Dolasetron mesylate - Generic Drug Details

What are the generic sources for dolasetron mesylate and what is the scope of patent protection?

Dolasetron mesylate is the generic ingredient in one branded drug marketed by Validus Pharms and is included in two NDAs. Additional information is available in the individual branded drug profile pages.

Summary for dolasetron mesylate

US Patents:	0
Tradenames:	1
Applicants:	1
NDAs:	2
Drug Master File Entries:	5
Raw Ingredient (Bulk) Api Vendors:	185
Clinical Trials:	4
What excipients (inactive ingredients) are in dolasetron mesylate?	dolasetron mesylate excipients list
DailyMed Link:	dolasetron mesylate at DailyMed

Recent Clinical Trials for dolasetron mesylate

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

Sponsor	Phase
Vanderbilt University	N/A
University of Washington	N/A
University of Southern California	N/A

See all dolasetron mesylate clinical trials

Anatomical Therapeutic Chemical (ATC) Classes for dolasetron mesylate

A04AA	Serotonin (5HT3) antagonists
A04A	ANTIEMETICS AND ANTINAUSEANTS
A04	ANTIEMETICS AND ANTINAUSEANTS
A	Alimentary tract and metabolism

US Patents and Regulatory Information for dolasetron mesylate

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Validus Pharms	ANZEMET	dolasetron mesylate	INJECTABLE;INJECTION	020624-001	Sep 11, 1997		DISCN	Yes	No
Validus Pharms	ANZEMET	dolasetron mesylate	TABLET;ORAL	020623-001	Sep 11, 1997		DISCN	Yes	No
Validus Pharms	ANZEMET	dolasetron mesylate	INJECTABLE;INJECTION	020624-003	Dec 11, 2001		DISCN	No	No

Expired US Patents for dolasetron mesylate

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	Patent No.	Patent Expiration
Validus Pharms	ANZEMET	dolasetron mesylate	INJECTABLE;INJECTION	020624-002	Sep 11, 1997
Validus Pharms	ANZEMET	dolasetron mesylate	TABLET;ORAL	020623-002	Sep 11, 1997
Validus Pharms	ANZEMET	dolasetron mesylate	INJECTABLE;INJECTION	020624-003	Dec 11, 2001

Dolasetron Mesylate Market Dynamics, Patent Status, and Financial Trajectory

Last updated: September 1, 2026

Dolasetron mesylate has largely exited the pharmaceutical market. The active ingredient, marketed primarily as Anzemet by Sanofi, lost commercial relevance after safety restrictions on intravenous use, broad generic competition from alternative 5-HT3 antagonists, and the introduction of longer-acting agents such as palonosetron. No material current revenue stream is publicly disclosed for dolasetron, and the product is listed as discontinued in major U.S. drug databases.[1][2]

What is the current market status of dolasetron mesylate?

Dolasetron is a selective serotonin 5-HT3 receptor antagonist used to prevent nausea and vomiting associated with chemotherapy and surgery. Its main branded product was Anzemet, supplied as tablets and an injectable formulation.

The U.S. commercial market has effectively collapsed:

Market factor	Current assessment
Branded product	Anzemet is discontinued in the United States
Active ingredient	Dolasetron mesylate
Primary historical holder	Sanofi, through Anzemet
U.S. injectable product	Commercially discontinued and subject to major safety restrictions
U.S. oral product	Discontinued in standard commercial databases
Generic competition	Historically available or approved, but limited current commercial presence
Main substitutes	Ondansetron, granisetron, palonosetron, and combination antiemetic regimens
Current revenue	No separately reported material revenue
Growth outlook	No credible growth platform without reformulation or a new clinical use

Dolasetron remains relevant as a historical antiemetic, but it is not a major current pharmaceutical-market asset.

When did dolasetron lose exclusivity?

Dolasetron lost meaningful commercial exclusivity years ago. Anzemet was first approved in the United States in the 1990s, and any original composition, formulation, or use patents would have expired no later than the mid-2010s under standard U.S. patent-term rules.

The product’s commercial decline was therefore driven by two overlapping factors:

1. Patent and regulatory exclusivity ended.
2. Safety and competitive disadvantages reduced prescribing demand.

The original product was approved by the FDA in 1997. The approval date placed the product well beyond the effective life of ordinary pre-URAA patent terms by the late 2000s and early 2010s.[3]

Dolasetron exclusivity timeline

Event	Approximate timing	Commercial effect
U.S. FDA approval of Anzemet tablets	1997	Established branded market
U.S. FDA approval of injectable Anzemet	1990s	Expanded hospital use
Generic competition and loss of practical exclusivity	Late 2000s to early 2010s	Reduced pricing power
FDA warning on injectable dolasetron	2010	Restricted chemotherapy-related use
Further decline in branded utilization	2010s	Shift to competing 5-HT3 agents
U.S. product discontinuation listings	2010s to 2020s	Effectively ended broad commercial availability

An exact current patent-expiration date for a commercially relevant dolasetron patent cannot be treated as the principal market issue. The product no longer has a meaningful branded exclusivity position.

What patents protect dolasetron mesylate?

The historical intellectual-property estate likely included patents covering the active compound, pharmaceutical formulations, and antiemetic uses. Those rights are no longer a material barrier to entry in the United States.

The relevant patent categories were:

• Dolasetron compound and salt forms
• Oral solid dosage formulations
• Injectable formulations
• Methods for preventing nausea and vomiting
• Use in chemotherapy-induced nausea and vomiting
• Use in postoperative nausea and vomiting

The FDA Orange Book remains the principal source for determining whether an approved U.S. drug has listed patents or exclusivity. The current commercial significance of any historic Anzemet listing is limited because the branded products are discontinued and the core patent term has expired.[4]

Are there active formulation patents for dolasetron?

No active, commercially important formulation patent position is evident from the product’s current market status. Formulation patents, if any remain in force in isolated jurisdictions, have not supported a meaningful U.S. commercial franchise.

Dolasetron had no durable delivery-system advantage. The product was available in conventional oral and injectable forms, while competing drugs offered comparable administration options and, in some cases, longer duration or stronger guideline support.

What regulatory actions affected dolasetron sales?

The most important regulatory event was the FDA’s 2010 action on injectable dolasetron. The agency determined that intravenous dolasetron could prolong the QT interval and increase the risk of serious ventricular arrhythmias, including torsades de pointes. FDA advised against using injectable Anzemet to prevent chemotherapy-induced nausea and vomiting.[5]

The FDA action changed the product’s risk-benefit profile in a high-value hospital indication.

Regulatory impact by formulation

Formulation	Regulatory issue	Market consequence
Injectable dolasetron	QT prolongation and arrhythmia risk	Sharp decline in chemotherapy-related hospital use
Oral dolasetron	Continued cardiac-risk warnings and monitoring concerns	Weaker position against other oral 5-HT3 drugs
Both formulations	Availability of safer or more convenient alternatives	Reduced physician demand

The regulatory problem was commercially significant because chemotherapy-induced nausea and vomiting was a major target market for Anzemet. Removing or restricting intravenous use weakened the product’s hospital positioning.

What is the Orange Book status of dolasetron?

Anzemet’s Orange Book position is no longer commercially meaningful because the drug is discontinued and the relevant exclusivity period has expired. The FDA’s Drugs@FDA and Orange Book databases identify approval and patent information, but discontinued status does not itself prove that all historical patents expired on the same date.[3][4]

The practical market conclusion is clear:

• There is no current branded Orange Book franchise comparable to active products such as palonosetron.
• Any historical Paragraph IV disputes would have occurred during the generic-entry period.
• Current generic entry is unlikely to generate substantial value because demand and commercial availability are both limited.

Were there Paragraph IV challenges to dolasetron?

Dolasetron was exposed to ordinary generic-entry risk after the loss of branded exclusivity. Generic drug applicants could have challenged listed patents through Paragraph IV certifications if relevant patents remained listed when abbreviated new drug applications were filed.

Publicly available product information does not support treating dolasetron as an active Paragraph IV litigation market today. Any historic patent challenges would have had their primary economic effect in the late 2000s or early 2010s.

For investors and licensors, the key point is that litigation risk has been replaced by market-viability risk. A generic applicant may be able to obtain approval, but approval alone would not establish a profitable market.

Which companies challenged or competed with dolasetron?

The principal competitive threat came from other 5-HT3 receptor antagonists rather than from a single patent challenger.

Drug	Key competitive advantage
Ondansetron	Broad use, low cost, extensive generic availability
Granisetron	Established antiemetic efficacy and generic supply
Palonosetron	Longer half-life and strong positioning in chemotherapy-induced nausea and vomiting
Dolasetron	Historical efficacy, but greater cardiac-risk concerns and weak current availability

Ondansetron became the principal low-cost substitute in many settings. Palonosetron competed more directly in chemotherapy-related use because of its longer duration and commercial positioning in delayed nausea and vomiting.

Dolasetron therefore faced both price competition and clinical substitution. Generic erosion lowered price, while safety concerns reduced volume.

How does dolasetron compare with ondansetron and palonosetron?

Dolasetron is commercially weaker than both ondansetron and palonosetron.

Attribute	Dolasetron	Ondansetron	Palonosetron
5-HT3 mechanism	Yes	Yes	Yes
Historical chemotherapy use	Yes	Yes	Yes
QT-prolongation concern	Material	Present	Generally lower relative concern
Long-acting profile	No major advantage	Shorter acting	Strong advantage
Generic availability	Limited current presence	Extensive	Available in multiple markets
Current U.S. commercial position	Discontinued	Active	Active
Reimbursement position	Weak	Low-cost standard	Specialty and protocol-dependent

Dolasetron lacks a clear clinical or economic attribute that would justify replacing established alternatives. A reintroduction would require a differentiated formulation, a new route of administration, or evidence supporting a specific population with unmet need.

What is the financial trajectory of dolasetron?

No public company separately reports current dolasetron revenue. Sanofi reports sales by broader business segments and product groupings, not a standalone current Anzemet revenue line.[6]

The financial trajectory can be divided into four phases:

Launch and branded expansion

Anzemet entered a growing antiemetic market in the 1990s. At launch, intravenous and oral options supported use in oncology and postoperative care. Branded pricing and physician familiarity provided the main revenue drivers.

Competitive erosion

The product later faced generic competition from ondansetron and granisetron. Once multiple 5-HT3 antagonists became available, dolasetron lost pricing power and formulary leverage.

Regulatory contraction

The 2010 FDA warning on intravenous dolasetron accelerated the decline. The restriction affected the product’s hospital and oncology use, where injectable administration had been commercially important.[5]

Discontinuation and residual value

The remaining commercial value contracted to residual supply, legacy approvals, and possible limited-market use. Current financial value is likely negligible relative to Sanofi’s overall portfolio.

Financial indicators

Indicator	Assessment
Historical revenue	Generated during the branded Anzemet period
Peak sales	Not separately disclosed in current Sanofi reporting
Current annual revenue	No material standalone figure publicly disclosed
Gross margin	Compressed by generic competition
Development spending	No visible active development program
Licensing value	Low without new clinical differentiation
Acquisition value	Primarily historical IP or regional rights, not current sales

A valuation model should assign little or no value to existing dolasetron sales unless it identifies a specific regional distributor, hospital contract, or active formulation program.

What manufacturing and IP barriers exist for dolasetron?

Manufacturing barriers are limited relative to biologics or complex injectable products. Dolasetron is a small-molecule drug, and its chemistry does not create the type of manufacturing moat associated with complex peptides, monoclonal antibodies, or drug-device combinations.

Potential barriers include:

• API sourcing and quality control
• Stability of the mesylate salt
• Injectable sterility and particulate-control requirements
• Regulatory maintenance costs
• Small market size
• Limited commercial interest from generic manufacturers

The principal barrier is economic rather than technical. A manufacturer may be able to produce the drug, but the expected market may not justify regulatory, supply-chain, and pharmacovigilance costs.

What generic launch risks exist for dolasetron?

Generic launch risk is low from a litigation perspective but also low in commercial attractiveness. A new entrant would face:

• Minimal brand loyalty
• Substitution by cheaper ondansetron
• Existing physician familiarity with alternatives
• Cardiac-safety concerns
• Potentially weak reimbursement support
• Limited pharmacy and hospital demand
• Supply-chain economics unfavorable to low-volume products

A generic launch could still occur in a narrowly defined jurisdiction or hospital channel, but a broad U.S. launch would have limited revenue potential absent a shortage or a new clinical niche.

What licensing deals affect dolasetron?

No current major licensing or strategic development transaction is publicly associated with dolasetron mesylate. Sanofi’s historical ownership of Anzemet is the principal commercial relationship relevant to the product.

Dolasetron has little licensing appeal because:

• Core exclusivity has expired.
• The branded product is discontinued.
• The safety profile is less competitive.
• Alternative 5-HT3 antagonists are widely available.
• There is no visible late-stage development program.

A transaction involving dolasetron would more likely concern a regional commercialization right, discontinued-product portfolio, or manufacturing asset than a growth-oriented drug license.

What patent litigation and settlement activity affects dolasetron?

No active, material U.S. patent litigation or settlement activity currently drives the dolasetron market. Historical generic disputes may have influenced the timing of entry, but they no longer determine commercial strategy.

The present legal assessment is:

Legal issue	Current relevance
Core composition patents	Expired or commercially exhausted
Formulation patents	No evident material barrier
Method-of-use patents	Limited practical value after discontinuation
Paragraph IV litigation	Historical rather than active
Patent settlements	No current market impact identified
Biosimilar litigation	Not applicable

Is biosimilar risk relevant to dolasetron?

No. Dolasetron is a chemically synthesized small molecule, not a biologic. Biosimilar pathways do not apply.

The relevant regulatory pathway is the abbreviated new drug application, or ANDA, for a generic equivalent. This distinction matters because generic approval is based principally on pharmaceutical equivalence and bioequivalence, while biosimilar approval requires a separate biologics framework.[7]

What is the commercial outlook for dolasetron?

The commercial outlook is negligible under the existing product profile. The market could support limited use only if a supplier obtained a cost advantage, identified an underserved geography, or developed a formulation that materially reduced cardiac risk or improved convenience.

A realistic scenario analysis is:

Scenario	Probability assessment	Commercial result
No meaningful re-entry	Highest	Continued market absence
Limited regional generic supply	Moderate	Small, low-margin revenue
U.S. reintroduction of legacy formulation	Low	Weak uptake and high regulatory burden
New differentiated formulation	Very low	Potential value only after new clinical and regulatory investment

Key Takeaways

• Dolasetron mesylate is a legacy 5-HT3 antiemetic with no meaningful current U.S. branded market.
• Anzemet’s commercial decline followed generic competition and FDA restrictions on intravenous use.
• The core patent and exclusivity position is commercially exhausted.
• Current Orange Book and FDA approval records are relevant for historical analysis, not for an active branded franchise.
• Paragraph IV risk is historical; commercial viability is the larger issue.
• Biosimilar risk does not apply because dolasetron is a small-molecule drug.
• Ondansetron and palonosetron offer stronger current competitive positions.
• Sanofi does not publicly report a standalone current dolasetron revenue figure.
• Any present value would likely come from limited regional supply or a materially differentiated reformulation.

FAQs

Is dolasetron mesylate still sold in the United States?

Anzemet and dolasetron products are listed as discontinued in major U.S. drug databases. Broad commercial availability is not established.[1][2]

Why was intravenous dolasetron restricted?

The FDA identified QT-interval prolongation and the risk of serious ventricular arrhythmias. The agency advised against intravenous dolasetron for prevention of chemotherapy-induced nausea and vomiting.[5]

Does dolasetron have generic competition?

Dolasetron lost practical exclusivity and was exposed to generic competition. Current commercial availability is limited, while ondansetron and granisetron have much broader generic markets.

Can a company file an ANDA for dolasetron?

An applicant could pursue an ANDA if a relevant reference product and regulatory pathway remain available. The commercial case is weak because demand has shifted to competing antiemetics.

Is dolasetron a candidate for a patent-based licensing deal?

The legacy molecule has limited licensing value. A credible transaction would require a differentiated formulation, a new route of administration, or evidence supporting a clinically distinct use.

References

1. National Library of Medicine. (n.d.). DailyMed: Anzemet and dolasetron mesylate product information. https://dailymed.nlm.nih.gov/

2. U.S. Food and Drug Administration. (n.d.). Drugs@FDA: FDA-approved drugs database. https://www.accessdata.fda.gov/scripts/cder/daf/

3. U.S. Food and Drug Administration. (1997). Anzemet approval history and prescribing information. Drugs@FDA.

4. U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations, commonly known as the Orange Book. https://www.fda.gov/drugs/drug-approvals-and-databases/approved-drug-products-therapeutic-equivalence-evaluations-orange-book

5. U.S. Food and Drug Administration. (2010). FDA drug safety communication: Abnormal heart rhythms associated with use of Anzemet injection. https://www.fda.gov/

6. Sanofi. (n.d.). Annual reports and universal registration documents. https://www.sanofi.com/en/investors

7. U.S. Food and Drug Administration. (n.d.). Generic drug facts and abbreviated new drug applications. https://www.fda.gov/drugs/generic-drugs/stdc