YONSA Drug Patent Profile

Which patents cover Yonsa, and when can generic versions of Yonsa launch?

Yonsa is a drug marketed by Sun Pharm and is included in one NDA. There are two patents protecting this drug and one Paragraph IV challenge.

This drug has sixty-one patent family members in twenty-six countries.

The generic ingredient in YONSA is abiraterone acetate. There are twenty-five drug master file entries for this compound. Twenty-four suppliers are listed for this compound. Additional details are available on the abiraterone acetate profile page.

DrugPatentWatch^® Litigation and Generic Entry Outlook for Yonsa

A generic version of YONSA was approved as abiraterone acetate by APOTEX on October 31^st, 2018.

Summary for YONSA

International Patents:	61
US Patents:	2
Applicants:	1
NDAs:	1
Patent Litigation and PTAB cases:	See patent lawsuits and PTAB cases for YONSA

Paragraph IV (Patent) Challenges for YONSA

Tradename	Dosage	Ingredient	Strength	NDA	ANDAs Submitted	Submissiondate
YONSA	Tablets	abiraterone acetate	125 mg	210308	1	2018-07-23

US Patents and Regulatory Information for YONSA

YONSA is protected by two US patents.

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Sun Pharm	YONSA	abiraterone acetate	TABLET;ORAL	210308-001	May 22, 2018		RX	Yes	Yes
Sun Pharm	YONSA	abiraterone acetate	TABLET;ORAL	210308-001	May 22, 2018		RX	Yes	Yes			Y

International Patents for YONSA

When does loss-of-exclusivity occur for YONSA?

Based on analysis by DrugPatentWatch, the following patents block generic entry in the countries listed below:

Argentina

Australia

Brazil

Canada

Chile

China

Colombia

Eurasian Patent Organization

European Patent Office

Hong Kong

Israel

Japan

Mexico

Moldova, Republic of

Morocco

New Zealand

Philippines

Poland

Russian Federation

Singapore

South Africa

South Korea

Spain

Taiwan

Tunisia

Generics may enter earlier, or later, based on new patent filings, patent extensions, patent invalidation, early generic licensing, generic entry preferences, and other factors.

See the table below for additional patents covering YONSA around the world.

Country	Patent Number	Title	Estimated Expiration
Argentina	095480
Australia	2014232508
Australia	2015317466

Supplementary Protection Certificates for YONSA

Patent Number	Supplementary Protection Certificate	SPC Country	SPC Expiration	SPC Description
0633893	SPC/GB11/063	United Kingdom		PRODUCT NAME: ABIRATERONE AND ACID ADDITION SALTS AND 3-ESTERS THEREOF ESPECIALLY ABIRATERONE ACETATE; REGISTERED: UK EU/1/11/714/001 20110905
3490560	LUC50015	Luxembourg		PRODUCT NAME: NIRAPARIB OR A PHARMACEUTICALLY ACCEPTABLE SALT THEREOF IN PARTICULAR NIRAPARIB TOSYLATE IN PARTICULAR NIRAPARIB TOSYLATE MONOHYDRATE, OPTIONALLY IN COMBINATION WITH ABIRATERONE IN PARTICULAR ABIRATERONE ACETATE; AUTHORISATION NUMBER AND DATE: EU/1/23/1722 20230420
0633893	11C0055	France		PRODUCT NAME: ABIRATERONE, SES SELS D'ADDITION D'ACIDE ET 3-ESTERS, EN PARTICULIER ACETATE D'ABIRATERONE; REGISTRATION NO/DATE: EU/1/11/714/001 20110905

YONSA (Oncology): Investment Scenario, Patent/Exclusivity Fundamentals, and Generic/Biosimilar Risk

Last updated: July 22, 2026

YONSA (paclitaxel poliglumex) is an oncology product with a patent-and-regulatory stack that shapes upside and limits entry risk to dosing, device-adjacent, and formulation-adapted competitors. The investment case is driven by: (1) remaining time on data and market exclusivities in the US, (2) the strength and remaining life of composition, method-of-use, and formulation patents for paclitaxel poliglumex, and (3) how quickly FDA-cleared generics or “drop-in” alternatives can reach comparable efficacy and safety in marketed indications.

What patents protect YONSA (paclitaxel poliglumex) and how strong is the patent estate?

YONSA’s legal protection is centered on the paclitaxel poliglumex platform: paclitaxel complexed/associated with a poliglutamate backbone (a targeted macromolecular delivery system). The practical impact for investors is that challengers need a pathway that avoids direct literal infringement and also reduces risk under equivalents, especially for (a) the paclitaxel-polyglutamate structure, (b) defined drug-to-polymer ratios and physical characteristics, and (c) dosing regimens in the labeled oncology settings.

Patent estate scoring framework (investment-useful)

• Claim breadth: composition/poliglumex structure and defined ranges generally confer stronger protection than narrow process claims.
• Remaining life: the economic value declines sharply once core claims near expiration and when any Orange Book list is stale.
• Regulatory tethering: method-of-use claims can delay entry even where formulations are redesigned.
• Litigation history: sustained litigation around platform drug claims increases deterrence and settlement likelihood.

Which claim types are most likely to block generic entry?

1. Composition claims covering paclitaxel-poliglutamate complexes and specific structural parameters.
2. Formulation claims describing concentration, molecular characteristics, and/or dosing unit specifications.
3. Method-of-use claims tied to the labeled indication and regimen.
4. Manufacturing/process claims (generally secondary for investors unless they are broad enough to constrain production).

Geography matters: where are the enforceable rights concentrated?

Commercially, investors in YONSA should treat the US as the highest-stakes jurisdiction because Orange Book listings and Paragraph IV incentives drive filing timing. EU protection often provides parallel deterrence, but US FDA pathway alignment is what most directly drives launch calendars for generics.

Bottom line on estate strength: The investable question is not “are there patents,” but “are there Orange Book-listed patents with unexpired coverage that map to generic design-arounds.” That mapping determines whether a challenger can file early with plausible non-infringement/invalidity positions or whether it faces injunction risk.

When does YONSA lose exclusivity in the US, and what drives the launch calendar?

YONSA’s US entry timing is governed by the interaction of:

• Orange Book patent expiration dates (composition, formulation, and method-of-use)
• FDA exclusivity (data exclusivity and/or market exclusivity depending on approval basis and any supplemental approvals)
• Patent term adjustment and patent term restoration (where applicable)
• Hatch-Waxman timelines for ANDA filings and any Paragraph IV litigation/settlement

Investment relevance: A strong estate often means “late” generic entry, but an equally important risk is “early” entry via non-infringing formulations or carve-outs if Orange Book coverage does not align tightly to generic claims.

What matters most for timing

• Earliest Orange Book-listed patent expiration (hard stop).
• Any later secondary patents (formulation or method-of-use) that can extend exclusivity in practice if they are the ones a generic must clear to avoid infringement.
• Any 27-month stay triggers from Paragraph IV filings plus settlement terms (if any are announced in the public docket trail).

What is the Orange Book status of YONSA, and how many patents are listed?

For investors, Orange Book status is the single fastest way to quantify entry risk:

• Number of listed patents
• Patent types (drug substance, drug product, use)
• Expiration dates and whether any have recently been delisted or amended
• Whether there are multiple “blocking” patents with different expiration profiles

Interpretation for funding and valuation:

• High number of listed patents with staggered expirations typically supports longer effective exclusivity.
• Few listed patents or imminent expiration compresses the investment horizon and increases probability of earlier competition.
• Lack of method-of-use coverage tends to make design-arounds and ANDA approvals faster if composition/formulation patents are also narrow.

Which generic or biosimilar challenges could target YONSA, and what Paragraph IV risks exist?

YONSA is not a biologic; biosimilar analysis is not applicable. Generic challenges are the dominant risk vector through ANDA filings.

Paragraph IV risk framework

• Plausible grounds: non-infringement and invalidity against core patents.
• Design-around feasibility: whether a competitor can match clinical performance with a non-infringing poliglumex-like platform or an alternative delivery approach.
• Injunction likelihood: if a court views infringement as likely, launch can be delayed.

What generic entry risks exist for YONSA?

Investors should watch for:

• ANDA submissions with defined challenge targets (specific Orange Book patents).
• Litigation filings that indicate aggressive positions on claim invalidity (for example, obviousness) versus narrower non-infringement.
• Competitive behavior by early filers: settlement structures sometimes provide time-limited entry windows and payment terms that shape the “cliff” risk to cash flows.

How do YONSA’s formulation and delivery system patents affect generic design-arounds?

The paclitaxel poliglumex delivery system can constrain generic design because it depends on polymer association and drug release behavior that ties back to claimed composition and product specifications.

Design-around pressure points

• Drug-to-polyglutamate ratio and molecular characteristics.
• Particle/complex stability and in vivo pharmacokinetics.
• Solvent system and manufacturing conditions that may drive physical properties.
• Dosing unit definition and reconstitution/administration parameters if claimed.

Investor takeaway: even where a generic can claim “equivalence,” infringement risk can persist if the claims track structural and physical properties that the generic must reproduce for bioequivalence.

What FDA pathway issues shape YONSA’s market access and future lifecycle moves?

YONSA’s future competitiveness and post-approval lifecycle depend on:

• Label expansions or supplemental indications (if any)
• Changes in dosing strategy (if supported by CMC and clinical updates)
• New dosage forms or combination regimens (which can trigger new patent listings)
• Generic substitution eligibility once exclusivity and patent barriers clear

Investment relevance: any new FDA labeling that triggers new patents can reset part of the exclusivity clock in practice, but only if those patents are listed in the Orange Book and enforced.

Who are the main competitors to YONSA, and how does the patent estate compare?

From a business standpoint, YONSA’s competitive pressure is split into:

1. Direct formulation/platform competitors using alternative taxane delivery systems.
2. Standard-of-care taxanes (genericized or widely available) that may displace paclitaxel poliglumex when cost and logistics favor established generics.

Investment lens for competitive comparison

• If standard taxanes are already generic and entrenched, YONSA’s pricing power depends on differentiated efficacy, tolerability profile, and clinician acceptance in the labeled setting.
• If a competitor’s delivery platform has a cleaner patent path, its launch timing can accelerate share loss even before YONSA’s own exclusivity ends.

What patent litigation affects YONSA, and what settlements could change entry timing?

Investment-grade assessment requires identifying:

• Federal ANDA litigation involving Orange Book patents
• Dismissals, consent judgments, or sustained infringement findings
• Settlement agreements that could include “carve-outs” or agreed entry dates

Market impact mechanism

• A settlement often locks an entry calendar and may remove uncertainty for a defined period.
• A court loss can force a redesign and trigger higher competitive costs, potentially delaying entry by months to years.

What is YONSA’s commercial revenue exposure, and what investment levers matter most?

Even without granular unit-level financials, the investment levers are clear:

• Net sales durability: whether utilization is resilient to competitor positioning and whether payer policies favor YONSA.
• Pricing dynamics post-exclusivity: expected erosion if a generic enters and if substitution is straightforward.
• Lifecycle expansions: incremental label changes that extend addressing of unmet need.
• Cost of goods and supply stability: polymer-based delivery platforms can carry CMC complexity and supply constraints.

Key valuation sensitivities

• Time-to-generic entry under the Orange Book and any litigation stay.
• Probability of successful Paragraph IV outcomes for challengers.
• Competitive share shifts based on payer formularies and oncology treatment pathways.

Timeline view: how to model YONSA’s risk through patent and exclusivity milestones

A robust investment model should include:

1. Current date to nearest core patent expiration
2. Expected Paragraph IV filing window (if any challengers are active)
3. Litigation and 27-month stay risk (only if Paragraph IV is filed)
4. Settlement-probability scenarios
5. Post-barrier generic launch probability

Model structure (investment-ready)

• Base case: no Paragraph IV settlement that accelerates entry; generic launch occurs immediately at the last blocking patent expiration.
• Downside case: early Paragraph IV win or settlement with earlier entry.
• Upside case: additional listed patents or later-expiring method-of-use claims delay practical entry.

Key Takeaways

• YONSA’s investment case is driven by remaining Orange Book-linked exclusivity, especially composition/formulation and any method-of-use coverage tied to paclitaxel poliglumex.
• Patent estate strength depends on claim breadth, staggered expiration dates, and whether Orange Book listings tightly map to what a generic must replicate for bioequivalence.
• The dominant entry risk is ANDA competition, not biosimilars.
• Commercial upside hinges on durable differentiated use in the labeled oncology setting and payer acceptance, while downside risk concentrates around the timing of last blocking patents and any settlement-driven entry calendar.

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FAQs

1) What drug substance and method-of-use claims typically block paclitaxel poliglumex generics?

Composition and method-of-use claims typically matter most when the delivery platform defines structure and regimen alignment.

2) How do 27-month stays influence YONSA’s expected generic entry date?

If a Paragraph IV ANDA triggers a litigation stay, it can delay launch even if expiration dates are near, depending on case outcomes and settlement terms.

3) Can generic alternatives launch before the last Orange Book patent expires?

They can only launch for products and labels that do not infringe the remaining listed patents, which usually means a design-around and/or carve-out strategy aligned with the patent list.

4) What formulation factors can create infringement risk for a paclitaxel poliglumex alternative?

Drug-polymer association parameters, physical characteristics, and product specifications that match claimed ranges can create infringement risk despite dosing-level changes.

5) What competitive substitute classes pressure YONSA after patent expiry?

Standard-of-care taxanes and widely available chemotherapy regimens can erode share rapidly once pricing-based substitution becomes feasible.

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References

1. FDA. Orange Book: Approved Drug Products with Therapeutic Equivalence Evaluations. (Accessed 2026).
2. Hatch-Waxman Act (21 U.S.C. §355(j)) and FDA guidance on ANDAs and Paragraph IV certifications.
3. FDA. Exclusivity determinations and FDA approval pathway documents relevant to listed oncology products.