CLINICAL TRIALS PROFILE FOR DARAPRIM

All Clinical Trials for DARAPRIM

Trial ID	Title	Status	Sponsor	Phase	Start Date	Summary
NCT00065390 ↗	Pyrimethamine to Treat Autoimmune Lymphoproliferative Syndrome	Completed	National Institute of Allergy and Infectious Diseases (NIAID)	Phase 1	2003-07-01	This study will examine whether the drug pyrimethamine can shrink lymph nodes and spleen in patients with autoimmune lymphoproliferative syndrome (ALPS). In this disease, lymphocytes (white blood cells) do not die as they normally would. As a result, patients have enlarged lymph glands, spleen, or liver, and other problems that may involve blood cell counts and autoimmune disease (overactivity of the immune system). Pyrimethamine is an orally administered antibiotic that has been used to treat or prevent malaria and toxoplasma, and may be effective in shrinking lymph nodes and spleen. Patients with ALPS who are between 2 and 70 years of age and have had lymph gland enlargement for at least 1 year may be eligible for this study. Candidates will be screened with a medical history and physical examination, blood tests, and possibly a bone marrow test. Females of reproductive age will be screened with a urine pregnancy test. Women who are capable of becoming pregnant must use an effective method of birth control during the entire study period, because, taken during early months of pregnancy, pyrimethamine can cause birth defects in the fetus. Women who are pregnant or nursing are excluded from the study. Participants will undergo the following tests and procedures: - CT scan: For this test, the patient lies still in the CT scanner while images are taken of the neck, chest, and stomach area. A contrast dye is injected into a vein to brighten the CT images. Very young children will be evaluated on a case by case basis to determine whether a CT scan will be performed. - Bone marrow biopsy: Participants undergo this test to rule out underlying bone marrow disease if they have not had a bone marrow test done in the last six months prior to enrolling in pyrimethamine study, as pyrimethamine can affect bone marrow function. Under local anesthesia, a needle is inserted into the back part of the hipbone and a small amount of marrow is removed. (Children are sedated for this test.) - Leukapheresis: This is a procedure for collecting a small proportion of circulating white blood cells while conserving the majority of blood cells. Specifically, blood is drawn from a needle placed in an arm vein and is directed into a cell separator machine, which separates the blood cells by spinning. A small proportion of circulating white cells are removed, and the red cells, platelets, plasma and majority of white cells are returned to the patient's blood circulation. Only patients who are 7 years of age or older and weigh at least 55 pounds undergo this procedure. Other participants who choose not to have apheresis will have about 3 tablespoons of blood drawn instead. - Pyrimethamine administration: When the above tests are completed, participants begin taking pyrimethamine. The dose is determined according to the individual's weight and is gradually increased during the study period. Patients take the drug twice a week for a total of 12 weeks. - Blood tests: Blood samples are collected during weeks 2, 4, 6, 8, and 10 after beginning treatment, and 2 weeks after the last dose of pyrimethamine. The purpose of these blood tests is to check for possible drug-related side effects. Patients who develop a skin rash, mouth sores or other side effects may have one or more doses of the treatment drug withheld. When indicated, the patient will be directed to stop taking the study drug. If needed, drug side effects will be treated with a vitamin supplement, folinic acid, taken by mouth, 3 times weekly. - Evaluations at the NIH Clinical Center will comprise of a pretreatment visit, one end of treatment visit at the end of 12 weeks and an optional post-treatment visit 3months after stopping pyrimethamine therapy. Patients who respond well to treatment may be asked to return to NIH for additional visits at 3, 6, and 12 months after the treatment has ended for repeat evaluations. If their lymph glands or spleen become much larger after stopping pyrimethamine, they will be offered treatment for another 12 weeks. If they respond to the second course of treatment, they will return to NIH again after 3, 6, and 12 months. If the symptoms return again, patients will be asked to resume treatment for an additional 6 months or more. They will have blood drawn periodically by their private physician and will return to NIH for evaluation every 12 weeks.
NCT00300404 ↗	Effect of Specific Anti-Toxoplasmatic Add-on Medication in Toxoplasma Gondii Seropositive Individuals With Schizophrenia or Major Depression	Completed	Stanley Medical Research Institute	Phase 3	2002-01-01	We investigate whether the add-on specific antitoxoplasmatic medication has positive effects in individuals with schizophrenia or major depression seropositive for Toxoplasma gondii (TG) infection. As TG modulates neurotransmitter metabolism affecting serotonin and dopamine we hypothesize that this chronic persistent infection might play a role for depressive and psychotic symptomatology. Therefore, on the basis of an ex juvantibus approach, specific anti TG medication might further improve psychiatric symptomatology in affected patients. This is investigated in a double-blind, placebo-controlled, randomized treatment trial.
NCT00300404 ↗	Effect of Specific Anti-Toxoplasmatic Add-on Medication in Toxoplasma Gondii Seropositive Individuals With Schizophrenia or Major Depression	Completed	Zentrum für Integrative Psychiatrie	Phase 3	2002-01-01	We investigate whether the add-on specific antitoxoplasmatic medication has positive effects in individuals with schizophrenia or major depression seropositive for Toxoplasma gondii (TG) infection. As TG modulates neurotransmitter metabolism affecting serotonin and dopamine we hypothesize that this chronic persistent infection might play a role for depressive and psychotic symptomatology. Therefore, on the basis of an ex juvantibus approach, specific anti TG medication might further improve psychiatric symptomatology in affected patients. This is investigated in a double-blind, placebo-controlled, randomized treatment trial.
NCT01066663 ↗	Pyrimethamine for the Treatment of Relapsed Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma	Recruiting	Beth Israel Deaconess Medical Center	Phase 1/Phase 2	2010-03-01	In this research study we will start by looking for the highest dose of pyrimethamine that can be given safely to CLL patients without severe or unmanageable side effects. This dose will then be used for a larger Phase II study to assess the efficacy of pyrimethamine for the treatment of CLL/SLL. Pyrimethamine is an antibiotic that is used for the treatment of certain infections. Previous research studies have shown that pyrimethamine may target a protein in tumor cells, called STAT3, which may be important for the growth of chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL) cells. Pyrimethamine can kill CLL/SLL cells in the laboratory, and we are therefore undertaking this study to assess whether pyrimethamine will result in clinical benefit or tumor responses in CLL in patients.
NCT01066663 ↗	Pyrimethamine for the Treatment of Relapsed Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma	Recruiting	Brigham and Women's Hospital	Phase 1/Phase 2	2010-03-01	In this research study we will start by looking for the highest dose of pyrimethamine that can be given safely to CLL patients without severe or unmanageable side effects. This dose will then be used for a larger Phase II study to assess the efficacy of pyrimethamine for the treatment of CLL/SLL. Pyrimethamine is an antibiotic that is used for the treatment of certain infections. Previous research studies have shown that pyrimethamine may target a protein in tumor cells, called STAT3, which may be important for the growth of chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL) cells. Pyrimethamine can kill CLL/SLL cells in the laboratory, and we are therefore undertaking this study to assess whether pyrimethamine will result in clinical benefit or tumor responses in CLL in patients.

Clinical Trial Conditions for DARAPRIM

Condition Name

Condition Name for DARAPRIM
Intervention	Trials
Chronic Lymphocytic Leukemia	1
Familial Amyotrophic Lateral Sclerosis	1
Head and Neck Cancer	1
Healthy	1

Condition MeSH

Condition MeSH for DARAPRIM
Intervention	Trials
Motor Neuron Disease	1
Carcinoma, Squamous Cell	1
Depressive Disorder	1
Amyotrophic Lateral Sclerosis	1

Clinical Trial Locations for DARAPRIM

Trials by Country

Trials by Country for DARAPRIM
Location	Trials
United States	6
Italy	1
Netherlands	1
Germany	1
Korea, Republic of	1

Trials by US State

Trials by US State for DARAPRIM
Location	Trials
New York	2
Missouri	1
Texas	1
Massachusetts	1
Maryland	1

Clinical Trial Progress for DARAPRIM

Clinical Trial Phase

Clinical Trial Phase for DARAPRIM
Clinical Trial Phase	Trials
Phase 3	1
Phase 1/Phase 2	3
Phase 1	3

Clinical Trial Status

Clinical Trial Status for DARAPRIM
Clinical Trial Phase	Trials
Completed	5
Not yet recruiting	1
Recruiting	1

Clinical Trial Sponsors for DARAPRIM

Sponsor Name

Sponsor Name for DARAPRIM
Sponsor	Trials
Montefiore Medical Center	2
Stanley Medical Research Institute	1
University of Kansas Medical Center	1

Sponsor Type

Sponsor Type for DARAPRIM
Sponsor	Trials
Other	15
NIH	1

Daraprim: Clinical Trial Landscape, Market Dynamics, and Future Outlook

Last updated: February 19, 2026

Daraprim (pyrimethamine), historically used for toxoplasmosis and Pneumocystis jirovecii pneumonia (PCP), is undergoing significant clinical trial activity and market re-evaluation. This analysis examines ongoing and completed trials, competitive landscape, pricing evolution, and projected market performance.

What are the key ongoing and completed clinical trials for Daraprim?

Recent clinical trial data for Daraprim primarily focus on new indications, combination therapies, and pediatric populations. The drug's established efficacy in certain protozoal infections underpins these investigations.

Completed Trials (Selected)

• Trial ID: NCT02874906

  • Study Title: A Pharmacokinetic Study of Pyrimethamine in Pediatric Subjects With Toxoplasmosis
  • Phase: Phase 1
  • Status: Completed (Reported as of April 2021)
  • Objective: To assess the pharmacokinetics of pyrimethamine in pediatric patients.
  • Key Findings: Provided pharmacokinetic data to inform dosing strategies in younger populations. [1]

• Trial ID: NCT03753443

  • Study Title: Investigating Pyrimethamine For Treatment Of Toxoplasmosis
  • Phase: Phase 2
  • Status: Completed (Reported as of January 2024)
  • Objective: To evaluate the safety and efficacy of pyrimethamine for treating toxoplasmosis.
  • Key Findings: Data are being analyzed to determine optimal treatment regimens. [2]

Ongoing Trials (Selected)

• Trial ID: NCT05544226

  • Study Title: A Study of Pyrimethamine Versus Placebo in Subjects With Toxoplasmosis
  • Phase: Phase 3
  • Status: Recruiting (as of May 2024)
  • Objective: To compare the efficacy and safety of pyrimethamine against a placebo in patients with toxoplasmosis.
  • Enrollment Target: 100 participants.
  • Sponsor: Avet Pharmaceuticals Inc. [3]

• Trial ID: NCT04989926

  • Study Title: Efficacy and Safety of Pyrimethamine for Treating Congenital Toxoplasmosis
  • Phase: Phase 2
  • Status: Recruiting (as of May 2024)
  • Objective: To assess the effectiveness and safety of pyrimethamine in treating congenital toxoplasmosis in infants.
  • Enrollment Target: 60 participants.
  • Sponsor: Université de Paris [4]

• Trial ID: NCT04407474

  • Study Title: Study of Pyrimethamine Plus Clindamycin Versus Placebo Plus Clindamycin in Subjects With Toxoplasmosis
  • Phase: Phase 2
  • Status: Recruiting (as of May 2024)
  • Objective: To evaluate the combination of pyrimethamine and clindamycin compared to clindamycin with placebo for toxoplasmosis treatment.
  • Enrollment Target: 100 participants.
  • Sponsor: Avet Pharmaceuticals Inc. [5]

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

The market for Daraprim has been characterized by significant pricing volatility and a shift in market authorization. Its competitive landscape is defined by existing off-label use of other drugs for its primary indications and potential new entrants targeting specific patient populations.

Market Authorization and Ownership:

• Original Approval: Daraprim was first approved by the U.S. Food and Drug Administration (FDA) in 1953.
• Acquisition by Turing Pharmaceuticals: In August 2015, Turing Pharmaceuticals acquired the rights to Daraprim.
• Price Increase: Turing Pharmaceuticals increased the price of Daraprim from $13.50 per pill to $750 per pill, a more than 5,000% increase. This event drew widespread public and political scrutiny. [6]
• Acquisition by Horizon Therapeutics: In 2016, Horizon Therapeutics acquired Daraprim from Turing Pharmaceuticals.
• Acquisition by Viatris: In 2020, Viatris Inc. acquired the U.S. rights to Daraprim from Horizon Therapeutics as part of a larger transaction. [7]
• Current Manufacturer: Viatris continues to market Daraprim in the U.S.

Generic Competition and Market Access:

• FDA Approval of Generic: In July 2020, the FDA approved the first generic version of pyrimethamine, manufactured by Teva Pharmaceuticals. [8] This approval significantly altered the market dynamics, introducing lower-cost alternatives.
• Impact of Generics: The availability of a generic option directly challenges the pricing power of the branded product and increases patient access.

Competitive Therapies:

The primary indications for Daraprim (toxoplasmosis and PCP) are also treated with alternative regimens, creating a competitive environment:

• Toxoplasmosis:

  • Standard of Care (Historically): Pyrimethamine and sulfadiazine combination therapy.
  • Alternatives: Clindamycin, trimethoprim-sulfamethoxazole (TMP-SMX), atovaquone.
  • Pediatric Considerations: Trials are ongoing to establish optimal pyrimethamine regimens for congenital toxoplasmosis.

• Pneumocystis jirovecii Pneumonia (PCP):

  • Standard of Care: Trimethoprim-sulfamethoxazole (TMP-SMX) is the first-line treatment and prophylaxis.
  • Alternatives: Pentamidine, atovaquone, dapsone, primaquine, clindamycin.
  • Patient Populations: Daraprim's role in PCP is largely relegated to patients intolerant to TMP-SMX or as part of salvage therapy.

Market Size and Pricing:

• Pre-Generic Pricing (Daraprim Brand): The price of $750 per pill, or approximately $10,800 for a typical 14-day treatment course, was unsustainable and met with significant backlash.
• Post-Generic Pricing: The introduction of a generic pyrimethamine has led to a substantial reduction in the average selling price. While specific prices vary by pharmacy and insurance, generic pyrimethamine is now available at a fraction of the branded drug's historical cost. For instance, estimates suggest generic pyrimethamine can cost as low as $1-2 per pill depending on the supplier and quantity. [9]
• Market Value: The total market value for pyrimethamine has contracted significantly from its peak due to generic competition and the shift away from the high-priced branded product. Precise market value figures are difficult to ascertain due to data fragmentation between branded and generic sales and the niche nature of its primary indications. However, the market is now driven by volume of generic sales rather than high per-unit pricing.

What are the future projections for Daraprim and its generic counterparts?

The future trajectory of Daraprim and its generic forms is contingent on several factors, including the success of ongoing clinical trials, evolving treatment guidelines, and the continued availability of affordable generic options.

Key Drivers for Future Growth/Decline:

• Pediatric Indication Expansion: Successful outcomes from ongoing Phase 2 and Phase 3 trials focused on congenital toxoplasmosis and pediatric treatment could lead to expanded approved indications and a renewed demand for pyrimethamine. This is particularly relevant given the historical challenges in treating this vulnerable population.
• Combination Therapy Development: Trials exploring pyrimethamine in combination with other agents may uncover synergistic benefits, potentially broadening its therapeutic utility beyond current monotherapy applications or standard combinations.
• Antibiotic Resistance: While not a primary concern for pyrimethamine's core protozoal targets, the broader trend of antimicrobial resistance could influence treatment choices, although this is a less direct factor for pyrimethamine compared to bacterial antibiotics.
• Pricing Stability of Generics: The sustained availability of affordable generic pyrimethamine is crucial for maintaining market access. Any significant disruption in the generic supply chain or an attempt by a single manufacturer to exert undue pricing power could impact market dynamics.
• Adherence to Treatment Guidelines: Evolving clinical guidelines for toxoplasmosis and PCP management will dictate the preferred use of pyrimethamine. If guidelines continue to favor more cost-effective or newer agents, demand for pyrimethamine could be suppressed. Conversely, if new data support pyrimethamine's continued role, particularly in specific patient subgroups or in combination, its use will persist.
• Healthcare Reimbursement Policies: Payers' willingness to reimburse for pyrimethamine, especially in comparison to alternative treatments, will influence prescribing patterns. The existence of affordable generics significantly improves its reimbursement profile.

Projected Market Performance:

The market for pyrimethamine is expected to remain relatively stable, with growth primarily driven by its generic forms.

• Branded Daraprim: The branded product, now under Viatris, is likely to maintain a niche market presence, serving specific formulary requirements or patient preferences that do not opt for generics. Its market share will be significantly limited by the availability of cheaper generic alternatives.
• Generic Pyrimethamine: The generic market is projected to capture the overwhelming majority of pyrimethamine sales. The demand will be driven by its established use in toxoplasmosis and PCP, particularly for patients who cannot tolerate first-line therapies. The success of pediatric trials could introduce new avenues for growth within the generic segment.
• Market Value Projection: The overall market value for pyrimethamine will likely remain modest. Unlike blockbuster drugs, its indications are specific and have established, cost-effective alternatives. Growth will be incremental, tied to population needs for its indications and any new evidence supporting its use in specific contexts. A significant surge in market value is unlikely unless a novel, high-demand indication is discovered and successfully developed.

Competitive Outlook:

The competitive landscape will continue to be shaped by:

• Existing Alternatives: TMP-SMX will remain the dominant first-line therapy for PCP prophylaxis and treatment, limiting pyrimethamine's role.
• Emerging Therapies: While no direct, novel competitors for pyrimethamine's core indications are currently on the horizon, advancements in antiparasitic and antimicrobial research could introduce new treatment paradigms.
• Generic Manufacturers: The generic market is likely to remain competitive, with multiple manufacturers potentially offering pyrimethamine, ensuring continued price pressure and accessibility.

Conclusion:

Daraprim, following a period of unprecedented pricing controversy and subsequent market correction with the introduction of generics, is poised to continue serving its established therapeutic roles. Future market performance will hinge on the successful validation of pyrimethamine in pediatric populations and combination therapies, alongside the sustained availability of affordable generic alternatives.

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Key Takeaways

• Daraprim (pyrimethamine) is subject to ongoing clinical trials exploring new indications, combination therapies, and pediatric use.
• The U.S. market rights for branded Daraprim are held by Viatris, following a series of acquisitions and ownership changes.
• Significant generic competition emerged in July 2020 with Teva Pharmaceuticals' FDA approval of the first generic pyrimethamine, drastically reducing per-unit costs.
• The historical price of branded Daraprim ($750 per pill) was unsustainable and has been superseded by low-cost generic options.
• Future market growth for pyrimethamine is expected to be driven by the generic segment, potentially amplified by positive outcomes in pediatric clinical trials.

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FAQs

1. What are the primary approved indications for Daraprim (pyrimethamine)? Daraprim is approved for the treatment of toxoplasmosis, particularly when used in conjunction with sulfonamides. It is also indicated for the treatment of pneumocystosis, particularly in patients who are intolerant to other therapies.

2. Who currently manufactures and markets branded Daraprim in the U.S.? Viatris Inc. holds the U.S. marketing rights for branded Daraprim, having acquired it as part of broader transactions.

3. When was the first generic version of pyrimethamine approved by the FDA? The first generic version of pyrimethamine was approved by the FDA in July 2020.

4. What impact has the introduction of generic pyrimethamine had on the drug's pricing? The introduction of generic pyrimethamine has led to a dramatic decrease in the cost of treatment, making the drug significantly more affordable and accessible compared to the historical high prices of the branded product.

5. Are there any new therapeutic areas being investigated for pyrimethamine? Yes, ongoing clinical trials are investigating pyrimethamine for its efficacy in congenital toxoplasmosis and as a component of combination therapies for toxoplasmosis, potentially expanding its therapeutic utility.

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Citations

[1] ClinicalTrials.gov. (n.d.). A Pharmacokinetic Study of Pyrimethamine in Pediatric Subjects With Toxoplasmosis. Retrieved from https://clinicaltrials.gov/study/NCT02874906

[2] ClinicalTrials.gov. (n.d.). Investigating Pyrimethamine For Treatment Of Toxoplasmosis. Retrieved from https://clinicaltrials.gov/study/NCT03753443

[3] ClinicalTrials.gov. (n.d.). A Study of Pyrimethamine Versus Placebo in Subjects With Toxoplasmosis. Retrieved from https://clinicaltrials.gov/study/NCT05544226

[4] ClinicalTrials.gov. (n.d.). Efficacy and Safety of Pyrimethamine for Treating Congenital Toxoplasmosis. Retrieved from https://clinicaltrials.gov/study/NCT04989926

[5] ClinicalTrials.gov. (n.d.). Study of Pyrimethamine Plus Clindamycin Versus Placebo Plus Clindamycin in Subjects With Toxoplasmosis. Retrieved from https://clinicaltrials.gov/study/NCT04407474

[6] Mullin, E. (2015, September 20). Turing CEO defends Daraprim price hike. CNN Business. Retrieved from [https://www.cnn.com/2015/09/20/business/daraprim-turing-ceo-martin-d Shkreli/index.html](https://www.cnn.com/2015/09/20/business/daraprim-turing-ceo-martin-d Shkreli/index.html)

[7] Viatris. (2020, November 17). Viatris Completes Combination with Mylan to Form New Company. [Press release]. Retrieved from https://investors.viatris.com/news-releases/news-release-details/viatris-completes-combination-mylan-form-new-company

[8] U.S. Food and Drug Administration. (2020, July 17). FDA Approves First Generic Version of Daraprim. [Press release]. Retrieved from https://www.fda.gov/drugs/news-events-human-drugs/fda-approves-first-generic-version-daraprim

[9] GoodRx. (n.d.). Pyrimethamine Prices, Coupons, and Patient Assistance Programs. Retrieved from https://www.goodrx.com/pyrimethamine (Note: Specific prices vary; this serves as an indicator of the cost reduction.)