Hypobaric HypoxiaPhase 4NCT05300477
Pharmacological Countermeasures for High Altitude
A Phase 4 study testing Acetazolamide and Erythropoietin in people with Hypobaric Hypoxia, run by United States Army Research Institute of Environmental Medicine at 1 site in United States.
Trial summary
The aim of this randomized, double-blind study is to determine whether erythropoietin (Procrit) and acetazolamide: 1) mitigates altitude-induced decrements in performance at moderate altitude (3,000 m) and 2) mitigates altitude-induced decrements in performance and reduce acute mountain sickness during prolonged… Read more about this study
- Who is it for?
- Ages 18 to 40 yearsHealthy volunteers can take part
- Conditions the study is for
- Hypobaric Hypoxia
- What is being tested?
- Acetazolamide and Erythropoietin
- Type of treatment
- Pill or oral medicine, Injection or infusion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 18 participants
- Where
- 1 siteUnited States
- Study dates
- 27 May 2022to 30 Sep 2025
- Phase
- Phase 4
- Are there results?
- Not yet: the study is under way
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 40 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Age 18-40 years
- In good health as determined by the Office of Medical Support \& Oversight (OMSO) General Medical Clearance
- Runs at least 3 times per week and able to complete a two mile run in ≤ 21 minutes (Civilian Volunteers) or passed his/her most recent Army Combat Fitness Test (ACFT) (Military Volunteers Only)
- Willing to not exercise, or drink alcoholic and/or caffeinated beverages 24 hours prior to each testing session or the acute altitude exposure to 3,000 m
- Abstain from alcoholic beverages during the 15 day residence at the summit of Pikes Peak
- Abstain from drinking alcohol or caffeine at least 24 hours before a testing session during Phases 1 and 3
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- Willing to stay and exercise in an altitude chamber (the size of a dorm room) for ~2.5 hours
- Wiling to reside at the summit of Pikes Peak (4,300 m altitude) and share dormitory area (bunk area, shower, and bathroom), potentially with people of the opposite sex for 15 days
- Up to date on COVID-19 vaccination
Who cannot join
- Women who are pregnant or planning to become pregnant during the study
- Taking prescription medication, or over-the-counter medications other than contraceptives, unless approved by OMSO \& PI
- Born at altitudes greater than 2,100 m (7,000 ft)
- Living in areas that are more than 1,200 m (4,000 ft) or have traveled to areas that are more than 1,200 m for five days or more within the last 2 months
- Prior diagnosis of High Altitude Pulmonary Edema (HAPE) or High Altitude Cerebral Edema (HACE)
- Musculoskeletal injuries that compromise the ability to walk/run on a treadmill or hike steep terrain
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- Abnormal blood count in accordance with OMSO - Normal Hb men: 12.6-17.7 g·dL-1 and women: 11.1-15.9 g·dL-1 or Normal Hct men: 37.5-48% and women: 34.0-45%, or presence of abnormal blood chemicals (hemoglobin S or Sickle Cell Trait)
- Any history of malignancy
- Personal or family history of blood clots
- Abnormal prothrombin time/partial thromboplastin time (PT/PTT) test or problems with blood clotting
- History of thromboembolic disease, hypertension, and known risk factors of cardiovascular disease
- Blood donation within 8 weeks of beginning the study
- History of seizures
- History of inflammatory bowel disease
- Any recent (within 4-6 weeks) and or expected history of prolonged periods of immobility or limited activity (including recent or upcoming surgery)
- No evidence of iron deficiency (ferritin < 45 ng/ml)
- Smokers or tobacco/nicotine (unless quit > 1 month prior to study orientation)
- History of asthma
- Experience recent (< 1 month of starting the study) cold, coughs, or respiratory tract infections
- Allergy to skin adhesive
- Known allergy to sulfa drugs
- Evidence of apnea or sleeping disorder
- Present condition of alcoholism, use of anabolic steroids, other substance abuse issues
- Inability to tolerate iron supplement
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Augmentation of Medical Readiness and Physical Performance at High Altitude Using Pharmacological Countermeasures
The aim of this randomized, double-blind study is to determine whether erythropoietin (Procrit) and acetazolamide: 1) mitigates altitude-induced decrements in performance at moderate altitude (3,000 m) and 2) mitigates altitude-induced decrements in performance and reduce acute mountain sickness during prolonged exposure to high altitude (4,300 m; 15 days). Volunteers will complete 5 study phases: Phase 1) sea level baseline testing and a moderate altitude exposure; Phase 2) 4 week study intervention - randomly assigned to receive erythropoietin or placebo); Phase 3) 3 1/2 days of acetazolamide and a moderate altitude exposure; Phase 4) high altitude acclimatization - 15 days at Pikes Peak; and Phase 5) two week deacclimatization. Test battery include VO2peak, 3.2 km treadmill time trial, measures of gas exchange and ventilation during rest and exercise, and blood collection.
Read the detailed description
This study will use a double-blind randomized study design in which one group will receive erythropoietin and the other a placebo (saline) for 4 weeks, then both groups will receive acetazolamide. Eighteen men and women volunteers will complete 5 study phases: Phase 1) two week sea level baseline testing (orientation, two VO2peak assessments, three 3.2 km treadmill time-trial, assessment of resting ventilation, venipuncture and capillary blood collection, and Hbmass assessment), and a VO2peak and 3.2 km treadmill time-trial moderate altitude (3,000 m); Phase 2) 4 week intervention to receive subcutaneously erythropoietin or placebo. The erythropoietin (Procrit) dosing regimen will consist of 50 IU/kg three times a week (M-W-F); Phase 3) a second moderate altitude exposure (VO2peak and 3.2 km treadmill time-trial with acetazolamide administered (orally; 250 mg b.i.d) for 3 1/2 nights starting the day before the altitude exposure; Phase 4) high altitude acclimatization in which volunteers will reside for 15 days at 4,300 m altitude (Pikes Peak, Colorado Springs) completing multiple VO2peak assessments and 3.2 km treadmill time-trials, resting ventilation, venipuncture and capillary blood collection; and Phase 5) deacclimatization phase to assess changes in hematological biomarkers after returning from Pikes Peak. This study consists of 41 visits over a ~10 week time period. Visits will take place in Natick, MA and the Pikes Peak High Altitude Research Laboratory at Colorado Springs. Additional assessments that will be completed multiple times during the study include: acute mountain sickness questionnaire, lung gas diffusion at rest and during exercise, oxygen saturation, arterialized blood gases (PO2, PCO2, pH, HCO3) and heart rate during rest, exercise, and sleep, and muscle tissue oxygenation. The primary outcome is 3.2 km treadmill time-trial performance. Secondary outcomes include: incidence and severity of acute mountain sickness, ventilation and gas exchange, Hbmass, Hb concentration, Hct, arterialized blood gases, lung diffusion at rest and during exercise, oxygen saturation and heart rate during rest, exercise, and sleep.
- Conditions
- Hypobaric Hypoxia
- Being tested
- Acetazolamide, Erythropoietin
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
AcetazolamideDrug
Also called Diamox
Carbonic Anhydrase Inhibitor
ErythropoietinDrug
Also called Procrit
Hormone for red blood cell
| Study group | Role | What they receive |
|---|---|---|
| Acetazolamide | Experimental | Acetazolamide (orally) 250 mg twice a day for 3 1/2 days. Receives: Drug: Acetazolamide |
| Erythropoietin and Acetazolamide | Experimental | Erythropoietin (subcutaneously) 50 IU /kg three times a week for 4 weeks. After the 4 week Erythropoietin, acetazolamide (orally) 250 mg twice a day for 3 1/2 days. Receives: Drug: Acetazolamide; Drug: Erythropoietin |
What is being measured
The primary outcome is the main question the study is designed to answer.
3.2 km self-paced treadmill time trial performance
Time to complete self-paced 3.2 km treadmill time trial (min:sec)
Measured: 35 minutes
Secondary outcomes (17)
VO2peak
Peak aerobic capacity will be assessed using a metabolic cart.
Measured: 30 minutes
Lake Louise Acute Mountain Sickness Score
Acute mountain sickness and severity will be assessed using the Lake Louise acute mountain sickness questionnaire. This Likert scale assess acute mountain sickness with scores ranging from 0 to 12. Zero indicates no acute mountain sickness and 12 indicates severe acute mountain sickness.
Measured: 10 minutes
Ventilation rate
Ventilation rate will be assessed using a pneumotachometer.
Measured: 20 minutes
Percent body fat
Percent body fat will be assessed using Dual Energy X-ray Absorptiometry.
Measured: 10 minutes
Oxygen Saturation
Oxygen saturation will be assessed using a finger pulse oximeter.
Measured: 35 minutes
Erythropoietin
Erythropoietin will be assessed using an ELISA.
Measured: 4 hours
Hematocrit
Hematocrit will be assessed using manual hematocrit method.
Measured: 5 minutes
Reticulocyte
Reticulocyte will be assessed using a hematology analyzer.
Measured: 2 hours
Ferritin
Ferritin will be assessed using an ELISA.
Measured: 2 hours
C-reactive protein
C-reactive protein will be assessed using an ELISA.
Measured: 2 hours
Soluble transferrin
Soluble transferrin will be assessed using an ELISA.
Measured: 2 hours
Arterialized capillary PO2
Arterialized capillary PO2 will be assessed using a blood gas analyzer.
Measured: 5 minutes
Arterialized capillary PCO2
Arterialized capillary PCO2 will be assessed using a blood gas analyzer.
Measured: 5 minutes
Arterialized capillary pH
Arterialized capillary pH will be assessed using a blood gas analyzer.
Measured: 5 minutes
Hbmass
Hbmass will be assessed using the CO-rebreathing procedure.
Measured: 20 minutes
Muscle tissue oxygenation
Muscle tissue oxygenation will be assessed using a non-invasive near-infrared spectroscopy.
Measured: 35 minutes
Lung Diffusion of carbon monoxide
Lung Diffusion of carbon monoxide will be assessed using a spirometer.
Measured: 35 minutes
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted29 Mar 2022
- Study start27 May 2022
- Primary completion30 Sep 2023
- Study completion30 Sep 2025 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Hypobaric HypoxiaStudies of the same condition, open and under way.
- 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 4
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- This study will use a double-blind randomized study design in which one group will receive erythropoietin and the other group will receive the placebo for 4 weeks. After the 4 weeks, both groups will receive acetazolamide.
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 18 participants (estimated)
Sponsor and investigators
- Lead sponsor
- United States Army Research Institute of Environmental Medicine
- Sponsor type
- US federal agency
- Collaborators
- University of Puget Sound
- Responsible party
- Principal investigator, Roy Salgado, United States Army Research Institute of Environmental Medicine
- Investigators
- Roy Salgado, PhD, Principal investigator, United States Army Research Institute of Environmental Medicine
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05300477
- Sponsor's protocol ID
- 21-06HC (M-10910)
- Status last verified
- Mar 2025
- First submitted
- 17 Mar 2022
- Last updated
- 26 Mar 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 26 Mar 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Augmentation of Medical Readiness and Physical Performance at High Altitude Using Pharmacological Countermeasures
- ClinicalTrials.gov ID
- NCT05300477
- Acronym / sponsor ID
- 21-06HC (M-10910)
- Conditions
- Hypobaric Hypoxia
- Phase
- Phase 4
- Study type
- Interventional
- Recruitment status
- Active, not recruiting
- Enrolment
- 18 participants (estimated)
- Lead sponsor
- United States Army Research Institute of Environmental MedicineUS federal agency
- Collaborators
- University of Puget Sound
- Study start
- 27 May 2022 (actual)
- Primary completion
- 30 Sep 2023 (actual)
- Study completion
- 30 Sep 2025 (estimated)
- First posted
- 29 Mar 2022 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The aim of this randomized, double-blind study is to determine whether erythropoietin (Procrit) and acetazolamide: 1) mitigates altitude-induced decrements in performance at moderate altitude (3,000 m) and 2) mitigates altitude-induced decrements in performance and reduce acute mountain sickness during prolonged exposure to high altitude (4,300 m; 15 days). Volunteers will complete 5 study phases: Phase 1) sea level baseline testing and a moderate altitude exposure; Phase 2) 4 week study intervention - randomly assigned to receive erythropoietin or placebo); Phase 3) 3 1/2 days of acetazolamide and a moderate altitude exposure; Phase 4) high altitude acclimatization - 15 days at Pikes Peak; and Phase 5) two week deacclimatization. Test battery include VO2peak, 3.2 km treadmill time trial, measures of gas exchange and ventilation during rest and exercise, and blood collection.
Detailed description
This study will use a double-blind randomized study design in which one group will receive erythropoietin and the other a placebo (saline) for 4 weeks, then both groups will receive acetazolamide. Eighteen men and women volunteers will complete 5 study phases: Phase 1) two week sea level baseline testing (orientation, two VO2peak assessments, three 3.2 km treadmill time-trial, assessment of resting ventilation, venipuncture and capillary blood collection, and Hbmass assessment), and a VO2peak and 3.2 km treadmill time-trial moderate altitude (3,000 m); Phase 2) 4 week intervention to receive subcutaneously erythropoietin or placebo. The erythropoietin (Procrit) dosing regimen will consist of 50 IU/kg three times a week (M-W-F); Phase 3) a second moderate altitude exposure (VO2peak and 3.2 km treadmill time-trial with acetazolamide administered (orally; 250 mg b.i.d) for 3 1/2 nights starting the day before the altitude exposure; Phase 4) high altitude acclimatization in which volunteers will reside for 15 days at 4,300 m altitude (Pikes Peak, Colorado Springs) completing multiple VO2peak assessments and 3.2 km treadmill time-trials, resting ventilation, venipuncture and capillary blood collection; and Phase 5) deacclimatization phase to assess changes in hematological biomarkers after returning from Pikes Peak. This study consists of 41 visits over a ~10 week time period. Visits will take place in Natick, MA and the Pikes Peak High Altitude Research Laboratory at Colorado Springs. Additional assessments that will be completed multiple times during the study include: acute mountain sickness questionnaire, lung gas diffusion at rest and during exercise, oxygen saturation, arterialized blood gases (PO2, PCO2, pH, HCO3) and heart rate during rest, exercise, and sleep, and muscle tissue oxygenation. The primary outcome is 3.2 km treadmill time-trial performance. Secondary outcomes include: incidence and severity of acute mountain sickness, ventilation and gas exchange, Hbmass, Hb concentration, Hct, arterialized blood gases, lung diffusion at rest and during exercise, oxygen saturation and heart rate during rest, exercise, and sleep.
Study design
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (participant, investigator)
- Number of arms
- 2
- Model description
- This study will use a double-blind randomized study design in which one group will receive erythropoietin and the other group will receive the placebo for 4 weeks. After the 4 weeks, both groups will receive acetazolamide.
| Arm | Type | Receives |
|---|---|---|
| Acetazolamide | Experimental | Drug: AcetazolamideAcetazolamide (orally) 250 mg twice a day for 3 1/2 days. |
| Erythropoietin and Acetazolamide | Experimental | Drug: Acetazolamide, Drug: ErythropoietinErythropoietin (subcutaneously) 50 IU /kg three times a week for 4 weeks. After the 4 week Erythropoietin, acetazolamide (orally) 250 mg twice a day for 3 1/2 days. |
Who may qualify
- Ages
- 18 to 40 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (9 listed)
- Age 18-40 years
- In good health as determined by the Office of Medical Support \& Oversight (OMSO) General Medical Clearance
- Runs at least 3 times per week and able to complete a two mile run in ≤ 21 minutes (Civilian Volunteers) or passed his/her most recent Army Combat Fitness Test (ACFT) (Military Volunteers Only)
- Willing to not exercise, or drink alcoholic and/or caffeinated beverages 24 hours prior to each testing session or the acute altitude exposure to 3,000 m
- Abstain from alcoholic beverages during the 15 day residence at the summit of Pikes Peak
Key exclusion criteria (24 listed)
- Women who are pregnant or planning to become pregnant during the study
- Taking prescription medication, or over-the-counter medications other than contraceptives, unless approved by OMSO \& PI
- Born at altitudes greater than 2,100 m (7,000 ft)
- Living in areas that are more than 1,200 m (4,000 ft) or have traveled to areas that are more than 1,200 m for five days or more within the last 2 months
- Prior diagnosis of High Altitude Pulmonary Edema (HAPE) or High Altitude Cerebral Edema (HACE)
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| AcetazolamideAlso: DiamoxCarbonic Anhydrase Inhibitor | Drug | Acetazolamide, Erythropoietin and Acetazolamide |
| ErythropoietinAlso: ProcritHormone for red blood cell | Drug | Erythropoietin and Acetazolamide |
Primary outcome
3.2 km self-paced treadmill time trial performance
Time frame: 35 minutes
Time to complete self-paced 3.2 km treadmill time trial (min:sec)
17 secondary outcomes
VO2peak
Time frame: 30 minutes
Lake Louise Acute Mountain Sickness Score
Time frame: 10 minutes
Ventilation rate
Time frame: 20 minutes
Percent body fat
Time frame: 10 minutes
Oxygen Saturation
Time frame: 35 minutes
Erythropoietin
Time frame: 4 hours
Hematocrit
Time frame: 5 minutes
Reticulocyte
Time frame: 2 hours
Ferritin
Time frame: 2 hours
C-reactive protein
Time frame: 2 hours
Soluble transferrin
Time frame: 2 hours
Arterialized capillary PO2
Time frame: 5 minutes
Arterialized capillary PCO2
Time frame: 5 minutes
Arterialized capillary pH
Time frame: 5 minutes
Hbmass
Time frame: 20 minutes
Muscle tissue oxygenation
Time frame: 35 minutes
Lung Diffusion of carbon monoxide
Time frame: 35 minutes
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 26 Mar 2025.
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Program Protocol for a Population That Works in Conditions of Hypobaric Hypoxia
Changes in the Intestinal Microbiota Under Hypobaric Hypoxia Conditions, Changes in Blood Glucose Under Hypobaric Hypoxia Conditions
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Roy Salgado, PhD principal investigator
United States Army Research Institute of Environmental Medicine
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 4 study testing Acetazolamide and Erythropoietin in people with Hypobaric Hypoxia, run by United States Army Research Institute of Environmental Medicine at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 9 inclusion and 24 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: under way, not looking for participants, as of the sponsor's last update on 26 Mar 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 4 studies take place after a treatment is approved, to learn more about its long-term benefits and risks in everyday use.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
3.2 km self-paced treadmill time trial performance (time frame: 35 minutes). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 26 Mar 2025.