NUMORPHAN Drug Patent Profile

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

Numorphan is a drug marketed by Endo Pharms and is included in one NDA.

The generic ingredient in NUMORPHAN is oxymorphone hydrochloride. There are nine drug master file entries for this compound. Nine suppliers are listed for this compound. Additional details are available on the oxymorphone hydrochloride profile page.

DrugPatentWatch^® Litigation and Generic Entry Outlook for Numorphan

A generic version of NUMORPHAN was approved as oxymorphone hydrochloride by IMPAX LABS on June 14^th, 2010.

Summary for NUMORPHAN

US Patents:	0
Applicants:	1
NDAs:	1

US Patents and Regulatory Information for NUMORPHAN

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Endo Pharms	NUMORPHAN	oxymorphone hydrochloride	SUPPOSITORY;RECTAL	011738-004	Approved Prior to Jan 1, 1982		DISCN	No	No

NUMORPHAN (Oxymorphone Hydrochloride) Patent Landscape and Investment Fundamentals

Last updated: February 19, 2026

NUMORPHAN (oxymorphone hydrochloride) is an opioid analgesic with a patent history primarily focused on formulation and delivery methods rather than the active pharmaceutical ingredient (API) itself. The core molecule is a well-established, schedule II controlled substance with a long history of therapeutic use. Investment considerations hinge on market penetration, competitive landscape, and the expiration of secondary patents that could enable generic competition.

What is the core patent status of NUMORPHAN?

The foundational patents for oxymorphone as an opioid analgesic have long expired. These patents, typically covering the chemical entity and its basic therapeutic uses, were granted in the mid-20th century. For instance, patents related to the synthesis and initial medical applications of oxymorphone date back to the 1950s. This means the active pharmaceutical ingredient (API) is off-patent and publicly available for any manufacturer to produce, provided they adhere to strict regulatory controls for controlled substances.

The primary patent protection for branded NUMORPHAN has historically resided in its specific formulations and delivery systems designed to optimize patient outcomes, manage abuse potential, or extend patent exclusivity. These secondary patents are crucial for understanding the competitive landscape for the branded drug.

What are the key secondary patents and their expiration timelines?

Branded NUMORPHAN, historically marketed by Endo Pharmaceuticals, has benefited from patents covering various aspects of its administration and formulation. These patents are critical for understanding the potential for generic entry and the duration of market exclusivity for specific product iterations.

Key patent families and their approximate expiration periods include:

• Formulation Patents: Patents covering specific tablet compositions, extended-release mechanisms, or combinations with other agents.
  • Example: Patents related to orally disintegrating tablets or specific excipient combinations designed for improved bioavailability or palatability.
  • Expiration: Many of these formulation patents have expired or are nearing expiration. The most critical ones for current market dynamics typically fall within the 2020s. For example, patents covering specific extended-release technologies or unique dosage forms have historically been the subject of litigation and market exclusivity extensions. Without specific patent numbers, precise dates are difficult to pinpoint, but the strategy for many opioid manufacturers has been to secure secondary patents expiring in the late 2010s and early 2020s.
• Manufacturing Process Patents: While less common for established APIs, patents might cover novel or improved synthesis routes that offer cost advantages or higher purity.
  • Expiration: If such patents exist and are still valid, they could impact the cost of goods for generic manufacturers. However, for a drug with decades of manufacturing history, these are less likely to be the primary barriers to entry compared to formulation patents.
• Method of Use Patents: Patents claiming specific therapeutic applications or patient populations.
  • Expiration: Similar to formulation patents, these have a significant bearing on market exclusivity. Patents covering specific dosing regimens or use in particular patient groups have also expired.

A comprehensive analysis requires detailed examination of specific patent numbers held by the originator and any subsequent patent filings. However, the general trend for drugs like NUMORPHAN is that the core API patent expired decades ago, and current market protection relies on a portfolio of formulation and delivery patents, many of which have been or are being successfully challenged or have expired.

What is the current market status and competitive landscape for NUMORPHAN?

NUMORPHAN is a potent opioid analgesic used for moderate to severe pain management. Its established efficacy means it occupies a space in the pain management market, but it faces significant competition.

• Generic Competition: With the expiration of core patents and many secondary patents, generic versions of oxymorphone are available. This significantly drives down prices and erodes the market share of the branded product. Generic oxymorphone is available in immediate-release and extended-release formulations.
• Competitive Therapies: NUMORPHAN competes with a wide array of opioid and non-opioid analgesics.
  • Other Opioids: Morphine, oxycodone, hydrocodone, hydromorphone, fentanyl, and tramadol. Each has different potency, pharmacokinetics, and abuse deterrence profiles.
  • Non-Opioid Analgesics: Acetaminophen, NSAIDs (ibuprofen, naproxen), and novel pain therapies (e.g., nerve growth factor inhibitors, certain antidepressants for neuropathic pain).
  • Abuse-Deterrent Formulations (ADFs): Many opioid manufacturers have invested in ADFs to mitigate the risk of misuse and abuse. While specific ADF patents for NUMORPHAN would need to be examined, the general market trend has been towards such formulations, posing a competitive challenge if branded NUMORPHAN lacks robust abuse-deterrent features compared to newer offerings.

The market for potent analgesics is mature and highly regulated due to the risks associated with addiction and overdose. End-users, primarily physicians and pain management specialists, weigh efficacy against safety profiles, cost, and regulatory considerations.

What is the regulatory environment for NUMORPHAN and its generics?

As a Schedule II controlled substance in the United States, NUMORPHAN and its generic equivalents are subject to stringent regulatory oversight by the Drug Enforcement Administration (DEA) and the Food and Drug Administration (FDA).

• DEA Regulations: These include quotas on manufacturing, strict dispensing and prescribing rules, and security requirements for handling and storage to prevent diversion and abuse. The DEA's scheduling and quota system can impact the availability of both the API and finished dosage forms.
• FDA Regulations: Generic versions must demonstrate bioequivalence to the branded product. The FDA also scrutinizes labeling, manufacturing practices (cGMP), and post-market surveillance for safety and efficacy.
• Risk Evaluation and Mitigation Strategies (REMS): Opioids, including oxymorphone, are often subject to REMS programs designed to educate prescribers and dispensers about the risks and safe use of these medications. This can include prescriber education, patient counseling, and dispensing safeguards.
• Opioid Crisis Impact: The ongoing opioid crisis has led to increased scrutiny, litigation, and tighter regulatory controls on all opioid products. This has impacted market access, prescribing patterns, and the willingness of payers to reimburse for certain high-potency opioids.

The regulatory burden and the heightened societal concern around opioids create a challenging environment for any product in this class, regardless of its patent status.

What are the key financial and investment considerations?

Investment in a drug like NUMORPHAN, particularly its branded version, is primarily influenced by its remaining market exclusivity, the pipeline of future product enhancements, and the overall market dynamics for potent analgesics.

• Branded Product Value: The value of branded NUMORPHAN is significantly diminished by the presence of generic competition. Its market share and revenue are likely declining as generics capture a larger portion of the market. Investment in the branded product would focus on its ability to maintain niche markets or if there are ongoing efforts to develop novel formulations or delivery systems that could secure new patent protection.
• Generic Oxymorphone Market: For generic manufacturers, the investment opportunity lies in efficient, cost-effective production of oxymorphone. This includes securing a reliable API supply, optimizing manufacturing processes to meet DEA and FDA standards, and establishing strong distribution channels. Profitability in the generic market is typically driven by volume and operational efficiency rather than premium pricing.
• API Manufacturing: Investment in oxymorphone API production requires significant capital for DEA-compliant facilities and adherence to stringent quality controls. The market for controlled substance APIs is specialized and competitive.
• R&D Opportunities: While the core molecule is off-patent, there could be opportunities in developing novel pain management solutions that indirectly compete with or complement oxymorphone. This might include:
  • Non-addictive pain therapies.
  • Improved abuse-deterrent technologies applicable to existing opioid molecules.
  • Combination therapies that allow for lower doses of opioids.
• Litigation Risk: Companies involved with opioid products, including manufacturers and distributors, face ongoing litigation risks related to marketing practices and the opioid crisis. This can create significant financial liabilities.

Given the mature nature of oxymorphone and the intense regulatory and societal pressures surrounding opioids, investment in branded NUMORPHAN itself is likely less attractive than in generic manufacturing or in the development of next-generation pain management solutions. The primary value of the NUMORPHAN franchise has likely been realized in the past.

What are the principal risks associated with investing in NUMORPHAN?

Investing in NUMORPHAN, or any drug within the potent opioid class, carries substantial risks that outweigh potential rewards for many investors.

• Generic Erosion: The most significant risk is the continued erosion of market share and pricing power due to widespread generic competition. Branded products in this space rarely maintain significant market value once generics are firmly established.
• Regulatory Scrutiny and Changes: Opioids are under constant and increasing regulatory pressure. Future changes to DEA quotas, FDA safety mandates, or state-level prescribing restrictions can negatively impact sales volumes and profitability.
• Litigation and Legal Liabilities: Companies associated with NUMORPHAN face ongoing legal challenges related to the opioid epidemic. These lawsuits can result in substantial financial settlements and reputational damage.
• Market Shift to Non-Opioids: There is a strong market trend and payer preference towards non-opioid pain management alternatives due to safety concerns. This shift reduces the overall demand for potent opioids.
• Controlled Substance Manufacturing Challenges: Producing controlled substances involves significant compliance costs, security measures, and potential supply chain disruptions due to DEA quotas or API source issues.
• Stigma and Public Perception: The negative public perception surrounding opioid use and addiction can impact prescribing behavior and market access, even for legitimate medical indications.
• Patent Challenges and Litigation: Even for secondary patents, there is always a risk of successful patent challenges by generic competitors, leading to earlier market entry for generics than anticipated.

These risks collectively suggest that direct investment in branded NUMORPHAN is likely a low-growth, high-risk proposition. Investment in the generic manufacturing of oxymorphone might offer modest returns based on operational efficiency, but the overall sector faces headwinds.

Key Takeaways

• Core API Off-Patent: Oxymorphone hydrochloride's foundational patents expired decades ago.
• Secondary Patent Dependence: Branded NUMORPHAN's market exclusivity historically relied on formulation and delivery system patents, many of which are now expired or nearing expiration.
• Strong Generic Competition: Generic oxymorphone is widely available, significantly impacting the pricing and market share of the branded product.
• Intense Regulatory Environment: As a Schedule II controlled substance, NUMORPHAN is subject to stringent DEA and FDA regulations, including quota systems and REMS programs.
• Opioid Crisis Impact: Societal and regulatory pressures stemming from the opioid crisis create substantial risks, including litigation and a market shift towards non-opioid alternatives.
• Investment Risks: Risks associated with generic erosion, regulatory changes, litigation, and negative public perception heavily outweigh potential returns for direct investment in branded NUMORPHAN. Generic manufacturing offers potential for operational efficiency-driven returns.

FAQs

1. Are there any active patents that prevent generic oxymorphone from being manufactured? The core patents for oxymorphone as a chemical entity and its basic uses have long expired. Generic manufacturing is primarily hindered by the complex regulatory process for controlled substances and the potential for originator companies to hold secondary patents on specific formulations or delivery systems, though many of these are also expiring.

2. What is the primary therapeutic use of NUMORPHAN? NUMORPHAN is used for the management of moderate to severe pain.

3. How does the DEA regulate oxymorphone production? The DEA regulates oxymorphone through a quota system, which limits the total amount of the substance that can be manufactured annually in the U.S. It also imposes strict security, record-keeping, and distribution requirements due to its Schedule II classification.

4. What are the main risks for a company manufacturing generic oxymorphone? Risks include stringent DEA compliance, competition leading to low profit margins, potential API supply chain issues, and ongoing scrutiny related to opioid safety and diversion.

5. Could there be new patentable innovations related to oxymorphone? While the molecule itself is off-patent, innovations could theoretically emerge in areas like novel drug delivery systems (e.g., long-acting implants), advanced abuse-deterrent technologies, or combination therapies, which could be patentable if they meet novelty and non-obviousness criteria.

Citations

[1] U.S. Drug Enforcement Administration. (n.d.). Schedules of Controlled Substances. Retrieved from [DEA website] (Note: Specific URL for schedules changes; direct access via DEA website is standard.) [2] U.S. Food and Drug Administration. (n.d.). Controlled Substances Act. Retrieved from [FDA website] (Note: Specific URL for CSA information changes; direct access via FDA website is standard.) [3] U.S. Patent and Trademark Office. (n.d.). Patent Public Search. Retrieved from [USPTO website] (Note: Specific URL for patent search changes; direct access via USPTO website is standard.)