CLINICAL TRIALS PROFILE FOR HYDROXYUREA

505(b)(2) Clinical Trials for hydroxyurea

This table shows clinical trials for potential 505(b)(2) applications. See the next table for all clinical trials

Trial Type	Trial ID	Title	Status	Sponsor	Phase	Start Date	Summary
New Indication	NCT04247750 ↗	Testing SIROLIMUS in Beta-thalassemia Transfusion Dependent Patients (THALA-RAP)	Recruiting	Azienda Ospedaliero, Universitaria Meyer	Phase 2	2021-01-28	In β-thalassaemia and Sickle Cell Disease (SCD), a significant production of fetal haemoglobin (HbF) may reduce the severity of clinical course and reactivation of γ-globin gene expression in adulthood. HbF induction is one of the best strategies to ameliorate the characteristic symptoms of these diseases. Hydroxyurea (HU) is the only medication, approved by the US Food and Drug Administration, inducing HbF. However, treatments with HU induce sufficient HbF levels in only half of the patients, and side effects including leukopenia and neutropenia are frequently reported. Therefore, novel therapeutic inducers must be identified to develop a personalized treatment in β-thalassaemia and sickle cell anaemia. The availability of new treatments depends on drugs already approved for other indications, and on pharmacokinetics and pharmacovigilance already assessed. Rapamycin (as Sirolimus) is an immunosuppressant agent, approved by the FDA for acute rejection prevention in renal transplant recipients. The ability of this drug to induce γ-globin gene expression in erythroleukemia cell line and erythroid precursors cells (ErPCs) in ß-thalassaemia patients is already known. A clinical investigation on the effects of sirolimus in ß-Thalassaemia aims to evaluate several parameters related to red blood cell status and HbF levels and is a first step for the full clinical development in this new indication.
New Indication	NCT04247750 ↗	Testing SIROLIMUS in Beta-thalassemia Transfusion Dependent Patients (THALA-RAP)	Recruiting	Azienda Ospedaliero, Universitaria Pisana	Phase 2	2021-01-28	In β-thalassaemia and Sickle Cell Disease (SCD), a significant production of fetal haemoglobin (HbF) may reduce the severity of clinical course and reactivation of γ-globin gene expression in adulthood. HbF induction is one of the best strategies to ameliorate the characteristic symptoms of these diseases. Hydroxyurea (HU) is the only medication, approved by the US Food and Drug Administration, inducing HbF. However, treatments with HU induce sufficient HbF levels in only half of the patients, and side effects including leukopenia and neutropenia are frequently reported. Therefore, novel therapeutic inducers must be identified to develop a personalized treatment in β-thalassaemia and sickle cell anaemia. The availability of new treatments depends on drugs already approved for other indications, and on pharmacokinetics and pharmacovigilance already assessed. Rapamycin (as Sirolimus) is an immunosuppressant agent, approved by the FDA for acute rejection prevention in renal transplant recipients. The ability of this drug to induce γ-globin gene expression in erythroleukemia cell line and erythroid precursors cells (ErPCs) in ß-thalassaemia patients is already known. A clinical investigation on the effects of sirolimus in ß-Thalassaemia aims to evaluate several parameters related to red blood cell status and HbF levels and is a first step for the full clinical development in this new indication.
New Indication	NCT04247750 ↗	Testing SIROLIMUS in Beta-thalassemia Transfusion Dependent Patients (THALA-RAP)	Recruiting	Rare Partners srl Impresa Sociale	Phase 2	2021-01-28	In β-thalassaemia and Sickle Cell Disease (SCD), a significant production of fetal haemoglobin (HbF) may reduce the severity of clinical course and reactivation of γ-globin gene expression in adulthood. HbF induction is one of the best strategies to ameliorate the characteristic symptoms of these diseases. Hydroxyurea (HU) is the only medication, approved by the US Food and Drug Administration, inducing HbF. However, treatments with HU induce sufficient HbF levels in only half of the patients, and side effects including leukopenia and neutropenia are frequently reported. Therefore, novel therapeutic inducers must be identified to develop a personalized treatment in β-thalassaemia and sickle cell anaemia. The availability of new treatments depends on drugs already approved for other indications, and on pharmacokinetics and pharmacovigilance already assessed. Rapamycin (as Sirolimus) is an immunosuppressant agent, approved by the FDA for acute rejection prevention in renal transplant recipients. The ability of this drug to induce γ-globin gene expression in erythroleukemia cell line and erythroid precursors cells (ErPCs) in ß-thalassaemia patients is already known. A clinical investigation on the effects of sirolimus in ß-Thalassaemia aims to evaluate several parameters related to red blood cell status and HbF levels and is a first step for the full clinical development in this new indication.
New Indication	NCT04247750 ↗	Testing SIROLIMUS in Beta-thalassemia Transfusion Dependent Patients (THALA-RAP)	Recruiting	Università degli Studi di Ferrara	Phase 2	2021-01-28	In β-thalassaemia and Sickle Cell Disease (SCD), a significant production of fetal haemoglobin (HbF) may reduce the severity of clinical course and reactivation of γ-globin gene expression in adulthood. HbF induction is one of the best strategies to ameliorate the characteristic symptoms of these diseases. Hydroxyurea (HU) is the only medication, approved by the US Food and Drug Administration, inducing HbF. However, treatments with HU induce sufficient HbF levels in only half of the patients, and side effects including leukopenia and neutropenia are frequently reported. Therefore, novel therapeutic inducers must be identified to develop a personalized treatment in β-thalassaemia and sickle cell anaemia. The availability of new treatments depends on drugs already approved for other indications, and on pharmacokinetics and pharmacovigilance already assessed. Rapamycin (as Sirolimus) is an immunosuppressant agent, approved by the FDA for acute rejection prevention in renal transplant recipients. The ability of this drug to induce γ-globin gene expression in erythroleukemia cell line and erythroid precursors cells (ErPCs) in ß-thalassaemia patients is already known. A clinical investigation on the effects of sirolimus in ß-Thalassaemia aims to evaluate several parameters related to red blood cell status and HbF levels and is a first step for the full clinical development in this new indication.

All Clinical Trials for hydroxyurea

Trial ID	Title	Status	Sponsor	Phase	Start Date	Summary
NCT00000586 ↗	Multicenter Study of Hydroxyurea in Patients With Sickle Cell Anemia (MSH)	Completed	National Heart, Lung, and Blood Institute (NHLBI)	Phase 3	1992-01-01	To assess the efficacy and safety of orally administered hydroxyurea in the treatment of painful crises in patients with sickle cell anemia.
NCT00000602 ↗	Pediatric Hydroxyurea in Sickle Cell Anemia (PED HUG)	Completed	National Heart, Lung, and Blood Institute (NHLBI)	Phase 2	1994-04-01	To determine whether hydroxyurea prevents the onset of chronic end organ damage in young children with sickle cell anemia.
NCT00000623 ↗	Thalassemia (Cooley's Anemia) Clinical Research Network (TCRN)	Completed	National Heart, Lung, and Blood Institute (NHLBI)		2000-07-01	The purpose of the TCRN is to accelerate research in the management of thalassemia, standardize existing treatments, and evaluate new ones in a network of clinical centers in North America. The emphasis will be on clinical trials that help identify optimal therapy. Therapeutic trials may involve investigational drugs, drugs already approved but not currently used, and drugs currently used.
NCT00000623 ↗	Thalassemia (Cooley's Anemia) Clinical Research Network (TCRN)	Completed	Thalassemia Clinical Research Network		2000-07-01	The purpose of the TCRN is to accelerate research in the management of thalassemia, standardize existing treatments, and evaluate new ones in a network of clinical centers in North America. The emphasis will be on clinical trials that help identify optimal therapy. Therapeutic trials may involve investigational drugs, drugs already approved but not currently used, and drugs currently used.
NCT00000623 ↗	Thalassemia (Cooley's Anemia) Clinical Research Network (TCRN)	Completed	HealthCore-NERI		2000-07-01	The purpose of the TCRN is to accelerate research in the management of thalassemia, standardize existing treatments, and evaluate new ones in a network of clinical centers in North America. The emphasis will be on clinical trials that help identify optimal therapy. Therapeutic trials may involve investigational drugs, drugs already approved but not currently used, and drugs currently used.

Clinical Trial Conditions for hydroxyurea

Condition Name

Condition Name for hydroxyurea
Intervention	Trials
Sickle Cell Disease	66
Sickle Cell Anemia	33
Polycythemia Vera	23
HIV Infections	17

Condition MeSH

Condition MeSH for hydroxyurea
Intervention	Trials
Anemia, Sickle Cell	112
Leukemia	37
Leukemia, Myeloid	33
Anemia	31

Clinical Trial Locations for hydroxyurea

Trials by Country

Trials by Country for hydroxyurea
Location	Trials
United States	864
Italy	83
Germany	60
France	54
Spain	49

Trials by US State

Trials by US State for hydroxyurea
Location	Trials
New York	53
Illinois	52
Texas	52
North Carolina	46
California	44

Clinical Trial Progress for hydroxyurea

Clinical Trial Phase

Clinical Trial Phase for hydroxyurea
Clinical Trial Phase	Trials
PHASE4	3
PHASE3	2
PHASE2	9

Clinical Trial Status

Clinical Trial Status for hydroxyurea
Clinical Trial Phase	Trials
Completed	141
RECRUITING	65
Terminated	33

Clinical Trial Sponsors for hydroxyurea

Sponsor Name

Sponsor Name for hydroxyurea
Sponsor	Trials
National Heart, Lung, and Blood Institute (NHLBI)	29
National Cancer Institute (NCI)	25
Novartis Pharmaceuticals	22

Sponsor Type

Sponsor Type for hydroxyurea
Sponsor	Trials
Other	365
Industry	134
NIH	78

Hydroxyurea Clinical Trials Update, Market Analysis, and 2030–2035 Projection

Last updated: July 27, 2026

Hydroxyurea is an established, off-patent small molecule used across sickle cell disease (SCD) and myeloproliferative neoplasms (MPNs), with an industry focus shifting from primary “blockbuster” development to lifecycle studies, new formulations/dosing strategies, expanded pediatric use, and combination regimens. New clinical-trial activity is concentrated in SCD subpopulations and MPN response durability, with market growth driven mainly by SCD prevalence management and continued standard-of-care uptake rather than new molecular entity launches.

What clinical trials are ongoing for hydroxyurea (SCD and MPN), and what are the latest results?

Hydroxyurea development in 2024–2026 is primarily execution of clinical programs that refine patient selection, dose optimization, adherence, and clinical endpoints. The highest-value signals are typically in SCD trials targeting hemoglobin F (HbF) response kinetics, vaso-occlusive event reduction, and long-term safety in pediatrics, plus MPN studies tracking molecular or hematologic milestones.

Sickle cell disease trials: what endpoints and dose strategies are used

Featured search intent: “hydroxyurea sickle cell trial HbF endpoint hemoglobin F durability.”

Commonly used trial endpoints in SCD include:

• Rate of vaso-occlusive crises (VOCs) per patient-year
• Time to first VOC
• Hospitalizations and acute care utilization
• HbF change from baseline and proportion reaching HbF thresholds
• Hematologic toxicity profiles (neutropenia, thrombocytopenia, anemia)
• Adherence proxies (pharmacy refills, missed dosing)
• Long-term outcomes (growth parameters, organ function) in pediatric cohorts

Lifecycle programs often evaluate:

• Starting dose and titration algorithms for children versus adults
• Dose interruption rules to balance toxicity and HbF response
• Real-world dosing adherence and patient-education interventions
• Combination regimens with add-on agents (trial-specific)

MPN trials: what outcomes are tracked for hydroxyurea

Featured search intent: “hydroxyurea trial essential thrombocythemia polycythemia vera myelofibrosis endpoints.”

Hydroxyurea trials in MPNs tend to measure:

• Hematologic response (normalization of blood counts)
• Thrombotic event rates (arterial/venous)
• Transformation endpoints (progression to myelofibrosis or acute leukemia) in longer follow-up designs
• Symptom burden
• Durability of response under continued dosing

In many geographies, hydroxyurea’s role is reinforced by guideline positioning rather than novel endpoint targets, which reduces the “breakthrough” probability of new trials but improves commercial predictability.

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Where is hydroxyurea in regulatory status: FDA approval history, Orange Book listings, and label scope?

Hydroxyurea is FDA-approved for multiple indications (core use in SCD and certain MPNs). The key regulatory question for market participants is not “is it approved,” but “how the label scope affects substitution, payer coverage, and uptake,” particularly for pediatric dosing and SCD management.

What is the Orange Book status for hydroxyurea

Featured search intent: “hydroxyurea Orange Book patents listed and expiration.”

For an off-patent or near-expiry small molecule, the Orange Book landscape typically shows:

• Drug product listings for multiple ANDA/generic products
• Patent expirations on active-substance or formulation components (with limited remaining exclusivity)
• Potential residual listing for specific formulations, dosing regimens, or method claims

Commercial impact: generic substitution is generally available widely, compressing pricing power and shifting competition to availability, inventory reliability, contracting, and patient-specific tolerability.

Which hydroxyurea products are typically listed for ANDA substitution

Featured search intent: “hydroxyurea generic manufacturers FDA.”

In practice, the market has multiple generic suppliers; procurement dynamics depend on:

• Contract awards to low-cost suppliers
• Shortage risk management
• Distribution capacity in pediatric and specialty care centers
• State substitution rules and payer formularies

(Exact manufacturer lists require pulling Orange Book entries for each strength and dosage form.)

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When does hydroxyurea lose exclusivity, and how does that affect generic launch timing?

Hydroxyurea’s exclusivity profile is mainly historical and is not a primary barrier to generic access. The market is dominated by long-standing generics, so “loss of exclusivity” translates into already-available generic access rather than a near-term shift.

What does exclusivity mean for hydroxyurea business planning

• The near-term commercial risk is not delayed generic approvals.
• The near-term upside is not new exclusivity.
• Value creation comes from: contracting, supply chain execution, and positioning for SCD treatment algorithms and MPN guideline adherence.

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What patents protect hydroxyurea, and how strong is the remaining patent estate?

Featured search intent: “hydroxyurea patent estate remaining strength process formulation method of treatment.”

For hydroxyurea, the remaining patent estate is usually limited, and the market outcome is generic-driven. Patent analysis for business planning typically focuses on:

• Any remaining formulation or method-of-use patents (if present for specific dosing forms or described regimens)
• Any regional late-life patents affecting a subset of formulations

Commercially, generic entry risk is usually low for core hydroxyurea active ingredient, but may vary by:

• Specific dosage forms or strength-dependent patents
• Specialty delivery claims
• Line-extension patents in some markets

(Exact patent numbers and jurisdictions require a fresh patent file pull across USPTO, EPO, and national offices.)

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How do hydroxyurea generic entry risks compare with other SCD therapies and MPN drugs?

Featured search intent: “hydroxyurea vs voxelotor vs crizanlizumab vs L-glutamine generic competition.”

Hydroxyurea’s business risk profile differs from newer SCD therapies:

• Hydroxyurea: generic-saturated, price-sensitive, supply-chain and contracting dominate.
• Newer biologics/small molecules: patent-led exclusivity and biosimilar transition drive higher pricing power, but with higher reimbursement friction and clinical differentiation uncertainty.

In MPNs, hydroxyurea competes with:

• JAK inhibitors and other targeted agents (availability and guideline-driven second-line preference in some subtypes)
• Other cytoreductive regimens (interferon-based approaches in selected patients)

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What is the market for hydroxyurea in sickle cell disease and myeloproliferative neoplasms, and what segment drivers matter most?

Featured search intent: “hydroxyurea market size SCD MPN growth drivers.”

Key commercial demand drivers

1. SCD population growth and survival improvements
   • Expanded newborn screening and treatment programs increase treated prevalence.
2. Guideline penetration
   • Hydroxyurea is widely recommended as a foundational SCD disease-modifying therapy.
3. Payer coverage and formulary positioning
   • Generic hydroxyurea usually receives favorable reimbursement economics relative to newer agents.
4. Clinician familiarity and long dosing experience
   • Established titration practices and safety monitoring protocols support routine uptake.
5. Therapy adherence and persistence
   • Dose optimization programs and patient education can improve persistence and reduce treatment discontinuations.

Pricing and contracting dynamics

• Generic competition compresses margins.
• Volume growth and inventory stability are the principal levers.
• Shortages in any strength/dose can create temporary pricing and contract premium opportunities.

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How will hydroxyurea pricing and reimbursement trend through 2030–2035?

Featured search intent: “hydroxyurea generic price forecast 2030.”

For off-patent generics:

• Net price growth is typically low unless shortage or contracting dynamics create transient premiums.
• Reimbursement increasingly depends on PBM contracting and specialty pharmacy distribution in pediatrics rather than headline list price.
• Health-system formularies tend to prefer lowest net cost versions, except where there are tolerability or supply constraints.

Net effect: market value growth is slower than unit demand growth, with value growth driven by treated patient count and persistence rather than price expansion.

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What is the 2030–2035 market projection for hydroxyurea, and what are base-case assumptions?

Featured search intent: “hydroxyurea market projection 2030 2035 units value forecast assumptions.”

Given hydroxyurea’s established status and generic saturation, projections should be modeled around:

• Treated population growth in SCD and MPNs
• Average annual dosing intensity (adherence, titration stability)
• Share of patients receiving hydroxyurea among eligible cohorts
• Incidence and survival trends influencing prevalence
• Generic mix and net price erosion rates

Projection framework (for investment and licensing models)

Base-case logic:

• Volume CAGR: driven by SCD-treated prevalence increases and continued MPN cytoreduction needs.
• Value CAGR: lower than volume due to net price erosion and competitive contracting.
• Risk factors: guideline shifts to alternative therapies in subsets, payer restrictions, safety monitoring capacity constraints, supply interruptions.

(High-integrity numeric forecasts require validated market sizing inputs; no primary market dataset is provided in the prompt.)

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What hydroxyurea clinical development themes can create upside despite generic saturation?

Featured search intent: “hydroxyurea lifecycle management trials outcomes commercial impact.”

Even with an off-patent active ingredient, new evidence can create commercial lift by changing care pathways:

• Earlier initiation in pediatric or mild-to-moderate disease states
• Improved titration algorithms that reduce toxicity-driven discontinuations
• Combination regimens that extend use cases
• Real-world adherence programs that improve persistence and HbF response
• Expanded guideline endorsements in specific MPN risk strata

The commercial mechanism is not new exclusivity. It is increased eligible patient share and stronger payer acceptance of hydroxyurea as a first-line modifier.

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What patent litigation, settlements, and Paragraph IV challenges affect hydroxyurea availability?

Featured search intent: “hydroxyurea Paragraph IV litigation settlement.”

For mature off-patent products, litigation is typically sporadic and more common for:

• Specific formulation patents
• Method-of-use claims tied to defined dosing regimens or monitoring approaches
• Geographic or product-line protection that lingers for certain manufacturers

Litigation can influence:

• Short-term supply constraints
• Contract procurement timing
• Temporary reimbursement shifts to alternative strengths during disputes

(Accurate case lists require a docket pull by active ingredient and specific product names.)

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Which companies compete in hydroxyurea, and what is the competitive landscape?

Featured search intent: “hydroxyurea manufacturers competitive landscape generic suppliers.”

Competitive structure:

• Many generic entrants and contract suppliers
• Strong dependence on procurement, distribution, and consistent supply
• Specialty distribution partnerships for pediatric centers

The companies most relevant for licensing or supply strategy are typically those:

• With broad ANDA portfolios covering multiple strengths
• With stable manufacturing capacity and low shortage history
• With PBM contracting maturity in major formularies

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How does hydroxyurea compare with newer SCD drugs on efficacy, safety, and market access?

Featured search intent: “hydroxyurea vs crizanlizumab vs voxelotor vs L-glutamine outcomes cost effectiveness.”

Relative positioning:

• Hydroxyurea: disease-modifying, broad guideline use, low acquisition cost, requires monitoring and dose titration.
• Newer agents (e.g., HbF modulators, anti-adhesion therapies, anti-inflammatory metabolic therapies): higher acquisition cost, route-dependent adoption, specific patient fit, and payer criteria.

Market access driver:

• Hydroxyurea generally clears payer scrutiny more easily due to lower cost and extensive evidence base.
• Newer drugs can capture incremental patients not responding to hydroxyurea or those where hydroxyurea is not tolerated, but they tend to face stricter reimbursement controls.

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Key Takeaways

• Hydroxyurea remains standard-of-care in SCD and is entrenched in MPN cytoreduction, with clinical activity focused on dose optimization, endpoints refinement, pediatric safety, and care-pathway expansion.
• The market is generic-saturated; exclusivity and patent blocking are not the primary near-term determinants of competition.
• Growth through 2030–2035 is likely driven by treated patient prevalence and persistence more than by pricing power.
• Commercial upside targets are supply reliability, contracting execution, and pathway-driven uptake rather than new molecule commercialization.
• High-quality numeric market forecasts and patent/litigation tables require primary dataset pulls (Orange Book, FDA label history, ClinicalTrials.gov/IP docket), which are not included in the prompt.

FAQs

1) What are the most common hydroxyurea clinical trial endpoints in sickle cell disease?
VOC rate, time to first VOC, HbF increase, and hematologic toxicity.

2) Does hydroxyurea have an Orange Book patent that blocks generic entry today?
Most active ingredient access is already generic-saturated; blocking depends on product-specific remaining listings.

3) What patient groups are typically targeted in hydroxyurea pediatric trials?
SCD children requiring optimized dosing with monitoring for cytopenias and HbF response.

4) How does hydroxyurea’s market growth differ from newer SCD therapies?
Hydroxyurea growth is prevalence and adherence-led; newer therapies are differentiation and payer-access led.

5) What are the main commercial risks for hydroxyurea generic manufacturers?
Net price compression from contracting, supply interruptions, and safety-monitoring capacity affecting persistence.

References

1. U.S. Food and Drug Administration (FDA). Orange Book: Approved Drug Products with Therapeutic Equivalence Evaluations.
2. U.S. National Library of Medicine. ClinicalTrials.gov. Hydroxyurea.
3. FDA. Drug Labeling for hydroxyurea (approved indications and dosing language).