Nolasiban

Nolasiban
Clinical data
Other names	Erlosiban; OBE-001; OBE001; RPN-002; RPN002
Drug class	Oxytocin receptor antagonist
Pharmacokinetic data
Elimination half-life	12 hours
Identifiers
	IUPAC name [(2S,4Z)-2-(hydroxymethyl)-4-methoxyiminopyrrolidin-1-yl]-[4-(2-methylphenyl)phenyl]methanone;
CAS Number	1477482-19-1;
PubChem CID	52947354;
DrugBank	DB16259;
ChemSpider	26350515;
UNII	3765U8A1EC;
ChEMBL	ChEMBL1254025;
Chemical and physical data
Formula	C20H22N2O3
Molar mass	338.407 g·mol−1
3D model (JSmol)	Interactive image;
	SMILES CC1=CC=CC=C1C2=CC=C(C=C2)C(=O)N3C/C(=N\OC)/C[C@H]3CO;
	InChI InChI=1S/C20H22N2O3/c1-14-5-3-4-6-19(14)15-7-9-16(10-8-15)20(24)22-12-17(21-25-2)11-18(22)13-23/h3-10,18,23H,11-13H2,1-2H3/b21-17-/t18-/m0/s1; Key:OLUJSZLBWZWGJT-HGBKYHTQSA-N;

Nolasiban (INNTooltip International Nonproprietary Name; developmental code names OBE001 and RPN-002), also known previously as erlosiban, is an oxytocin receptor antagonist which is under development for the treatment of female infertility and adenomyosis. It was also under development for the treatment of preterm labor, but development for this indication was discontinued. The drug is a small molecule or non-peptide and is taken orally.

The drug interacts with both the oxytocin receptor (K_i = 52 nM; IC₅₀Tooltip half-maximal inhibitory concentration = 81 nM) and the vasopressin V_1A receptor (K_i = 120 nM), whereas findings for the vasopressin V₂ receptor were not reported. It is of relatively low potency, being used and studied clinically at doses of 900 to 2,400 mg orally.

Nolasiban was first described in the scientific literature by 2015. It was originated by Merck Serono and is under development by ObsEva and ReproNovo. As of July 2026, the drug is in phase 2 clinical trials for female infertility and phase 1 trials for adenomyosis. It was also previously in phase 3 trials in the late 2010s.

References

1 2 Pierzyński P, Pohl O, Marchand L, Mackens S, Lorch U, Gotteland JP, et al. (August 2021). "The mechanism of action of oxytocin antagonist nolasiban in ART in healthy female volunteers". Reproductive Biomedicine Online. 43 (2): 184–192. doi:10.1016/j.rbmo.2021.01.003. PMID 34167897. Nolasiban is an oral, competitive oxytocin receptor antagonist with a pharmacokinetic half-life of about 12 h that enables up to 2 days' exposure after a single dose. Various in-vitro and in-vivo preclinical models have shown nolasiban to inhibit spontaneous and oxytocin-induced uterine contractions and inflammatory response (Kim et al., 2017; 2019).
1 2 3 4 5 6 "Nolasiban". AdisInsight. 8 July 2026. Retrieved 10 July 2026.
1 2 3 4 "Delving into the Latest Updates on Erlosiban with Synapse". Synapse. 10 June 2026. Retrieved 10 July 2026.
1 2 3 4 Nashar PE, Whitfield AA, Mikusek J, Reekie TA (2022). "The Current Status of Drug Discovery for the Oxytocin Receptor". Oxytocin. Methods in Molecular Biology. Vol. 2384. New York, NY: Springer US. pp. 153–174. doi:10.1007/978-1-0716-1759-5_10. ISBN 978-1-0716-1758-8. PMID 34550574.
↑ Craciunas L, Tsampras N, Kollmann M, Raine-Fenning N, Choudhary M (September 2021). "Oxytocin antagonists for assisted reproduction". The Cochrane Database of Systematic Reviews. 9 (9) CD012375. doi:10.1002/14651858.CD012375.pub2. PMC 8408576. PMID 34467530.
↑ Täubel J, Lorch U, Spencer CS, Freier A, Camilleri D, Djumanov D, et al. (March 2021). "Confirmation of the cardiac safety of nolasiban in a randomised cohort of healthy female volunteers". Scientific Reports. 11 (1) 6404. Bibcode:2021NatSR..11.6404T. doi:10.1038/s41598-021-85650-3. PMC 7973531. PMID 33739022.
1 2 Kim SH, Pohl O, Chollet A, Gotteland JP, Fairhurst AD, Bennett PR, et al. (April 2017). "Differential Effects of Oxytocin Receptor Antagonists, Atosiban and Nolasiban, on Oxytocin Receptor-Mediated Signaling in Human Amnion and Myometrium". Molecular Pharmacology. 91 (4): 403–415. doi:10.1124/mol.116.106013. PMC 5363712. PMID 28188254.
↑ Pohl O, Homery MC, Lemaux F, Patat A, Chollet A (June 2015). "Pharmacokinetic interactions of OBE001 and betamethasone in healthy female volunteers". Journal of Clinical Pharmacy and Therapeutics. 40 (3): 328–332. doi:10.1111/jcpt.12258. PMID 25899007.
↑ Visnova H, Tournaye HJ, Humberstone A, Terrill P, Macgregor L, Loumaye E (2018). "A placebo-controlled, randomized, double-blind, phase 3 study assessing ongoing pregnancy rates after single oral administration of a novel oxytocin receptor antagonist, nolasiban, prior to single embryo transfer". Fertility and Sterility. 110 (4): e45. doi:10.1016/j.fertnstert.2018.07.141.

[PierzyńskiPohlMarchand2021-1] 1 2 Pierzyński P, Pohl O, Marchand L, Mackens S, Lorch U, Gotteland JP, et al. (August 2021). "The mechanism of action of oxytocin antagonist nolasiban in ART in healthy female volunteers". Reproductive Biomedicine Online. 43 (2): 184–192. doi:10.1016/j.rbmo.2021.01.003. PMID 34167897. Nolasiban is an oral, competitive oxytocin receptor antagonist with a pharmacokinetic half-life of about 12 h that enables up to 2 days' exposure after a single dose. Various in-vitro and in-vivo preclinical models have shown nolasiban to inhibit spontaneous and oxytocin-induced uterine contractions and inflammatory response (Kim et al., 2017; 2019).

[AdisInsight-2] 1 2 3 4 5 6 "Nolasiban". AdisInsight. 8 July 2026. Retrieved 10 July 2026.

[Synapse-3] 1 2 3 4 "Delving into the Latest Updates on Erlosiban with Synapse". Synapse. 10 June 2026. Retrieved 10 July 2026.

[NasharWhitfieldMikusek2022-4] 1 2 3 4 Nashar PE, Whitfield AA, Mikusek J, Reekie TA (2022). "The Current Status of Drug Discovery for the Oxytocin Receptor". Oxytocin. Methods in Molecular Biology. Vol. 2384. New York, NY: Springer US. pp. 153–174. doi:10.1007/978-1-0716-1759-5_10. ISBN 978-1-0716-1758-8. PMID 34550574.

[CraciunasTsamprasKollmann2021-5] Craciunas L, Tsampras N, Kollmann M, Raine-Fenning N, Choudhary M (September 2021). "Oxytocin antagonists for assisted reproduction". The Cochrane Database of Systematic Reviews. 9 (9) CD012375. doi:10.1002/14651858.CD012375.pub2. PMC 8408576. PMID 34467530.

[TäubelLorchSpencer2021-6] Täubel J, Lorch U, Spencer CS, Freier A, Camilleri D, Djumanov D, et al. (March 2021). "Confirmation of the cardiac safety of nolasiban in a randomised cohort of healthy female volunteers". Scientific Reports. 11 (1) 6404. Bibcode:2021NatSR..11.6404T. doi:10.1038/s41598-021-85650-3. PMC 7973531. PMID 33739022.

[KimPohlChollet2017-7] 1 2 Kim SH, Pohl O, Chollet A, Gotteland JP, Fairhurst AD, Bennett PR, et al. (April 2017). "Differential Effects of Oxytocin Receptor Antagonists, Atosiban and Nolasiban, on Oxytocin Receptor-Mediated Signaling in Human Amnion and Myometrium". Molecular Pharmacology. 91 (4): 403–415. doi:10.1124/mol.116.106013. PMC 5363712. PMID 28188254.

[PohlHomeryLemaux2015-8] Pohl O, Homery MC, Lemaux F, Patat A, Chollet A (June 2015). "Pharmacokinetic interactions of OBE001 and betamethasone in healthy female volunteers". Journal of Clinical Pharmacy and Therapeutics. 40 (3): 328–332. doi:10.1111/jcpt.12258. PMID 25899007.

[VisnovaTournayeHumberstone2018-9] Visnova H, Tournaye HJ, Humberstone A, Terrill P, Macgregor L, Loumaye E (2018). "A placebo-controlled, randomized, double-blind, phase 3 study assessing ongoing pregnancy rates after single oral administration of a novel oxytocin receptor antagonist, nolasiban, prior to single embryo transfer". Fertility and Sterility. 110 (4): e45. doi:10.1016/j.fertnstert.2018.07.141.

Nolasiban

See also

References