CLINICAL TRIALS PROFILE FOR QUINAPRIL HYDROCHLORIDE

All Clinical Trials for QUINAPRIL HYDROCHLORIDE

Trial ID	Title	Status	Sponsor	Phase	Start Date	Summary
NCT00065559 ↗	Treatment of Diabetic Nephropathy	Terminated	National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)	N/A	2003-04-01	COX-2 is an enzyme that is found in several different tissues in the body. COX-2 appears to produce a substance called prostaglandins, mainly at sites of inflammation. Several drugs have been approved by the FDA that inhibit COX-2 such as celecoxib, or brand name Celebrex®. These drugs are primarily used in patients with osteoarthritis and rheumatoid arthritis to decrease inflammation and pain. COX-2 inhibitors have been developed because they are more selective in treatment of inflammation and pain and tend to have fewer gastrointestinal side effects than NSAIDs (nonsteroidal anti-inflammatory drugs) such as aspirin, ibuprofen, naproxen, etc. The normal adult kidney expresses COX-2 in various regions. Prostaglandins, which are produced in the kidney by COX-2, may contribute to glomerular and tubulointerstitial inflammatory diseases (types of kidney diseases due to inflammation). In some animal studies, COX-2 inhibitors have been shown to be potentially beneficial in reducing the amount of protein spilled in the urine and preserving kidney function with these inflammatory kidney diseases. This study will compare the effects of COX-2 inhibitor to placebo (an inactive substance) in patients with diabetic nephropathy (kidney disease due to diabetes) and proteinuria (spilling protein in the urine) on 24-hour urinary protein excretion. This study is designed to see whether COX-2 inhibitors are useful in treating diabetic patients with kidney disease. The purpose of this study is a short-term pilot study that will allow the gathering of important data such as the ability to carry out the study and carry it out safely. Subjects with proteinuria and diabetic kidney disease already on ACE (Angiotensin-Converting Enzyme) inhibitor or ARB (Angiotensin Receptor Blocker) therapy (types of blood pressure medicines) will be randomized to a type of study in which each subject will serve as their own control. The study is set up so that each subject will receive either the COX-2 inhibitor or placebo for a period followed by a period of no drug and then followed by a period of receiving either the COX-2 inhibitor or placebo (whichever they did not receive the first period).
NCT00147524 ↗	Non-Comparative Study To Evaluate Changes In FMD After Quinapril Therapy In Hypertensive Women	Completed	Pfizer	Phase 4	2003-10-01	ACE inhibitors are thought to modify the endothelium in a number of ways. Quinapril is an effective and well-tolerated ACE-I for the treatment of patients with hypertension and congestive heart failure. Quinapril produces favourable haemodynamic changes and improves ventricular and endothelial function in patients with various cardiovascular disorders. These effects are mediated through the binding of quinaprilat to both tissue and plasma-ACE. Quinapril 10 to 40 mg once daily improved endothelial function (as measured by improved FMD or reduced vasoconstrictive/increased vasodilative response to Ach) in patients with CAD and hypertension over 2 to 6 months of therapy; improved endothelial function was also observed in patients with CHF receiving a single infusion of quinaprilat. In general, quinapril showed neutral or beneficial effects on lipid profiles, glycaemia and renal haemodynamics. (3) There are no data available considering effects of quinapril on endothelial dysfunction in post- menopausal woman with mild to moderate hypertension and with pathological endothelial function.
NCT00150826 ↗	QWISE - Study of Quinapril in Women With Chest Pain, Coronary Flow Reserve Limitations and Evidence of Myocardial Ischemia	Completed	National Heart, Lung, and Blood Institute (NHLBI)	Phase 4	2000-05-01	INDICATION Microvascular angina. OBJECTIVES To investigate the effect of ACE (angiotensin converting enzyme) inhibition (quinapril) in improving coronary microvascular function. PATIENT POPULATION Women who meet the National Heart, Lung and Blood Institute-sponsored WISE (Women Ischemia Syndrome Evaluation) study criteria of chest discomfort, coronary flow reserve limitations and evidence for myocardial ischemia in the absence of significant coronary artery stenosis. STUDY DESIGN A prospective, randomized, placebo-controlled, comparative trial. TREATMENT Quinapril 80 mg/d versus placebo for four months. PRIMARY EFFICACY PARAMETER(S) Coronary flow reserve (CFR) at Week 16 adjusted for baseline CFR, treatment group assignment, site-specific variables, and site by treatment effects. SECONDARY EFFICACY PARAMETERS Week 16 change in chest discomfort as measured by the Seattle Angina Questionnaire adjusting for baseline values, site, and site by treatment effects. SAFETY PARAMETERS Hematology, blood chemistries, blood pressure and pulse, and frequency and occurrence of adverse events. STATISTICAL RATIONALE AND ANALYSIS A statistical rationale for the number of patients in the study has been provided. Interim analyses are planned after 15 patients have been enrolled in each group. ANTICIPATED TOTAL NUMBER OF PATIENTS 78 (39 per group). ANTICIPATED NUMBER OF PATIENTS AT EACH SITE Approximately 26
NCT00150826 ↗	QWISE - Study of Quinapril in Women With Chest Pain, Coronary Flow Reserve Limitations and Evidence of Myocardial Ischemia	Completed	University of Florida	Phase 4	2000-05-01	INDICATION Microvascular angina. OBJECTIVES To investigate the effect of ACE (angiotensin converting enzyme) inhibition (quinapril) in improving coronary microvascular function. PATIENT POPULATION Women who meet the National Heart, Lung and Blood Institute-sponsored WISE (Women Ischemia Syndrome Evaluation) study criteria of chest discomfort, coronary flow reserve limitations and evidence for myocardial ischemia in the absence of significant coronary artery stenosis. STUDY DESIGN A prospective, randomized, placebo-controlled, comparative trial. TREATMENT Quinapril 80 mg/d versus placebo for four months. PRIMARY EFFICACY PARAMETER(S) Coronary flow reserve (CFR) at Week 16 adjusted for baseline CFR, treatment group assignment, site-specific variables, and site by treatment effects. SECONDARY EFFICACY PARAMETERS Week 16 change in chest discomfort as measured by the Seattle Angina Questionnaire adjusting for baseline values, site, and site by treatment effects. SAFETY PARAMETERS Hematology, blood chemistries, blood pressure and pulse, and frequency and occurrence of adverse events. STATISTICAL RATIONALE AND ANALYSIS A statistical rationale for the number of patients in the study has been provided. Interim analyses are planned after 15 patients have been enrolled in each group. ANTICIPATED TOTAL NUMBER OF PATIENTS 78 (39 per group). ANTICIPATED NUMBER OF PATIENTS AT EACH SITE Approximately 26
NCT00154050 ↗	High Dose Candesartan Versus Quinapril for Restenosis Prophylaxis After Stent Angioplasty	Completed	Technische Universität Dresden	N/A	2004-05-01	The study is designed to test the hypothesis that high dose candesartan treatment compared to quinapril is able to reduce intima hyperproliferation and the restenosis rate after stent angioplasty in peripheral occlusive artery disease.
NCT00159692 ↗	Amlodipine Diabetic Hypertension Efficacy Response Trial	Completed	Pfizer	Phase 4	2003-03-01	To evaluate the percentage of subjects that reach the diabetic hypertensive blood pressure goal of
NCT00159692 ↗	Amlodipine Diabetic Hypertension Efficacy Response Trial	Completed	Pfizer's Upjohn has merged with Mylan to form Viatris Inc.	Phase 4	2003-03-01	To evaluate the percentage of subjects that reach the diabetic hypertensive blood pressure goal of

Clinical Trial Conditions for QUINAPRIL HYDROCHLORIDE

Condition Name

Condition Name for QUINAPRIL HYDROCHLORIDE
Intervention	Trials
Hypertension	10
Healthy	6
Type 2 Diabetes Mellitus	1
Essential Hypertension	1

Condition MeSH

Condition MeSH for QUINAPRIL HYDROCHLORIDE
Intervention	Trials
Hypertension	10
Diabetes Mellitus	4
Kidney Diseases	2
Myocardial Ischemia	2

Clinical Trial Locations for QUINAPRIL HYDROCHLORIDE

Trials by Country

Trials by Country for QUINAPRIL HYDROCHLORIDE
Location	Trials
United States	12
India	11
Spain	4
Canada	3
Turkey	2

Trials by US State

Trials by US State for QUINAPRIL HYDROCHLORIDE
Location	Trials
North Dakota	4
Tennessee	2
Nebraska	1
Georgia	1
Texas	1

Clinical Trial Progress for QUINAPRIL HYDROCHLORIDE

Clinical Trial Phase

Clinical Trial Phase for QUINAPRIL HYDROCHLORIDE
Clinical Trial Phase	Trials
Phase 4	16
Phase 3	1
Phase 1	4

Clinical Trial Status

Clinical Trial Status for QUINAPRIL HYDROCHLORIDE
Clinical Trial Phase	Trials
Completed	24
Terminated	2
Unknown status	1

Clinical Trial Sponsors for QUINAPRIL HYDROCHLORIDE

Sponsor Name

Sponsor Name for QUINAPRIL HYDROCHLORIDE
Sponsor	Trials
Pfizer	7
Mylan Pharmaceuticals	4
Ranbaxy Laboratories Limited	2

Sponsor Type

Sponsor Type for QUINAPRIL HYDROCHLORIDE
Sponsor	Trials
Other	23
Industry	18
NIH	4

Last updated: July 23, 2026

Quinapril Hydrochloride (quinapril HCl): Clinical trial updates, market status, and near-term projections

What is quinapril hydrochloride and what clinical-trial signals matter right now?

Quinapril hydrochloride is an angiotensin-converting enzyme (ACE) inhibitor used for hypertension and heart failure indications. As a widely used, off-patent small-molecule therapy, current clinical-trial activity is typically limited to small studies, formulation/bioequivalence work, and post-approval safety or quality investigations rather than late-stage registrational programs.

What kinds of trials are most likely being run for quinapril now?

• Bioequivalence and pharmacokinetic studies for generic manufacturers’ fixed-dose combinations and reformulations.
• Real-world evidence and observational studies (adherence, persistence, adverse event surveillance).
• Switch studies (e.g., conversion across ACE inhibitors).
• Safety studies focused on renal outcomes, hyperkalemia incidence, and angioedema surveillance.

What trial endpoints are most relevant for adoption and payer use?

• Systolic/diastolic blood pressure change from baseline (hypertension studies).
• Morbidity-mortality proxies and hospitalization rates (heart failure cohorts, if present in new trials).
• Renal function metrics (eGFR change, creatinine rise).
• Hyperkalemia incidence and treatment discontinuation rates.

If a registrational trial existed at scale (e.g., phase 3), the drug’s market access would show clearer differentiation versus existing ACE inhibitor generics, which is not the typical pattern for quinapril. Market dynamics therefore tend to be driven more by generic competitive intensity, formulary placement, and supply stability than by new efficacy breakthroughs.

How is the quinapril hydrochloride market positioned today and which geographies drive demand?

Quinapril’s market is shaped by:

• High generic penetration in the US and multiple established suppliers.
• Strong competition from other ACE inhibitors and, increasingly, from angiotensin receptor blockers (ARBs) and angiotensin receptor-neprilysin inhibitors (ARNIs) for heart failure, depending on guideline adherence and payer preferences.
• Pharmacy benefit design that often favors low net-cost generics.

US demand and channel dynamics

In the US, quinapril functions as a mature generic ACE inhibitor. Growth is typically modest and tied to:

• Population aging and heart failure prevalence trends.
• Indication maintenance and persistence rather than new patient acquisition at high incremental rates.
• Substitution patterns at the pharmacy: generic switching, therapeutic interchange, and dose-form substitution.

Europe and other developed markets

In Europe, ACE inhibitor class competition is similar. Demand hinges on:

• Formulary tenders and price compression.
• Local generic brand ecosystems.
• National reimbursement rules for hypertension and heart failure.

What do pricing, competition, and reimbursement trends imply for quinapril hydrochloride revenue?

For mature ACE inhibitors, revenue is usually constrained by:

• Automatic substitution and tender pricing.
• Ongoing erosion of unit price as additional generics enter.
• Low willingness-to-pay for incremental benefit absent clinical differentiation.

Pricing behavior typical for mature generics

• High volume, low margin.
• Periodic price dips after additional entrants or tender cycles.
• Net revenue sensitivity to wholesaler inventory and supply.

How class competition affects quinapril share

ACE inhibitors face persistent substitution pressure from:

• ARBs (especially when ACE intolerance occurs).
• Newer heart failure standards of care (ARNI-based regimens) in segments with access and payer coverage.

For hypertension, however, ACE inhibitors remain common, and quinapril’s position depends heavily on historical prescribing patterns and formulary status.

When does quinapril hydrochloride lose exclusivity and what IP barriers remain?

Quinapril is an established active ingredient with expired or near-expired primary compound patents in major markets. The practical IP landscape is usually dominated by:

• Process patents and intermediate/control of impurities (if any are active).
• Formulation patents (typically limited scope for immediate-release tablets).
• Brand-specific lifecycle patents (if a legacy brand still exists in some jurisdictions).

Net implication: For licensing and generic-entry planning, quinapril typically does not carry the high-stakes exclusivity runway seen in modern small-molecule assets. Most value is in manufacturing capability, bioequivalence compliance, and securing formulatory access.

What is the Orange Book status of quinapril hydrochloride?

Quinapril hydrochloride is expected to be widely represented with multiple approved generic ANDAs and limited remaining brand exclusivities.

A complete Orange Book risk view (specific listed patents, expiry dates, and regulatory exclusivity blocks) requires Orange Book listing-level extraction for each strength and dosage form. Without that listing-level data, the only business-credible takeaway is that quinapril’s US market is already post-exclusivity and structurally exposed to generic competition.

Which patents protect quinapril hydrochloride formulations and methods of use?

For a mature ACE inhibitor, any active patent estate is more likely to cover:

• Tablet composition and specific excipient systems (limited breadth).
• Specific manufacturing processes or impurity controls.
• Narrow method-of-use claims tied to particular dosing regimens, patient subgroups, or combination therapy.

Key business angle: Generic entrants generally route around formulation IP through design freedom plus bioequivalence, and litigation risk is usually low unless a still-active patent targets a core formulation, a unique strength, or a combination product.

What generic entry risks exist for quinapril hydrochloride (Paragraph IV and litigation)?

For quinapril, the probability of material Paragraph IV-driven litigation is lower than for newer specialty drugs, because:

• Many entries have already occurred.
• The therapeutic space is crowded with multiple ACE inhibitor generics.
• Remaining patents, if any, tend to be narrow and procedural in nature.

Execution focus for entrants: The binding constraints are more likely FDA compliance, bioequivalence, cGMP robustness, and inventory continuity than active patent injunction threats.

How does quinapril hydrochloride compare with other ACE inhibitors and ARBs?

Quinapril competes directly with:

• Other ACE inhibitors: lisinopril, enalapril, benazepril, ramipril, captopril.
• ARBs: losartan, valsartan, irbesartan, telmisartan.
• Heart failure pathway shifts: ARNI-based therapies in select patients.

What decides market share in practice?

• Lowest net cost at formulary level.
• Physician familiarity and substitution policies.
• Patient tolerability and prior response.
• Product availability and fulfillment reliability.

Quinapril does not typically win on clinically differentiated endpoints versus other ACE inhibitors, so it tends to be a price and supply game.

What clinical-trial themes are most likely to influence future labeling or differentiation?

In mature ACE inhibitors, labeling changes usually come from:

• Expanded safety monitoring language.
• Drug-drug interaction updates.
• Renal impairment or pediatric updates (if ever pursued in a targeted way).
• Post-marketing requirements.

No major differentiation is expected from new efficacy trials unless a unique population, combination, or delivery system emerges, which is atypical for quinapril’s stage in the lifecycle.

Market projection for quinapril hydrochloride: base case, drivers, and sensitivities

Baseline scenario (most likely)

• Demand: stable to low single-digit growth driven by population and persistence.
• Price: gradual downward trend tied to generic competition and tender cycles.
• Revenue: modest growth or flat performance depending on market share shifts and net price erosion.

Upside scenario

• Formulary inclusion improvements (switching into quinapril from other ACE inhibitors due to price advantage).
• Supply stabilization avoiding stock-outs that push payers temporarily to substitutes.
• Increased use in specific care pathways where quinapril is already established.

Downside scenario

• Accelerated price erosion from new entrants or tender resets.
• Higher substitution to ARBs/ARNIs in heart failure segments.
• Manufacturing disruptions leading to temporary shortages and lost prescriptions.

What you should model in a projection model

• Unit volumes by strength (5 mg, 10 mg, 20 mg, 40 mg in many markets, depending on local labeling).
• Average net price (after rebates/wholesaler/contract adjustments).
• Market share change versus competing ACE inhibitors and ARBs.
• Tender cadence and formulary renewals.
• Supply and inventory cycles that affect fill rates.

Key takeaways

• Quinapril hydrochloride is a mature, widely generic ACE inhibitor where new clinical trials are likely incremental (bioequivalence and observational safety) rather than registrational.
• Revenue trajectory is dominated by generic price erosion and formulary placement rather than patent exclusivity.
• Market projections are best modeled as low-growth, price-down dynamics with share sensitivity to competing ACE inhibitors and ARBs.
• Material patent and litigation risk is generally low for this class at this lifecycle stage, with any remaining IP likely narrow and formulation- or process-focused rather than broad method-of-use protection.

FAQs

Are there any ongoing phase 3 trials for quinapril hydrochloride?

Clinical-trial activity for mature quinapril is typically limited to non-registrational studies; phase 3 activity is not the expected norm for the asset class and lifecycle stage.

Will quinapril hydrochloride see new indications in the next 12–24 months?

Label expansion is more likely to be limited to safety language or population-specific updates than new indications, absent a targeted clinical development push.

How does quinapril hydrochloride pricing typically behave versus other ACE inhibitors?

Pricing generally tracks the lowest net-cost leader in the ACE inhibitor generics cohort, with periodic tender-driven drops.

What are the main regulatory risks for generic quinapril launches?

The main risks tend to be bioequivalence execution, dissolution performance for specific strengths, and consistent cGMP manufacturing, not patent injunctions.

Is quinapril more likely to lose share to ARBs or to other ACE inhibitors?

The largest competitive pressure usually comes from ARBs in heart failure intolerance and from ACE inhibitors with stronger formulary positioning or net price advantages.

References

1. FDA Orange Book: Approved Drug Products with Therapeutic Equivalence Evaluations. US Food and Drug Administration. https://www.accessdata.fda.gov/scripts/cder/daf/ (accessed 2026-07-23).
2. DailyMed. Quinapril hydrochloride prescribing information (varies by manufacturer). US National Library of Medicine. https://dailymed.nlm.nih.gov/ (accessed 2026-07-23).
3. ClinicalTrials.gov. Quinapril hydrochloride search results. US National Library of Medicine. https://clinicaltrials.gov/ (accessed 2026-07-23).