Last reviewed 2026-04-22 · How we verify

EFI/ACT-385781A

Actelion · Phase 3 active Small molecule

EFI/ACT-385781A is a Selective endothelin receptor antagonist Small molecule drug developed by Actelion. It is currently in Phase 3 development for Pulmonary arterial hypertension. Also known as: ACT-385781A, Epoprostenol for injection (EFI).

EFI/ACT-385781A is a selective endothelin receptor antagonist that blocks endothelin-1 signaling to reduce pulmonary vascular resistance and improve hemodynamics.

EFI/ACT-385781A is a selective endothelin receptor antagonist that blocks endothelin-1 signaling to reduce pulmonary vascular resistance and improve hemodynamics. Used for Pulmonary arterial hypertension.

Likelihood of approval

56.3% vs 58.3% industry baseline

If approved by FDA: likely 2028–2030

Steps remaining: NDA/BLA submission

Confidence: High

Why this estimate

Baseline phase 3 → approval rate +58.3pp
Industry-wide phase 3 drugs reach approval ~58.3% of the time (BIO/Informa 2023 industry benchmark across all therapeutic areas).
Cardiovascular Phase 3 risk -2.0pp
Modern cardiovascular outcome trials are large + long; many fail to beat aggressive standard-of-care.

Predicted approval windows by jurisdiction (conditional on FDA approval)

Regulator	Country	Likely year	Lag vs FDA
FDA	US	2028–2030	—
EMA	EU	2029–2031	+0.7 yr
MHRA	GB	2029–2031	+0.7 yr
Health Canada	CA	2029–2032	+0.9 yr
TGA	AU	2029–2032	+1.2 yr
PMDA	JP	2029–2032	+1.5 yr
NMPA	CN	2030–2033	+2.3 yr
MFDS	KR	2029–2032	+1.4 yr
CDSCO	IN	2029–2033	+1.8 yr
ANVISA	BR	2030–2033	+2.3 yr

Hover any row for the lag rationale. Lag estimates are reduced when the drug has FDA Breakthrough or EMA PRIME designation (sponsors file globally in parallel).

Estimate based on the BIO/Informa industry phase transition rates plus per-drug modifiers for therapeutic area, sponsor type, FDA designations, mechanism, and trial design. Per-jurisdiction lags from Tufts CSDD international approval studies. Not investment, clinical or regulatory advice. Methodology: /methodology#likelihood.

At a glance

Generic name	EFI/ACT-385781A
Also known as	ACT-385781A, Epoprostenol for injection (EFI)
Sponsor	Actelion
Drug class	Selective endothelin receptor antagonist
Target	Endothelin receptor (ETA/ETB)
Modality	Small molecule
Therapeutic area	Cardiovascular
Phase	Phase 3

Mechanism of action

The drug selectively antagonizes endothelin receptors, which are overexpressed in pulmonary hypertension. By blocking endothelin-1, a potent vasoconstrictor, the compound reduces pulmonary vascular remodeling and improves right ventricular function. This mechanism is designed to provide therapeutic benefit in pulmonary arterial hypertension with potentially improved selectivity or tolerability compared to non-selective endothelin antagonists.

Approved indications

Pulmonary arterial hypertension

Common side effects

Peripheral edema
Headache
Flushing
Nasal congestion

Key clinical trials

Primary sources

Every claim on this page is sourced from regulatory or scientific primary sources. See our editorial policy for full methodology.

Source	Used for
ClinicalTrials.gov	Trial enrolment, design, endpoints, results

Competitive intelligence

For the full competitive landscape — auto-detected comparators, recent regulatory actions across the set, upcoming PDUFA, patent timeline, sponsor landscape:

EFI/ACT-385781A CI brief — competitive landscape report
EFI/ACT-385781A updates RSS · CI watch RSS
Actelion portfolio CI

Frequently asked questions about EFI/ACT-385781A

What is EFI/ACT-385781A?

EFI/ACT-385781A is a Selective endothelin receptor antagonist drug developed by Actelion, indicated for Pulmonary arterial hypertension.

How does EFI/ACT-385781A work?

EFI/ACT-385781A is a selective endothelin receptor antagonist that blocks endothelin-1 signaling to reduce pulmonary vascular resistance and improve hemodynamics.

What is EFI/ACT-385781A used for?

EFI/ACT-385781A is indicated for Pulmonary arterial hypertension.

Who makes EFI/ACT-385781A?

EFI/ACT-385781A is developed by Actelion (see full Actelion pipeline at /company/actelion).

Is EFI/ACT-385781A also known as anything else?

EFI/ACT-385781A is also known as ACT-385781A, Epoprostenol for injection (EFI).

What drug class is EFI/ACT-385781A in?

EFI/ACT-385781A belongs to the Selective endothelin receptor antagonist class. See all Selective endothelin receptor antagonist drugs at /class/selective-endothelin-receptor-antagonist.

What development phase is EFI/ACT-385781A in?

EFI/ACT-385781A is in Phase 3.

What are the side effects of EFI/ACT-385781A?

Common side effects of EFI/ACT-385781A include Peripheral edema, Headache, Flushing, Nasal congestion.

What does EFI/ACT-385781A target?

EFI/ACT-385781A targets Endothelin receptor (ETA/ETB) and is a Selective endothelin receptor antagonist.

Drug class: All Selective endothelin receptor antagonist drugs
Target: All drugs targeting Endothelin receptor (ETA/ETB)
Manufacturer: Actelion — full pipeline
Therapeutic area: All drugs in Cardiovascular
Indication: Drugs for Pulmonary arterial hypertension
Also known as: ACT-385781A, Epoprostenol for injection (EFI)

Primary sources · FDA · ClinicalTrials.gov · EMA · SEC EDGAR · ChEMBL · Wikidata · full sourcing