When do the DUPHALAC patents expire, and when will DUPHALAC go generic?

Sponsor	Phase
I.M. Sechenov First Moscow State Medical University	NA
RenJi Hospital	Phase 4
Bogomolets National Medical University	N/A

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Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Solvay	DUPHALAC	lactulose	SOLUTION;ORAL	072372-001	Mar 22, 1989		DISCN	No	No	⤷ Start Trial	⤷ Start Trial				⤷ Start Trial
>Applicant	>Tradename	>Generic Name	>Dosage	>NDA	>Approval Date	>TE	>Type	>RLD	>RS	>Patent No.	>Patent Expiration	>Product	>Substance	>Delist Req.	>Exclusivity Expiration

Last updated: June 30, 2026

DUPHALAC (lactulose) is an established, off-patent gastrointestinal osmotic laxative with broad generic availability in most markets. Market dynamics are dominated by guideline-driven constipation demand, strong payer familiarity, low WAC-to-NBR elasticity at the patient level, and intensity of local generic competition. The financial trajectory is typically characterized by steady underlying category growth offset by share erosion after generic entries, with premium protecting levers limited to branding, formulation formats (oral solution/syrup), channel execution, and contract pricing.

What is DUPHALAC and how is lactulose marketed commercially?

Executive snapshot

Active ingredient: lactulose (disaccharide; osmotic laxative).
Indications in practice: constipation; also used for hepatic encephalopathy in many geographies (labeling varies by market/label version).
Form: oral liquid/syrup and related formulations depending on market (brands, pack sizes, and concentrations vary).
Market structure: branded originators compete against numerous generics; pricing power is constrained.

Core commercial drivers

Chronic and recurring use in constipation management supports repeat dispensing.
Switching friction is usually low because lactulose is a standard molecule and pharmacy substitution is common.
Channel and reimbursement matter more than clinical differentiation.

Where revenue usually comes from

Retail pharmacy demand (OTC and reimbursed use depending on country).
Institutional supply where hepatic encephalopathy protocols favor lactulose (tender dynamics can be decisive).

How does the lactulose category grow: constipation prevalence, guideline use, and payer behavior?

Category demand mechanics

Constipation prevalence is stable-to-growing with aging populations and chronic comorbidity profiles.
Treatment algorithms frequently start with osmotics (lactulose) when first-line measures are indicated and when access is favorable versus alternatives.
In many markets, lactulose is positioned as a cost-effective option, which shapes payer negotiations.

Guideline and formulary effects

When formularies specify “osmotic laxatives” with lactulose included, volume is buffered.
When formularies tighten to preferred agents, lactulose can lose share to other osmotics (eg, macrogol/PEG formulations) if pricing contracts favor them.

Patient-level utilization

Adherence tends to be moderate for chronic constipation; patients may cycle between osmotics based on tolerability and bowel response.
Lactulose can be constrained by taste/galenic tolerability, which impacts switching within the category.

What market dynamics shift DUPHALAC revenue: pricing, pack architecture, and substitution?

Key dynamics

Substitution pressure: High. Generics and retailer brands compete on price.
Pack strategy: Brand holders often defend revenue through pack variety and dosing convenience, but molecule-level substitutes narrow the benefit.
Contracting: Payer and hospital tenders can reprice the category quickly. Once a payer designates a low-cost generic, brand share typically compresses.

Pricing behavior (typical for off-patent CNS GI small molecules)

After generic entries: WAC declines and net revenue falls faster than volume growth.
Long tail: Brand can remain profitable where differentiating elements exist (market positioning, service-level agreements, distributor relationships), but price competition usually dominates.

What is the competitive landscape for lactulose: which generics and local brands matter most?

Competitive set

Global generic supply: multiple manufacturers across EU, UK, and other regulated markets.
Local brand competition: many countries maintain legacy brand portfolios using lactulose under multiple tradenames.

How competition usually plays out

The molecule is substitutable, so the differentiator shifts to:
- distributor strength,
- reimbursement status,
- tender inclusion,
- and pack availability.

Implication for DUPHALAC

DUPHALAC’s revenue trajectory is usually driven less by “new prescribing” and more by:
- share retention after generic erosion,
- and maintaining distribution agreements.

When does DUPHALAC lose exclusivity in major markets, and what does that mean for revenue?

Featured snippet answer DUPHALAC is off-patent in most developed markets, so exclusivity risk is less about molecule patent cliffs and more about local patent expirations, first-generic launches, and branded-to-generic substitution windows by formulation and brand packaging.

Exclusivity timeline framework (market mechanics)

Patent expiry for molecule and/or formulation triggers generic permission.
Market entry follows based on regulatory and manufacturing readiness.
Revenue impact tracks to when:
- major pharmacy chains list generics,
- reimbursement switches to generics,
- and hospital formularies award tenders to lowest cost.

Commercial consequence

Branded revenue typically declines in steps: initial softening at launch announcements, then a sharper drop upon broad channel adoption of generics.

What generic entry risks exist for DUPHALAC (Paragraph IV, ANDA, biosimilar risk)?

Paragraph IV (ANDA) risk

For lactulose, the dominant threat is usually generic entry under ANDA (not Paragraph IV-specific litigation), because the molecule is longstanding and many patents are likely expired. Where patents exist for packaging, formulation, or method-of-use, ANDA applicants may file challenge certifications, but Paragraph IV is not the typical driver for older off-patent GI agents.

Biosimilar risk

None. Lactulose is a small molecule; no biologic pathway applies.

Primary generic entry risk

Regulatory and commercial barriers are minimal:
- generic bioequivalence is straightforward for liquid oral products,
- manufacturing is established,
- and pharmacy substitution is common.

What patents protect lactulose/DUPHALAC, and how strong is the patent estate?

Patent estate reality for older GI small molecules

For historical products like lactulose, the enforceable landscape usually narrows to:
- secondary patents (formulation/process),
- packaging/combination claims (where applicable),
- or method-of-use claims in specific indications in specific jurisdictions.

Commercial strength implication

Even where some secondary patents remain in select markets, generic entry often happens through:
- licensing,
- design-around,
- or expiration-only timing, depending on local enforcement.
For DUPHALAC specifically, market behavior for lactulose classically reflects limited residual exclusivity and high generic substitution.

(No patent list can be provided here because the prompt does not include jurisdictional scope, dosage form identifiers, reference product specifics for each market, or Orange Book/National patent numbers.)

What is the FDA and Orange Book status of DUPHALAC, and how does that affect US revenue?

Executive snapshot

DUPHALAC has historically been treated as an established, off-patent product in the US market. US competition is therefore typically shaped by:
- listed generic products,
- reimbursement,
- and contract pricing, rather than active US regulatory exclusivity.

Orange Book implications

Where Orange Book listings for older products persist, they are usually limited and may be tied to formulation or method-of-use. Those listings can slow specific generic entries if patents are still in force, but for lactulose the dominant market pattern is broad generic availability.

(A precise Orange Book status table (patent numbers, expiration dates, and dosage forms) is not included because the prompt does not provide the specific US NDA/label mapping to verify current listing details.)

How does DUPHALAC compare with key lactulose alternatives (PEG/macrogol, other osmotics, secretagogues)?

Market substitution map

If payers or formularies prefer PEG/macrogol osmotics, lactulose can lose share even when lactulose remains available as a covered option.
If clinicians prefer lactulose due to patient tolerability or specific clinical positioning, lactulose share remains steadier.

Competitive pricing

Competition is largely price-led. If PEG/macrogol gains formulary preference, DUPHALAC faces net revenue pressure even if volume remains stable.

Which therapeutic segments drive lactulose sales: constipation vs hepatic encephalopathy?

Constipation

Largest addressable use case for many markets.
Revenue is sensitive to:
- pharmacy substitution,
- OTC presence,
- and tender-linked hospital dynamics when constipation is managed in inpatient settings.

Hepatic encephalopathy

Smaller patient pool but can support institutional volumes.
Tender dynamics can drive sharp pricing changes.
Clinical protocols may favor established osmotics, but availability of alternatives and dosing practices shape demand.

(A split by segment requires market-region sales breakdowns that are not provided.)

How does manufacturing cost and supply chain stability affect DUPHALAC’s margin trajectory?

Margin levers

Lactulose is commodity-like relative to branded specialty drugs, so gross margin is primarily influenced by:
- raw material procurement terms,
- excipient/packaging costs,
- and logistics.
When generics enter, the price compression typically overwhelms cost-efficiency gains.

Supply risk

For older molecules with diversified manufacturing, supply stability tends to be adequate.
Margin resilience depends more on commercial pricing and channel mix than on novel process advantages.

What have been the major financial trajectory patterns for DUPHALAC-like products after generic entry?

Typical trajectory

Pre-generic: branded revenue supported by brand loyalty and reimbursement positioning.
First wave of generics: revenue begins to soften; volume can hold temporarily as patients remain with the brand.
Broad channel listing: net revenue declines faster than volume; netback compresses.
Long tail: brand becomes a niche or contracts into certain channels where distribution and formulary inclusion remain favorable.

What to watch for in reporting

Decline in net sales vs stabilizing prescription counts (signals share erosion).
Revenue mix shift to higher priced pack sizes, institutional contracts, or specific indications (if relevant).
Promotional intensity changes (often increases around channel switching, then normalizes).

(No specific company financials were provided in the prompt, so a quantified trajectory with revenue figures by year cannot be produced.)

What litigation or settlement agreements affect lactulose brand economics?

For lactulose, litigation is typically not the dominant driver of commercial trajectory in the way it is for newer biotech or high-value branded small molecules. When disputes occur, they usually relate to:

late-expiring secondary patents,
formulation/process claims,
or method-of-use claims in specific jurisdictions.

(No litigation docket or settlement data is provided in the prompt, so no case list can be generated.)

How does DUPHALAC route-to-market strategy affect revenue resilience?

Channel tactics that matter most

Distributor relationships and hospital account management.
Formulary contracting in key provinces/states/countries.
Maintaining consistent pack availability and dosing guidance.

Why this matters

In off-patent small molecules, sales force effectiveness can slow brand erosion but rarely prevents it once reimbursement switches to generic.
Brand value persists where payers prefer fewer SKUs or where contracts lock in brand supply.

DUPHALAC revenue exposure: what metrics indicate whether the brand is gaining or losing share?

Forward-looking indicators

Market share by prescription count vs net sales
Pharmacy chain listing status
Hospital tender wins/losses
Average selling price (ASP) and price per dose trends by geography
Ex-factory pricing changes relative to the generic basket

Signals of share loss

ASP decline larger than volume decline
Net revenue down while demand remains stable in the category
Product-level declines in cohorts tied to formulary changes

Key Takeaways

DUPHALAC (lactulose) sits in a high-substitution, off-patent GI category where revenue trajectory is dominated by pricing compression and generic share erosion rather than exclusivity cliffs.
Market dynamics depend on local generic intensity, reimbursement and contracting, and channel inclusion more than clinical novelty.
The financial profile typically shows stepwise net sales declines after broader generic listing, with any brand resilience coming from pack/channel execution and targeted institutional contracts.
Generic entry risk in most markets is usually practical and commercial (ANDAs and substitution) rather than Paragraph IV-driven litigation for molecule-level protection.

FAQs

1) How fast do lactulose prices fall after generic entry in retail pharmacy markets?
Typically within the first pricing cycle after broad generic listing and payer/chain formulary adoption; net revenue falls can outpace volume decline.

2) Does lactulose maintain volume after net price erosion versus PEG/macrogol?
Often volume can remain stable at the molecule level, but branded net revenue can decline as substitution shifts patients toward lower-priced equivalents and alternative osmotics.

3) What reimbursement changes most affect DUPHALAC net sales?
Tender awards and formulary revisions that designate preferred generics can quickly compress netbacks even when patients continue using lactulose.

4) Are there formulation-level barriers to generic lactulose oral liquids?
For established oral solutions, barriers are usually limited; bioequivalence is generally straightforward, shifting competition to price and channel inclusion.

5) What business events should investors monitor for DUPHALAC-like brands?
Chain listing changes, payer contract resets, hospital tender outcomes, and company disclosures showing ASP decline versus category volume trends.

References

(No sources were provided in the prompt, and no DUPHALAC-specific FDA/Orange Book, patent, litigation, or financial dataset was supplied. Therefore, no citations can be generated.)

US Patents:	0
Applicants:	1
NDAs:	1
Raw Ingredient (Bulk) Api Vendors:	28
Clinical Trials:	5
DailyMed Link:	DUPHALAC at DailyMed

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