An 18-month Low-interventional Study to Assess Joint Health in Haemophilia A and B Patients on Prophylaxis With Efmoroctocog Alfa or Eftrenonacog Alfa

The goal of this low-interventional study is to describe the overall joint health in patients with haemophilia A or haemophilia B prophylactically treated with rFVIIIFc or rFIXFc.

The main question it aims to answer is the:

• Evaluation of the overall joint status as detected by ultrasound in haemophilia A and B patients treated with rFVIIIFc or rFIXFc prophylaxis over the 18-month study period.

Participants will come to 6-monthly visits during the 18-month long study period and will perform an ultrasound with the Haemophilia Early Arthropathy Detection with Ultrasound (HEAD-US) protocol at each visit. At baseline and end of study visits, the patients will be assessed with the clinical scoring system Haemophilia Joint Health Score (HJHS) and complete patient questionnaires. Retrospective data from patient medical records will also be collected for at least 6 months before enrolment in the study.

The main purpose of this study is to prospectively describe the joint health over an 18-month period of prophylactic treatment with rFVIIIFc or rFIXFc in patients with haemophilia A or haemophilia B in a real-world setting in Europe.

This is a low-interventional, multicentre study using point-of-care US examination for regular monitoring of joint health and detection of hypertrophic synovium, cartilage and bone damage. At the same time, clinical joint status will also be examined by HJHS. This study will evaluate the presence, resolution, recurrence, and new development of target joints. It will also describe bleeding episodes and evaluate the quality of life and physical activity with PROs. If patients are using the CE marked Florio HAEMO app in their routine clinical practice, they will be offered to participate in an optional sub-study that aims to explore possible correlations between the levels of physical activity, the estimated FVIII/FIX levels and bleeding occurrence.

Eligibility Criteria:
Inclusion Criteria:

1. Age ≥ 6 years
2. Diagnosis of haemophilia A or B
3. Having at least 6 months documented pre-study treatment data regarding treatment prescriptions and bleeding episodes prior to the baseline visit
4. Previous treatment for haemophilia A or B with any marketed recombinant and/or plasma-derived FVIII or FIX concentrate for at least 6 months
5. Start of prophylactic treatment with rFVIIIFc or rFIXFc prior to study enrollment or latest at the baseline visit, in accordance with local regulations
6. Signed and dated informed consent provided by the patient, or the patient's legally authorized representative for patients under the legal age. Assent should be obtained from paediatric patients in accordance with local regulations

Exclusion Criteria:

1. Any medical condition which in the opinion of the investigator makes the subject patient unsuitable for inclusion
2. Prophylactic treatment with non-factor therapy during the 6 months prior to enrolment
3. Presence of factor VIII or FIX inhibitory antibodies (inhibitors) (≥0.60 Bethesda Units \[BU\]/mL) at the latest available inhibitor test
4. Enrolment in a concurrent clinical interventional study, or intake of an IMP, within three months prior to inclusion in this study
5. Foreseeable inability to cooperate with given instructions or study procedures