A Phase 1 interventional study of Vitamin C in Pyruvate Kinase Deficiency and Glucose 6 Phosphate Dehydrogenase Deficiency, sponsored by University of Utah. Not yet recruiting at 1 site in United States. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-05-28.
Sponsored by University of Utah · Phase 1, Interventional, and Treatment
Among 14 studies in Glucosephosphate Dehydrogenase Deficiency with a site in United States — 1 open to participants now, 2 under way, none of them phase 3. Glucosephosphate Dehydrogenase Deficiency · United States.
Among the 14 studies in Glucosephosphate Dehydrogenase Deficiency with a site in United States, this one is the only one that started in 2026, is one of 3 in phase 1, and was the 14th registered.
41 studies on the registry are indexed under Glucosephosphate Dehydrogenase Deficiency; 4 are open to participants now.
This study's planned enrollment of 3 is below the median of 96 across 26 interventional studies indexed under Glucosephosphate Dehydrogenase Deficiency.
Browse Glucosephosphate Dehydrogenase Deficiency studies →1 of the 14 studies in Glucosephosphate Dehydrogenase Deficiency with a site in United States is open now, in 1 country. Each count lists the studies.
Of the 2 Glucosephosphate Dehydrogenase Deficiency studies recruiting now, 1 (50%) set no upper age limit and 1 (50%) stop at 75 or younger; 1 take children under 18; 0 take healthy volunteers.
This study: 18 Years and older · all sexes · no healthy volunteers.
The full table on the hub →14 studies; the count open now beside each. This study's row is marked.
First in 1999; this study’s year is marked. 1 started in 2026.
Median enrollment 50 across the 8 interventional studies, 450 across the 5 observational. Of the 12 that completed or were terminated, 3 (25%) have results posted.
4 of 14 have an industry lead sponsor. The 10 most frequent:
University of Utah is the lead sponsor of 994 studies on the registry; 175 are open to participants now.
Of its 114 completed or terminated interventional studies of FDA-regulated products, 69 (61%) have results posted.
University of Utah has 1 study filed under Glucosephosphate Dehydrogenase Deficiency — fewer than ten, so there is no comparison to draw.
2 of the studies in Glucosephosphate Dehydrogenase Deficiency with a site in United States that are under way reach primary completion within a year, 0 of them phase 3. Phase 3 first, then by date:
| Study | Primary completion |
|---|---|
| NCT03655223RTI InternationalEarly Check: Expanded Screening in Newborns | 2026-11-30 |
| NCT07612345University of UtahHigh-Dose Vitamin C in G6PDA and Pyruvate Kinase Deficiency: A Safety Study | 2027-07-15 |
Among the 14 studies in Glucosephosphate Dehydrogenase Deficiency with a site in United States, from their registry updates:
Nothing recorded among them since 2026-09-25.
This study is testing whether high-dose Vitamin C is safe and well-tolerated in patients with two inherited red blood cell disorders - Pyruvate Kinase Deficiency (PKD) and Class A Glucose-6-Phosphate Dehydrogenase Deficiency (G6PDA). Both conditions cause red blood cells to break down too quickly, leading to anemia and related complications.
Our earlier research showed that a single oral dose of Vitamin C (250 mg, 500 mg, or 750 mg) reduced red blood cell breakdown by approximately 50% within one hour. This study builds on those findings by testing different doses and frequencies of Vitamin C to find the safest and most effective dosing schedule.
Participants will take Vitamin C once, twice, or three times daily over a 3-week period, with careful monitoring of blood counts, red blood cell survival, iron levels, and any side effects. The study will first enroll 3 adult patients with PKD at Huntsman Cancer Institute. If the results are safe and promising, the study will be extended to patients with G6PDA deficiency, and eventually to children ages 4 and older at Primary Children's Hospital in Salt Lake City.
The goal is to establish a foundation for Vitamin C as a novel therapy to reduce anemia and red blood cell destruction in these rare inherited disorders.
Pyruvate kinase deficiency (PKD) and Class A Glucose-6-Phosphate Dehydrogenase deficiency (G6PDA) are inherited red blood cell enzyme disorders characterized by chronic hemolytic anemia. Current treatment options are limited and do not fully address the underlying mechanisms of red blood cell destruction, iron overload, and oxidative stress.
Our preliminary studies demonstrated that oral Vitamin C administration at doses of 250 mg, 500 mg, and 750 mg reduced the rate of hemolysis by approximately 50% within one hour of administration, as measured by end-tidal carbon monoxide corrected for ambient CO (ETCOc) - a validated marker of red blood cell breakdown. These findings provide a strong rationale for evaluating the safety and optimal dosing frequency of Vitamin C supplementation in these patient populations.
Study Design:
This is a Phase I, single-site, sequential within-patient dose escalation study. Three adult PKD patients will be enrolled in the initial cohort, each assigned to a different starting dose:
Patient 1: 250 mg daily → 250 mg twice daily → 250 mg three times daily Patient 2: 500 mg daily → 500 mg twice daily → 500 mg three times daily Patient 3: 750 mg daily → 750 mg twice daily → 750 mg twice daily + 500 mg once daily (to reach the NIH-recommended maximum daily dose of 2,000 mg/day)
Each dosing frequency will be maintained for one week, for a total active treatment period of 3 weeks per participant. Safety and hematologic assessments will be performed at baseline and at each dose adjustment visit (9 assessments per participant).
Assessments:
At each visit, participants will undergo:
ETCOc measurement to assess real-time hemolysis Complete blood count and reticulocyte count Metabolic panel including bilirubin and LDH Iron studies including serum iron, transferrin, ferritin, hepcidin, and erythroferrone Vital signs and adverse event assessment
Study Extension:
Following successful completion of the PKD cohort, the study will be extended to G6PDA patients, including 5 G6PDA males and 5 G6PDA heterozygous females from a well-characterized family. A subsequent extension to pediatric patients ages 4 and older is planned at Primary Children's Hospital in Salt Lake City, pending safety and preliminary efficacy data from the adult cohort.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hypersensitivity
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants receive oral Vitamin C at 250 mg once daily during Week 1, 250 mg twice daily during Week 2, and 250 mg three times daily during Week 3
Drug: Vitamin C
Participants receive oral Vitamin C at 500 mg once daily during Week 1, 500 mg twice daily during Week 2, and 500 mg three times daily during Week 3
Drug: Vitamin C
Participants receive oral Vitamin C at 750 mg once daily during Week 1, 750 mg twice daily during Week 2, and 750 mg twice daily plus 500 mg once daily during Week 3, to reach the NIH-recommended maximum daily dose of 2,000 mg/day
Drug: Vitamin C
Oral pharmacological grade Vitamin C (Ascorbic Acid) administered at escalating doses and frequencies over a 3-week period. Three dose levels are evaluated: 250 mg, 500 mg, and 750 mg, administered once daily (QD), twice daily (BID), or three times daily (TID) depending on the assigned arm. The maximum daily dose does not exceed 2,000 mg/day, consistent with the NIH-recommended maximum daily dose.
Incidence of Dose-Limiting Toxicities (DLTs)
Number of participants experiencing Grade 3 or higher adverse events as defined by NCI CTCAE v5.0 that are possibly, probably, or definitely related to oral Vitamin C administration at each dose level (250 mg, 500 mg, and 750 mg) and dosing frequency (once daily, twice daily, and three times daily). Hematologic DLTs include Grade ≥3 hemolysis above patient baseline, Grade ≥3 anemia (hemoglobin \<8 g/dL), Grade 4 neutropenia (ANC \<0.5 × 10⁹/L), and Grade 4 thrombocytopenia (platelet count \<25 × 10⁹/L). Non-hematologic DLTs include Grade 3 acute kidney injury, Grade 3 ALT or AST elevation, and any other Grade 3 or higher toxicity considered related to study intervention.
Time frame: From first dose of study intervention through the 28-day safety follow-up visit (approximately 7 weeks per participant)
Number of Participants With Treatment-Related Adverse Events as Assessed by NCI CTCAE v5.0
Incidence and severity of all adverse events reported during the study, graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE v5.0), including all adverse events possibly, probably, or definitely related to oral Vitamin C administration.
Time frame: From first dose of study intervention through the 28-day safety follow-up visit (approximately 7 weeks per participant)
Change in Hemoglobin Concentration from Baseline
Change in hemoglobin concentration from baseline to each dose adjustment visit, measured by complete blood count (CBC).
Time frame: Baseline (Day 1) through Week 3 of treatment and 28-day safety follow-up visit
Change in Reticulocyte Count from Baseline
Change in reticulocyte count from baseline to each dose adjustment visit, measured by complete blood count (CBC).
Time frame: Baseline (Day 1) through Week 3 of treatment and 28-day safety follow-up visit
Change in Lactate Dehydrogenase (LDH) from Baseline
Change in serum LDH levels from baseline to each dose adjustment visit as a marker of hemolysis.
Time frame: Baseline (Day 1) through Week 3 of treatment and 28-day safety follow-up visit
Change in Systolic Blood Pressure from Baseline
Change in systolic blood pressure from baseline to each study visit as part of vital signs assessment.
Time frame: Baseline (Day 1) through Week 3 of treatment and 28-day safety follow-up visit
Change in Heart Rate from Baseline
Change in heart rate from baseline to each study visit as part of vital signs assessment.
Time frame: Baseline (Day 1) through Week 3 of treatment and 28-day safety follow-up visit
Plan to share: Yes — De-identified individual participant data will be made available upon reasonable request following publication of study results. Data will be stored securely at the Huntsman Cancer Institute and shared in accordance with applicable IRB and institutional data sharing policies.
Supporting information: Study protocol, Statistical analysis plan, Informed consent form, Clinical study report, Analytic code
Time frame: Beginning 6 months after primary results publication and available for 5 years thereafter
Access criteria: Researchers may submit data access requests to the Principal Investigator (Jihyun Song, PhD) at jihyun.song@utah.edu. Requests will be reviewed on a case-by-case basis.
Start is estimated for Jul 2026; primary completion for Jul 2027, 12 months later.
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This study is not yet recruiting, as verified in May 2026. You cannot join it, but the record below documents what was studied.
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Studies of the drug tested here: Ascorbic Acid
Glucosephosphate Dehydrogenase Deficiency →