CLINICAL TRIALS PROFILE FOR EXTENDED PHENYTOIN SODIUM

All Clinical Trials for EXTENDED PHENYTOIN SODIUM

Trial ID	Title	Status	Sponsor	Phase	Start Date	Summary
NCT00004817 ↗	Phase III Double Blind Trial of Valproate Sodium for Prophylaxis of Post Traumatic Seizures	Completed	Harborview Injury Prevention and Research Center	Phase 3	1991-02-01	OBJECTIVES: I. Determine whether treating head injured patients with valproate sodium will reduce the risk of developing seizures as a result of the head injury. II. Determine the safety of valproate, the appropriate dose, and the effect valproate may have on the recovery of the brain's ability to compute numbers, solve problems, remember information, and control the movement of limbs after head injury.
NCT00004817 ↗	Phase III Double Blind Trial of Valproate Sodium for Prophylaxis of Post Traumatic Seizures	Completed	National Institute of Neurological Disorders and Stroke (NINDS)	Phase 3	1991-02-01	OBJECTIVES: I. Determine whether treating head injured patients with valproate sodium will reduce the risk of developing seizures as a result of the head injury. II. Determine the safety of valproate, the appropriate dose, and the effect valproate may have on the recovery of the brain's ability to compute numbers, solve problems, remember information, and control the movement of limbs after head injury.
NCT00140179 ↗	Valnoctamide in Mania	Completed	Stanley Medical Research Institute	Phase 3	2004-09-01	Valproic acid is a leading mood stabilizer for the treatment of bipolar disorder. Its well-known teratogenicity limits its use in young women of childbearing age. According to toxicologic studies the teratogenicity of valproate stems from its free carboxylic group. Valnoctamide is an isomer and an analog of valpromide. Unlike valpromide, valnoctamide does not undergo a biotransformation to the corresponding free acid. It is also likely or at least possible that valnoctamide is anti-bipolar. In mice valnoctamide has been shown to be distinctly less teratogenic than valproate. An injection at day 8 of gestation produced only 1% exencephaly (as compared to 0-1% in control mice and 53% in valproate treated mice). The investigators are performing a double-blind controlled trial of valnoctamide as an anti-bipolar drug. If shown to be anti-bipolar, valnoctamide could be an important valproate substitute for young women with bipolar disorder who are at risk of pregnancy. Patients newly admitted to the Beersheva Mental Health Center may participate if they meet Diagnostic and Statistical Manual of Mental Disorders - 4th edition (DSM-IV) criteria for mania or schizoaffective disorder, manic type. Patients admitted to the study are treated with risperidone at doses of the physicians' discretion beginning with 2 mg daily on days 1 and 2. Valnoctamide or placebo is begun at doses of 600 mg per day (200 mg three times daily) and increased to 1200 mg (400 mg three times daily) after four days. Weekly ratings by a psychiatrist blind to the study drug are conducted using the Brief Psychiatric Rating Scale (BPRS), the Young Mania Rating Scale (YMS), and the Clinical Global Impression (CGI). Weekly blood is drawn for drug levels of valnoctamide to be measured by gas chromatography. Each patient receives valnoctamide or placebo for 5 weeks. Low teratogenic mood stabilizers are a high priority for current research.
NCT00140179 ↗	Valnoctamide in Mania	Completed	Beersheva Mental Health Center	Phase 3	2004-09-01	Valproic acid is a leading mood stabilizer for the treatment of bipolar disorder. Its well-known teratogenicity limits its use in young women of childbearing age. According to toxicologic studies the teratogenicity of valproate stems from its free carboxylic group. Valnoctamide is an isomer and an analog of valpromide. Unlike valpromide, valnoctamide does not undergo a biotransformation to the corresponding free acid. It is also likely or at least possible that valnoctamide is anti-bipolar. In mice valnoctamide has been shown to be distinctly less teratogenic than valproate. An injection at day 8 of gestation produced only 1% exencephaly (as compared to 0-1% in control mice and 53% in valproate treated mice). The investigators are performing a double-blind controlled trial of valnoctamide as an anti-bipolar drug. If shown to be anti-bipolar, valnoctamide could be an important valproate substitute for young women with bipolar disorder who are at risk of pregnancy. Patients newly admitted to the Beersheva Mental Health Center may participate if they meet Diagnostic and Statistical Manual of Mental Disorders - 4th edition (DSM-IV) criteria for mania or schizoaffective disorder, manic type. Patients admitted to the study are treated with risperidone at doses of the physicians' discretion beginning with 2 mg daily on days 1 and 2. Valnoctamide or placebo is begun at doses of 600 mg per day (200 mg three times daily) and increased to 1200 mg (400 mg three times daily) after four days. Weekly ratings by a psychiatrist blind to the study drug are conducted using the Brief Psychiatric Rating Scale (BPRS), the Young Mania Rating Scale (YMS), and the Clinical Global Impression (CGI). Weekly blood is drawn for drug levels of valnoctamide to be measured by gas chromatography. Each patient receives valnoctamide or placebo for 5 weeks. Low teratogenic mood stabilizers are a high priority for current research.
NCT00257855 ↗	A Randomised Controlled Trial of Neuroprotection With Lamotrigine in Secondary Progressive Multiple Sclerosis	Completed	University College London Hospitals	Phase 2	2005-11-01	A present there is no safe treatment for reducing rate at which disability worsens in people with secondary progressive multiple sclerosis. Recent research has suggested the possibility that drugs that act by blocking the entry of sodium into nerve cells can protect nerve fibres in the brain and spinal cord. In this trial, the investigators will test whether one such drug, called lamotrigine, can prevent damage to nerve fibres and reduce the rate at which MS worsens. The period of treatment in the trial will run for 2 years.
NCT00511745 ↗	Safety of Rabeprazole in Patients Under Multiple Treatments	Terminated	Janssen-Cilag, S.A.		1969-12-31	The purpose of this study is to evaluate the safety of rabeprazole 20mg/day in polymedicated patients and to examine the necessity of adjusted dosage in both therapies (rabeprazole and concomitant drug). Proton pump inhibitors (PPI) act in the final step of the gastric secretion. PPI's block ATP-ase H+/K+ in gastric parietals cells. It has been described that inhibition of acid secretion has produced the recovery of the gastroesophageal pathology in a high percentage of the patients resistant to conventional drugs. In this context, the objective of the study is to evaluate the safety of rabeprazole as a concomitant treatment and examine the clinical practice the interaction with drugs whose absorption has gastric pH dependence.
NCT00647621 ↗	Steady-State Study of Extended Phenytoin Sodium Capsules 100 mg and Dilantin® Kapseals® 100 mg	Completed	Mylan Pharmaceuticals	Phase 1	2005-10-01	The objective of this study was to investigate the steady-state bioequivalence of Mylan's extended phenytoin sodium capsules, 100mg (3x100mg), to Pfizer's Dilantin® Kapseals®, 100mg (3x100mg), under both fasting and fed conditions.

Clinical Trial Conditions for EXTENDED PHENYTOIN SODIUM

Condition Name

Condition Name for EXTENDED PHENYTOIN SODIUM
Intervention	Trials
Optic Neuritis	2
Healthy	2
Healthy Male Volunteers	1
Post Traumatic Seizures	1

Condition MeSH

Condition MeSH for EXTENDED PHENYTOIN SODIUM
Intervention	Trials
Neoplasm Metastasis	2
Neuritis	2
Status Epilepticus	2
Epilepsy	2

Clinical Trial Locations for EXTENDED PHENYTOIN SODIUM

Trials by Country

Trials by Country for EXTENDED PHENYTOIN SODIUM
Location	Trials
United States	4
United Kingdom	2
China	2
Germany	1
Taiwan	1

Trials by US State

Trials by US State for EXTENDED PHENYTOIN SODIUM
Location	Trials
New York	1
Georgia	1
California	1
North Dakota	1

Clinical Trial Progress for EXTENDED PHENYTOIN SODIUM

Clinical Trial Phase

Clinical Trial Phase for EXTENDED PHENYTOIN SODIUM
Clinical Trial Phase	Trials
PHASE4	2
Phase 4	3
Phase 3	4

Clinical Trial Status

Clinical Trial Status for EXTENDED PHENYTOIN SODIUM
Clinical Trial Phase	Trials
Completed	12
Unknown status	3
Not yet recruiting	2

Clinical Trial Sponsors for EXTENDED PHENYTOIN SODIUM

Sponsor Name

Sponsor Name for EXTENDED PHENYTOIN SODIUM
Sponsor	Trials
Huizhou Third People's Hospital, Guangzhou Medical University	1
Fundação de Amparo à Pesquisa do Estado de São Paulo	1
Sun Yat-Sen Memorial Hospital of Sun Yat-Sen University	1

Sponsor Type

Sponsor Type for EXTENDED PHENYTOIN SODIUM
Sponsor	Trials
Other	60
Industry	5
OTHER_GOV	2

Last updated: April 28, 2026

Clinical Trials Update, Market Analysis, and Projection: Extended Phenytoin Sodium

What is extended phenytoin sodium and how is it positioned clinically?

Extended phenytoin sodium is a long-acting formulation of phenytoin sodium, an established antiepileptic drug used for seizure control. In the US market, extended-release (ER) phenytoin products are typically positioned for maintenance therapy and for improving adherence versus immediate-release (IR) dosing schedules. Clinical value is driven by seizure control in epilepsy populations and by exposure stability that reduces peaks and troughs relative to IR dosing.

Key clinical context

• Active ingredient: phenytoin sodium
• Form: extended-release (ER)
• Therapeutic area: epilepsy (maintenance and seizure control)

What is the current clinical-trials landscape for extended phenytoin sodium?

No complete, reliable, and product-specific clinical-trials update can be produced from the information provided. A compliant trials update requires verifiable trial registry data tied to the exact drug name, formulation type (ER), route, and sponsor or manufacturer. Without that, producing a “current” landscape with endpoints, enrollment status, and timeline would risk inaccuracies.

Clinical-trials update (content requirement)

• Trial registry status (e.g., recruiting, active, completed)
• Phase, sample size, geography
• Endpoints (bioequivalence, PK, safety)
• Submission-linked milestones (e.g., NDA/ANDA supplements)
• Recent publications tied to ER phenytoin sodium product development

How is the ER phenytoin sodium market structured today?

The market for extended-release phenytoin sodium sits inside a mature generic CNS portfolio. Phenytoin is off-patent in most major markets, which shifts competition toward:

• Bioequivalence-based generic entry
• Cost and formulary access
• Switching dynamics among IR and ER products
• Therapeutic drug monitoring practices that can blunt formulation switching if clinicians maintain stable regimens

Market structure drivers

1. Long-standing standard of care: phenytoin remains a common option where indicated and tolerated.
2. Generic-driven pricing: extended-release versions compete heavily on acquisition cost and contracting.
3. Interchangeability constraints: phenytoin is narrow-therapeutic-index; many systems restrict nonmedical switching or require monitoring after product changes (policy varies by insurer and health system).
4. Formulary inclusion: ER positioning depends on plan formularies and pharmacy benefit manager contracting.

What is the competitive and regulatory benchmark for extended phenytoin sodium?

For ER formulations, competitive entry generally hinges on demonstrating bioequivalence to a reference listed drug (RLD) under US FDA pathway rules (typical for generics of established drugs). Market share then follows:

• Pharmacy distribution agreements
• Hospital formulary committees
• Clinician preference for a stable product experience
• Monitoring protocols following substitution

Regulatory checkpoint logic (market-relevant)

• Product must meet generic approval requirements for ER profile.
• Labeling must match active ingredient and release characteristics.
• Substitution policies influence uptake.

How should investors and R&D teams think about demand and forecast sizing?

Extended phenytoin sodium demand is primarily driven by persistent underlying epilepsy prevalence, plus:

• Treatment duration (chronic use)
• Substitution patterns between IR and ER
• Payer behavior (generic utilization targets)
• Access and contracting in long-term care and neurology clinics

In a mature generic category, projections should focus less on clinical novelty and more on:

• number of approved products and their market share distribution
• anticipated competitive moves (new entrants, label changes)
• pricing trend and contract renewals
• any line extension or manufacturing shifts that could affect supply continuity

What market projection can be made for extended phenytoin sodium?

No numbers can be produced without a data source baseline (e.g., current US and ex-US sales by product, unit volume, average selling price, channel mix, and historical price erosion). The information provided does not include any such inputs.

Projection framework (what would drive the model)

• Base year demand: US and major ex-US territories (units and $)
• Price erosion curve: generic segment trend and contract behavior
• Share drift: IR to ER switching and product-to-product substitution
• Regulatory and supply events: recalls, shortages, and manufacturing outages
• Formulary constraints: policies on therapeutic switching for narrow-therapeutic-index drugs

What are the practical business implications given the likely generic reality?

Extended phenytoin sodium is best approached as a portfolio and access problem:

• Supply reliability matters as much as acquisition cost because phenytoin is used in chronic regimens.
• Bioequivalence strategy and manufacturing reproducibility reduce approval and post-market disruption risk.
• Payer contracting determines unit movement more than marketing.
• Clinician switching restrictions can preserve incumbents even as generics expand.

Key Takeaways

• Extended phenytoin sodium is an ER phenytoin sodium product positioned for chronic seizure maintenance with more stable exposure than IR.
• A product-specific clinical trials update cannot be completed without verifiable registry and endpoint data tied to the exact ER formulation.
• The market is mature and generic-driven, where uptake depends on bioequivalence, contracting, substitution policies, and supply reliability more than clinical differentiation.
• A quantitative market projection requires baseline sales/units, historical pricing erosion, and competitive share data; none is provided here.

FAQs

1) Is extended phenytoin sodium a brand or generic market?
It is largely a generic competitive market in most regions because phenytoin as a drug substance has long exited patent exclusivity, leaving ER formulations to compete via generic approval and contracting.

2) What endpoints matter most for ER phenytoin sodium development?
For generic or line-extension ER development, the core endpoints are typically bioequivalence-related PK measures and safety/tolerability aligned to labeling requirements.

3) Does the narrow-therapeutic-index profile affect market uptake?
Yes. Many health systems apply tighter monitoring or restriction policies around substitution for phenytoin, which can slow switching from one ER product to another even when alternatives are available.

4) What drives pricing in extended-release phenytoin markets?
Generic competition and payer/contract mechanisms drive pricing more than clinical differentiation.

5) What is the most important risk for suppliers?
Supply continuity. For chronic CNS therapies, shortages or manufacturing disruptions can immediately disrupt patient continuity and trigger temporary reversion to other formulations.

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References

[1] FDA. “Bioequivalence Recommendations” and generic approval framework materials. US Food and Drug Administration.