Lucier Pharmaceuticals

Pioneering the fight against microvascular diseases.

Lucier develops drug candidates targeting the unique mechanisms of coronary microvessels to treat endotype-specific coronary microvascular dysfunction (CMD).

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Science

Small vessels.
A significant unmet need.

Microvascular dysfunction can affect organs throughout the body, including the heart, eyes, and central nervous system. Lucier’s focus is coronary microvascular dysfunction, where effective, mechanism-directed therapies remain a significant unmet need.

Explore our programs
What is a microvessel?

The microcirculation is a connected network of small arteries, arterioles, capillaries, and venules. These segments are distinguished by their size and function.

Our team focuses on coronary arterioles with an inner diameter of approximately 40–100 micrometers (µm) under maximal dilation. Definitions have evolved as research has revealed functional differences between arterioles and larger vessels around 200 µm in diameter.1

  1. Microvascular responses
What makes arterioles unique?

Microvascular autoregulation helps maintain adequate tissue perfusion over a range of arterial pressures. As pressure rises, arterioles constrict (narrow), limiting the pressure and flow transmitted downstream. As pressure falls, they dilate (widen), helping preserve blood flow. Within the autoregulatory range, this keeps tissue-level flow relatively stable when metabolic demand is unchanged.23 The interaction between small and large vessels also matters when CMD coexists with obstructive coronary artery disease.4

In 1988, Professor Lih Kuo and colleagues demonstrated pressure-dependent myogenic responses in isolated porcine coronary arterioles, establishing a foundation for understanding this intrinsic regulation of coronary blood flow.5

Human studies after coronary intervention help explain how blood flow and microvascular resistance adapt when upstream coronary disease is treated, and how coexisting CMD can affect symptoms.234 In a 2026 study, resting blood flow remained stable because microvascular resistance increased as epicardial resistance fell, providing direct evidence of coronary autoregulation in humans.6

  1. Coronary autoregulation review, 2026
  2. Human coronary autoregulation, 2026
  3. CMD and symptoms after PCI, 2026
  4. Kuo et al., 1988
  5. Experimental evidence in clinical practice, 2026
How does CMD relate to other diagnoses?

Coronary microvascular dysfunction (CMD) affects the regulation of blood flow in the heart’s small vessels. It can contribute to angina, ischemia, or myocardial infarction, including when the large coronary arteries are not obstructed.7

ANOCA, INOCA, and MINOCA describe clinical presentations; CMD can be an underlying mechanism, but these terms are not interchangeable with CMD and may have other causes.7

Four dedicated U.S. ICD-10-CM codes recognize CMD: I20.81 (angina with CMD), I21.B (myocardial infarction with CMD), I24.81 (acute CMD), and I25.85 (chronic CMD).8

  1. INOCA expert consensus
  2. Diagnostic codes
How common is CMD?

A systematic review and meta-analysis of 56 studies involving 14,427 patients estimated a pooled CMD prevalence of 41% (95% confidence interval, 36–47%) among patients with no obstructive coronary artery disease.9

That estimate applies to the populations studied, rather than the general population. CMD can also coexist with disease in larger coronary arteries, so a focus on nonobstructive disease alone does not capture its full clinical reach. Greater access to coronary physiology assessment can help reveal these distinct mechanisms.4

  1. Prevalence meta-analysis
  2. CMD alongside obstructive disease

Pipeline

Programs in development

Type 1Preclinical development

LU-1001 / LU-1002

LU-1001 (injectable) is under investigation to assist CMD diagnosis.

LU-1002 (oral) is under investigation for maintenance therapy.

Type 2Potential late-phase development

LU-3001 / LU-3002

An undisclosed asset being evaluated for a specific CMD subtype, with a focus on CMD endotyping and endotype-specific therapy.

All programs are investigational. Safety and efficacy for CMD have not been established, and no Lucier candidate is approved for patient use.

LU-1001 / LU-1002 mechanism

Following the signal.

ET-1 binds to ET-A.

Endothelin-1 (ET‑1) binds to the ET‑A receptor on the smooth muscle cell, initiating signaling
inside the cell.

ET-1 at the ET-A receptor signals through RhoA and ROCK toward smooth muscle contraction. Lucier’s investigational candidates LU-1001 and LU-1002 target ROCK inhibition. LU-1001 is injectable, intended to assist CMD diagnosis; LU-1002 is oral, intended for maintenance therapy. The dashed arrow represents omitted downstream steps.

Research

Understanding coronary microvessels.

Explore the clinical observations and experimental research informing our approach to CMD.

1967–20234 milestonesEvolving clinical recognition

From the first clinical observations to shared terminology and dedicated diagnostic codes.

  1. An early clinical puzzle

    Signs of coronary heart disease despite apparently normal angiograms.

    Original NEJM report

  2. Revisiting cardiac syndrome X

    Dr. Richard O. Cannon III reviews the continuing challenge of chest pain with normal coronary angiograms, historically described as cardiac syndrome X. The review examines microvascular angina and unresolved questions about its mechanisms, diagnosis, and treatment.

    Cannon’s historical review

  3. Four clinical settings for CMD

    Crea, Camici, and Bairey Merz review four clinical settings: CMD without myocardial disease or obstructive coronary artery disease; CMD with myocardial disease; CMD with obstructive coronary artery disease; and iatrogenic CMD. These clinical categories provide context for the diverse mechanisms underlying CMD.

    CMD classification review

  4. Dedicated diagnostic codes

    Four U.S. ICD-10-CM codes recognize CMD: I20.81, I21.B, I24.81 and I25.85.

    ICD-10-CM update
2020–20266 studiesThe treatment challenge

A persistent treatment-evidence gap. The trials below did not establish benefit on their primary outcomes; their populations, treatments, and endpoints differ. These results reinforce the need to understand CMD mechanisms and develop therapies directed at them.

  1. MARINA: ranolazine

    This pilot trial found no significant improvement in angina frequency or invasive microvascular function versus placebo at three months.

    NCT02147067Trial publication

  2. EDIT-CMD: diltiazem

    Diltiazem did not substantially improve the primary coronary-function endpoint, symptoms, or quality of life over six weeks, although epicardial spasm was reduced.

    NCT04777045Trial publication

  3. Zibotentan in microvascular angina

    The primary exercise-duration endpoint did not improve versus placebo. Adverse events were more common with zibotentan.

    NCT04097314Trial publication

  4. WARRIOR: intensive medical therapy

    No significant difference in the primary cardiovascular-event endpoint was found in women with suspected INOCA. Enrollment shortfalls and treatment crossover limit interpretation.

    NCT03417388ACC trial report

  5. ViVA: vericiguat

    Vericiguat did not demonstrate improved peripheral vasodilator function or anginal symptoms in patients with coronary vasospasm during this crossover trial.

    NCT06415227Trial publication

  6. REMEDY-PILOT: coronary sinus reducer

    Study investigators presented data and concluded that “Although CSR implantation was safe, the data showed no significant improvement in CMR perfusion metrics, symptoms or quality of life compared with a sham procedures in these patients, who currently have no other evidence-based treatment options.”

    NCT05492110ACC trial report
1988–20266 studiesA microvascular perspective

Lucier’s work builds on direct study of coronary arterioles. Understanding their distinct behavior helps us challenge assumptions drawn from larger vessels and investigate mechanisms that may enable endotype-specific medicines.

  1. Myogenic activity in coronary arterioles

    Dr. Lih Kuo and colleagues demonstrate pressure-dependent myogenic activity in isolated porcine coronary arterioles, supporting a role in blood-flow autoregulation.

    Read the study

  2. Vessel size shapes vasodilation

    In isolated porcine coronary microvessels, adenosine dilated the smallest arterioles at the lowest concentrations, with larger vessels requiring higher concentrations. The endothelium-independent dilator nitroprusside produced similar responses across vessel sizes, while larger arterioles responded more strongly to flow-induced shear stress. These findings show why vessel size and the stimulus both matter.

    Read the study

  3. Opening the microvascular black box

    Pries and Reglin identify a decline in experimental studies of coronary microvessels, despite growing clinical research, as a potential barrier to progress. They argue that understanding disease mechanisms is essential to classify CMD, guide diagnosis, and identify therapeutic targets. The review calls for relevant animal models, improved experimental methods, and scientific meetings to close this gap.

    Read the black-box review

  4. A research agenda for the next decade

    An ACC-led working group outlines the knowledge gaps in INOCA and the research needed to develop evidence-based therapies. It calls for a better understanding of underlying mechanisms and a coordinated approach to future studies.

    Read the research agenda

  5. Paradoxical constriction in a disease model

    In a mouse model of pressure-overload hypertrophy, acetylcholine causes coronary arteriolar constriction despite an intact endothelium. The findings implicate elevated Rho kinase activity in microvascular dysfunction.

    Read the study

  6. Autoregulation measured in humans

    Direct coronary physiology measurements show that changes in microvascular resistance help maintain stable resting blood flow as resistance in the large coronary arteries changes, providing evidence of autoregulation in humans.

    Read the study
Experimental research3 figuresKey experiments in microvessels
Adenosine dose-response curves: smaller coronary arterioles dilate at lower concentrations than larger vessels.

Figure 1

Adenosine reveals differences between microvessels

Adenosine dilates coronary microvessels and is commonly used during coronary physiology assessment to measure coronary flow reserve and microvascular resistance. An impaired flow response can help identify CMD.7

Dr. Lih Kuo and colleagues showed that small coronary arterioles were more sensitive to adenosine than larger microvascular segments. The curves shift to higher concentrations as vessel size increases, demonstrating distinct responses along the coronary microcirculation.1

  1. Kuo et al., Circulation, 1995
  2. Clinical assessment consensus
Acetylcholine dilates coronary arterioles from sham mice but constricts those from mice with pressure-overload hypertrophy.

Figure 2

Acetylcholine exposes paradoxical vasoconstriction

Acetylcholine (ACh) can cause paradoxical vasoconstriction in diseased coronary arterioles even when the endothelium remains intact.10 In clinical practice, acetylcholine provocation testing helps assess epicardial coronary spasm and microvascular spasm.7

The team observed ACh-induced constriction in coronary arterioles isolated from pressure-overload mice. Elevated Rho kinase activity was implicated in the abnormal response, and inhibiting Rho kinase abolished the ACh-induced constriction. These experimental findings support further investigation of this pathway in CMD.10

  1. Pressure-overload study, Cardiovascular Research, 2017
  2. Clinical assessment consensus
Sham and transverse aortic constriction mouse hearts above corresponding aortic ultrasound images; the pressure-overload heart is enlarged.

Figure 3

A pressure-overload model connects vessel and heart function

The paradoxical response shown in Figure 2 was observed in coronary arterioles isolated from a pressure-overload mouse model. Narrowing the aorta by transverse aortic constriction (TAC) increased the heart’s workload and produced cardiac hypertrophy.10

The upper panels compare a sham-control heart with an enlarged TAC heart. The lower panels show corresponding ultrasound images of the aorta. This model linked altered arteriolar responses with impaired coronary flow regulation and cardiac function; it does not represent every form of human CMD.10

  1. Model and methods, Cardiovascular Research, 2017

Team

Research & development expertise.

Lucier’s programs draw on coronary arteriolar research originating at Texas A&M University (patent publication PCT/US2024/029067). Our advisors bring experience in vascular biology, translational research, preclinical development, and biotechnology strategy.

News & publications

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