CLINICAL TRIALS PROFILE FOR DELSYM

All Clinical Trials for DELSYM

Trial ID	Title	Status	Sponsor	Phase	Start Date	Summary
NCT00593957 ↗	Trial of Dextromethorphan in Rett Syndrome	Terminated	Hugo W. Moser Research Institute at Kennedy Krieger, Inc.	Phase 2	2004-08-01	Increased brain glutamate and its N-methyl-D-aspartate (NMDA) receptors found in the brain of younger Rett syndrome (RTT) patients cause toxic damage to neurons (the brain's nerve cells), and contributing to EEG spikes. Dextromethorphan (DM) acts by blocking NMDA/glutamate receptors. This study is being done to determine if DM will prevent the harmful over-stimulation of the neurons thereby reducing EEG spike activity. Treatment with DM consists of one of 3 different doses (0.25 mg/kg per day; or 2.5 mg/kg/day; or 5mg/kg/day), and aims to find out which dose if any will help improve EEG abnormalities, behavior, cognition, and reduce seizures, as well as improve breathing abnormalities, motor capabilities, bone density, and GI dysfunction. The study will include 90 females and males with RTT, 2 years-14.99 years of age, with a mutation in the methyl CpG binding protein 2 (MECP2) gene, and spikes on EEG, with or without clinical seizures.
NCT01441102 ↗	Dextromethorphan for Diabetic Macular Edema	Completed	The Emmes Company, LLC	Phase 1/Phase 2	2011-08-01	Background: Many people with diabetes have macular edema (swelling) at the back of the eye. Macular edema can cause loss of vision. Studies suggest that inflammation may be involved in the swelling. A drug called dextromethorphan may help prevent the inflammation and the swelling. Dextromethorphan is approved for use as a cough medicine, but it has not been studied to see if it can help in diabetic macular edema. Objectives: To see if dextromethorphan can help treat diabetic macular edema. Eligibility: Individuals at least 18 years of age who have diabetic macular edema in at least one eye. Design: - This study lasts 2 years, and will require at least 14 visits to the National Eye Institute outpatient clinic. Study visits will be every month for the first 2 months and then every other month. Each visit will take about 2 to 4 hours. - Participants will be screened with a physical exam, medical history, eye exam, and blood tests. One eye with macular edema will be chosen as the study eye for testing. - Participants will take dextromethorphan twice a day, about 12 hours apart, for 2 years. A study diary will help keep track of the date, time, and number of pills taken. - Participants will have study visits once a month for the first 2 months and then every other month for the rest of the study. Each study visit will involve eye exams and blood and urine tests. - Four months after starting the study medication, participants may have laser surgery or other treatments for the macular edema, if it is needed.
NCT01441102 ↗	Dextromethorphan for Diabetic Macular Edema	Completed	The EMMES Corporation	Phase 1/Phase 2	2011-08-01	Background: Many people with diabetes have macular edema (swelling) at the back of the eye. Macular edema can cause loss of vision. Studies suggest that inflammation may be involved in the swelling. A drug called dextromethorphan may help prevent the inflammation and the swelling. Dextromethorphan is approved for use as a cough medicine, but it has not been studied to see if it can help in diabetic macular edema. Objectives: To see if dextromethorphan can help treat diabetic macular edema. Eligibility: Individuals at least 18 years of age who have diabetic macular edema in at least one eye. Design: - This study lasts 2 years, and will require at least 14 visits to the National Eye Institute outpatient clinic. Study visits will be every month for the first 2 months and then every other month. Each visit will take about 2 to 4 hours. - Participants will be screened with a physical exam, medical history, eye exam, and blood tests. One eye with macular edema will be chosen as the study eye for testing. - Participants will take dextromethorphan twice a day, about 12 hours apart, for 2 years. A study diary will help keep track of the date, time, and number of pills taken. - Participants will have study visits once a month for the first 2 months and then every other month for the rest of the study. Each study visit will involve eye exams and blood and urine tests. - Four months after starting the study medication, participants may have laser surgery or other treatments for the macular edema, if it is needed.
NCT01441102 ↗	Dextromethorphan for Diabetic Macular Edema	Completed	National Eye Institute (NEI)	Phase 1/Phase 2	2011-08-01	Background: Many people with diabetes have macular edema (swelling) at the back of the eye. Macular edema can cause loss of vision. Studies suggest that inflammation may be involved in the swelling. A drug called dextromethorphan may help prevent the inflammation and the swelling. Dextromethorphan is approved for use as a cough medicine, but it has not been studied to see if it can help in diabetic macular edema. Objectives: To see if dextromethorphan can help treat diabetic macular edema. Eligibility: Individuals at least 18 years of age who have diabetic macular edema in at least one eye. Design: - This study lasts 2 years, and will require at least 14 visits to the National Eye Institute outpatient clinic. Study visits will be every month for the first 2 months and then every other month. Each visit will take about 2 to 4 hours. - Participants will be screened with a physical exam, medical history, eye exam, and blood tests. One eye with macular edema will be chosen as the study eye for testing. - Participants will take dextromethorphan twice a day, about 12 hours apart, for 2 years. A study diary will help keep track of the date, time, and number of pills taken. - Participants will have study visits once a month for the first 2 months and then every other month for the rest of the study. Each study visit will involve eye exams and blood and urine tests. - Four months after starting the study medication, participants may have laser surgery or other treatments for the macular edema, if it is needed.

Clinical Trial Conditions for DELSYM

Condition Name

Condition Name for DELSYM
Intervention	Trials
Rett Syndrome	2
Colitis, Ulcerative	1
Crohn Disease	1
Diabetic Macular Edema	1

Condition MeSH

Condition MeSH for DELSYM
Intervention	Trials
Syndrome	2
Rett Syndrome	2
Colitis, Ulcerative	1
Colitis	1

Clinical Trial Locations for DELSYM

Trials by Country

Trials by Country for DELSYM
Location	Trials
United States	5

Trials by US State

Trials by US State for DELSYM
Location	Trials
Maryland	3
Florida	1
California	1

Clinical Trial Progress for DELSYM

Clinical Trial Phase

Clinical Trial Phase for DELSYM
Clinical Trial Phase	Trials
Phase 4	2
Phase 2	2
Phase 1/Phase 2	1

Clinical Trial Status

Clinical Trial Status for DELSYM
Clinical Trial Phase	Trials
Completed	2
Terminated	2
Withdrawn	1

Clinical Trial Sponsors for DELSYM

Sponsor Name

Sponsor Name for DELSYM
Sponsor	Trials
Hugo W. Moser Research Institute at Kennedy Krieger, Inc.	2
The Emmes Company, LLC	1
The EMMES Corporation	1

Sponsor Type

Sponsor Type for DELSYM
Sponsor	Trials
Other	4
Industry	3
NIH	1

DELSYM (dextromethorphan) clinical trials update, market analysis, and projection (US and major markets)

Last updated: May 14, 2026

DELSYM is an FDA-approved, over-the-counter (OTC) cough suppressant brand containing dextromethorphan (typically dextromethorphan polistirex extended-release). As an OTC product, it generally does not have the same FDA “approval pathway,” Rx-style NDA/BLA exclusivity, or patent-exclusivity cadence that drives clinical development for prescription drugs. Public clinical-trials activity is therefore limited in visibility and is usually focused on formulation, bioequivalence, label changes, or manufacturing/process work rather than new molecular entities.

Given the OTC status, market dynamics are driven by (1) brand switching within cough/cold aisles, (2) insurer and PBM dynamics are minimal, (3) seasonal demand cycles, (4) competitive pressure from private label and other dextromethorphan ER brands, and (5) regulatory labeling requirements.

What clinical trials exist for DELSYM and dextromethorphan polistirex ER?

Which trial types are most visible for OTC dextromethorphan products

Most publicly indexed studies for dextromethorphan-containing OTC products tend to fall into these buckets:

• Formulation or dissolution profile studies (especially ER matrix or salt changes)
• Pharmacokinetic (PK) or bioequivalence studies for generic/authorized alternatives
• Safety studies in specific subpopulations (children, elderly) if label updates occur
• Manufacturing/scale-up work reported as “in vivo” studies when required by regulators

Expected clinical-trials footprint you should look for

For DELSYM specifically, the public trial footprint typically includes:

• Bioequivalence endpoints (Cmax, Tmax, AUC) for extended-release dextromethorphan formulations
• Tolerability endpoints (adverse events, vital signs) consistent with OTC labeling
• ER behavior confirmation (time to maximum concentration, sustained exposure)

No material, high-signal late-stage “Phase 3” program is usually associated with DELSYM as a mature OTC brand containing a long-established active ingredient. Any clinical development tends to be incremental.

What is the FDA status of DELSYM and how is it regulated as an OTC drug?

OTC drug classification and labeling

DELSYM is marketed under OTC drug monograph frameworks and/or legacy approvals depending on the exact product/strength form. The relevant regulatory mechanics for OTC cough products center on:

• Indications and dosing consistency with dextromethorphan monograph language (where applicable)
• Child dosing limits and age language in compliance with OTC cough-cold rules
• Signal words and warnings (CNS effects, misuse, interaction cautions)

How FDA oversight changes impact market

Key FDA dynamics that can change OTC performance include:

• Labeling revisions that constrain pediatric use
• Consumer safety communications that shift purchasing away from specific combinations
• Limits around “multi-symptom” combinations versus single-ingredient products

How does the DELSYM market perform and what drives seasonality?

Core demand drivers

The OTC dextromethorphan ER category is mainly driven by:

• Respiratory virus seasonality (fall and winter peaks in the US)
• Consumer preference for extended relief versus immediate-release cough suppressants
• Substitution among competing brands and private label in mass retail and e-commerce

Key market mechanics for an ER cough suppressant

Extended-release dextromethorphan brands often win on:

• Perceived “longer-lasting” relief messaging
• Convenience of fewer dosing administrations versus IR products (depending on label)
• Brand habit in legacy consumers

Pricing and promotional exposure

For OTC cough suppressants, volume can grow without premium pricing because:

• Retailers use trade spend to defend shelf space
• Private label captures value during low season

What is the competitive landscape for DELSYM (dextromethorphan ER) and where does it face substitution risk?

Main competitive set

DELSYM competes in the cough suppressant aisle against:

• Other dextromethorphan ER brands (same active, ER delivery)
• Dextromethorphan immediate-release formulations (lower price, different dosing frequency)
• Combination products (cough + congestion + antihistamines) that steal shelf share during peak cold seasons
• Private label extended-release and immediate-release dextromethorphan

Substitution risk: where it concentrates

Substitution risk tends to concentrate in:

• Retail channels with strong private-label share
• Periods of heavy promotion where private label match pricing
• Consumer preference shifts when brands fail to deliver perceived duration benefits

How many patents protect DELSYM and dextromethorphan polistirex ER, and what is the practical IP barrier?

OTC reality: the active is long established

Dextromethorphan is an established active ingredient with broad historical patent coverage. In practice, for OTC users and manufacturers, the “IP barrier” is usually dominated by:

• Process and formulation-specific patents (if any still active)
• Secondary patents tied to particular salt forms, release systems, or manufacturing methods
• Trademark (brand) protection rather than composition-of-matter blocking

Practical barrier for market entrants

If composition-of-matter is widely expired, entrants typically use:

• Generic dextromethorphan ER with label-compliant dosing
• Authorized generics or OTC monograph-consistent products
• Bioequivalence and formulation proof rather than clinical trials

When does DELSYM lose exclusivity and what generic entry risks exist?

Exclusivity timeline

DELSYM is not a modern biologic or new drug with a well-defined Hatch-Waxman exclusivity schedule in the way prescription brands are. The operative “exclusivity” is typically:

• Trademark brand differentiation
• Any remaining formulation/manufacturing IP (if still active)
• Retail trade agreements and category shelf positioning

Generic entry risks

Generic entry risk is structurally present in any dextromethorphan ER segment where:

• Bioequivalence can be demonstrated
• Label is compatible with monograph or existing approvals
• Formulation differences are not protected by enforceable, unexpired patents

In mature OTC dextromethorphan markets, competitive pressure typically comes from non-branded supply and channel-specific private label.

What clinical development is most likely next for DELSYM-like products?

Incremental paths consistent with OTC behavior

If new studies occur, they most likely target:

• Extended-release performance optimization to maintain consistent PK exposure
• Stability and manufacturing validation studies
• Pediatric label refinements tied to regulatory updates
• Line extensions (new pack sizes, new dosage strengths) with regulatory-required evidence

Market projection for DELSYM: base-case growth, downside, and upside

Base-case assumptions (category-consistent)

For an OTC mature brand like DELSYM:

• Growth follows category volume and share, not platform innovation
• Performance is seasonal with annual trough-to-peak swings
• Share stability depends on retail execution and substitution defenses

Projection framework (what moves numbers)

A workable projection for DELSYM should be modeled with:

• US seasonal index (respiratory season length and severity)
• Market share drift vs private label
• Price/mix via retailer promotions and pack strategy
• Competitive intensity (number of promoted SKUs and private-label depth)

Likely directional outlook

In absence of a new Rx-like launch cycle, DELSYM’s market trajectory is typically:

• Stable-to-moderate growth when the brand holds share against private label
• Volume declines if price premiums widen and consumer substitutes to lower-cost ER or IR
• Upside only when the brand increases distribution, improves shelf visibility, or sustains promotion through a stronger season

Key Takeaways

• DELSYM is an OTC dextromethorphan ER brand, so public “late-stage” clinical-trials signals are typically limited; activity is most often formulation, PK, and compliance driven.
• Market performance is dominated by respiratory seasonality, retailer promotion, and substitution risk from private label and competing ER/IR dextromethorphan products.
• Practical IP barriers for entrants are usually limited to any remaining formulation or manufacturing-specific patents; brand protection and channel execution drive much of the competitive outcome.
• Projections should be modeled on seasonal demand, share vs private label, and promotion intensity rather than on new clinical milestones.

FAQs

1) Is DELSYM ever studied in Phase 3 trials?
OTC dextromethorphan products generally do not run Phase 3 programs for new efficacy because the active ingredient is established; if studies appear, they are commonly PK, bioequivalence, or formulation compliance work.

2) What endpoints matter most in OTC dextromethorphan ER trials?
Bioavailability and sustained exposure endpoints such as Cmax, Tmax, and AUC, plus tolerability and safety under labeled use.

3) How does private label affect DELSYM pricing and volume?
Private label increases price competition, compressing margins and forcing promotional activity; volume shifts are most pronounced during peak cold season sales cycles.

4) Are patent challenges common for dextromethorphan ER products?
In mature OTC segments, competition is more commonly driven by bioequivalence and regulatory fit than by headline patent litigation, though formulation-specific IP can still matter.

5) What regulatory changes most impact DELSYM demand?
Labeling updates affecting dosing language and pediatric use, plus any OTC cough-cold safety communications that shift consumer selection away from certain formats or combinations.

References

1. FDA. OTC Drug Product with therapeutic equivalence evaluations and regulatory framework materials (OTC monograph/labeling resources). U.S. Food and Drug Administration website.
2. ClinicalTrials.gov. Search results for dextromethorphan and dextromethorphan polistirex extended-release under registered studies. National Library of Medicine (NLM).
3. FDA. Regulations and guidance for OTC drug labeling and safety communications. U.S. Food and Drug Administration website.