ISTODAX Drug Patent Profile

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

Istodax is a drug marketed by Bristol-myers and is included in one NDA.

The generic ingredient in ISTODAX is romidepsin. There are three drug master file entries for this compound. Two suppliers are listed for this compound. Additional details are available on the romidepsin profile page.

DrugPatentWatch^® Litigation and Generic Entry Outlook for Istodax

A generic version of ISTODAX was approved as romidepsin by FRESENIUS KABI USA on October 12^th, 2021.

Summary for ISTODAX

US Patents:	0
Applicants:	1
NDAs:	1
Finished Product Suppliers / Packagers:	1
Raw Ingredient (Bulk) Api Vendors:	42
Clinical Trials:	46
Patent Applications:	5,110
Drug Prices:	Drug price information for ISTODAX
Patent Litigation and PTAB cases:	See patent lawsuits and PTAB cases for ISTODAX
What excipients (inactive ingredients) are in ISTODAX?	ISTODAX excipients list
DailyMed Link:	ISTODAX at DailyMed

See drug prices for ISTODAX

Recent Clinical Trials for ISTODAX

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

Sponsor	Phase
GWT-TUD GmbH	Phase 1/Phase 2
AstraZeneca	Phase 1/Phase 2
Columbia University	Phase 1

See all ISTODAX clinical trials

Paragraph IV (Patent) Challenges for ISTODAX

Tradename	Dosage	Ingredient	Strength	NDA	ANDAs Submitted	Submissiondate
ISTODAX	Injection	romidepsin	10 mg/vial	022393	1	2013-11-05

US Patents and Regulatory Information for ISTODAX

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Bristol-myers	ISTODAX	romidepsin	POWDER;INTRAVENOUS	022393-001	Nov 5, 2009	AP	RX	Yes	Yes

Expired US Patents for ISTODAX

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	Patent No.	Patent Expiration
Bristol-myers	ISTODAX	romidepsin	POWDER;INTRAVENOUS	022393-001	Nov 5, 2009	7,611,724
Bristol-myers	ISTODAX	romidepsin	POWDER;INTRAVENOUS	022393-001	Nov 5, 2009	4,977,138
Bristol-myers	ISTODAX	romidepsin	POWDER;INTRAVENOUS	022393-001	Nov 5, 2009	7,608,280

EU/EMA Drug Approvals for ISTODAX

Company	Drugname	Inn	Product Number / Indication	Status	Generic	Biosimilar	Orphan	Marketing Authorisation	Marketing Refusal
Celgene Europe Ltd.	Istodax	romidepsin	EMEA/H/C/002122treatment of peripheral T-cell lymphoma (PTCL),	Refused	no	no	yes		2013-02-12

International Patents for ISTODAX

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

Country	Patent Number	Title	Estimated Expiration
Canada	1335083	SUBSTANCE FR901228 ET SA PREPARATION (FR901228 SUBSTANCE AND PREPARATION THEREOF)
Denmark	366889
Australia	3829089
Japan	2004508049
South Africa	8905121
Finland	893359
Australia	8010901

ISTODAX (romidepsin): Market Dynamics and Financial Trajectory

Last updated: April 25, 2026

What is the market positioning of ISTODAX?

ISTODAX is the brand name for romidepsin, a histone deacetylase (HDAC) inhibitor. In the commercial market, its positioning is defined by (1) restricted oncology indications, (2) competition from multiple HDAC classes and other epigenetic agents, and (3) payer and hospital formulary scrutiny typical for oncology drugs after initial launch.

Key commercial fact pattern

Item	Detail
Drug	ISTODAX (romidepsin)
Mechanism	HDAC inhibitor
FDA approval	Indicated for relapsed or refractory peripheral T-cell lymphoma (PTCL) after at least one prior therapy in the US label framework
Administration	Intravenous infusion (as per label-based use in oncology settings)
Launch era impact	Launch and early growth were shaped by the limited PTCL segment and the rate at which oncology centers adopted HDAC regimens

Regulatory anchor point: FDA labeling includes boxed warning and oncology safety communications for ISTODAX, which contributes to hospital governance and formulary gatekeeping. (Source: FDA label for ISTODAX) [1]

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How do indication scope and competitive intensity shape demand?

Demand for ISTODAX is structurally constrained by: 1) Narrow indication geography and patient pool in PTCL versus blockbuster oncology classes. 2) Line-of-therapy dynamics: uptake depends on where HDAC inhibition fits relative to other PTCL standards and salvage options. 3) Therapy switching: once patients progress, prescriber preference migrates toward newer options, reducing long-tail share.

Competitive landscape drivers

ISTODAX competes in a therapeutic area where the main demand drivers are:

• Other HDAC inhibitors and combination regimens targeting epigenetic pathways.
• Checkpoint and targeted therapies that can displace HDAC use in salvage settings depending on evolving treatment protocols.
• Clinical adoption speed: even within a narrow lymphoma segment, regimen selection depends on peer-reviewed experience and guideline inclusion, not only efficacy.

Market implication: In narrow oncology niches, sales often rise quickly after launch if evidence aligns with practice, then flatten as either newer standards emerge or sequencing shifts. ISTODAX’s sales trajectory follows that profile due to limited addressable population and the rapid re-optimization of PTCL treatment pathways.

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What does the financial trajectory look like and why?

ISTODAX’s commercial trajectory is dominated by the post-launch pattern common to specialty oncology drugs: initial adoption, followed by plateau, then pressure from price erosion, formulary controls, and therapy migration.

Observable financial dynamics to expect in ISTODAX

Financial driver	Mechanism	Expected effect on sales
Label-constrained addressable market	PTCL relapsed/refractory population is smaller than broad oncology segments	Upper-bound revenue ceiling
Hospital contracting and rebates	Oncology buy-and-bill and contracting reduce net realizations	Revenue stabilization with margin compression
Sequencing competition	Treatment guidelines and local practice move toward alternative salvage regimens	Share loss after early adoption
Category scrutiny	Safety management requirements and infusion handling increase operational friction	Slower repeat adoption versus lower-burden regimens
Patent and exclusivity calendar	Competitive entry risk after exclusivity expiry	Potential post-exclusivity demand shock in many markets

Regulatory burden effect: ISTODAX’s label includes serious safety-related elements that require clinical monitoring and can affect adoption patterns, especially where prescribers compare risk-benefit tradeoffs across HDAC options. (Source: FDA label) [1]

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How does pricing and payer behavior impact net revenue?

Even when gross prescriptions hold, net revenue typically shifts due to:

• Contracting in oncology and significant rebates tied to hospital purchasing.
• Formulary tiering that can reduce access if a competitor establishes preferred status.
• Usage restrictions driven by prior authorization and care pathway guidance.

Net revenue sensitivity

For an oncology specialty IV drug like ISTODAX, net revenue typically tracks:

• Number of treated patients (volume)
• Net price after rebates and discounts
• Mix shift across settings (community vs academic centers)

Because the patient pool is fixed by the indication and line of therapy, even modest changes in treated-patient counts create outsized percentage revenue moves.

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What role do manufacturing and supply risks play in stability?

ISTODAX is delivered as an infused oncology therapy, so supply continuity depends on manufacturing robustness and lot release throughput.

Supply chain influence on revenue

Supply chain element	Why it matters	Typical revenue impact
Lot availability	Oncology centers plan infusions; shortages disrupt scheduled treatment	Sales volatility
Distribution lead times	IV specialty drugs require dependable logistics	Net sales smoothing or disruptions
Quality system stability	Regulatory compliance affects market continuity	Avoidable missed doses and cancellations

These factors rarely create long-run growth, but they can worsen near-term performance if adverse events disrupt shipments.

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What market milestones affect the commercial curve?

The commercial curve for ISTODAX depends on milestones in: 1) Regulatory lifecycle (label revisions, safety communications) 2) Clinical evidence updates that shift sequencing (how it is used in PTCL) 3) Competitive entries in HDAC inhibition and lymphoma salvage therapy 4) Exclusivity and patent events altering competitive threat

Milestones to anchor the lifecycle

• FDA label status defines the baseline clinical use framing and ongoing risk communication requirements. (Source: FDA label) [1]
• Any safety communications or label changes alter prescribing behavior through risk management protocols.

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How does ISTODAX compare with major HDAC competitors on market mechanics?

Comparisons across HDAC inhibitors typically show:

• Broadness of indications drives patient pool.
• Oral vs IV route affects convenience, formulary acceptance, and site-of-care economics.
• Combination readiness affects how quickly a regimen becomes part of standard salvage or consolidation pathways.

Route and formulary dynamics

Variable	ISTODAX (romidepsin)	Typical impact versus other HDACs
Route	IV infusion	Higher administration burden can slow adoption versus simpler regimens
Indication scope	PTCL relapsed/refractory context	Smaller ceiling versus drugs with broader oncology label coverage
Category acceptance	Requires clinical monitoring	Can limit switching if competing options have simpler safety management

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What is the forward-looking financial outlook?

The forward trajectory for ISTODAX is likely to be shaped by:

• Ongoing competition in PTCL salvage settings
• Pricing and access tightening through payer governance
• Exclusivity and patent-driven competitive risk

Given that ISTODAX sits in a narrow oncology segment, its longer-term financial outlook is usually “steady-to-declining” unless:

• It gains label expansions
• Stronger clinical positioning places it earlier in sequencing
• It secures preferred formulary status against alternative HDACs

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Key Takeaways

• ISTODAX’s market is structurally narrow: sales are anchored to a relapsed or refractory PTCL patient pool and line-of-therapy rules typical for HDAC inhibitors. (Source: FDA label) [1]
• Demand and net revenue move together only early; later, contracting, rebating, and formulary decisions create net price pressure even if treated patients hold.
• Competition and sequencing shifts are the dominant long-term drivers for revenue compression in PTCL salvage.
• Operational burden from IV administration and safety monitoring influences formulary access and adoption speed.
• Financial trajectory is consistent with specialty oncology pattern: initial uptake, followed by plateau, then pressure as standards evolve and access tightens.

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FAQs

1) What is ISTODAX used for?

ISTODAX (romidepsin) is used for relapsed or refractory peripheral T-cell lymphoma (PTCL) in the FDA-labeled treatment setting. (Source: FDA label) [1]

2) Why is the market ceiling for ISTODAX limited?

The addressable population is constrained by PTCL relapsed/refractory criteria and line-of-therapy sequencing, which caps total treated patients relative to broader oncology categories.

3) What drives net revenue versus prescription volume?

Net revenue is heavily affected by hospital contracting, rebates, and payer formulary tiering, which can reduce realized prices even when gross usage holds.

4) How do safety and label requirements affect uptake?

Safety communications and clinical monitoring requirements increase adoption friction in hospitals and can influence regimen selection versus competing therapies with different risk or administration profiles. (Source: FDA label) [1]

5) What is the biggest threat to future sales performance?

Therapy migration in PTCL salvage and competition from other epigenetic and lymphoma treatment options, compounded by contracting pressure and exclusivity-driven competitive dynamics.

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References

[1] U.S. Food and Drug Administration. (n.d.). ISTODAX (romidepsin) prescribing information / label. FDA. https://www.accessdata.fda.gov/