ZYDELIG Drug Patent Profile

Which patents cover Zydelig, and what generic alternatives are available?

Zydelig is a drug marketed by Gilead Sciences Inc and is included in one NDA. There are four patents protecting this drug and one Paragraph IV challenge.

This drug has sixty-five patent family members in thirty countries.

The generic ingredient in ZYDELIG is idelalisib. There are two drug master file entries for this compound. One supplier is listed for this compound. Additional details are available on the idelalisib profile page.

DrugPatentWatch^® Litigation and Generic Entry Outlook for Zydelig

A generic version of ZYDELIG was approved as idelalisib by NATCO on February 17^th, 2026.

Summary for ZYDELIG

International Patents:	65
US Patents:	4
Applicants:	1
NDAs:	1
Finished Product Suppliers / Packagers:	1
Raw Ingredient (Bulk) Api Vendors:	84
Clinical Trials:	13
Patent Applications:	4,381
Drug Prices:	Drug price information for ZYDELIG
Patent Litigation and PTAB cases:	See patent lawsuits and PTAB cases for ZYDELIG
What excipients (inactive ingredients) are in ZYDELIG?	ZYDELIG excipients list
DailyMed Link:	ZYDELIG at DailyMed

See drug prices for ZYDELIG

Recent Clinical Trials for ZYDELIG

Identify potential brand extensions & 505(b)(2) entrants

Sponsor	Phase
Loxo Oncology, Inc.	Phase 3
Oregon Health and Science University	Phase 1
Prospect Creek Foundation	Phase 1

See all ZYDELIG clinical trials

Pharmacology for ZYDELIG

Drug Class	Kinase Inhibitor
Mechanism of Action	Cytochrome P450 3A Inhibitors Kinase Inhibitors

Paragraph IV (Patent) Challenges for ZYDELIG

Tradename	Dosage	Ingredient	Strength	NDA	ANDAs Submitted	Submissiondate
ZYDELIG	Tablets	idelalisib	100 mg and 150 mg	205858	1	2022-03-23

US Patents and Regulatory Information for ZYDELIG

ZYDELIG is protected by four US patents.

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Gilead Sciences Inc	ZYDELIG	idelalisib	TABLET;ORAL	205858-001	Jul 23, 2014	AB	RX	Yes	No			Y	Y
Gilead Sciences Inc	ZYDELIG	idelalisib	TABLET;ORAL	205858-002	Jul 23, 2014	AB	RX	Yes	Yes			Y	Y
Gilead Sciences Inc	ZYDELIG	idelalisib	TABLET;ORAL	205858-001	Jul 23, 2014	AB	RX	Yes	No			Y	Y
Gilead Sciences Inc	ZYDELIG	idelalisib	TABLET;ORAL	205858-002	Jul 23, 2014	AB	RX	Yes	Yes				Y
Gilead Sciences Inc	ZYDELIG	idelalisib	TABLET;ORAL	205858-001	Jul 23, 2014	AB	RX	Yes	No

Expired US Patents for ZYDELIG

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	Patent No.	Patent Expiration
Gilead Sciences Inc	ZYDELIG	idelalisib	TABLET;ORAL	205858-001	Jul 23, 2014
Gilead Sciences Inc	ZYDELIG	idelalisib	TABLET;ORAL	205858-002	Jul 23, 2014
Gilead Sciences Inc	ZYDELIG	idelalisib	TABLET;ORAL	205858-002	Jul 23, 2014
Gilead Sciences Inc	ZYDELIG	idelalisib	TABLET;ORAL	205858-001	Jul 23, 2014
Gilead Sciences Inc	ZYDELIG	idelalisib	TABLET;ORAL	205858-002	Jul 23, 2014

EU/EMA Drug Approvals for ZYDELIG

Company	Drugname	Inn	Product Number / Indication	Status	Generic	Biosimilar	Orphan	Marketing Authorisation	Marketing Refusal
Gilead Sciences Ireland UC	Zydelig	idelalisib	EMEA/H/C/003843Zydelig is indicated in combination with an anti‑CD20 monoclonal antibody (rituximab or ofatumumab) for the treatment of adult patients with chronic lymphocytic leukaemia (CLL):who have received at least one prior therapy, oras first line treatment in the presence of 17p deletion or TP53 mutation in patients who are not eligible for any other therapies.Zydelig is indicated as monotherapy for the treatment of adult patients with follicular lymphoma (FL) that is refractory to two prior lines of treatment.	Authorised	no	no	no	2014-09-18

International Patents for ZYDELIG

When does loss-of-exclusivity occur for ZYDELIG?

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

Argentina

Australia

Brazil

Canada

Chile

China

Colombia

Costa Rica

Ecuador

Eurasian Patent Organization

European Patent Office

Hong Kong

India

Japan

Mexico

Moldova, Republic of

Morocco

New Zealand

Peru

Philippines

Poland

Portugal

Singapore

Slovenia

South Africa

South Korea

Spain

Taiwan

Uruguay

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 ZYDELIG around the world.

Country	Patent Number	Title	Estimated Expiration
Argentina	090253
Australia	2013203620
Brazil	112014021935
Canada	2864305
Chile	2014002358

Supplementary Protection Certificates for ZYDELIG

Patent Number	Supplementary Protection Certificate	SPC Country	SPC Expiration	SPC Description
1761540	PA2017004	Lithuania		PRODUCT NAME: IDELALISIBAS ARBA FARMACINIU POZIURIU PRIIMTINA JO DRUSKA; REGISTRATION NO/DATE: EU/1/14/938 20140918
1761540	300867	Netherlands		PRODUCT NAME: IDELALISIB OF EEN FARMACEUTISCH AANVAARDBAAR ZOUT DAARVAN; REGISTRATION NO/DATE: EU/1/14/938 20140919
1761540	122017000008	Germany		PRODUCT NAME: LDELALISIB ODER EIN PHARMAZEUTISCH UNBEDENKLICHES SALZ DAVON; REGISTRATION NO/DATE: EU/1/14/938 20140918
1761540	CA 2017 00007	Denmark		PRODUCT NAME: IDELALISIB; REG. NO/DATE: EU/1/14/938 20140924
1761540	1790006-9	Sweden		PRODUCT NAME: IDELALISIB OR A PHARMACEUTICALLY ACCEPTABLE SALT THEREOF; REG. NO/DATE: EU/1/14/938 20140919

Last updated: July 20, 2026

ZYDELIG (Idelalisib) Market Dynamics and Financial Trajectory: Sales Trends, Patient Demand Shifts, and Competitive Pricing Pressure

Executive summary: ZYDELIG (idelalisib) revenue peaked in the mid-2010s and then compressed as safety-related prescribing constraints, label tightening, guideline de-emphasis in some indications, and expanding alternative regimens reduced treatable demand. Financial trajectory moved from broad uptake to narrower, contestable niches, with post-2019 growth never regained. Competitive pressure increased as BTK inhibitors (ibrutinib, acalabrutinib, zanubrutinib) and other pathway agents displaced idelalisib for chronic lymphocytic leukemia (CLL)/SLL and certain follicular lymphoma (FL) use cases, while safety monitoring and discontinuation rates constrained net persistence.

What were ZYDELIG (idelalisib) peak sales drivers and when did demand start to contract?

ZYDELIG launched in the mid-2010s for hematologic cancers, with early commercial momentum tied to limited effective options and strong uptake in relapsed settings where kinase inhibition delivered rapid responses. The initial demand engine was clinically meaningful efficacy in indolent B-cell malignancies, including follicular lymphoma and CLL/SLL subtypes, where idelalisib fit treatment algorithms as an oral PI3K delta inhibitor.

Demand contraction timeline (market-facing drivers):

• Mid-to-late 2015 to 2016: Initial adoption accelerated as clinicians integrated idelalisib into relapsed indications. Uptake remained concentrated in specialist oncology centers and post-chemo relapse pathways.
• 2016 to 2018: Safety events shifted prescribing behavior. Real-world discontinuation and monitoring requirements increased. That reduced patient persistence and constrained new starts even where clinicians still recognized efficacy.
• 2018 to 2020: Label restrictions and growing preference for BTK-based regimens in CLL/SLL reduced addressable demand. In FL, competing PI3K and non-PI3K options plus earlier lines of therapy expanded, shrinking the pool of patients eligible for idelalisib positioning.
• 2020 to 2023: Portfolio-level and indication-level churn kept sales flat-to-declining. The remaining revenue base depended on narrower third-line and later-line use patterns, with payers increasingly demanding evidence of benefit versus alternatives.

Which indications and label constraints matter most for ZYDELIG revenue exposure?

ZYDELIG’s commercial destiny is tied to where it remains “preferred enough” for payers and prescribers to justify initiation under safety monitoring and eligibility rules.

Indication-level demand pressure:

• CLL/SLL: BTK inhibitors became the default targeted therapy backbone. Even where idelalisib could be used in certain relapsed or refractory contexts, time on therapy and discontinuation risk discouraged uptake versus gentler-to-manage targeted options.
• Follicular lymphoma: Demand weakened as other regimens and shifting sequencing reduced the marginal patient population needing idelalisib after prior therapies.
• Other B-cell malignancies within idelalisib’s label footprint: Similar sequencing effects applied, with substitution by competing pathway inhibitors and chemoimmunotherapy combinations.

Practical commercial effect: As guideline positioning shifted, the treatable population for idelalisib narrowed from “broad relapsed targeted option” to “later-line, specialist-selected option,” which typically carries lower volumes and higher payer friction.

How do safety, monitoring requirements, and discontinuation risk affect net sales for ZYDELIG?

Safety is the principal mechanism turning clinical outcomes into sales outcomes.

Mechanisms that translate to revenue compression:

• Initiation friction: Prescribers require stricter patient selection, baseline evaluation, and monitoring schedules. That delays starts and reduces the conversion rate from eligible to treated.
• Dose interruptions and discontinuations: PI3K delta inhibitor class risks (including serious adverse events that drive discontinuation in real-world practice) reduce persistence, cutting lifetime treatment duration per patient.
• Payer utilization management: When discontinuation and serious adverse event rates are prominent in real-world data, payers become more likely to require prior authorization, step therapy, or outcome-based justification.
• Hospital center behavior: Large oncology centers may carry higher tolerance for managing monitoring requirements, but smaller centers shift away due to operational burden, further tightening penetration.

Net effect: Even if list price is unchanged, lower persistence and lower initiation volume drive net sales down.

What competitive landscape pressure did ZYDELIG face as BTK inhibitors expanded?

BTK inhibitors changed the menu of first- and second-line targeted therapy, particularly in CLL/SLL. As these agents gained line-of-therapy priority, idelalisib lost addressable volume.

Key competitive categories affecting ZYDELIG:

• BTK inhibitor backbone substitution: Ibrutinib, acalabrutinib, and zanubrutinib expanded adoption due to convenient oral dosing, strong efficacy profiles, and growing clinician comfort.
• Alternative targeted pathways: Other non-PI3K targeted regimens competed for the same relapsed and refractory decision space.
• Chemotherapy and chemoimmunotherapy sequencing: Improvements and tailoring of chemoimmunotherapy plus targeted combinations reduced the “gap” idelalisib filled in earlier eras.

Commercial result: As competitors took earlier lines, idelalisib migrated downstream, where volume is smaller and payers apply tighter justification.

How did payer policy and pricing pressure shape ZYDELIG net revenue?

Even before direct generic or biosimilar competition, pricing and contracting dynamics can compress net sales.

Pricing levers that typically impacted idelalisib class products:

• Rebates and contracting discounts: Payers increased pressure on price-to-outcome ratios when multiple oral targeted options existed.
• Prior authorization: Safety events raise the operational and administrative burden for approval. Higher approval friction reduces treatment starts.
• Formulary placement: Where BTK inhibitors and other agents secured preferred tiers, idelalisib required exceptional justification.

Net effect: Contracting and utilization management reduce realized revenue per treated patient, on top of volume shrinkage.

Did ZYDELIG face generic entry threats, and how does exclusivity interact with market reality?

For market dynamics, generic entry risk is often secondary to real-world prescribing constraints and competitor displacement. By the time generic threats become credible, demand is already narrowed.

Exclusivity and substitution logic:

• When guideline and safety positioning devalue a product, “launch of a generic” may not cause abrupt collapse because usage volume is already structurally lower.
• In that scenario, the sales trajectory reflects clinical and competitive substitution rather than a single regulatory event.

What is the financial trajectory pattern for ZYDELIG after peak uptake?

Observed pattern (industry-consistent): Sales rise early, peak on first-wave adoption, then decline as safety constraints, label tightening, and competing regimens reduce eligible patient share. The product typically experiences:

• Volume compression first (fewer new starts and reduced persistence),
• then net sales erosion driven by lower throughput and higher contracting pressure.

Interpretation for financial trajectory:

• After peak, the revenue line becomes dependent on a smaller patient cohort. Even stable pricing cannot fully offset declining treated population.
• The product shifts from growth-oriented to cash-flow preservation mode, with marketing and medical affairs focus on niche prescriber segments.

How do sales, margins, and profitability typically evolve for a constrained oncology branded product like ZYDELIG?

A branded oncology product with a narrowing patient pool usually sees:

• Operating leverage decline: Fixed commercial and pharmacovigilance costs remain while volume falls, pressuring gross profit.
• Higher pharmacovigilance and medical support: Safety-heavy profiles lead to ongoing cost for monitoring and risk mitigation.
• Commercial spend reprioritization: Resources shift to defending formulary access in remaining niches.

Net effect: Profitability trends follow sales compression with limited ability to offset via volume growth.

What licensing and partnership dynamics affect ZYDELIG’s commercial outcomes?

Commercial and financial trajectories for oncology assets are shaped by ownership and distribution structures, and by whether partnering entities share responsibility for market access and safety programs.

Deal dynamics that matter in market practice:

• If the brand owner bears most of the post-launch access and risk mitigation, the financial burden rises when usage narrows.
• If a partner holds commercialization incentives aligned to volume, the product can see faster pullback in later phases.

How strong is the patent estate for ZYDELIG, and does it meaningfully change the sales outlook?

Patent coverage typically determines how long the branded product can fend off direct generic entry. But market dynamics for ZYDELIG are mainly governed by:

• safety-driven prescribing constraints,
• competitor displacement.

Business implication: Even with patent protection, commercial demand can erode. Conversely, even if patent protection holds, low demand reduces the “protectable” revenue base.

What are the generic launch scenarios and the practical risk if ZYDELIG demand is already reduced?

Market practice suggests that lower baseline demand reduces the impact of a generic entry event. The key question becomes not whether generics can enter, but whether payers and prescribers will adopt them in a constrained safety setting.

Scenario map:

• Scenario A: Patent still active + safety constraints persist: Decline continues gradually; generic entry risk is not the dominant driver.
• Scenario B: Generic entry occurs but payer policies restrict use: Adoption is partial; net revenue erosion is slower than a typical switch due to utilization management.
• Scenario C: Generic entry coincides with competitor dominance: The generic may not regain share because treatment algorithms no longer prioritize idelalisib.

How does ZYDELIG compare with BTK inhibitors on market adoption drivers?

Adoption drivers where BTK inhibitors historically outperformed idelalisib:

• simpler real-world management expectations,
• lower discontinuation friction,
• earlier line placement in CLL/SLL.

Where idelalisib retained niches:

• clinician-selected cases with demonstrated efficacy and established experience,
• limited alternatives in certain refractory contexts.

Market consequence: Even with comparable efficacy in selected settings, adoption usually tracks convenience, safety management, and guideline preference.

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Key Takeaways

• ZYDELIG’s financial trajectory followed a common oncology pattern: early uptake followed by sustained decline as safety constraints and sequencing changes narrowed the addressable patient pool.
• BTK inhibitors displaced idelalisib in CLL/SLL decision-making, compressing volumes even before generic entry became the dominant headline risk.
• Revenue erosion came through lower persistence, lower new starts, and payer contracting pressure, not just a single regulatory or exclusivity event.
• The product’s remaining commercial value became niche and specialist-dependent, limiting rebound potential.

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FAQs

1) What factors most reduced ZYDELIG new-patient starts after peak adoption?
Safety monitoring requirements, higher discontinuation rates in real-world practice, and shrinking guideline-aligned positioning versus BTK inhibitor regimens.

2) Does ZYDELIG face higher commercial risk from competitors than from generic entry?
Yes. Competitive displacement in treatment sequencing typically drove the demand contraction more than generic threat alone.

3) How do payer prior authorization and formulary tiering affect ZYDELIG revenue?
They reduce conversion of eligible patients to treated patients, especially when alternative targeted therapies are preferred and outcomes justify stricter utilization management.

4) What drives persistence for idelalisib in real-world oncology practice?
Patient selection, tolerability management, and adherence to monitoring schedules. Lower tolerability reduces treatment duration and net sales per patient.

5) Which market segment still supports ZYDELIG sales in a mature branded environment?
Later-line, specialist-selected patients where clinicians use idelalisib despite competing targeted options and where safety monitoring infrastructure is in place.

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References

1. FDA. (n.d.). Drug Trials Snapshots: Zydelig (idelalisib). U.S. Food and Drug Administration. https://www.fda.gov
2. FDA. (n.d.). Orange Book: Approved Drug Products with Therapeutic Equivalence Evaluations. U.S. Food and Drug Administration. https://www.accessdata.fda.gov/scripts/cder/daf/
3. FDA. (n.d.). Prescribing Information: Zydelig (idelalisib). U.S. Food and Drug Administration. https://www.accessdata.fda.gov/scripts/cder/daf/

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