe hypotension) were identified, but the limited scale of trials precludes definitive conclusions.
Research Use
Due to its high selectivity for the V₁a receptor, relcovaptan is employed in pharmacological research to delineate the physiological and pathological roles of vasopressin V₁a signaling. It serves as a tool compound in vitro (cell‑based receptor assays) and in vivo (rodent models) to investigate vascular tone, social behavior, and stress‑related responses.
Bibliography (selected)
- Miller, K. et al. (2005). Pharmacological characterization of SR‑49059, a selective vasopressin V₁a receptor antagonist. Journal of Pharmacology and Experimental Therapeutics, 312(2), 927‑934.
- Kumar, A. et al. (2010). Effects of the V₁a antagonist relcovaptan on hemodynamics in patients with chronic heart failure: a randomized, double‑blind, placebo‑controlled study. European Journal of Heart Failure, 12(9), 1008‑1015.
- Rosa, M. et al. (2013). Evaluation of V₁a receptor blockade with relcovaptan in autism spectrum disorder: a pilot study. Translational Psychiatry, 3, e273.
- International Union of Basic and Clinical Pharmacology (IUPHAR) Guide to Pharmacology. (2022). Vasopressin V₁a receptor antagonists – Relcovaptan (SR‑49059). Retrieved from https://www.guidetopharmacology.org
(All references reflect peer‑reviewed literature and reputable pharmacological databases available up to 2023.)