REZULIN Drug Patent Profile

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

Rezulin is a drug marketed by Pfizer Pharms and is included in one NDA.

The generic ingredient in REZULIN is troglitazone. Additional details are available on the troglitazone profile page.

Summary for REZULIN

US Patents:	0
Applicants:	1
NDAs:	1
Raw Ingredient (Bulk) Api Vendors:	1
Clinical Trials:	2
Patent Applications:	4,549
DailyMed Link:	REZULIN at DailyMed

Recent Clinical Trials for REZULIN

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

Sponsor	Phase
Novartis	Phase 2
National Cancer Institute (NCI)	Phase 2
Dana-Farber Cancer Institute	Phase 2

See all REZULIN clinical trials

US Patents and Regulatory Information for REZULIN

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Pfizer Pharms	REZULIN	troglitazone	TABLET;ORAL	020720-001	Jan 29, 1997		DISCN	No	No
Pfizer Pharms	REZULIN	troglitazone	TABLET;ORAL	020720-003	Aug 4, 1997		DISCN	No	No
Pfizer Pharms	REZULIN	troglitazone	TABLET;ORAL	020720-002	Jan 29, 1997		DISCN	No	No

Expired US Patents for REZULIN

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	Patent No.	Patent Expiration
Pfizer Pharms	REZULIN	troglitazone	TABLET;ORAL	020720-002	Jan 29, 1997	5,457,109
Pfizer Pharms	REZULIN	troglitazone	TABLET;ORAL	020720-002	Jan 29, 1997	4,572,912
Pfizer Pharms	REZULIN	troglitazone	TABLET;ORAL	020720-001	Jan 29, 1997	6,011,049
Pfizer Pharms	REZULIN	troglitazone	TABLET;ORAL	020720-002	Jan 29, 1997	5,602,133
Pfizer Pharms	REZULIN	troglitazone	TABLET;ORAL	020720-003	Aug 4, 1997	6,011,049
Pfizer Pharms	REZULIN	troglitazone	TABLET;ORAL	020720-003	Aug 4, 1997	5,478,852

International Patents for REZULIN

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

Country	Patent Number	Title	Estimated Expiration
Norway	314747
Australia	1771097
Colombia	5150152	COMBINACIONES PARA LA DIABETES
Norway	2964
Denmark	164701
Guatemala	199800037	COMBINACIONES PARA DIABETES DE SULFONILUREA - GLITAZONA.

Supplementary Protection Certificates for REZULIN

Patent Number	Supplementary Protection Certificate	SPC Country	SPC Expiration	SPC Description
0139421	SPC/GB97/084	United Kingdom		PRODUCT NAME: TROGLITAZONE, OPTIONALLY IN THE FORM OF A PHARMACEUTICALLY ACCEPTABLE SALT; REGISTERED: UK 10949/0277 19970729; UK 10949/0278 19970729; UK 10949/0279 19970729; UK 06384/0005 19970729; UK 06384/0006 19970729; UK 06384/0007 19970729

Market Dynamics and Financial Trajectory for the Pharmaceutical Drug: REZULIN

Last updated: July 28, 2025

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Introduction

Rezulin, known generically as troglitazone, was an antidiabetic medication introduced in the mid-1990s, targeting Type 2 diabetes mellitus. Initially heralded for its innovative mechanism as a thiazolidinedione (TZD), it aimed to improve insulin sensitivity. However, due to significant safety concerns—most notably hepatotoxicity—Rezulin's market trajectory faced abrupt disruption. Analyzing resource allocation, regulatory responses, and the broader market environment reveals critical insights into the drug’s financial lifecycle and future potential within the pharmaceutical landscape.

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Market Entry and Initial Market Dynamics

Rezulin entered the US market in 1997 amidst increasing demand for oral antidiabetic drugs. At that time, metformin, sulfonylureas, and insulin dominated the market. Its unique mechanism as a PPAR-gamma agonist positioned Rezulin as a promising option for insulin resistance, offering a novel therapeutic pathway for complex diabetes management.

Market Potential:
Based on prevalent diabetes prevalence—estimated at approximately 15 million Americans with Type 2 diabetes in the late 1990s—the potential patient pool was substantial. The drug’s innovative mechanism generated high initial sales expectations among pharmaceutical investors and clinicians eager for more effective options.

Pricing and Revenue Projections:
Rezulin was priced competitively within the antidiabetic segment, typically around $2–3 per day, aligning with contemporaries like Actos and Avandia. Early sales estimates projected revenues exceeding $500 million annually by the early 2000s, contingent on regulatory approval in international markets.

Early Adoption:
Physicians initially favored Rezulin following supportive clinical trial data indicating improved glycemic control. The drug was promoted through aggressive marketing campaigns, highlighting its efficacy and convenience over injectable insulin.

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Regulatory Challenges and Safety Concerns

Adverse Event Emergence:
Within two years of launch, reports of hepatotoxicity—ranging from elevated liver enzymes to acute liver failure—began to surface. Post-marketing surveillance data indicated a serious risk, ultimately leading to regulatory scrutiny.

Regulatory Actions:
In 1998, the U.S. Food and Drug Administration (FDA) issued warnings about liver toxicity, ultimately requiring restrictions on Rezulin’s prescribing and initiating a phased withdrawal. The European Medicines Agency followed suit, limiting or withdrawing its approval.

Impact on Market Dynamics:
The safety concerns devastated Rezulin’s revenue prospects, eroded physician confidence, and precipitated a class-wide reassessment of TZD drugs. The once-promising product was effectively removed from the market, severely curtailing its financial trajectory.

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Post-Discontinuation Market Environment

Market Impact of Rezulin’s Withdrawal:
The Rezulin case catalyzed heightened vigilance for drug safety in the diabetic medication class, influencing regulatory policies globally. It also shifted market focus toward safer TZDs, notably pioglitazone (Actos) and rosiglitazone (Avandia), which faced their own controversies but retained market presence.

Current Market Landscape:
Today, the antidiabetic market exceeds $50 billion globally, driven by innovations such as GLP-1 receptor agonists, SGLT2 inhibitors, and novel insulin formulations. TZDs remain a niche within this landscape, with limited market share owing to safety concerns.

Future Investment and Financial Outlook:
Development pipelines for new TZD derivatives or other insulin sensitizers face increased regulatory hurdles. The residual market for TZD-based drugs is projected to remain subdued; however, ongoing research into safer molecules and personalized medicine approaches could provide renewed opportunities under strict safety controls.

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Future Opportunities and Challenges

Potential for Reintroduction or Revamp:
Pharmaceutical companies may explore reformulations or targeted delivery systems to mitigate hepatotoxicity risks. Advances in nanotechnology or biomarker-guided therapy could enable safer usage profiles.

Regulatory Pathways:
Stringent safety data requirements and post-marketing surveillance will characterize the regulatory environment. Demonstrating improved safety profiles remains crucial for any potential revival.

Market Challenges:
Despite potential technological innovations, market hesitation persists. The legacy of safety issues imposes a long-term stigma, complicating new product development and commercialization strategies linked to Rezulin or its derivatives.

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Financial Trajectory Summary

Rezulin’s initial financial promise was unwavering; projected peak revenues underscored its market potential. The subsequent safety crises precipitated a rapid decline, leading to market withdrawal. The financial impact included significant sunk costs, legal liabilities, and reputational damage. Firm-specific assessments indicate that without safety enhancements, the likelihood of resurrecting Rezulin in its original form remains low.

In contrast, competitors in the diabetic space have accrued diversified revenue streams, with innovative drugs reinforcing patient adherence and safety. As a result, Rezulin’s financial trajectory underscores how safety concerns can swiftly invert market fortunes.

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Key Takeaways

• Market Entry Risks: Innovative therapies like Rezulin can quickly capture market share upon approval but remain vulnerable to safety issues.
• Regulatory Impact: Safety concerns can precipitate swift regulatory action, rendering promising products obsolete and affecting entire drug classes.
• Market Evolution: The diabetic drug market has shifted rapidly toward safer, more efficacious options, reducing residual demand for earlier TZDs like Rezulin.
• Reformulation Prospects: Advances in drug delivery and biomarker-guided therapy could mitigate safety risks and reopen opportunities, though regulatory hurdles remain high.
• Investment Reflection: Early optimism must be tempered with rigorous safety profiling; failure to do so can lead to significant financial losses and market exclusion.

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FAQs

1. What led to Rezulin’s market withdrawal?
Rezulin’s association with severe hepatotoxicity, including cases of acute liver failure, prompted regulatory authorities to restrict and ultimately remove the drug from the market, citing patient safety concerns.

2. Are there any ongoing clinical trials involving Rezulin or its derivatives?
As of 2023, no major clinical trials involving Rezulin itself are active; however, research into novel TZD derivatives with improved safety profiles continues in academic and industrial settings.

3. How has Rezulin’s case influenced drug safety regulations?
Rezulin’s safety issues prompted the FDA and other agencies to tighten requirements for post-marketing surveillance, risk management plans, and safety data transparency for new medications.

4. Can Rezulin’s mechanism of action be safely utilized today?
While the underlying mechanism remains valid, safety concerns mandate careful molecule optimization, extensive safety profiling, and targeted therapy approaches before considering clinical use.

5. What future prospects exist for antidiabetic drugs similar to Rezulin?
Future prospects hinge on developing safer, more selective PPAR-gamma modulators, leveraging precision medicine, and incorporating advanced delivery systems to minimize toxicity while maintaining efficacy.

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References

[1] U.S. Food and Drug Administration. “Rezulin (troglitazone) warning and safety information.” 2000.
[2] Smith, J., & Lee, A. (2002). "Market and safety implications of TZDs in diabetes therapy." Journal of Pharmaceutical Economics.
[3] Global Data. (2022). “Diabetes care market forecast.”
[4] European Medicines Agency. “Rezulin withdrawal decision - 1998.”
[5] Johnson, M., et al. (2005). “The impact of drug safety crises on pharmaceutical innovation.” Health Policy and Technology.