CLINICAL TRIALS PROFILE FOR ZANTAC

505(b)(2) Clinical Trials for ZANTAC

This table shows clinical trials for potential 505(b)(2) applications. See the next table for all clinical trials

Trial Type	Trial ID	Title	Status	Sponsor	Phase	Start Date	Summary
OTC	NCT00443963 ↗	Total Antioxidant Effects of Esomeprazole in Dyspeptic Patients Receiving Non-steroidal Anti-inflammatory Drugs	Withdrawn	AstraZeneca	Phase 4	2006-12-01	The principal investigator hypothesizes that participants receiving NSAID drugs with dyspeptic symptoms have increased production of gastric levels of free radicals. The primary objective of the study is to determine if Esomeprazole Magnesium increases gastric total antioxidant capacity and decreases gastric free radical production in humans. Participants (age 18 years and older) with no history of upper GI bleeding who are receiving non-steroidal anti-inflammatory drugs and then develop dyspepsia will be recruited from our primary care clinic in Washington, DC. All eligible participants will undergo biopsies of antrum and corpus. The participants will be randomized to receive either Zantac OTC or Nexium for 15 days. On day 15, all participants will undergo repeat upper endoscopy to obtain biopsies of antrum and corpus. Tissue samples will then be extracted to determine total antioxidant capacity and lipid peroxide levels (as an indirect marker of free radical production).
OTC	NCT00443963 ↗	Total Antioxidant Effects of Esomeprazole in Dyspeptic Patients Receiving Non-steroidal Anti-inflammatory Drugs	Withdrawn	Medstar Health Research Institute	Phase 4	2006-12-01	The principal investigator hypothesizes that participants receiving NSAID drugs with dyspeptic symptoms have increased production of gastric levels of free radicals. The primary objective of the study is to determine if Esomeprazole Magnesium increases gastric total antioxidant capacity and decreases gastric free radical production in humans. Participants (age 18 years and older) with no history of upper GI bleeding who are receiving non-steroidal anti-inflammatory drugs and then develop dyspepsia will be recruited from our primary care clinic in Washington, DC. All eligible participants will undergo biopsies of antrum and corpus. The participants will be randomized to receive either Zantac OTC or Nexium for 15 days. On day 15, all participants will undergo repeat upper endoscopy to obtain biopsies of antrum and corpus. Tissue samples will then be extracted to determine total antioxidant capacity and lipid peroxide levels (as an indirect marker of free radical production).
OTC	NCT03145012 ↗	Histamine Receptor 2 Antagonists as Enhancers of Anti-Tumour Immunity	Unknown status	Dalhousie University	Phase 4	2018-05-01	The immune response against tumors can be highly effective in preventing tumor development, growth and metastasis under certain circumstances. However, tumor associated immune suppression can profoundly limit the impact of natural tumor immunity and also reduce the effectiveness of tumor immunotherapy strategies. A major component of tumor associated immune suppression is mediated by myeloid cells, especially the monocytic subset of myeloid derived suppressor cells (MDSC). In recent studies that were conducted through a CCSRI Innovation grant, the investigators discovered that oral treatment of mice with the commonly used histamine receptor 2 (H2) antagonists ranitidine or famotidine inhibits both primary breast tumor development and metastasis, in three distinct mouse tumor models and reduces the numbers of monocytic MDSC. These findings have enormous potential to aid in effective cancer immunotherapy and may have immediate implications for cancer patients. The objective of this investigation is to determine whether treatment with the H2 receptor antagonist ranitidine alters immune suppression, through modulation of immune cell populations. The investigators will examine peripheral blood monocyte, neutrophil and NK cell numbers, subsets and activation status from healthy volunteers treated for 6 weeks with daily oral ranitidine. Ranitidine is widely available and used over the counter in Canada. These drugs are widely recognized as safe, well tolerated and have very few side effects. It has been suggested that among the general population, over 10% of those over the age of 65 take such medications on a regular basis for relief against gastrointestinal discomfort. The outcome of pre-clinical studies in mice warrant further investigation into transferability to humans. If the outcome of the current proposal proves to be viable, then these drugs could provide a safe method to reduce tumor associated immunosuppression with broad implications, both for current cancer patients and for those at high risk of developing cancer. Further to this, the outcome of our proposal may provide a new strategy for improving the effectiveness of T-cell mediated immunotherapy.
OTC	NCT03145012 ↗	Histamine Receptor 2 Antagonists as Enhancers of Anti-Tumour Immunity	Unknown status	Nova Scotia Health Authority	Phase 4	2018-05-01	The immune response against tumors can be highly effective in preventing tumor development, growth and metastasis under certain circumstances. However, tumor associated immune suppression can profoundly limit the impact of natural tumor immunity and also reduce the effectiveness of tumor immunotherapy strategies. A major component of tumor associated immune suppression is mediated by myeloid cells, especially the monocytic subset of myeloid derived suppressor cells (MDSC). In recent studies that were conducted through a CCSRI Innovation grant, the investigators discovered that oral treatment of mice with the commonly used histamine receptor 2 (H2) antagonists ranitidine or famotidine inhibits both primary breast tumor development and metastasis, in three distinct mouse tumor models and reduces the numbers of monocytic MDSC. These findings have enormous potential to aid in effective cancer immunotherapy and may have immediate implications for cancer patients. The objective of this investigation is to determine whether treatment with the H2 receptor antagonist ranitidine alters immune suppression, through modulation of immune cell populations. The investigators will examine peripheral blood monocyte, neutrophil and NK cell numbers, subsets and activation status from healthy volunteers treated for 6 weeks with daily oral ranitidine. Ranitidine is widely available and used over the counter in Canada. These drugs are widely recognized as safe, well tolerated and have very few side effects. It has been suggested that among the general population, over 10% of those over the age of 65 take such medications on a regular basis for relief against gastrointestinal discomfort. The outcome of pre-clinical studies in mice warrant further investigation into transferability to humans. If the outcome of the current proposal proves to be viable, then these drugs could provide a safe method to reduce tumor associated immunosuppression with broad implications, both for current cancer patients and for those at high risk of developing cancer. Further to this, the outcome of our proposal may provide a new strategy for improving the effectiveness of T-cell mediated immunotherapy.

All Clinical Trials for ZANTAC

Trial ID	Title	Status	Sponsor	Phase	Start Date	Summary
NCT00030992 ↗	BMS 247550 to Treat Kidney Cancer	Completed	National Cancer Institute (NCI)	Phase 2	2002-02-01	This study will examine whether the experimental drug BMS 247550 (Ixabepilone) is an effective treatment for kidney cancer. BMS 247550 belongs to a class of drugs called epothilones that interfere with the ability of cancer cells to divide. In the way they kill cells, they are very similar to a class of compounds known as the taxanes, which include the drug Taxol. Other characteristics of the epothilones, however, enable them to work in cells that are resistant to Taxol. Patients 18 years of age or older with kidney cancer that has not spread to the central nervous system (unless the brain tumor has remained stable for at least six months after surgical or radiation treatment) may be eligible for this study. Pregnant or nursing women may not participate. Candidates are screened with various tests that may include blood and urine tests, electrocardiogram (EKG), and chest x-ray. Computerized tomography (CT) scans or X-rays, and possibly nuclear medicine studies may be done to determine the extent of disease. Participants receive BMS 247550 by a 1-hour infusion into a vein for 5 consecutive days (days 1, 2, 3, 4 and 5) of each 21-day treatment cycle. Patients must stay in the National Institutes of Health (NIH) area near Bethesda, Maryland, for 7 to 8 days during the first treatment cycle and for the 5 days of treatment in subsequent cycles. The total number of cycles will vary among patients, depending on their individual clinical situation. The drug dose may be increased gradually in subsequent cycles in patients who can tolerate such increases. In addition, participants undergo the following tests and procedures: - Periodic physical examinations and frequent blood tests - X-ray and other imaging studies to determine if the tumor is responding to the treatment. - Tumor biopsies to confirm the diagnosis or spread of tumor and to examine the reaction of certain proteins in cancer cells to BMS 247550. Two biopsies will be done. For this procedure, a small piece of tumor tissue is withdrawn through a needle under local anesthetic. Treatment will be stopped in patients whose tumor grows while receiving BMS 247550. Patients whose tumor disappears completely will be followed at NIH periodically for examinations and tests. Patients whose disease does not completely resolve or whose disease recurs may be advised of other appropriate research protocols at NIH or, if none are available, will be returned to the care of their local doctor.
NCT00223691 ↗	Treatment of Orthostatic Hypotension in Autonomic Failure	Completed	Vanderbilt University	Phase 1	2002-03-01	The autonomic nervous system serves multiple regulatory functions in the body, including the regulation of blood pressure and heart rate, gut motility, sweating and sexual function. There are several diseases characterized by abnormal function of the autonomic nervous system. Medications can also alter autonomic function. Impairment of the autonomic nervous system by diseases or drugs may lead to several symptoms, including blood pressure problems (e.g., high blood pressure lying down and low blood pressure on standing), sweating abnormalities, constipation or diarrhea and sexual dysfunction. Because treatment options for these patients are limited. We propose to study patients autonomic failure and low blood pressure upon standing and determine the cause of their disease by history and examination and their response to autonomic testing which have already been standardized in our laboratory. Based on their possible cause, we will tests different medications that may alleviate their symptoms.
NCT00223691 ↗	Treatment of Orthostatic Hypotension in Autonomic Failure	Completed	Vanderbilt University Medical Center	Phase 1	2002-03-01	The autonomic nervous system serves multiple regulatory functions in the body, including the regulation of blood pressure and heart rate, gut motility, sweating and sexual function. There are several diseases characterized by abnormal function of the autonomic nervous system. Medications can also alter autonomic function. Impairment of the autonomic nervous system by diseases or drugs may lead to several symptoms, including blood pressure problems (e.g., high blood pressure lying down and low blood pressure on standing), sweating abnormalities, constipation or diarrhea and sexual dysfunction. Because treatment options for these patients are limited. We propose to study patients autonomic failure and low blood pressure upon standing and determine the cause of their disease by history and examination and their response to autonomic testing which have already been standardized in our laboratory. Based on their possible cause, we will tests different medications that may alleviate their symptoms.
NCT00233935 ↗	Defined Green Tea Catechin Extract in Preventing Esophageal Cancer in Patients With Barrett's Esophagus	Completed	National Cancer Institute (NCI)	Phase 1	2005-11-01	The goal of this clinical research study is to test the safety of defined green tea catechin extract at different dose levels. Researchers also want to find out what effects, good and bad, it may have on individual and their risk for esophagus cancer. Esophagus cancer is an increased risk associated with Barrett's esophagus. Chemoprevention is the use of certain drugs to keep cancer from forming, growing, or coming back. The use of defined green tea catechin extract may prevent esophageal cancer.

Clinical Trial Conditions for ZANTAC

Condition Name

Condition Name for ZANTAC
Intervention	Trials
Healthy	2
NSAID Associated Gastric Ulcers	2
Orthostatic Hypotension	1
Autonomic Failure	1

Condition MeSH

Condition MeSH for ZANTAC
Intervention	Trials
Ulcer	3
Stomach Ulcer	2
Hypotension	2
Job Syndrome	1

Clinical Trial Locations for ZANTAC

Trials by Country

Trials by Country for ZANTAC
Location	Trials
United States	12
Canada	2
Pakistan	2
United Kingdom	1
Egypt	1

Trials by US State

Trials by US State for ZANTAC
Location	Trials
Maryland	3
Texas	2
Tennessee	1
Wisconsin	1
Utah	1

Clinical Trial Progress for ZANTAC

Clinical Trial Phase

Clinical Trial Phase for ZANTAC
Clinical Trial Phase	Trials
Phase 4	5
Phase 3	3
Phase 2	6

Clinical Trial Status

Clinical Trial Status for ZANTAC
Clinical Trial Phase	Trials
Completed	13
Withdrawn	4
Terminated	2

Clinical Trial Sponsors for ZANTAC

Sponsor Name

Sponsor Name for ZANTAC
Sponsor	Trials
National Cancer Institute (NCI)	3
AstraZeneca	3
Benazir Bhutto Hospital, Rawalpindi	2

Sponsor Type

Sponsor Type for ZANTAC
Sponsor	Trials
Other	18
Industry	7
NIH	4

Last updated: July 28, 2026

Zantac (ranitidine) clinical trials update, market analysis and exclusivity timelines: what the ranitidine IP, FDA status, and generic/biosimilar pathway look like

Zantac is ranitidine, an H2-receptor antagonist. Commercially, ranitidine’s market has been structurally impaired by global safety actions linked to NDMA contamination. On the IP and regulatory side, there is no active, FDA-protected exclusivity story that would support new clinical development replacing the withdrawn brand. The practical path for competitors is generic continuation and switching, not new approvals built on brand-level exclusivity.

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Why was Zantac withdrawn and how did the NDMA contamination action affect market access?

Core outcome: Ranitidine was removed from sale in multiple jurisdictions after NDMA (N-nitrosodimethylamine) risks were identified. In the US, FDA requested withdrawal and stopped approvals.

What did regulators conclude about ranitidine’s NDMA risk?

• FDA communications in 2019–2020 identified NDMA contamination concerns for ranitidine across products and manufacturing lots, including products stored at higher temperatures.
• FDA’s regulatory action shifted ranitidine away from routine use and toward withdrawal/limits rather than continued marketing.

When did Zantac lose commercial viability?

• The primary market impact is post-2019. Even where some supply reappeared in limited ways in certain markets, brand-level momentum collapsed.

Does withdrawal end patent or exclusivity?

• No. Withdrawal ends or curtails marketing, but it does not erase existing patent estates. It does reduce the economic value of remaining patents because the branded sales base is impaired.

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What is the Orange Book status of Zantac (ranitidine) in the US?

Fast answer: Zantac is not protected by a continuing brand exclusivity moat that would prevent generic availability. The active competitive reality for ranitidine is generic substitution and historical, non-brand IP that already expired for key composition and method areas.

What this means for investors and litigators

• For a drug with broad generic coverage historically, the question is less “can generics enter” and more “how far NDMA actions and supply constraints affect ongoing dispensing.”

Orange Book and exclusivity logic for older small molecules

• For established small molecules, Orange Book protections tend to be composition, formulation, and use patents that generally expire decades after filing.
• If NDMA actions eliminated brand marketing, generic entries continue in the background where products meet current safety expectations.

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When does ranitidine exclusivity end and what patent expirations typically govern the US market?

Fast answer: Zantac is an older product whose key exclusivities and core patents are expected to have expired by the time NDMA actions arrived. The operative timeline today is regulatory, not exclusivity.

How to think about exclusivity for older H2 antagonists

• Composition patents generally control the original active ingredient and are older than the 2019–2020 safety actions.
• Formulation/combination and polymorph-related patents (if any remained) would have expired or be close, given ranitidine’s introduction era.

Patent term mechanics that would have mattered

• For filed in earlier decades, even with patent term adjustments, the term generally ends well before the NDMA withdrawal cycle.

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What clinical trials exist for ranitidine today, and did any NDMA-related changes trigger trial pauses?

Fast answer: The commercial and regulatory focus shifted away from ranitidine as an active therapy class rather than driving new pivotal trials for approval. Clinical development for “new ranitidine indications” largely did not translate into a major replacement product portfolio during the NDMA withdrawal period.

Trial landscape characteristics after 2019

• Ongoing trials, if any, faced recruitment and regulatory scrutiny.
• Sponsors shifted toward alternative acid-suppression agents and broader GI projects rather than re-investing in ranitidine approval pathways.

What counts as a “clinical trials update” for a withdrawn brand

• The key update for business decisions is whether any active late-stage studies exist that could lead to a new NDA, 505(b)(2), or label update that overcomes NDMA risk. For Zantac, that did not materialize as a sustained late-stage redevelopment narrative.

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Which companies marketed Zantac/ranitidine and how did NDMA actions shift competitive supply?

Fast answer: Original brand holders and major generic manufacturers dominated ranitidine supply before NDMA actions. Post-withdrawal, supply patterns shifted to whichever manufacturers could meet tighter contamination expectations and remain in the channel.

Competitive effects observable in the market

• Brand share collapsed after 2019.
• Generic substitution persisted where products could remain compliant.
• In markets outside the US, regulatory decisions varied, but global pressure moved the category down.

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What is the current market for ranitidine (Zantac) and how does it compare with alternatives?

Fast answer: The H2 antagonist market has shifted toward proton pump inhibitors (PPIs) and remaining H2 options that did not face the same NDMA event. Ranitidine’s addressable market contracted.

Substitution dynamics

• PPIs captured a large portion of the ranitidine consumer base.
• Continued use depends on patient tolerance, cost, and guideline positioning, but ranitidine’s category role shrank.

Pricing and volume impacts

• Post-withdrawal, volume fell sharply. Even where generics persisted, price pressure and safety-driven restrictions reduced revenue upside.

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How strong is the patent estate for ranitidine today, and does it affect generic competition?

Fast answer: Ranitidine’s patent estate is likely not a meaningful barrier for a drug that has been generically available for years and then faced safety withdrawal actions.

Likely patent estate components (historical)

• Composition of matter: ranitidine API and related salts.
• Method-of-use: acid-related therapeutic indications and dosing regimens.
• Formulation: extended release or dosage form-specific claims (where present).

Business conclusion

• For competitive entry, NDMA compliance and regulatory acceptability are more binding than late-expiring ranitidine patents.

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What patent litigation affected Zantac/ranitidine and did it delay generic entry?

Fast answer: For an older molecule with broad generic adoption, litigation is unlikely to be the gating factor that explains ranitidine’s present market position. The dominant gating factor is regulatory safety action.

How to interpret “litigation risk” for ranitidine now

• If core patents expired years ago, litigation no longer affects launch timing.
• If any remaining formulation/use patents existed late, the regulatory withdrawal likely overshadowed the commercial incentive to enforce them.

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What generic entry risks exist for ranitidine in the US now?

Fast answer: The generic launch risk is primarily regulatory compliance with contamination controls, not Paragraph IV timing against an active brand exclusivity barrier.

What would still create launch barriers

• NDMA control processes and stability requirements.
• FDA regulatory status of specific manufacturers or ANDA holders (product-by-product, not drug-by-drug).

Manufacturing/IP barriers

• Even when patents are expired, manufacturers still need suitable validated processes and impurity controls consistent with FDA expectations.

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What formulations are protected for ranitidine and do extended-release versions change IP risk?

Fast answer: Formulation-specific IP can exist for dosage form variants, but for ranitidine, the practical barrier is regulatory and safety compliance rather than formulation patent exclusivity.

Extended-release vs immediate-release

• If extended-release formulations were developed under later filings, they could have longer tail protection than the original API.
• For Zantac’s current status, category replacement and withdrawal effects largely decide commercial viability.

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What biosimilar risk applies to Zantac?

Fast answer: None. Zantac is a small molecule (ranitidine), not a biologic. Biosimilar frameworks do not apply.

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How does ranitidine compare with cimetidine, famotidine, and other H2 blockers from an IP and regulatory perspective?

Fast answer: The key difference is safety history. Ranitidine’s NDMA event drove withdrawal, while other H2 blockers did not face the same globally synchronized contamination action.

IP and competition structure across H2 blockers

• All are small molecules with older composition patents that generally expired long ago.
• Competitive separation is regulatory acceptability, impurity control, and current labeling/guideline use.

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Market projection for ranitidine (Zantac): baseline outlook, upside/downside drivers, and scenario ranges

Baseline: Low ongoing demand relative to pre-2019 periods, with continued reliance on remaining compliant supply. The market is structurally smaller and price-sensitive.

Key drivers

• Regulatory compliance and impurity control outcomes for individual ANDA products
• Substitution to PPIs and shifting GI guideline practice
• International policy divergence for H2 blockers
• Patient and provider safety-driven prescribing patterns after NDMA actions

Downside risks

• Further NDMA or nitrosamine findings tied to storage/conditions or additional lots
• Tighter FDA expectations that reduce eligible supply

Upside risks

• A stabilizing compliance regime that preserves limited supply and maintains niche use
• Label updates or controlled use frameworks that keep products on formularies

Scenario framing (investment-grade logic)

• In practice, projections should be built on (1) compliant manufacturer availability and (2) category shift toward alternatives, not on future brand re-entry. For Zantac, the “recovery” narrative is constrained by the safety event and substitution already in motion.

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Key Takeaways

• Zantac’s commercial arc ended in the US and other markets primarily due to NDMA-related safety withdrawal actions, not due to patent expiration timing.
• Remaining ranitidine competition is driven by generic supply compliance, not Paragraph IV or exclusivity barriers.
• IP estate strength is not the main determinant of current market access; regulatory NDMA controls and product acceptability are.
• Market upside is limited by substitution to PPIs and persistent safety-driven category contraction.

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FAQs

1. Is ranitidine still FDA-approved in the US?
2. Can generic ranitidine be marketed despite Zantac withdrawal?
3. What NDMA control requirements affect ranitidine ANDA approvals?
4. Do method-of-use patents still matter for ranitidine generic competition?
5. How do guidelines currently position H2 blockers versus PPIs after the ranitidine NDMA event?

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References

1. U.S. Food and Drug Administration. (2019). FDA requests removal of all ranitidine products (Zantac) from the market. FDA Drug Safety Communications.
2. U.S. Food and Drug Administration. (2020). NDMA in ranitidine: updates on FDA testing and regulatory actions. FDA Drug Safety Communications.
3. European Medicines Agency. (2020). Ranitidine medicines: referral and measures. EMA press resources and regulatory updates.