PolycythemiaACTIVAQNCT07341048
Potential Biological and Physiological Determinants for Exercice in Patients With Polycythemia Vera
A study testing Research samples blood viscosity and viscoelasticity: in people with Polycythemia and Polycythemia Vera (PV), run by Hospices Civils de Lyon at 1 site in France.
Trial summary
Polycythemia vera (PV) is a rare haematological disorder characterized by an excessive production of red blood cells, associated with the somatic JAK2 V617F mutation. Clinical manifestations are varied and often include exercise intolerance but the underlying mechanisms remain poorly understood. Read more about this study
- Who is it for?
- Ages 18 to 70 years
- Conditions the study is for
- Polycythemia, Polycythemia Vera (PV)
- What is being tested?
- Research samples blood viscosity and viscoelasticity:
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 54 participants
- Where
- 1 siteFrance
- Study dates
- Jan 2026to May 2027
- Phase
- Interventional
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 70 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Patient aged at least 18 years and under 70.
- Patient followed for a diagnosis of Polycytemia vera (confirmed JAK2 V617F mutation) and who were prescribed a CPET because of their wish to resume regular physical activity.
- Patient affiliated with or benefiting from a social security scheme.
Who cannot join
- Any known history of heart disease or chronic respiratory illness likely to affect VO₂max independently of Polycytemia vera (e.g., asthma), according to the investigator's judgment.
- Any known history of major thromboembolic complication, according to the investigator's judgment.
- Body mass index (BMI) greater than 35, according to the investigator's judgment.
- Participation in another interventional research protocol that may interfere with the present study, according to the investigator's judgment.
- Adult subject under legal protection measures (guardianship, curatorship).
- Subject currently receiving psychiatric care.
- Subject deprived of liberty by judicial or administrative decision.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
France1 site
Department of Sports Medicine and Physical Activity. Pulmonary Function Testing. Croix Rousse Hospital.
Lyon, 69001
Emeric Stauffer, Dr, +33 (0)4 72 07 18 62, emeric.stauffer@chu-lyon.fr
Marie Ducray, Phd, marie.ducray@univ-lyon1.fr
About this study
Official title: Characterization of Exercise Intolerance in Patients With Polycythemia Vera: Study of Potential Biological and Physiological Determinants.
Polycythemia vera (PV) is a rare haematological disorder characterized by an excessive production of red blood cells, associated with the somatic JAK2 V617F mutation. Clinical manifestations are varied and often include exercise intolerance but the underlying mechanisms remain poorly understood.
Physical activity is recommended in the management of chronic diseases, but it must be tailored to the physiological profile of the patient. A cardiopulmonary exercise test (CPET) is essential to ensure safety, detect possible contraindications, and assess maximal oxygen uptake (VO₂max), a key indicator of aerobic performance.
Read more
This prospective, experimental, non-randomized study will include patients with PV followed at Lyon Sud University Hospital and for which a CPET is scheduled in their routine clinical follow-up. The primary objective is to compare VO₂max between two groups of patients: moderate (<10%) versus marked (≥10%) extent of blood viscosity increase after the completion of the CPET. The main hypothesis is that a significant increase in blood viscosity during exercise (≥10%) is a major limiting factor in oxygen transport and leads to a reduced VO₂max, reflecting impaired exercise tolerance.
Secondary analyses will focus on hemorheological parameters, tissue oxygenation, and cardiorespiratory and metabolic responses. The study aims to better understand the biological and physiological determinants of exercise intolerance in this population.
- Conditions
- Polycythemia, Polycythemia Vera (PV)
- Being tested
- Research samples blood viscosity and viscoelasticity:
- Keywords
- Blood viscosity, polycythemia
- Medical subject headings
- Polycythemia, Polycythemia Vera
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Research samples blood viscosity and viscoelasticity:Biological
Also called the level of tissue oxygenation and hemoglobin oxygenation that will be measured by near-infrared spectroscopy (NIRS).
Research samples: Blood rheology: hematocrit, blood viscosity, deformability and erythrocyte aggregation, viscoelasticity
| Study group | Role | What they receive |
|---|---|---|
| Polycythemia vera | Experimental | Patients diagnosed with polycythemia vera, with confirmed presence of the JAK2 V617F mutation, who wish to resume regular daily physical activity and have been prescribed an exercise test for this purpose as part of their follow-up at Lyon Sud Hospital Receives: Biological: Research samples blood viscosity and viscoelasticity: |
What is being measured
The primary outcome is the main question the study is designed to answer.
Blood viscosity (Centipoise) at 6 shear rates.
Blood viscosity will be measured using a cone-plate viscometer (Brookfield, model LVDVII+ PRO, cone CPE 40) on native hematocrit blood, at 7 different shear rates: 2.25, 4.5, 11.5, 22.5, 45, 90, and 225 s-¹, using an ascending ramp shear protocol.
Measured: Measurements will be performed at baseline (pre-test), at 3 minutes post-CPET, and at 60 minutes post-CPET
Secondary outcomes (3)
Rheological properties of blood: deformability and aggregation of erythrocytes
Analyses will be performed on EDTA tubes. Erythrocyte deformability will be measured by ektacytometry at 9 shear stresses (0.3-30 Pa) under isotonic conditions. Maximal elongation index (EImax) and shear stress for 50% deformation (SS₁/₂) will be recorded. Aggregation/disaggregation will be assessed by syllectometry at 40% hematocrit. Parameters include aggregation index (AI) and minimal shear rate (γmin) for full disaggregation
Measured: Measurements will be performed at baseline (pre-test), at 3 minutes post-CPET, and at 60 minutes post-CPET.
Viscoelasticity of blood
Viscoelastic properties of blood will be assessed using rotational thromboelastometry (ROTEM delta) on citrated blood tubes. The following tests will be performed: NATEM, TEMACT, FIBTEM, and EXTEM. For each test, the following parameters will be measured: clotting time (CT, in seconds), clot amplitude at 5, 10, 20, and 30 minutes (A5, A10, A20, A30, in mm), alpha angle (indicating clot formation velocity, in degrees), maximum clot firmness (in mm), percentage of clot lysis at 30 minutes (LI30), as well as lysis onset time (LOT) and total lysis time (LT), both expressed in seconds
Measured: Measurements will be performed at baseline (pre-test), at 3 minutes post-CPET, and at 60 minutes post-CPET
Tissue and haemoglobin oxygenation with near-infrared spectroscopy (NIRS)
Near-infrared spectroscopy (NIRS) will be performed using the Portamon MKIII system (Artinis) with a sampling rate of 100 Hz. This non-invasive technique involves placing surface electrodes on the skin over the vastus lateralis muscle, halfway between the anterior superior iliac spine and the patella. NIRS enables continuous monitoring of changes in oxyhemoglobin (HbO₂) and deoxyhemoglobin (HHb) concentrations, allowing for the calculation of the tissue oxygenation index (TOI)
Measured: Measurement will be performed during the CPET.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted14 Jan 2026
- Study startJan 2026 (estimated)
- Primary completionMay 2027 (estimated)
- Study completionMay 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for PolycythemiaStudies of the same condition, open and under way.
- More trials run by Hospices Civils de LyonThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Not applicable
- Intervention model
- Single group
- Model description
- Prospective, experimental, single-center, non-randomized study.
- Masking
- None (open label)
- Enrolment
- 54 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Hospices Civils de Lyon
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07341048
- Sponsor's protocol ID
- 69HCL25_0364
- Other IDs
- 2025-A01032-47
- Acronym
- ACTIVAQ
- Status last verified
- Jan 2026
- First submitted
- 5 Jan 2026
- Last updated
- 15 Jan 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No