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Ensifentrine · Ohtuvayre, RPL-554

Small molecule · Inhibitor of PDE3 (PDE3A) and PDE4 (PDE4B) · developed by Msd

Approved FDA, Jun 2024
MRK Developer
1 Registered trials

What is Ensifentrine?

Ensifentrine is a small-molecule inhibitor of phosphodiesterase 3 (PDE3) and phosphodiesterase 4 (PDE4) enzymes. It increases intracellular cAMP and cGMP levels, triggering downstream signaling effects.

Summary written with AI from the sources listed at the end of this page.

At a glance

Also known as
Ohtuvayre, RPL-554
Drug type
Small molecule
Targets
PDE3 (PDE3A), PDE4 (PDE4B)
Mechanism
Inhibitor of PDE3 (PDE3A) and PDE4 (PDE4B)
Pathways
cAMP accumulation, cGMP accumulation
Therapy area
Respiratory
Developer
Msd (MRK)
FDA status
Approved as Ohtuvayre (June 26, 2024), NDA217389 · FDA label
UNII
3E3D8T1GIX

✅ FDA-approved uses

From the indications section of the FDA label (version of Apr 23, 2026). Read the full label for the exact wording, limitations and safety information.

🧪 Clinical trials

TrialPhaseConditionStatusSponsor
NCT05270525 Phase 2 COPD Active not recruiting MRK

Trials of the companies BioRadar tracks, from ClinicalTrials.gov, most advanced phase first.

Conditions studied

COPD

More from Msd

BCG Live FDA approved Belzutifan FDA approved Berahyaluronidase Alfa FDA approved Berahyaluronidase Alfa and Pembrolizumab FDA approved Enlicitide FDA approved Letermovir FDA approved Pembrolizumab FDA approved Probenecid FDA approved Alimatravir Phase 2 Bomedemstat Phase 2/3 Calderasib Phase 3 Favezelimab Phase 1/2

Sources

Updated Oct 3, 2026. Something wrong or missing? Report it on the MRK page.

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Data: FDA (Drugs@FDA, Purple Book, DailyMed), NIH (NCI Thesaurus, GSRS, RxNorm), ClinicalTrials.gov • Informational purposes only, not medical or investment advice. • All drugs A–Z

This data is for informational purposes only, not investment advice. BioRadar does not provide buy/sell recommendations. Past performance does not guarantee future results. Always do your own due diligence.