Pentoxifylline Add-On Therapy for Mild-to-Moderate Plaque Psoriasis (PTX-PSO)

June 3, 2026 updated by: Wasuchon Chaichan

Efficacy and Safety of Pentoxifylline as Add-On Therapy for Mild-to-Moderate Plaque Psoriasis: A Double-Blind Randomized Placebo-Controlled Trial

This study will evaluate whether pentoxifylline, when used as an add-on treatment to standard topical therapy, is effective and safe for adults with mild-to-moderate plaque psoriasis. Participants will be randomly assigned to receive either pentoxifylline or placebo twice daily for 12 weeks, while continuing their standard topical treatment. The study will compare improvement in psoriasis severity, itch, physician assessment, quality of life, and adverse events between the two groups. Participants will be followed for a total of 16 weeks.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

Psoriasis is a chronic inflammatory skin disease that may cause persistent plaques, itching, and impaired quality of life. Many patients with mild-to-moderate plaque psoriasis are treated mainly with topical therapy, but some patients have an inadequate response or ongoing symptoms. Pentoxifylline is an oral methylxanthine derivative with anti-inflammatory and microcirculatory effects, including inhibition of pro-inflammatory cytokines such as TNF-alpha, IL-1, and IL-6. These mechanisms may be relevant to the inflammatory pathways involved in psoriasis.

This study is a prospective, randomized, double-blind, placebo-controlled, parallel-group trial designed to evaluate pentoxifylline as an add-on therapy to standard topical treatment in adults with mild-to-moderate plaque psoriasis. Eligible participants will be randomly assigned in a 1:1 ratio to receive either pentoxifylline add-on therapy or placebo add-on therapy. All participants will continue standard topical treatment according to usual clinical care.

The treatment period will be 12 weeks, followed by an additional follow-up period until week 16. Clinical assessments will be performed at baseline and follow-up visits to evaluate psoriasis severity, body surface area involvement, physician global assessment, itch severity, quality of life, and safety. The primary objective is to compare the proportion of participants achieving PASI 50 at week 12 between the pentoxifylline and placebo groups. Safety will be assessed by monitoring adverse events, serious adverse events, and laboratory parameters.

Study Type

Interventional

Enrollment (Estimated)

140

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

  • Thailand
    • Changwat Phayao
      • Phayao, Changwat Phayao, Thailand, 56000
        • University of Phayao Hospital
        • Principal Investigator:
          • Wasuchon Chaichan, MD
        • Contact:
        • Contact:
        • Sub-Investigator:
          • Chonlawat Chaichan, MSc

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Adults aged 18 to 65 years.
  • Clinical diagnosis of mild-to-moderate plaque psoriasis, defined as Psoriasis Area and Severity Index (PASI) score 3 to 10 or body surface area (BSA) involvement 3% to 10%, as assessed by a physician.
  • Receiving stable standard topical therapy for at least 2 weeks before enrollment.
  • Able and willing to provide written informed consent.
  • Willing to comply with the study protocol and scheduled follow-up visits.

Exclusion Criteria:

  • Use of biologic agents within 12 weeks before enrollment.
  • Psoriatic arthritis requiring systemic therapy.
  • Pregnant or breastfeeding.
  • Severe liver disease or severe kidney disease.
  • History of significant bleeding disorder or current use of anticoagulant therapy that cannot be appropriately managed.
  • Known hypersensitivity to pentoxifylline or related xanthine derivatives.
  • Any serious medical condition or safety concern that, in the investigator's judgment, makes participation inappropriate.
  • Refusal or inability to provide informed consent

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Pentoxifylline Add-On Therapy
Participants in this arm will receive pentoxifylline 400 mg orally twice daily after meals for 12 weeks, in addition to standard topical therapy for plaque psoriasis. Participants will continue their usual standard topical treatment according to clinical care. Follow-up assessments will be performed through week 16.
Drug: Pentoxifylline 400 mg Oral Tablet
Pentoxifylline 400 mg capsule will be taken orally twice daily after meals, once in the morning and once in the evening, for 12 weeks. The intervention will be given as add-on therapy while participants continue standard topical treatment for plaque psoriasis.
Placebo Comparator: Placebo Add-On Therapy
Participants in this arm will receive matching placebo orally twice daily after meals for 12 weeks, in addition to standard topical therapy for plaque psoriasis. Participants will continue their usual standard topical treatment according to clinical care. Follow-up assessments will be performed through week 16.
Drug: Placebo
Matching placebo capsule will be taken orally twice daily after meals, once in the morning and once in the evening, for 12 weeks. The placebo will be given as add-on therapy while participants continue standard topical treatment for plaque psoriasis.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Proportion of Participants Achieving PASI 50
Time Frame: Week 12
Proportion of participants who achieve at least a 50% reduction from baseline in Psoriasis Area and Severity Index (PASI) score. PASI is a physician-assessed measure of psoriasis severity based on erythema, induration, scaling, and affected body surface area.
Week 12

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Proportion of Participants Achieving PASI 75
Time Frame: Week 12
Proportion of participants who achieve at least a 75% reduction from baseline in Psoriasis Area and Severity Index (PASI) score.
Week 12
Proportion of Participants Achieving PASI 90
Time Frame: Week 12
Proportion of participants who achieve at least a 90% reduction from baseline in Psoriasis Area and Severity Index (PASI) score.
Week 12
Percent Change in PASI Score From Baseline
Time Frame: Baseline to Week 12
Percent change from baseline in Psoriasis Area and Severity Index (PASI) score. PASI is assessed by a physician based on erythema, induration, scaling, and affected body surface area.
Baseline to Week 12

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Wasuchon Chaichan

Investigators

  • Principal Investigator: Wasuchon Chaichan, MD, University of Phayao

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

June 15, 2026

Primary Completion (Estimated)

March 1, 2027

Study Completion (Estimated)

October 1, 2028

Study Registration Dates

First Submitted

May 31, 2026

First Submitted That Met QC Criteria

May 31, 2026

First Posted (Actual)

June 4, 2026

Study Record Updates

Last Update Posted (Actual)

June 5, 2026

Last Update Submitted That Met QC Criteria

June 3, 2026

Last Verified

June 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • HREC-UP-HSST 1.3/032/69
  • MD69-10 (Other Grant/Funding Number: School of Medicine, University of Phayao)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Individual participant data (IPD) will not be shared because the dataset contains sensitive health information and the study sample size is small, making de-identification difficult. In addition, the informed consent form does not include permission for public sharing of individual-level data.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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