WELLBUTRIN Drug Patent Profile

When do Wellbutrin patents expire, and when can generic versions of Wellbutrin launch?

Wellbutrin is a drug marketed by Glaxosmithkline and Bausch and is included in three NDAs.

The generic ingredient in WELLBUTRIN is bupropion hydrochloride. There are thirty-eight drug master file entries for this compound. Seventy-four suppliers are listed for this compound. Additional details are available on the bupropion hydrochloride profile page.

DrugPatentWatch^® Litigation and Generic Entry Outlook for Wellbutrin

A generic version of WELLBUTRIN was approved as bupropion hydrochloride by SENORES PHARMS on February 7^th, 2000.

Summary for WELLBUTRIN

US Patents:	0
Applicants:	2
NDAs:	3

US Patents and Regulatory Information for WELLBUTRIN

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Glaxosmithkline	WELLBUTRIN	bupropion hydrochloride	TABLET;ORAL	018644-001	Dec 30, 1985		DISCN	Yes	No
Glaxosmithkline	WELLBUTRIN SR	bupropion hydrochloride	TABLET, EXTENDED RELEASE;ORAL	020358-004	Jun 14, 2002	AB1	RX	Yes	Yes
Glaxosmithkline	WELLBUTRIN SR	bupropion hydrochloride	TABLET, EXTENDED RELEASE;ORAL	020358-001	Oct 4, 1996		DISCN	No	No
Bausch	WELLBUTRIN XL	bupropion hydrochloride	TABLET, EXTENDED RELEASE;ORAL	021515-001	Aug 28, 2003	AB3	RX	Yes	No
Glaxosmithkline	WELLBUTRIN	bupropion hydrochloride	TABLET;ORAL	018644-002	Dec 30, 1985		DISCN	Yes	No
Glaxosmithkline	WELLBUTRIN	bupropion hydrochloride	TABLET;ORAL	018644-003	Dec 30, 1985		DISCN	Yes	No
Glaxosmithkline	WELLBUTRIN SR	bupropion hydrochloride	TABLET, EXTENDED RELEASE;ORAL	020358-003	Oct 4, 1996	AB1	RX	Yes	No

International Patents for WELLBUTRIN

See the table below for patents covering WELLBUTRIN around the world.

Country	Patent Number	Title	Estimated Expiration
Argentina	192302	UN METODO PARA PREPARAR ALFA ALQUILAMINOPROPIOFENONAS
Argentina	198945	METODO PARA PREPARAR ALFA-ALQUILAMINO PROPIOFENONAS
Austria	302276
Austria	307389
Belgium	759838
Canada	977777	BIOLOGICALLY ACTIVE KETONES
Canada	977778

Supplementary Protection Certificates for WELLBUTRIN

Patent Number	Supplementary Protection Certificate	SPC Country	SPC Expiration	SPC Description
2316456	CA 2017 00062	Denmark		PRODUCT NAME: NALTREXON ELLER ET FARMACEUTISK ACCEPTABELT SALT DERAF, ISAER NALTREXONHYDROCHLORID, OG BUPROPION ELLER ET FARMACEUTISK ACCEPTABELT SALT DERAF, ISAER BUPROPIONHYDROCHLORID; REG. NO/DATE: EU/1/14/988 20150330
2316456	65/2017	Austria		PRODUCT NAME: NALTREXON ODER EIN PHARMAZEUTISCH ANNEHMBARES SALZ DAVON, INSBESONDERE NALTREXONHYDROCHLORID, UND BUPROPION ODER EIN PHARMAZEUTISCH ANNEHMBARES SALZ DAVON, INSBESONDERE BUPROPIONHYDROCHLORID; REGISTRATION NO/DATE: EU/1/14/988 (MITTEILUNG) 20150330
2316456	C 2017 047	Romania		PRODUCT NAME: COMBINATIE DE NALTREXONA SAU O SARE ACCEPTABILA FARMACEUTIC A ACESTEIA, IN PARTICULAR CLORHIDRAT DE NALTREXONA SI BUPROPION SAU O SARE ACCEPTABILA FARMACEUTIC A ACESTUIA, IN PARTICULAR CLORHIDRAT DE BUPROPION; NATIONAL AUTHORISATION NUMBER: EU/1/14/988; DATE OF NATIONAL AUTHORISATION: 20150326; NUMBER OF FIRST AUTHORISATION IN EUROPEAN ECONOMIC AREA (EEA): EU/1/14/988; DATE OF FIRST AUTHORISATION IN EEA: 20150326
2316456	2017C/064	Belgium		PRODUCT NAME: NALTREXONE/BUPROPION; AUTHORISATION NUMBER AND DATE: EU/1/14/988 20150330
2316456	2017/059	Ireland		PRODUCT NAME: NALTREXONE OR A PHARMACEUTICALLY ACCEPTABLE SALT THEREOF, IN PARTICULAR NALTREXONE HYDROCHLORIDE, AND BUPROPION OR A PHARMACEUTICALLY ACCEPTABLE SALT THEREOF, IN PARTICULAR BUPROPION HYDROCHLORIDE; REGISTRATION NO/DATE: EU/1/14/988 20150326
2316456	132017000142109	Italy		PRODUCT NAME: NALTREXONE/BUPROPIONE(MYSIMBA); AUTHORISATION NUMBER(S) AND DATE(S): EU/1/14/988, 20150330
2316456	300918	Netherlands		PRODUCT NAME: NALTREXON OF EEN FARMACEUTISCH AANVAARDBAAR ZOUT DAARVAN, IN HET BIJZONDER NALTREXONHYDROCHLORIDE, EN BUPROPION OF EEN FARMACEUTISCH AANVAARDBAAR ZOUT DAARVAN, IN HET BIJZONDER BUPROPIONHYDROCHLORIDE; REGISTRATION NO/DATE: EU/1/14/988 20150330

WELLBUTRIN (bupropion) Investment Scenario and Patent/Regulatory Fundamentals Analysis

Last updated: July 25, 2026

Executive summary

• WELLBUTRIN is an established, off-patent bupropion brand franchise in the U.S. with multiple dosage forms (IR, SR, XL). Core economics are driven by unit demand stability, payor contracting, and generic/authorized generic penetration rather than near-term exclusivity.
• From a patent-risk perspective, the U.S. market is largely generic, with the practical investment question shifting from “time to exclusivity expiry” to “durability of brand pricing and share against generics” and “litigation and labeling risk.”
• The actionable fundamentals focus areas are: (1) competitive intensity from ANDA entrants, (2) interchangeability/substitution and PBM formularies for antidepressants, (3) gross-to-net compression dynamics, and (4) any product-specific reforms (new strengths, generics’ launch timing effects, or REMS/label updates).

What patents protect WELLBUTRIN (bupropion) in the US, and how many remain enforceable?

Short answer: WELLBUTRIN is widely off primary composition coverage in the U.S.; any remaining patent value is typically limited to specific formulations, manufacturing processes, or dosing regimens tied to particular branded dosage forms (IR vs SR vs XL).

Patent estate mapping framework (what to look for) For each dosage form, the investable question is whether any enforceable U.S. patent claims cover:

• Composition or polymorph (rare post-launch for legacy small molecules unless later-discovered forms exist)
• Extended-release matrix design or film-coating specifics for SR/XL
• Methods of use that are not covered by broad prior art (e.g., specific therapeutic claims or dosing regimens)
• Bioavailability/PK claims tied to manufacturing controls
• Device combination or packaging method claims (less common for bupropion)

Practical investment implication

• If the brand’s U.S. sales are already exposed to broad generic competition, residual patent coverage does not change near-term market share unless it blocks specific generic entry for a particular dosage form or strength.

Which WELLBUTRIN dosage forms are most relevant for patent and market exposure?

High-level portfolio view

• WELLBUTRIN (bupropion) Immediate Release (IR)
• WELLBUTRIN SR (sustained release)
• WELLBUTRIN XL (extended release)

Why it matters

• Generics often enter at the level of specific strengths and dosage forms. Residual patents, if any, are usually scoped to those product attributes.

When does WELLBUTRIN lose exclusivity, and what drives generic launch timing?

Short answer: For WELLBUTRIN, exclusivity is not the primary driver of ongoing market competition. Generic launches and PBM behavior are.

What “exclusivity” types matter for WELLBUTRIN in the U.S.?

For legacy antidepressants like bupropion, the main timing levers investors track are:

• Patent expiration and any patent term adjustments (PTA)
• Patent term extensions (PTE) for pediatric or other mechanisms, where applicable
• Orange Book “listed drug” status by dosage form and strength
• Whether any additional blocking patents exist for a particular entry pathway

How PBMs and interchangeability change the economics even after patents expire

• Antidepressants are heavily formulary-managed; brand retention depends on contracted pricing, rebates, and formulary placement.
• Even where a brand remains on formulary, gross-to-net declines can cause material margin compression once generic competition widens.

What is the Orange Book status of WELLBUTRIN, and which ANDA filings are most exposed to Paragraph IV?

Short answer: WELLBUTRIN has extensive generic competition; Paragraph IV filings are typically more relevant for later entrants or for specific dosage form/strength protection pockets.

How investors should interpret Orange Book listings for a legacy small molecule

Key indicators:

• Number of “Orange Book” patents listed for each dosage form and strength
• Whether patents are expiration-dated well into the future (rare for primary bupropion composition for an older brand)
• Whether listed patents are tied to formulation/process rather than composition
• Suit posture signals in the Orange Book Patent Litigation (“PLE”/lawsuit) data (if available)

What to monitor for future Paragraph IV dynamics

• Re-launches: new strengths, new manufacturer changes, authorized generics tied to settlements
• New formulation approvals that create a separate Orange Book entry
• Labeling changes that trigger new exclusivity regimes (usually non-core for bupropion unless a novel indication is added)

How strong is the patent estate for WELLBUTRIN: composition vs formulation vs method-of-use?

Short answer: The investable strength, if any, is usually in formulation/process claims for SR/XL and in narrow method-of-use claims, not in broad composition claims.

Composition claims

For a legacy active ingredient, composition patents are typically long expired in most major markets.

Investor takeaway: composition strength is usually not the basis for continued brand earnings.

Formulation and manufacturing claims (SR/XL relevance)

• Extended-release is where patentable manufacturing and formulation details can cluster.
• Even then, many generic products can be designed around formulation specifics.

Investor takeaway: formulation estates can influence entry for specific product configurations, but they often decay quickly with generic iterative improvements.

Method-of-use claims

• If any method-of-use patents exist, they must be tied to a live FDA-approved label claim to maintain practical enforcement leverage.
• Depression indications have extensive prior art, reducing the ability for broad new method-of-use claims to survive.

Investor takeaway: method claims rarely protect a broad legacy antidepressant franchise from generic substitution over time.

What WELLBUTRIN formulations are protected by patents, and do SR and XL have different IP risk?

Short answer: SR and XL have different development histories and often different release mechanisms, which can translate into distinct IP profiles.

Typical release-mechanism differences that affect generic design-around

• SR uses a sustained-release matrix optimized for longer exposure but not necessarily the same release curve as XL.
• XL uses extended-release technology targeting a longer dosing interval.

Investor takeaway: even if one dosage form is fully generic, another can retain marginal pricing power if a specific formulation configuration remains tied to a stronger legal pocket.

What patent litigation affects WELLBUTRIN, and how does it impact the investment thesis?

Short answer: For legacy bupropion, litigation impact is usually secondary to already-existing generic saturation, but it can matter around particular launches (specific strengths, authorized generics, or reformulations).

Litigation signals investors should use (once patent cases are identified)

• Case filing dates and court schedules
• Motions outcomes (claim construction, injunction posture)
• Settlement terms that influence market entry timing
• Whether a settlement led to an authorized generic or delayed entry

Investment interpretation

• If litigation resolved into earlier generic entry than expected, brand pricing pressure accelerates.
• If litigation delayed entry for a meaningful period for specific dosage forms, the brand can protect margins temporarily.

What generic entry risks exist for WELLBUTRIN in the US?

Short answer: The generic entry risk is largely structural, not event-driven: multiple ANDA pathways are already open, so incremental risk comes from additional competitors, authorized generics, and strength-level re-entries rather than new regulatory “unlocking” events.

Key risk categories

• Market share risk: additional generic entrants increase substitution
• Price risk: net price declines due to bid-based PBM contracting
• Margin risk: rebates and chargebacks rise to defend share
• Supply risk: generic supply interruptions can temporarily support brand pricing but are not predictable

How does WELLBUTRIN compare with other antidepressant brands on durability vs generic pressure?

Short answer: bupropion competes in a crowded antidepressant class where generics are dominant; durability is usually tied to dosing convenience and formulary positioning rather than remaining exclusivity.

Competitive comparison dimensions

• Prescription write patterns (once- vs twice-daily dosing)
• Switching friction (patients already stable on one bupropion ER product)
• PBM tier placement vs competing branded entries
• Safety and tolerability perceptions in real-world practice

Biosimilar risk: does it apply to WELLBUTRIN?

Short answer: No. WELLBUTRIN is a small molecule, so biosimilar frameworks do not apply.

FDA regulatory status of WELLBUTRIN: what pathway issues matter for investment?

Short answer: WELLBUTRIN is an established FDA-approved drug; the investment lens centers on labeling stability, ongoing REMS requirements if any, and whether any future supplemental approvals create new regulatory exclusivity or change generic substitution dynamics.

What to monitor with ongoing FDA activity

• Labeling changes that affect compliance burden or prescriber behavior
• Safety communications that could alter volume trajectories
• Pediatric or conversion-related labeling edits
• Manufacturing site updates that could create supply intermittency

Commercial fundamentals: what drives WELLBUTRIN revenue and margin performance?

Short answer: Gross-to-net compression and substitution effects are the dominant levers in legacy bupropion markets.

Where revenue tends to come from

• ER formulations (SR/XL) often support better adherence patterns versus IR
• Formulary placement drives the majority of volume outcomes

Cost and margin drivers

• Rebates and discounts are the biggest swing factors under generic competition
• Inventory management and manufacturing efficiency matter more as brand pricing erodes

Investment-ready KPIs (used to track brand durability)

• Prescription share vs category
• Net price trends and gross-to-net ratio shifts
• Share of ER vs IR mix
• Net sales by wholesaler channel and by major PBM contracting cycles

Geographic coverage: is WELLBUTRIN risk US-only?

Short answer: bupropion’s generic saturation is typically global, so the investable risk is not bounded to the U.S. Markets outside the U.S. also experience generic entry.

What changes by geography

• Timing of generic market entry
• Parallel import and pricing controls
• Local settlement practices between innovator and ANDA sponsors

Key competitive landscape: which companies compete with WELLBUTRIN in US generics?

Short answer: Multiple ANDA holders compete across bupropion ER and IR dosage forms. The relevant business question is not the identity of a single generic, but whether the number of bidding competitors at PBMs increases during contracting cycles.

What to monitor in competitor landscape

• Authorized generic behavior (can spike share loss)
• Launch sequencing (strength-by-strength)
• Supply continuity after launches

Investment scenario playbooks (how investors can underwrite WELLBUTRIN)

Scenario 1: “Stability with gradual share drift”

• Assumption: generic competition continues but does not materially accelerate.
• Underwrite: net price decline slows due to formularies’ stickiness and patient stabilization.

What would validate

• Prescription share stabilizes for ER while net price declines remain within historical ranges.

Scenario 2: “Contracting-driven margin compression”

• Assumption: PBM contracting becomes more aggressive, and additional generic bids shift tier placement.
• Underwrite: gross-to-net rises enough to offset any volume stability.

What would validate

• Gross-to-net step-ups and net price declines outpace volume trends.

Scenario 3: “Temporary support from supply shocks”

• Assumption: generic supply constraints create intermittent brand lift.
• Underwrite: short-duration demand supports net sales and margin.

What would validate

• Short bursts of outperformance followed by normalization; earnings volatility increases.

Key Takeaways

• WELLBUTRIN’s investment fundamentals are dominated by legacy small-molecule economics: generic substitution, PBM contracting, and gross-to-net compression, not by future patent exclusivity.
• The patent lens is still relevant, but it is usually dosage-form and strength scoped (IR vs SR vs XL), and its investment value is highest only when it blocks a specific generic entry window.
• The practical underwriting inputs are prescription share durability, net price and gross-to-net trajectories, and whether competitor bidding intensifies during PBM cycles.
• Biosimilar risk does not apply.

FAQs

1. How do PBM formulary tier changes affect WELLBUTRIN net price versus volume?
2. Do WELLBUTRIN SR and XL generics differ materially in bioavailability or substitution performance?
3. What labeling changes for bupropion would most likely drive prescriber switching behavior?
4. How does authorized generic strategy typically alter market share for legacy antidepressants like WELLBUTRIN?
5. What indicators best predict whether additional ANDA entrants will pressure bupropion ER pricing in the next 12–24 months?

References

No sources provided in the prompt.