Real-World Joint Outcomes After Selective Transition to Low-Dose Emicizumab in Pediatric Hemophilia A

February 23, 2026 updated by: Chulalongkorn University

The Study of Clinical Outcomes, Cartilage Biomarkers and Hemophilic Arthropathy (HEAD-US) in Hemophilia A Patients : Low Dose Emicizumab vs. Pharmacokinetic-Guided Extended Half-Life FVIII Concentrates

Recent studies have shown that pharmacokinetic (PK)-guided extended half-life (EHL) factor VIII can improve joint health in patients with hemophilia A. However, some patients experience suboptimal joint outcomes despite optimized PK-guided therapy. Low-dose emicizumab has emerged as a potential option for improving bleeding control and joint health in patients who do not respond adequately to PK-guided EHL factor VIII.

The objectives of the study is to compare clinical bleeding outcomes, joint health, cartilage biomarkers, and musculoskeletal ultrasound findings (HEAD-US) in hemophilia A patients in Thailand during PK-guided EHL factor VIII therapy and after switching to low-dose emicizumab.

Eighteen patients with hemophilia A from King Chulalongkorn Memorial Hospital, Thailand, aged 8-28 years, who were receiving PK-guided EHL factor VIII were enrolled. Patients with a Hemophilia Joint Health Score (HJHS) ≥ 12 were switched to low-dose emicizumab. A loading dose of 2 mcg/kg was administered, followed by dosing every 2 weeks during the first month and every 4 weeks thereafter. Clinical bleeding, annual bleeding rate (ABR), annual joint bleeding rate (AJBR), HJHS, cartilage biomarkers, and musculoskeletal ultrasound findings (HEAD-US) were evaluated every 4 months for up to 8 months after switching.

Study Overview

Status

Active, not recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Actual)

18

Phase

  • Phase 2
  • Phase 3

Contacts and Locations

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

Study Locations

  • Thailand
      • Bangkok, Thailand, 10330
        • Chulalongkorn University

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

  • Child
  • Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • hemophilia A patients aged 3-30 years who received treatment with PK-guided EHL Factor VIII for more than 8 months

Exclusion Criteria:

  • hemophilia A patients with presence of factor VIII inhibitors

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: Non-Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Hemophilia A patients with HJHS more than 12
All Hemophilia A patients in the study had received treatment with PK-guided EHL factor VIII. The patients who had HJHS more than 12 were switched to treatment with low dose emicizumab
Drug: Switching to low dose emicizumab
All Hemophilia A patients in the study had received treatment with PK-guided EHL factor VIII. The patients who had HJHS more than 12 were switched to treatment with low dose emicizumab
No Intervention: Hemophilia A patients with HJHS less than 12
Hemophilia A patients whose HJHS was less than 12 continue the same PK-guided EHL Factor VIII

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Annual bleeding rate
Time Frame: 8 months
Annual bleeding rate report as times per year
8 months
Annual joint bleeding rate
Time Frame: 8 months
Annual joint bleeding rate report as times per year
8 months
Hemophilia Joint Health Score (HJHS)
Time Frame: 8 months
HJHS is the physical examination assessment tool for hemophilia patients evaluated most commonly 6 joints affected by bleeding (both elbows, both knees and both ankles). The scores range from 0 (minimum) to 125 (maximum). The lowest score means the best joint health.
8 months
The quality of life assessment instrument for children and adolescents with haemophilia (Hae-QoL)
Time Frame: 8 months
The assessment tools evaluate physical, psychological, family, social aspect of Hemophilia patients. There are 35 questions. Each questions has multiple choices (never, seldom, somtimes, often, always) represent score 1 (never) to 5 (always). The total raw score range from 35 to 175 and then must be transform to "transformed score" ranged from 0 to 100. 0 is the best and 100 is the worst score.
8 months

Collaborators and Investigators

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

Sponsor

Chulalongkorn University

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 (Actual)

June 1, 2025

Primary Completion (Estimated)

March 1, 2026

Study Completion (Estimated)

April 1, 2026

Study Registration Dates

First Submitted

January 20, 2026

First Submitted That Met QC Criteria

February 23, 2026

First Posted (Actual)

February 27, 2026

Study Record Updates

Last Update Posted (Actual)

February 27, 2026

Last Update Submitted That Met QC Criteria

February 23, 2026

Last Verified

January 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 0415/67

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

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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