Last reviewed 2026-05-14 · How we verify

L50/H12.5

Merck Sharp & Dohme LLC · Phase 3 active Small molecule

L50/H12.5 is a Angiotensin II receptor antagonist / Thiazide diuretic combination Small molecule drug developed by Merck Sharp & Dohme LLC. It is currently in Phase 3 development for Hypertension. Also known as: MK-0954H.

L50/H12.5 is a fixed-dose combination of losartan and hydrochlorothiazide that reduces blood pressure by blocking angiotensin II receptors and inhibiting sodium reabsorption in the kidney.

L50/H12.5 is a fixed-dose combination of losartan and hydrochlorothiazide that reduces blood pressure by blocking angiotensin II receptors and inhibiting sodium reabsorption in the kidney. Used for Hypertension.

Likelihood of approval

59.3% 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.
Big-pharma sponsor +3.0pp
Merck Sharp & Dohme LLC is a top-20 pharma sponsor — historical approval rates run ~3pp above average due to scale, regulatory experience, and trial-design quality.

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	L50/H12.5
Also known as	MK-0954H
Sponsor	Merck Sharp & Dohme LLC
Drug class	Angiotensin II receptor antagonist / Thiazide diuretic combination
Target	AT1 receptor (angiotensin II type 1 receptor); sodium-chloride cotransporter
Modality	Small molecule
Therapeutic area	Cardiovascular
Phase	Phase 3

Mechanism of action

Losartan is an angiotensin II receptor antagonist (ARB) that blocks the AT1 receptor, preventing vasoconstriction and aldosterone secretion. Hydrochlorothiazide is a thiazide diuretic that inhibits sodium and chloride reabsorption in the distal convoluted tubule, promoting sodium and water excretion. The combination provides synergistic antihypertensive effects through complementary mechanisms.

Approved indications

Hypertension

Common side effects

Dizziness
Fatigue
Hyperuricemia
Hypokalemia
Cough

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:

L50/H12.5 CI brief — competitive landscape report
L50/H12.5 updates RSS · CI watch RSS
Merck Sharp & Dohme LLC portfolio CI

Frequently asked questions about L50/H12.5

What is L50/H12.5?

L50/H12.5 is a Angiotensin II receptor antagonist / Thiazide diuretic combination drug developed by Merck Sharp & Dohme LLC, indicated for Hypertension.

How does L50/H12.5 work?

L50/H12.5 is a fixed-dose combination of losartan and hydrochlorothiazide that reduces blood pressure by blocking angiotensin II receptors and inhibiting sodium reabsorption in the kidney.

What is L50/H12.5 used for?

L50/H12.5 is indicated for Hypertension.

Who makes L50/H12.5?

L50/H12.5 is developed by Merck Sharp & Dohme LLC (see full Merck Sharp & Dohme LLC pipeline at /company/merck).

Is L50/H12.5 also known as anything else?

L50/H12.5 is also known as MK-0954H.

What drug class is L50/H12.5 in?

L50/H12.5 belongs to the Angiotensin II receptor antagonist / Thiazide diuretic combination class. See all Angiotensin II receptor antagonist / Thiazide diuretic combination drugs at /class/angiotensin-ii-receptor-antagonist-thiazide-diuretic-combination.

What development phase is L50/H12.5 in?

L50/H12.5 is in Phase 3.

What are the side effects of L50/H12.5?

Common side effects of L50/H12.5 include Dizziness, Fatigue, Hyperuricemia, Hypokalemia, Cough.

What does L50/H12.5 target?

L50/H12.5 targets AT1 receptor (angiotensin II type 1 receptor); sodium-chloride cotransporter and is a Angiotensin II receptor antagonist / Thiazide diuretic combination.

Drug class: All Angiotensin II receptor antagonist / Thiazide diuretic combination drugs
Target: All drugs targeting AT1 receptor (angiotensin II type 1 receptor); sodium-chloride cotransporter
Manufacturer: Merck Sharp & Dohme LLC — full pipeline
Therapeutic area: All drugs in Cardiovascular
Indication: Drugs for Hypertension
Also known as: MK-0954H

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