DARAPRIM Drug Patent Profile

When do Daraprim patents expire, and what generic alternatives are available?

Daraprim is a drug marketed by Tilde Sciences and is included in one NDA.

The generic ingredient in DARAPRIM is pyrimethamine. There are three drug master file entries for this compound. Seven suppliers are listed for this compound. Additional details are available on the pyrimethamine profile page.

DrugPatentWatch^® Litigation and Generic Entry Outlook for Daraprim

A generic version of DARAPRIM was approved as pyrimethamine by SANALUZ on February 28^th, 2020.

Summary for DARAPRIM

US Patents:	0
Applicants:	1
NDAs:	1
Finished Product Suppliers / Packagers:	3
Raw Ingredient (Bulk) Api Vendors:	95
Clinical Trials:	8
Patent Applications:	4,743
Drug Prices:	Drug price information for DARAPRIM
What excipients (inactive ingredients) are in DARAPRIM?	DARAPRIM excipients list
DailyMed Link:	DARAPRIM at DailyMed

See drug prices for DARAPRIM

Recent Clinical Trials for DARAPRIM

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

Sponsor	Phase
Washington University School of Medicine	Early Phase 1
Montefiore Medical Center	Phase 1
Albert Einstein College of Medicine	Phase 1

See all DARAPRIM clinical trials

Pharmacology for DARAPRIM

Drug Class	Dihydrofolate Reductase Inhibitor Antimalarial
Mechanism of Action	Dihydrofolate Reductase Inhibitors

US Patents and Regulatory Information for DARAPRIM

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Tilde Sciences	DARAPRIM	pyrimethamine	TABLET;ORAL	008578-001	Approved Prior to Jan 1, 1982	AB	RX	Yes	Yes

Daraprim Market Dynamics, Financial Trajectory, and Competitive Risk

Last updated: August 6, 2026

Daraprim, the brand name for pyrimethamine, is a low-volume, high-price pharmaceutical product used primarily with sulfadiazine and leucovorin to treat toxoplasmosis. Its commercial value rose sharply after Turing Pharmaceuticals increased the U.S. price from $13.50 to $750 per tablet in 2015. The price increase created substantial short-term revenue leverage but also triggered congressional scrutiny, federal antitrust litigation, distribution restrictions, reputational damage, and substitution by compounded products.

Daraprim has limited conventional patent protection. Its main barriers are commercial and regulatory: small patient volume, restricted distribution, manufacturing requirements, prescriber familiarity, reimbursement friction, and the cost of developing an approved generic for a narrow market. The product’s current financial performance is difficult to quantify because the rights holder is private and does not publish audited Daraprim revenue.

What is Daraprim and how is it used?

Daraprim contains pyrimethamine, an antiparasitic antifolate. The FDA-approved indication is the treatment of toxoplasmosis when used with a sulfonamide and folinic acid, also called leucovorin. The drug is particularly relevant for immunocompromised patients, including people with HIV/AIDS, transplant recipients, and certain oncology patients.

Product attribute	Daraprim detail
Active ingredient	Pyrimethamine
Dosage form	Oral tablet
Strength	25 mg
U.S. NDA	NDA 008578
FDA approval	1953
Primary indication	Toxoplasmosis
Current U.S. marketer	Vyera Pharmaceuticals and related Phoenixus entities
Original developer	Burroughs Wellcome
Main treatment partners	Sulfadiazine and leucovorin
Biosimilar exposure	None; Daraprim is a small-molecule drug
Main substitution risk	Compounded pyrimethamine and alternative toxoplasmosis regimens

Daraprim’s clinical use is specialized. That limits unit demand but makes uninterrupted access important because clinicians may have few convenient alternatives for some patients.

When did Daraprim lose exclusivity?

Daraprim’s original regulatory and patent exclusivity expired decades ago. The product was first approved in the 1950s, so its original patent rights and any applicable historical exclusivity no longer constrain generic entry.

The FDA Orange Book does not identify a current Daraprim patent listing that would create a conventional patent-based barrier to an abbreviated new drug application, or ANDA. The commercial issue is therefore not patent expiry. It is whether a manufacturer can justify the regulatory, manufacturing, distribution, and market-access investment required for a low-volume product. [1]

What patents protect Daraprim?

No material current patent estate is publicly associated with the active ingredient or the original Daraprim tablet that would block generic entry. Pyrimethamine is an old small molecule, and the original composition and use rights are long expired.

Potentially relevant intellectual-property categories could include:

• Tablet formulation or excipient combinations.
• Manufacturing processes.
• Packaging or stability improvements.
• Distribution and dispensing software.
• New combination regimens.

These categories do not appear to provide a broad, Orange Book-listed exclusivity position for the marketed Daraprim product. Distribution controls are contractual and operational tools, not patent rights.

How did Daraprim’s price increase affect revenue?

Turing raised the U.S. list price from $13.50 to $750 per tablet in August 2015, an increase of approximately 5,455%. Before the increase, reported U.S. annual Daraprim sales were approximately $9 million. The transaction and price strategy demonstrated that a small patient population could generate materially higher gross revenue without a proportional increase in prescriptions. [2]

Period	Commercial event	Financial effect
Before 2015	Daraprim sold at a low legacy price	Reported U.S. sales of about $9 million annually
August 2015	Turing raised price to $750 per tablet	Large increase in gross revenue per prescription
Late 2015 onward	Distribution controls and public backlash	Greater payer, hospital, and prescriber resistance
2016-2019	Vyera operated Daraprim under a restricted-access model	Revenue remained dependent on pricing rather than volume growth
2020 onward	Litigation, bankruptcy-related pressure, and alternative supply channels	Higher legal and operational risk
Current period	Private ownership and limited public disclosure	No reliable audited Daraprim revenue series

Public reporting placed post-increase Daraprim sales in the tens of millions of dollars annually, but figures vary depending on whether they measure gross sales, net revenue, calendar-year sales, or sales attributable to U.S. prescriptions. The company has not provided a current public segment-level revenue disclosure that supports a precise annual forecast.

The financial model has three defining characteristics:

1. Low prescription volume.
2. High revenue per tablet.
3. High sensitivity to access restrictions, payer controls, and substitution.

The model can produce attractive gross margins when reimbursement is obtained, but its cash economics are weaker than the list price suggests. Discounts, patient assistance, specialty dispensing costs, inventory management, litigation expenses, and collection delays reduce realized net revenue.

What is the financial trajectory for Daraprim?

Daraprim’s financial trajectory has moved through four phases.

Legacy low-price phase

Before Turing acquired U.S. rights, Daraprim generated modest revenue from a small, stable market. The product’s commercial importance was greater than its sales volume because clinicians relied on it for a narrow but medically significant indication.

Price-maximization phase

Turing’s 2015 strategy converted Daraprim from a low-revenue legacy product into a high-price specialty asset. The move increased revenue per treated patient but did not create a larger clinical market. The resulting revenue growth was therefore exposed to payer intervention and public-policy scrutiny.

Litigation and access-friction phase

The pricing decision led to investigations and litigation. Turing, later renamed Vyera Pharmaceuticals, faced allegations that its distribution arrangements restricted access to samples and impeded potential generic development. These arrangements included limited distribution through specialty pharmacies and controls over access to product samples. [3]

The company’s distribution model made it more difficult for competitors to obtain sufficient product for bioequivalence studies. That strategy could delay generic development, but it also increased litigation risk and intensified scrutiny from the Federal Trade Commission and state attorneys general.

Private-company and restructuring phase

Vyera and its parent Phoenixus operated under substantial legal and financial pressure. The company’s private status reduced financial transparency. Daraprim remained a revenue-generating asset, but its value was increasingly discounted for:

• Antitrust liability.
• Restricted-channel compliance costs.
• Potential generic entry.
• Reimbursement resistance.
• Brand damage.
• Limited market growth.
• Dependence on one primary indication.

The product’s current enterprise value cannot be inferred from historical gross sales alone. A buyer would need to discount revenue for litigation exposure, channel remediation, manufacturing continuity, and the possibility that an approved generic or reliable compounded supply would rapidly compress price.

What is the FDA regulatory status of Daraprim?

Daraprim remains an FDA-approved prescription drug. Its regulatory position is based on an old NDA rather than a recent innovation or modern specialty-drug exclusivity program.

The product does not have biologic status, so biosimilar competition is irrelevant. The principal regulatory competition would come from an FDA-approved generic pyrimethamine tablet or an approved alternative product for toxoplasmosis.

Compounded pyrimethamine is not equivalent to an FDA-approved generic. Compounding pharmacies can offer access to pyrimethamine under applicable federal and state pharmacy rules, but compounded products do not automatically carry the same premarket approval, manufacturing controls, labeling review, or substitution status as an ANDA-approved product.

What is the Orange Book status of Daraprim?

The Orange Book is not the primary source of protection for Daraprim because the product has no meaningful current patent or regulatory-exclusivity barrier publicly identified for the marketed tablet. A generic applicant would generally focus on pharmaceutical equivalence, bioequivalence, chemistry, manufacturing, controls, and labeling rather than a Paragraph IV patent challenge.

Orange Book issue	Daraprim position
Listed active-ingredient patent	No material current listing identified
Listed formulation patent	No material current listing identified
New chemical entity exclusivity	Expired
Orphan exclusivity	No current exclusivity controlling the legacy product
Paragraph IV exposure	Limited because there is no principal listed patent to challenge
Generic pathway	ANDA, subject to FDA requirements
Biosimilar pathway	Not applicable

Are there Paragraph IV challenges to Daraprim?

No major public Paragraph IV campaign is associated with Daraprim’s current product. Paragraph IV litigation is used when an ANDA applicant certifies that a listed patent is invalid, unenforceable, or not infringed. Because Daraprim lacks a material current Orange Book patent position, a competitor’s central challenge would more likely involve regulatory approval and market access than patent litigation.

The absence of Paragraph IV activity does not mean generic entry is impossible. It means patent litigation is not the dominant entry mechanism.

Which companies are challenging Daraprim?

The principal competitive pressure has come from compounding pharmacies and potential generic manufacturers rather than a large branded pharmaceutical rival.

ImprimisRx and compounded pyrimethamine

ImprimisRx, a compounding pharmacy business associated with Harrow, promoted compounded pyrimethamine as a lower-cost alternative after the 2015 price increase. Compounded supply provided a practical pressure valve for patients and institutions, although it did not have the same regulatory status as Daraprim. [4]

Potential ANDA manufacturers

A generic manufacturer could enter if it can establish:

• Reliable pyrimethamine API supply.
• A reproducible 25 mg tablet process.
• Acceptable stability data.
• Bioequivalence.
• A commercially viable distribution plan.
• Sufficient market demand to recover development costs.

The market may support one or more generic entrants, but the small volume creates a classic low-revenue trap. A generic could reduce Daraprim’s price while also reducing the economic incentive for additional competitors.

What formulation patents protect Daraprim?

No important formulation patent has been publicly identified as protecting the current 25 mg Daraprim tablet. The commercial product is not known to rely on a complex delivery system, extended-release technology, injectable formulation, or device combination.

The formulation risk is therefore technical rather than patent-based. A generic applicant must still demonstrate that its tablet meets the FDA’s requirements for identity, strength, quality, purity, and performance.

What method-of-use patents protect Daraprim?

The historical toxoplasmosis use is too old to support an active, commercially meaningful method-of-use patent estate. There is no known current method-of-use patent that broadly protects the approved use of pyrimethamine in toxoplasmosis.

New clinical research involving pyrimethamine could theoretically create separate intellectual property around a new disease, dosing regimen, or combination. Such rights would not necessarily protect the established Daraprim indication.

What patent litigation affects Daraprim?

Daraprim’s major legal exposure has been antitrust and distribution litigation, not patent infringement litigation.

The Federal Trade Commission and state plaintiffs alleged that Vyera and executives used restricted distribution arrangements to prevent potential generic competitors from obtaining samples and conducting testing. In 2022, a federal court ordered Martin Shkreli to pay approximately $64.6 million and imposed a lifetime ban from the pharmaceutical industry after finding violations related to Daraprim conduct. [5]

In 2024, Vyera and former executive Kevin Mulleady agreed to a settlement with the FTC and states that included monetary relief and restrictions on future conduct. The litigation materially affected the asset’s value by converting distribution strategy into a compliance liability. [6]

What licensing deals involve Daraprim?

Turing acquired U.S. rights to Daraprim from Impax Laboratories in 2015 in a transaction reported at approximately $55.3 million. Turing later changed its name to Vyera Pharmaceuticals. The product was held through the Phoenixus corporate structure. [7]

The transaction illustrates the economics of acquiring legacy drugs: the buyer can purchase an established FDA-approved product without funding clinical development, then attempt to increase value through pricing, distribution, or repositioning. Daraprim showed the limits of that strategy when the product has a small patient population and high public sensitivity.

How strong is the Daraprim patent estate?

Daraprim has a weak patent estate but a historically strong access position.

Value driver	Assessment
Active-ingredient patents	Weak or expired
Formulation patents	No material current protection identified
Method-of-use patents	Weak or expired for toxoplasmosis
FDA approval	Durable regulatory asset
Brand recognition	Strong among infectious-disease specialists
Clinical substitution	Moderate, depending on patient and regimen
Generic development barrier	Moderate because of market size and access
Distribution barrier	Previously strong, now constrained by litigation
Pricing power	Reduced by compounding and payer scrutiny
Biosimilar risk	None

The asset’s defensibility has been operational rather than legal. A company could preserve share through physician familiarity, reliable supply, reimbursement support, and distribution relationships. Those advantages are less durable than patents and can be weakened by an approved generic or a stable lower-cost compounded source.

What generic launch scenarios exist for Daraprim?

Scenario one: No approved generic

Daraprim retains a high list price, but actual net revenue remains constrained by payer negotiations, institutional restrictions, and compounded alternatives. This scenario favors the incumbent only if product availability and reimbursement remain stable.

Scenario two: One approved generic

A single generic would likely force substantial price concessions. The incumbent could retain some demand through brand familiarity and supply reliability, but its premium would narrow.

Scenario three: Multiple approved generics

Multiple entrants would create rapid price erosion, especially in hospital and specialty-pharmacy channels. Daraprim could become a low-margin, low-volume product with limited strategic value.

Scenario four: Compounded supply expands without an ANDA launch

Compounding would continue to cap the incumbent’s pricing power while avoiding the full substitution effect of an FDA-approved generic. This is a plausible pressure scenario because compounded products can address a narrow market without requiring a full commercial launch.

What revenue exposure does Daraprim create for the owner?

Daraprim is unlikely to be a major growth asset for a diversified pharmaceutical company. Its value is concentrated in cash flow from an established niche product rather than market expansion.

The principal revenue risks are:

• A generic tablet entering the market.
• Compounding pharmacies gaining payer and institutional acceptance.
• Hospitals restricting use because of acquisition cost.
• FDA or state action affecting distribution.
• Declining reimbursement for high-cost legacy drugs.
• Supply interruption or API procurement problems.
• Continued legal costs and settlement obligations.

The principal upside is limited. Revenue could improve through broader access, better reimbursement, or a lower price that increases utilization, but the toxoplasmosis market is too narrow to support large volume growth.

How does Daraprim compare with competing toxoplasmosis treatments?

Daraprim remains clinically important but competes within regimen-based treatment rather than as a stand-alone product. Sulfadiazine and leucovorin are commonly used alongside pyrimethamine. Atovaquone-based regimens and other alternatives may be used when toxicity, allergy, intolerance, or resistance affects treatment selection.

Product or approach	Role	Commercial implication
Daraprim	Branded pyrimethamine	High price, established approval
Compounded pyrimethamine	Lower-cost access alternative	Caps brand pricing
Generic pyrimethamine	Direct substitution	Highest price-erosion risk
Sulfadiazine plus leucovorin	Common companion regimen	Complements rather than replaces pyrimethamine
Atovaquone-based treatment	Alternative in selected patients	Limits pricing power in some cases

Key Takeaways

• Daraprim is an FDA-approved pyrimethamine tablet used mainly for toxoplasmosis.
• Turing increased the price from $13.50 to $750 per tablet in 2015.
• Reported pre-increase U.S. sales were approximately $9 million annually.
• The product has no meaningful current patent estate publicly identified in the Orange Book.
• Paragraph IV litigation is not the central generic-entry risk.
• Compounded pyrimethamine has provided an important lower-cost alternative.
• The largest legal risk came from alleged distribution practices that restricted generic development.
• Shkreli faced a $64.6 million monetary judgment and a lifetime industry ban.
• Daraprim’s current revenue is not publicly reported in a reliable audited product-level series.
• The asset’s commercial value depends on distribution, reimbursement, and supply reliability rather than patent exclusivity.

FAQs

Is Daraprim still sold in the United States?

Yes. Daraprim remains an FDA-approved U.S. prescription product for toxoplasmosis, although access is controlled through specialized distribution channels.

Does Daraprim have a generic version?

Compounded pyrimethamine products are available through compounding pharmacies. A compounded product is not the same as an FDA-approved ANDA generic and does not automatically qualify for pharmacy-level substitution.

Why is Daraprim expensive if its patents expired?

Its price reflects market control, limited patient volume, restricted distribution, and the absence of a widely available FDA-approved generic. Patent expiry alone does not guarantee immediate generic supply in a small market.

Can a company launch a generic Daraprim without a Paragraph IV certification?

Yes. If no relevant patent is listed in the Orange Book, a generic applicant would not need to challenge a listed Daraprim patent through a conventional Paragraph IV certification.

Is Daraprim exposed to biosimilar competition?

No. Pyrimethamine is a chemically synthesized small molecule, not a biologic. Competition would come from generic or compounded products rather than biosimilars.

References

1. U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations, Orange Book. https://www.accessdata.fda.gov/scripts/cder/ob/index.cfm
2. U.S. Senate Special Committee on Aging. (2016). Suddenly sky-high: A spotlight on the questionable pricing practices of specialty drug companies. U.S. Government Publishing Office.
3. Federal Trade Commission. (2020). FTC charges Vyera Pharmaceuticals, Martin Shkreli, and others with anticompetitive scheme to illegally maintain monopoly over lifesaving drug. https://www.ftc.gov
4. Harrow, Inc. (2019). Annual report. U.S. Securities and Exchange Commission.
5. U.S. District Court for the Southern District of New York. (2022). Federal Trade Commission et al. v. Shkreli et al., No. 20-cv-706.
6. Federal Trade Commission. (2024). FTC and states settle antitrust case involving Vyera Pharmaceuticals and Daraprim distribution practices. https://www.ftc.gov
7. Impax Laboratories, Inc. (2016). Annual report for fiscal year 2015. U.S. Securities and Exchange Commission.