A Phase 4 interventional study of IV Repletion and PO Repletion in Cystic Fibrosis, Iron Deficiencies and Iron Deficiency Diseases, sponsored by University of Michigan. Not yet recruiting at 8 sites in United States. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-10-29.
Sponsored by University of Michigan · Phase 4, Interventional, and Treatment
The researchers in this study hope to learn whether oral (PO) or intravenous (IV) iron treatments are better for treating iron deficiency in patients with cystic fibrosis (CF). This research will help doctors better treat iron deficiency in patients with CF in the future by examining blood and other health measures.
Participants with cystic fibrosis (CF) will be enrolled in this study. Approximately 80 participants will be enrolled in the Iron Deficient (ID) Cohort; and approximately 20 participants will be enrolled in the Borderline ID Cohort. Participants enrolled in the ID Cohort will be randomized to either an IV versus PO route of iron repletion. Participants enrolled in the Borderline ID Cohort will be randomized to a PO route of iron repletion versus usual care without specific assignment of iron repletion. The focus of the study is the ID Cohort; the Borderline ID Cohort is exploratory.
1,609 studies on the registry are indexed under Cystic Fibrosis; 197 are open to participants now.
This study's planned enrollment of 100 is above the median of 36 across 1,052 interventional studies indexed under Cystic Fibrosis.
Browse Cystic Fibrosis studies →University of Michigan is the lead sponsor of 1,505 studies on the registry; 191 are open to participants now.
Of its 168 completed or terminated interventional studies of FDA-regulated products, 133 (79%) have results posted.
Counted across the registry records on this site, refreshed daily.
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.
A CF diagnosis as evidenced by one or more clinical features consistent with the CF phenotype and at least one of the following criteria:
Ability to provide written informed consent and to comply with the requirements of the study
--------------------------------------------------
Additional Inclusion Criteria for ID Cohort:
ID defined by at least one of the following criteria:
a. Both of the following: i. transferrin saturation (TSAT) \< 20% OR ferritin \< 30 ug/L ii. hemoglobin \< 12.0 g/dL in female OR hemoglobin \< 13.0 g/dL in male per World Health Organization (WHO) anemia definition b. TSAT \< 15% or ferritin \< 15 ug/L irrespective of hemoglobin value
--------------------------------------------------
Additional Inclusion Criteria for Borderline ID Cohort:
Borderline ID defined by both of the following criteria:
not meeting ID Cohort criteria above
--------------------------------------------------
Exclusion Criteria for All Study Participants:
Participants enrolled in the ID Cohort will be randomized to an IV versus PO route of iron repletion in a 1:1 ratio. Participants are only randomized by route of repletion, not to a specified drug or dose. Rather, selection of the iron repletion formulation and dose will be determined by the participant's treating clinician. This arm is randomized to the IV route of administration.
Drug: IV Repletion
Participants enrolled in the ID Cohort will be randomized to an IV versus PO route of iron repletion in a 1:1 ratio. Participants are only randomized by route of repletion, not to a specified drug or dose. Rather, selection of the iron repletion formulation and dose will be determined by the participant's treating clinician. This arm is randomized to the PO route of administration.
Drug: PO Repletion
Participants enrolled in the Borderline ID Cohort will be randomized to a PO route of iron repletion versus usual care without specific assignment of iron repletion in a 1:1 ratio. Participants are not randomized to a specific drug or dose. Rather, selection of the iron repletion formulation and dose will be determined by the participant's treating clinician. This arm is randomized to the PO route of administration.
Drug: PO Repletion
Participants enrolled in the Borderline ID Cohort will be randomized to a PO route of iron repletion versus usual care without specific assignment of iron repletion in a 1:1 ratio. Usual care is defined as continued clinical care as usual without a specific plan to replete iron. This arm is randomized to usual care.
Possible formulation and dose will depend on the participant's treating clinician, and may include but is not limited to the following: low molecular weight iron dextran; ferric carboxymaltose; ferric derisomaltose.
Possible formulation and dose will depend on the participant's treating clinician, and may include but is not limited to the following: ferrous sulfate (325 mg/65 mg elemental iron every other day).
Estimated absolute change in whole blood hemoglobin - ID Cohort
Whole blood hemoglobin in g/dL at 3 months after the start of IV versus PO treatment. Full longitudinal study data from all study visits will be modeled in a linear mixed-effects model which will include time from start of treatment, the treatment (IV versus PO), and interactions between the time and treatment at approximately 1, 3, and 6 months.
Time frame: Baseline, and approximately 3 months
Estimated absolute change in whole blood hemoglobin - ID Cohort
Whole blood hemoglobin in g/dL at 1 and 6 months after the start of IV versus PO treatment will be modeled using approaches described in Outcome 1.
Time frame: Baseline, and approximately 1 and 6 months
Estimated proportion of non-anemic participants - ID Cohort
Proportion of non-anemic participants over time will be modeled based on an inverse probability weighted generalized estimating equations (GEE) model for the binary variable of hemoglobin value meeting WHO criteria for anemia versus not anemia.
Time frame: Baseline, and approximately 1, 3, and 6 months
Estimated relative change in soluble transferrin receptor (sTfR) - ID Cohort
Serum sTfR in % of mg/L at 1, 3, and 6 months will be modeled using approaches described in Outcome 1.
Time frame: Baseline, and approximately 1, 3, and 6 months
Estimated absolute change in transferrin saturation (TSAT) - ID Cohort
Serum TSAT in % at 1, 3, and 6 months, determined by total serum iron and iron binding capacity, will be modeled using approaches described in Outcome 1.
Time frame: Baseline, and approximately 1, 3, and 6 months
Estimated absolute change in serum iron - ID Cohort
Serum iron in ug/dL at 1, 3, and 6 months will be modeled using approaches described in Outcome 1.
Time frame: Baseline, and approximately 1, 3, and 6 months
Estimated absolute change in serum ferritin - ID Cohort
Serum ferritin in ng/mL at 1, 3, and 6 months will be modeled using approaches described in Outcome 1.
Time frame: Baseline, and approximately 1, 3, and 6 months
Estimated absolute change in serum ferritin(adj-factor) - ID Cohort
Adjusted serum ferritin using the correction factor method for C-reactive protein (CRP) in ng/mL at 1, 3, and 6 months will be modeled using approaches described in Outcome 1.
Time frame: Baseline, and approximately 1, 3, and 6 months
Estimated absolute change in serum ferritin(adj-BRINDA) - ID Cohort
Adjusted serum ferritin using the BRINDA method for CRP in ng/mL at 1, 3, and 6 months will be modeled using approaches described in Outcome 1.
Time frame: Baseline, and approximately 1, 3, and 6 months
Estimated absolute change in sTfR index - ID Cohort
sTfR index calculated by sTfR / log (ferritin) at 1, 3, and 6 months will be modeled using approaches described in Outcome 1.
Time frame: Baseline, and approximately 1, 3, and 6 months
Estimated absolute change in whole blood red blood cell (RBC) mean corpuscular volume (MCV) - ID cohort
RBC MCV in fL at 1, 3, and 6 months will be modeled using approaches described in Outcome 1.
Time frame: Baseline, and approximately 1, 3, and 6 months
Estimated absolute change in 6-minute walk distance (6MWD) - ID Cohort
6MWD in meters at 1, 3, and 6 months will be modeled using approaches described in Outcome 1.
Time frame: Baseline, and approximately 1, 3, and 6 months
Estimated change in percent predicted forced expiratory volume in the first second (ppFEV1) - ID Cohort
ppFEV1 measured by spirometry in % at 1, 3, and 6 months will be modeled using approaches described in Outcome 1.
Time frame: Baseline, and approximately 1, 3, and 6 months
Estimated absolute change in hand grip strength - ID Cohort
Hand grip strength in lbs, assessed using the Jamar dynamometer, at 1, 3, and 6 months will be modeled using approaches described in Outcome 1.
Time frame: Baseline, and approximately 1, 3, and 6 months
Estimated absolute change in body mass index (BMI) - ID Cohort
BMI measured by height and weight in kg/m2 at 1, 3, and 6 months will be modeled using approaches described in Outcome 1.
Time frame: Baseline, and approximately 1, 3, and 6 months
Estimated absolute change in fatigue severity score (FSS) - ID Cohort
FSS at 1, 3, and 6 months will be modeled using approaches described in Outcome 1. The FSS is a 9 question scale, with raw score range of 9-63, and final score range of 1-7, with higher scores indicating more fatigue.
Time frame: Baseline, and approximately 1, 3, and 6 months
Estimated absolute change in cystic fibrosis questionnaire revised (CFQ-R) - ID Cohort
CFQ-R scores captured using the ≥ 14 years of age questionnaire at 1, 3, and 6 months will be modeled using approaches described in Outcome 1. The CFQ-R is reported in separate domains, with a score range of 0-100 for each domain, with higher scores indication better health-related quality of life.
Time frame: Baseline, and approximately 1, 3, and 6 months
Estimated absolute change in gastrointestinal symptom score (GI-SS) - ID Cohort
Total number of present GI symptoms, out of 8 total assessed in Section C of the questionnaire, at 1, 3, and 6 months will be modeled using approaches described in Outcome 1. Additionally, numerical severity of symptoms will be modeled (0=absent, 1=mild, 2=moderate, 3=severe) using the same approach. A higher number indicates more severe GI symptoms.
Time frame: Baseline, and approximately 1, 3, and 6 months
Time to next distal intestinal obstruction syndrome (DIOS) event - ID Cohort
All unique DIOS events which occur from start of IV versus PO treatment through the duration of follow-up will be modeled using the Xia/Murray/Tayob method, which is a robust multivariable restricted time model with the capacity to analyze repeated time-to-event data throughout the study period.
Time frame: Start of treatment through the approximate 6-month study period
Time to next pulmonary exacerbation (PEx) - ID Cohort
All unique PEx events which occur from start of IV versus PO treatment through the duration of follow-up will be modeled using the Xia/Murray/Tayob method, which is a robust multivariable restricted time model with the capacity to analyze repeated time-to-event data throughout the study period.
Time frame: Start of treatment through the approximate 6-month study period
Adherence - ID Cohort
Adherence to treatment will be defined as cumulative % of doses of respect treatment arm estimated over the study period relative to the total prescribed doses. Adherence to IV versus PO iron treatment as a % will be analyzed by 2-sample t-test.
Time frame: Start of treatment through the approximate 6-month study period
Plan to share: Yes — All data collected, generated, and used in this research study will be preserved and shared, exclusive of data for which we do not have participant consent or IRB approval (e.g., data which may be used to identify individual patients). Deidentified study data will be maintained and shared to aid in future validation of the study results, accelerate future potential research in the field.
Supporting information: Study protocol, Statistical analysis plan, Informed consent form, Analytic code
Time frame: Data will be made accessible no later than the time of the associated publication or the end of the grant period, whichever comes first. It will be available for a minimum of 10 years after contribution to Vivli.
Access criteria: To access anonymized individual participant-level data from these projects, users will need to complete the Vivli data request form and sign the Vivli data use agreement (DUA).
Data sharing details ↗ · vivli.org
No publications or documents are linked to this record.
Start is estimated for Nov 2026; primary completion for Jan 2030, 38 months later.
Of 29 phase 4 interventional studies under Cystic Fibrosis, half reached primary completion within 29 months of starting (the median), counting those still running; a quarter within 20 and three quarters within 48. This study's planned 38 months is above that.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
This study is not yet recruiting, as verified in Oct 2026. You cannot join it, but the record below documents what was studied.
Get an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.