Vorinostat - Generic Drug Details

What are the generic drug sources for vorinostat and what is the scope of patent protection?

Vorinostat is the generic ingredient in one branded drug marketed by Msd Sub Merck and is included in one NDA. There are four patents protecting this compound. Additional information is available in the individual branded drug profile pages.

Vorinostat has one hundred and thirty-one patent family members in thirty-five countries.

There are two drug master file entries for vorinostat. One supplier is listed for this compound.

Summary for vorinostat

International Patents:	131
US Patents:	4
Tradenames:	1
Applicants:	1
NDAs:	1
Drug Master File Entries:	2
Finished Product Suppliers / Packagers:	1
Raw Ingredient (Bulk) Api Vendors:	136
Clinical Trials:	286
What excipients (inactive ingredients) are in vorinostat?	vorinostat excipients list
DailyMed Link:	vorinostat at DailyMed

DrugPatentWatch^® Estimated Loss of Exclusivity (LOE) Date for vorinostat

Dosage:

CAPSULE;ORAL

^*The generic entry opportunity date is the latter of the last compound-claiming patent and the last regulatory exclusivity protection. Many factors can influence early or later generic entry. This date is provided as a rough estimate of generic entry potential and should not be used as an independent source.

Recent Clinical Trials for vorinostat

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

Sponsor	Phase
Sung Won Choi	PHASE2
Unravel Biosciences, Inc.	PHASE1
US Military HIV Research Program	PHASE1

See all vorinostat clinical trials

Pharmacology for vorinostat

Drug Class	Histone Deacetylase Inhibitor
Mechanism of Action	Histone Deacetylase Inhibitors

Anatomical Therapeutic Chemical (ATC) Classes for vorinostat

L01XH	Histone deacetylase (HDAC) inhibitors
L01X	OTHER ANTINEOPLASTIC AGENTS
L01	ANTINEOPLASTIC AGENTS
L	Antineoplastic and immunomodulating agents

US Patents and Regulatory Information for vorinostat

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Msd Sub Merck	ZOLINZA	vorinostat	CAPSULE;ORAL	021991-001	Oct 6, 2006		RX	Yes	Yes
Msd Sub Merck	ZOLINZA	vorinostat	CAPSULE;ORAL	021991-001	Oct 6, 2006		RX	Yes	Yes				Y
Msd Sub Merck	ZOLINZA	vorinostat	CAPSULE;ORAL	021991-001	Oct 6, 2006		RX	Yes	Yes
Msd Sub Merck	ZOLINZA	vorinostat	CAPSULE;ORAL	021991-001	Oct 6, 2006		RX	Yes	Yes			Y

Expired US Patents for vorinostat

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	Patent No.	Patent Expiration
Msd Sub Merck	ZOLINZA	vorinostat	CAPSULE;ORAL	021991-001	Oct 6, 2006
Msd Sub Merck	ZOLINZA	vorinostat	CAPSULE;ORAL	021991-001	Oct 6, 2006
Msd Sub Merck	ZOLINZA	vorinostat	CAPSULE;ORAL	021991-001	Oct 6, 2006
Msd Sub Merck	ZOLINZA	vorinostat	CAPSULE;ORAL	021991-001	Oct 6, 2006
Msd Sub Merck	ZOLINZA	vorinostat	CAPSULE;ORAL	021991-001	Oct 6, 2006
Msd Sub Merck	ZOLINZA	vorinostat	CAPSULE;ORAL	021991-001	Oct 6, 2006
Msd Sub Merck	ZOLINZA	vorinostat	CAPSULE;ORAL	021991-001	Oct 6, 2006

International Patents for vorinostat

Country	Patent Number	Title	Estimated Expiration
Iceland	8357	Aðferð við að meðhöndla krabbamein með HDAC hindrum
Israel	173846
South Africa	200407942	Methods of including terminal differentiation
Japan	5264174
World Intellectual Property Organization (WIPO)	2005039498
Australia	2009201650	Formulations of suberoylanilide hydroxamic acid and methods for producing same
Australia	2009201668	Methods of Treating Cancer with HDAC Inhibitors

Market Dynamics and Financial Trajectory for Vorinostat

Last updated: July 28, 2025

Introduction

Vorinostat, commercially marketed as Zolinza, is a histone deacetylase (HDAC) inhibitor approved by the U.S. Food and Drug Administration (FDA) for treating cutaneous manifestations of cutaneous T-cell lymphoma (CTCL). Since its introduction, vorinostat has garnered attention due to its unique mechanism of epigenetic modulation and potential applications beyond approved indications. This analysis examines the current market landscape, drivers, challenges, and the financial trajectory influencing vorinostat's commercial viability.

Pharmacological Profile and Approved Indications

Vorinostat functions by inhibiting class I and II HDAC enzymes, leading to chromatin remodeling, cell cycle arrest, apoptosis, and differentiation in cancer cells [1]. Its initial approval in 2006 targeted CTCL, a rare lymphoid malignancy characterized by malignant T-cell proliferation in the skin. The drug’s oral administration and manageable safety profile have positioned it as a second-line therapy after systemic therapies like methotrexate or interferons.

Despite its orphan drug status for CTCL, vorinostat's broader therapeutic potential remains under investigation, encompassing applications in other hematologic malignancies, solid tumors, and metabolic disorders. These exploratory indications, however, have yet to translate into significant commercial expansion.

Market Dynamics

1. Therapeutic Market Landscape

The niche of HDAC inhibitors has expanded considerably, with multiple agents entering the market since vorinostat’s approval. Notably, agents such as panobinostat, romidepsin, and belinostat have entered oncology arsenals, often with broader or more potent activity profiles [2]. The competitive landscape constrains vorinostat's market share due to differences in efficacy, safety, and dosing convenience.

CTCL remains a limited market, with an estimated global prevalence of approximately 5,000–10,000 cases [3], translating into an annual market size of roughly $100–$200 million, considering global sales and pricing constraints. Given the rarity of the disease, the commercial upside remains inherently limited.

2. Pricing and Reimbursement Climate

Vorinostat is priced at a premium reflecting its orphan drug status, with treatment costs potentially exceeding $90,000 annually per patient [4]. Reimbursement policies in various markets (e.g., U.S., EU) influence access, with payers scrutinizing cost-effectiveness vis-à-vis marginal benefits. The high-price model sustains revenue but underscores the importance of market access strategies.

3. Off-Label and Investigational Uses

Research exploring vorinostat's role in other malignancies, such as multiple myeloma, glioblastoma, and solid tumors, fuels optimism about future indications. However, translational setbacks, including inconsistent clinical trial data, have tempered expectations [5]. The absence of substantial off-label adoption limits revenue expansion derived from these avenues.

4. Competition and Drug Development Trends

The evolution of targeted therapies and immune checkpoint inhibitors has reshaped oncology treatment paradigms. For epigenetic agents like vorinostat, this shift presents both challenge and opportunity. The advent of combination therapies incorporating HDAC inhibitors aims to enhance efficacy, potentially rejuvenating interest. However, the crowded development pipeline increases the risk of displacement or obsolescence.

Financial Trajectory

1. Revenue Trends

During its initial launch, vorinostat achieved peak sales around $100 million annually, driven by demand in the CTCL market [6]. Since then, revenues have declined due to market saturation, competition, and generics in certain jurisdictions (anticipated post-patent expiry). Current estimates peg U.S. annual sales between $20–$30 million, with minimal contribution from international markets owing to regulatory and reimbursement barriers.

2. Patent and Market Exclusivity

The primary patent protecting vorinostat lapsed around 2016, exposing it to generic competition in several markets. This transition has precipitated a sharp decline in price and sales volume. While orphan drug exclusivity extended market protection until 2016, the subsequent loss of patent rights has accelerated generic uptake.

3. R&D and Pipeline Investment

Ongoing clinical trials are exploring new formulations, combination regimens, and novel indications. However, the high costs associated with late-stage development, coupled with uncertain outcomes, pose investment risks. A lack of blockbuster potential constrains R&D funding and could lead to strategic licensing or divestment by pharmaceutical companies seeking revenue recoupment.

4. Licensing and Strategic Partnerships

Developer collaborations are vital for expanding vorinostat's utility. Notably, partnerships with biotech firms for combination therapies or with academic institutions for mechanistic studies have facilitated pipeline progress. These arrangements can offset development costs and expand market reach, but their success remains uncertain.

Challenges and Opportunities

Challenges

• Limited Market Size: Rare disease designation caps revenue potential.
• Generic Competition: Patent expiry led to price erosion.
• Efficacy Limitations: Modest response rates restrict broader adoption.
• Emerging Competitors: More potent targeted epigenetic agents are entering or developing.
• Regulatory Hurdles: Expanding indications require substantial evidence, with high developmental costs.

Opportunities

• Combination Therapies: Augmenting efficacy with immune checkpoint inhibitors or targeted agents.
• Biomarker-Driven Patient Selection: Precision medicine approaches could improve response rates.
• Emerging Indications: Investigational uses in neurodegenerative, inflammatory, or infectious diseases may unlock new markets.
• Regulatory Incentives: Orphan designation and fast-track pathways can accelerate development and approval.

Future Outlook

The financial path of vorinostat will largely hinge on its ability to demonstrate superior efficacy and safety in new indications or combinatorial regimens. Market growth prospects are modest, with anticipated revenues declining further absent significant breakthroughs. The focus for stakeholders should include optimizing niche positioning, leveraging strategic partnerships, and exploring innovative delivery approaches to extend lifecycle value.

Key Takeaways

• Market Size is Limited: Vorinostat primarily serves a niche CTCL market with annual global sales below $50 million.
• Patent Expiry Diminished Revenue: Loss of exclusivity and generic competition have significantly eroded profits.
• Growth Potential Lies in Combinations and New Indications: Success hinges on demonstrating improved clinical outcomes in expanded applications.
• Development Risks are Elevated: Clinical trial outcomes and regulatory hurdles pose ongoing challenges.
• Strategic Collaborations Are Crucial: Partnerships can offset developmental costs and facilitate market access.

FAQs

1. How does vorinostat compare to other HDAC inhibitors in the market?
Vorinostat is one of several HDAC inhibitors approved for hematologic malignancies; however, agents like romidepsin and panobinostat often feature broader indication profiles, higher potency, or improved administration routes, limiting vorinostat’s competitiveness [2].

2. What are the key barriers to expanding vorinostat's indications?
Major obstacles include limited clinical efficacy data in non-CTCL diseases, toxicity profiles, high development costs, and regulatory challenges requiring substantial evidence of benefit in new therapeutic areas.

3. Could biosimilars impact vorinostat’s market share in the future?
Given vorinostat’s small molecule nature, biosimilar competition is irrelevant; however, generic versions of its original formulations may reduce prices and revenue in markets where patents have expired.

4. What strategic moves could revitalize vorinostat’s market presence?
Investing in combination therapy development, biomarker-driven clinical trials, and exploring unmet needs in related diseases may open new revenue streams.

5. How does the orphan drug status influence vorinostat’s market?
Orphan designation offers market exclusivity and tax benefits, providing a temporary competitive advantage. Nonetheless, patent expiry eventually exposes the drug to generic competition, diminishing revenues over time.

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References:

[1] de la Cruz, M. C., et al. (2020). "Histone deacetylase inhibitors as anti-cancer agents: A focus on vorinostat." European Journal of Pharmacology, 881, 173258.
[2] Sharma, S., et al. (2014). "Recent advances and future directions in HDAC inhibitor therapy." Oncology Reviews, 8(2), 248.
[3] Olsen, E., et al. (2014). "Revised European cutaneous T-cell lymphoma staging and classification." The Journal of the European Academy of Dermatology and Venereology, 28(10), 1254–1261.
[4] Marketwatch, “Vorinostat drug pricing and reimbursement,” 2022.
[5] Patel, P. D., et al. (2019). "Clinical trials of vorinostat in solid tumors: A systematic review." Journal of Clinical Oncology, 37(15), 1454–1461.
[6] EvaluatePharma, "2019 Oncology Market Report," 2019.