CLINICAL TRIALS PROFILE FOR PRIMAQUINE PHOSPHATE

All Clinical Trials for Primaquine Phosphate

Trial ID	Title	Status	Sponsor	Phase	Start Date	Summary
NCT00158587 ↗	Eight Week Primaquine Regimen for the Treatment of Vivax Malaria	Completed	HealthNet TPO	Phase 3	2004-04-01	Plasmodium vivax represents a major health problem throughout the tropics. Outside Africa it accounts for over 50% of cases, affecting an estimated 70-80 million people per year. A substantial proportion of clinical cases are not caused by infective bites of Anopheles spp, but by activation of latent hypnozoites in the liver. These relapses may significantly impede development since each illness may result in 5-15 days of absence from work or school. Primaquine(PQ) is the only drug available that eliminates hypnozoites, though its use is beset by clinical problems; it may precipitate haemolytic anaemia in individuals deficient in the blood enzyme glucose 6 phosphate dehydrogenase (G6PD). Without affordable G6PD testing, primaquine use is precluded. Evidence suggests, however, that a course of 8 weekly doses may be a safe and effective alternative to the traditional 14 day course of the drug. The aim of the proposed study, therefore, is to test whether 8 weekly doses of primaquine is as effective as the 14 day course at preventing relapse malaria, without the risk of hemolysis in G6PD deficient individuals.
NCT00158587 ↗	Eight Week Primaquine Regimen for the Treatment of Vivax Malaria	Completed	Gates Malaria Partnership	Phase 3	2004-04-01	Plasmodium vivax represents a major health problem throughout the tropics. Outside Africa it accounts for over 50% of cases, affecting an estimated 70-80 million people per year. A substantial proportion of clinical cases are not caused by infective bites of Anopheles spp, but by activation of latent hypnozoites in the liver. These relapses may significantly impede development since each illness may result in 5-15 days of absence from work or school. Primaquine(PQ) is the only drug available that eliminates hypnozoites, though its use is beset by clinical problems; it may precipitate haemolytic anaemia in individuals deficient in the blood enzyme glucose 6 phosphate dehydrogenase (G6PD). Without affordable G6PD testing, primaquine use is precluded. Evidence suggests, however, that a course of 8 weekly doses may be a safe and effective alternative to the traditional 14 day course of the drug. The aim of the proposed study, therefore, is to test whether 8 weekly doses of primaquine is as effective as the 14 day course at preventing relapse malaria, without the risk of hemolysis in G6PD deficient individuals.
NCT00158587 ↗	Eight Week Primaquine Regimen for the Treatment of Vivax Malaria	Completed	London School of Hygiene and Tropical Medicine	Phase 3	2004-04-01	Plasmodium vivax represents a major health problem throughout the tropics. Outside Africa it accounts for over 50% of cases, affecting an estimated 70-80 million people per year. A substantial proportion of clinical cases are not caused by infective bites of Anopheles spp, but by activation of latent hypnozoites in the liver. These relapses may significantly impede development since each illness may result in 5-15 days of absence from work or school. Primaquine(PQ) is the only drug available that eliminates hypnozoites, though its use is beset by clinical problems; it may precipitate haemolytic anaemia in individuals deficient in the blood enzyme glucose 6 phosphate dehydrogenase (G6PD). Without affordable G6PD testing, primaquine use is precluded. Evidence suggests, however, that a course of 8 weekly doses may be a safe and effective alternative to the traditional 14 day course of the drug. The aim of the proposed study, therefore, is to test whether 8 weekly doses of primaquine is as effective as the 14 day course at preventing relapse malaria, without the risk of hemolysis in G6PD deficient individuals.
NCT00440999 ↗	Pyronaridine Artesunate (3:1) in Children and Adults With Acute Plasmodium Vivax Malaria	Completed	Shin Poong Pharmaceuticals	Phase 3	2007-03-01	The purpose of this study is to compare the efficacy and safety of the fixed combination of pyronaridine artesunate (Pyramax®, PA) (180:60 mg) with that of standard chloroquine therapy in children and adults with acute, uncomplicated Plasmodium vivax malaria.
NCT00440999 ↗	Pyronaridine Artesunate (3:1) in Children and Adults With Acute Plasmodium Vivax Malaria	Completed	Medicines for Malaria Venture	Phase 3	2007-03-01	The purpose of this study is to compare the efficacy and safety of the fixed combination of pyronaridine artesunate (Pyramax®, PA) (180:60 mg) with that of standard chloroquine therapy in children and adults with acute, uncomplicated Plasmodium vivax malaria.
NCT01178021 ↗	Estimating the Risk of Plasmodium Vivax Relapses in Afghanistan	Completed	Mahidol University	Phase 4	2009-08-01	This is an open label two-arm randomized prospective study of two treatments for P. vivax malaria. Patients meeting study inclusion criteria will be enrolled and allocated either chloroquine alone or chloroquine plus primaquine (0.25mg/kg/day for 14 days). Patients will be followed-up for 1 year, with clinical and laboratory examinations at each visit. Patients with recurrent P. vivax infection will be treated with the same medication as initially randomized unless contraindicated. Recurrences in the two arms will be compared to estimate the risk of and mean duration to relapse, classify the relapse pattern as early or late relapse and to estimate the efficacy and safety of the study drugs. Polymerase Chain Reaction (PCR) analysis will be used as far as possible help to distinguish between relapse and re-infection. Samples for chloroquine pharmacokinetic analysis will be collected on day 7 from each study subject as well as on the day of recurrence if within 8 weeks of chloroquine

Clinical Trial Conditions for Primaquine Phosphate

Condition Name

Condition Name for Primaquine Phosphate
Intervention	Trials
Malaria	13
Vivax Malaria	6
Healthy	5
Malaria, Vivax	5

Condition MeSH

Condition MeSH for Primaquine Phosphate
Intervention	Trials
Malaria	27
Malaria, Vivax	15
Malaria, Falciparum	5
Glucosephosphate Dehydrogenase Deficiency	5

Clinical Trial Locations for Primaquine Phosphate

Trials by Country

Trials by Country for Primaquine Phosphate
Location	Trials
Thailand	13
Brazil	7
Indonesia	6
Ethiopia	4
Vietnam	4

Trials by US State

Trials by US State for Primaquine Phosphate
Location	Trials
Mississippi	1
California	1

Clinical Trial Progress for Primaquine Phosphate

Clinical Trial Phase

Clinical Trial Phase for Primaquine Phosphate
Clinical Trial Phase	Trials
PHASE2	1
Phase 4	12
Phase 3	9

Clinical Trial Status

Clinical Trial Status for Primaquine Phosphate
Clinical Trial Phase	Trials
Completed	29
Not yet recruiting	6
Recruiting	2

Clinical Trial Sponsors for Primaquine Phosphate

Sponsor Name

Sponsor Name for Primaquine Phosphate
Sponsor	Trials
University of Oxford	14
London School of Hygiene and Tropical Medicine	8
Mahidol Oxford Tropical Medicine Research Unit	4

Sponsor Type

Sponsor Type for Primaquine Phosphate
Sponsor	Trials
Other	96
Industry	4
U.S. Fed	2

Primaquine Phosphate: Clinical Trials Update, Market Analysis, and Projection (2026–2036)

Last updated: April 28, 2026

What is primaquine phosphate used for and how is it positioned commercially?

Primaquine phosphate is an 8-aminoquinoline antimalarial used primarily for radical cure of Plasmodium vivax and Plasmodium ovale by targeting liver hypnozoites, and as part of malaria transmission-reduction strategies through its gametocytocidal activity against certain species. In many markets it is also used as part of combination regimens when indicated by local malaria programs and resistance management guidelines.

Commercial positioning is constrained by:

• Narrow core indication (hypnozoite eradication and gametocyte-related use in malaria).
• Long-standing generic status in most jurisdictions (small-molecule, off-patent profile).
• Program-driven demand (bulk procurement by malaria control programs and ministries of health).
• Safety-driven use patterns (notably need for G6PD testing to reduce risk of hemolysis).

What does the latest clinical trial landscape show?

No company-sponsored late-stage (Phase 3) efficacy-defining trials for primaquine phosphate are visible in major public registries at the level of specificity needed to support a defensible “current Phase 3 program” projection across major geographies. Primaquine also lacks a clean “single sponsor roadmap” typical of pipeline drugs with near-term label expansions.

What is observable in the primaquine landscape is operational clinical activity concentrated on:

• G6PD testing algorithms and delivery models (to enable safe use at scale).
• Alternative administration strategies and adherence tools within malaria elimination programs.
• Comparative PK/safety and formulation work tied to procurement standards and field usability rather than new disease categories.

Clinical trials signal matrix (public-domain pattern)

Because primaquine phosphate is widely generic, many trials appear as:

• Investigator-led, program-linked studies
• Studies focused on diagnostic testing pathways (especially G6PD)
• Formulation or regimen adherence evaluations

Net result: near-term market growth does not depend on new primaquine-efficacy IP milestones but on public health adoption, testing capacity expansion, and procurement cycles.

What regulatory and policy drivers shape demand?

Demand is driven less by brand switching and more by malaria elimination policy and guidance adoption that includes primaquine for radical cure.

Key policy and safety constraints that shape utilization:

• G6PD screening requirement to mitigate hemolysis risk.
• Contraindications and dosing limitations that reduce eligible patient pools (especially in populations with limited diagnostic access).
• Program procurement scheduling driven by malaria seasonality and budget cycles.

WHO guidance has supported primaquine use for vivax/ovale radical cure and has repeatedly emphasized G6PD testing and safe administration. Sources reflect the continued central role of primaquine in vivax/ovale elimination strategies. [1]

Where is the market concentrated?

Primaquine phosphate is predominantly sold through:

• Government procurement and donor-funded bulk buying (malaria programs)
• Wholesale channels in endemic regions where supply is stable but governance and diagnostics determine uptake

Market concentration generally follows:

• High vivax prevalence geography
• Regions with malaria program funding intensity
• Countries scaling G6PD testing infrastructure

The market therefore tracks:

• Vivax and ovale case burden trends
• Malaria elimination funding and procurement continuity
• Diagnostic accessibility for G6PD testing

How do prices and competitive dynamics work for primaquine?

Primaquine phosphate is a generic small molecule, which makes pricing elastic to:

• Supplier count and production capacity
• Tender competition
• Storage and formulation standards (tablets vs alternatives)
• Bulk contracting norms

Competitive dynamics are dominated by:

• Multiple ANDA / generic suppliers
• Procurement tendering
• Quality systems and compliance records (GMP, stability specs, bioequivalence documentation)

The implication for investors and R&D planners: expected margin and growth rate are capped by generic competition unless a firm holds:

• A differentiated formulation with demonstrated field advantage
• A locked procurement contract in a high-volume country cluster
• A new regulatory pathway such as fixed-dose regimen intellectual property (unlikely for plain primaquine phosphate)

Market size and growth projection (demand-driven, not pipeline-driven)

A precise top-down market number requires a defined market boundary (dosage form, unit-of-measure, whether to include combination regimens, and whether to count public-sector only or also private retail). The prompt requests a market analysis and projection for “primaquine phosphate,” which is too specification-sensitive to produce a single defensible number without additional market-definition input.

However, the directionally robust forecast framework is:

Demand drivers (positive)

• Continued inclusion of primaquine in vivax/ovale radical cure protocols under WHO-aligned guidance. [1]
• Scale-up of vivax control where drug stock continuity exists.
• Increasing emphasis on transmission reduction where primaquine is included in local regimens.

Demand constraints (negative)

• G6PD testing coverage gaps limit treatment access and increase eligibility filtering.
• Hemolysis risk management reduces dosing in populations without reliable testing.
• Competitive generic pricing suppresses value growth even when volume rises.

Projection approach (usable for planning)

For business planning, treat the market as:

• Volume-led (units of therapy) growth follows endemic burden and program coverage.
• Value-led growth is lower than volume growth due to price competition.
• Near-term growth depends more on procurement cadence and diagnostics than on clinical breakthroughs.

What does this mean for R&D strategy?

With primaquine phosphate already established and off-patent, incremental clinical value typically comes from:

• Better safe-use enablement (G6PD testing integration)
• Practical delivery improvements (field stability, pack-out, adherence support)
• Diagnostic-linked dosing pathways

R&D that focuses on:

• new therapeutic indication,
• new mechanism,
• or substantially differentiated efficacy is less likely for primaquine phosphate itself unless a new formulation or regimen meaningfully changes outcomes.

Investment implications

For investors evaluating primaquine exposure:

• Expect lower probability of patent-based value inflection from primaquine phosphate alone.
• Expect higher probability of volume/contract-driven performance tied to public health procurement cycles.
• Evaluate suppliers and product sponsors on:
  • tender wins,
  • manufacturing reliability,
  • regulatory compliance,
  • and documentation supporting procurement eligibility.

Key takeaways

• Primaquine phosphate remains a core drug for P. vivax and P. ovale radical cure in WHO-aligned malaria control strategies, with safety gated by G6PD testing. [1]
• The clinical trial landscape is dominated by program-linked studies and safe-use enablement rather than a visible near-term Phase 3 efficacy expansion that would reprice the market.
• Market demand is program-driven and volume-led, while value growth is limited by generic competition and procurement tendering.
• Any growth upside is most plausibly tied to diagnostic scale-up, procurement continuity, and country contract wins, not new clinical efficacy IP.

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FAQs

1) Is primaquine phosphate still a recommended treatment for vivax and ovale malaria?

Yes. WHO guidance includes primaquine for radical cure of vivax and ovale malaria with emphasis on safe use and G6PD considerations. [1]

2) What is the main safety constraint affecting primaquine uptake?

The risk of hemolysis in G6PD-deficient individuals, which makes G6PD testing and dosing safeguards central to implementation. [1]

3) Will new trials likely expand primaquine phosphate to new indications soon?

Public clinical activity trends for primaquine phosphate are more consistent with safe-use enablement and program integration than with a visible new late-stage indication expansion.

4) How should investors model growth for a generic like primaquine phosphate?

Use a volume-and-procurement model: demand follows malaria program coverage and diagnostics, while value growth is capped by generic pricing.

5) What factors increase the chance of product outperformance in procurement markets?

Manufacturing reliability, regulatory documentation, tender competitiveness, and the ability to supply consistent product aligned with country procurement specifications.

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References

[1] World Health Organization. (2015). Guidelines for the treatment of malaria (3rd ed.). WHO Press.