Safety and Efficacy of Iron Reduction by Phlebotomy
Condition: Iron Overload
MeSH terms: Iron Overload
Study type: Interventional
Phase: Phase 2

Summary: 
      Hypothesis: The reduction of total body iron by phlebotomy will be safe and feasible in the
      post-HSCT setting

      Iron overload is common after hematopoietic stem cell transplantation. It is associated with
      chronic liver disease, with increased rates of infection and decreased survival.

      Eligible, consenting patients will have once monthly phlebotomy procedures (500ml) for 12
      months.

      SAFETY: At each visit, patients will have a comprehensive assessment prior to starting and
      after completing the phlebotomy. This assessment will include determination of pain at
      phlebotomy site, local infection and an assessment of symptoms of anemia including
      presyncope, fatigue and dyspnea. The patient's pulse, blood pressure, respiratory rate and
      temperature will also be determined before and following the phlebotomy.

      EFFICACY: Iron stores will be measured serially in each patient. Measurements will be
      performed prior to the start of phlebotomy, and at 6 months and 12 months following the start
      of the series of 12 phlebotomies. These evaluations will be undertaken regardless of the
      number of phlebotomies which the patient actually undergoes. Iron stores will be estimated by
      measuring serum ferritin and transferrin saturation levels. Total body iron will be estimated
      from hepatic and cardiac iron concentration as measured by magnetic resonance imaging (MRI).
      Gandon et al. (12) described a non-invasive technique using MRI to measure hepatic iron
      stores. Iron is a paramagnetic substance which causes local magnetic field inhomogeneities
      leading to dephasing and signal loss in MRI. Gradient echo sequences are most susceptible to
      their effects because they do not use a 180° refocusing pulse, unlike conventional spin-echo
      sequences. Gandon et al. used multiple gradient echo sequences, compared the signal in liver
      to adjacent muscle and used this ratio to correlate with hepatic iron levels measured on
      tissue biopsy samples using spectrophotometric analysis. Multiple sequences were used because
      the nomogram comparing the L/M signal ratio is linear over only a small concentration of
      tissue iron.
    

Detailed description: 
      Background Hematopoietic stem cell transplantation (HSCT) is increasingly used as a treatment
      for a variety of malignant and non-malignant conditions. With improvements in conditioning
      regimens and post-transplant care, more HSCT recipients are becoming long-term survivors and
      therefore increasing attention is being directed to studying the long-term consequences of
      successful HSCT.

      Iron overload is surprisingly common after HSCT. The pathophysiology of iron overload or
      siderosis is related to transfusional iron, inhibition of normal erythropoiesis and released
      iron stores from hepatocytes, tumour cells and bone marrow. It is associated with chronic
      liver disease in this patient population, as well as with increased rates of infection.
      Studies suggest that iron overload may also affect survival in this population, as has been
      shown in other populations who are susceptible to iron overload such as those with
      thalassemia and hereditary hemochromatosis (1,2).

      McKay et al. described 76 survivors of allogeneic and autologous HSCT who were at least 1
      year post-transplant (3). Sixty-seven (88%) had a ferritin level above the normal range.
      Thirty-one (41%) had abnormal liver enzymes and 30/31 also had elevated ferritin. At the time
      of publication, 10 of the patients had begun a venesection program; all showed a reduction in
      ferritin levels and nine patients had a reduction in alanine aminotransferase (ALT). Strasser
      et al. showed an increase of hepatic iron concentration in 10 consecutive patients who died
      post-HSCT (4). In a retrospective study to determine the characteristics of chronic liver
      disease post-HSCT, iron overload was felt to contribute to chronic liver dysfunction in 52.4%
      of patients post-HSCT who had liver disease (5).

      Iron overload has also been associated with an increased frequency of infection in HSCT
      recipients. A single-centre retrospective study of autopsies conducted post-HSCT revealed an
      association between high liver iron concentration and invasive Aspergillus infection (6). In
      a consecutive series of 263 allogeneic HSCT patients, 5 cases of mucormycosis all occurred in
      patients with severe iron overload (7).

      Iron overload prior to transplantation may also have a negative effect on survival. In a
      prospective study of 25 consecutive patients, Altes et al. showed that a very high ferritin
      level and a high transferrin saturation prior to conditioning was associated with a decreased
      overall survival and a high transferrin saturation was associated with an increase in
      transplant-related mortality (8).

      Therapeutic phlebotomy is well-established for treatment of iron overload associated with
      hereditary hemochromatosis (9) and beta thalassemia after HSCT (10). Phlebotomy has also been
      studied in survivors of acute leukemia with iron overload. Franchini et al. showed that
      phlebotomy was feasible and well-tolerated in this population and resulted in normalization
      of ferritin and transferrin saturation (11). This study demonstrated feasibility of
      phlebotomy but the effect of iron reduction on end-organ function was not addressed.

      In summary, iron overload is common following HSCT and has been associated with a number of
      adverse biochemical and clinical outcomes. In other clinical settings such as hereditary
      hemochromatosis and transfusional iron overload states such as thalassemia, the reduction of
      iron stores by phlebotomy or chelation has been unequivocally demonstrated to reduce both
      morbidity and mortality. We therefore postulate that the reduction of iron overload after
      HSCT will similarly be associated with lower morbidity and mortality.

      Objectives

        1. demonstrate the safety and feasibility of phlebotomy to reduce total body iron in HSCT
           recipients

        2. demonstrate reduction in total body iron by reduced ferritin and transferrin saturation
           and reduction in hepatic and cardiac iron

        3. demonstrate improvements in end-organ function by improved hepatic, cardiac and
           endocrine function.

      Study Design This is a prospective, single arm phase II trial designed to evaluate the safety
      and efficacy of decreasing total body iron in HSCT recipients by phlebotomy.

      Study Intervention Patients who are eligible to participate and who give informed consent
      will undergo a regimen of phlebotomy in the following manner. Starting after 60 days
      post-transplant, the patients will undergo a phlebotomy of 500 mL of whole blood monthly for
      a total of 12 treatments. There will be a determination of the complete blood count prior to
      each phlebotomy and if the hemoglobin level is less than 100 g/L, the phlebotomy will not be
      performed. Patients will not routinely receive crystalloid volume replacement following the
      phlebotomy. However, if a patient experiences syncope or pre-syncope, subsequent phlebotomies
      will be followed by the infusion of 500 mL of normal saline.

      Assessment of Safety and Feasibility The safety and feasibility of regular phlebotomy will be
      determined by assessing the proportion of patients who can complete the 12 planned
      phlebotomies. Delays in phlebotomy and reasons for stopping the phlebotomy program will be
      documented. At each visit, patients will have a comprehensive assessment prior to starting
      and after completing the phlebotomy. This assessment will include determination of pain at
      phlebotomy site, local infection and an assessment of symptoms of anemia including
      presyncope, fatigue and dyspnea. The patient's pulse, blood pressure, respiratory rate and
      temperature will also be determined before and following the phlebotomy.

      Assessment of Adverse Events and Serious Adverse Events In this study, only those adverse
      events felt to be related to study procedures will be recorded. Phlebotomy adverse events
      include: Pain at phlebotomy site, infection at phlebotomy site, evidence of phlebitis,
      fatigue, presyncope, syncope, dyspnea, bacteremia, cellulitis at the phlebotomy site. A fall
      in systolic blood pressure of greater than 20 mmHg post-phlebotomy will also be considered an
      adverse event.

      Only serious adverse events related to study procedures will be recorded.

      Patients will be carefully assessed before and after the phlebotomy procedure. Adverse events
      and serious adverse events related to study procedures will be assessed throughout the study
      and up to 30 days following the last phlebotomy.

      Assessment of Efficacy Determination of iron concentration Iron stores will be measured
      serially in each patient. Measurements will be performed prior to the start of phlebotomy,
      and at 6 months and 12 months following the start of the series of 12 phlebotomies. These
      evaluations will be undertaken regardless of the number of phlebotomies which the patient
      actually undergoes. Iron stores will be estimated by measuring serum ferritin and transferrin
      saturation levels. Total body iron will be estimated from hepatic and cardiac iron
      concentration as measured by magnetic resonance imaging (MRI). Gandon et al. (12) described a
      non-invasive technique using MRI to measure hepatic iron stores. Iron is a paramagnetic
      substance which causes local magnetic field inhomogeneities leading to dephasing and signal
      loss in MRI. Gradient echo sequences are most susceptible to their effects because they do
      not use a 180° refocusing pulse, unlike conventional spin-echo sequences. Gandon et al. used
      multiple gradient echo sequences, compared the signal in liver to adjacent muscle and used
      this ratio to correlate with hepatic iron levels measured on tissue biopsy samples using
      spectrophotometric analysis. Multiple sequences were used because the nomogram comparing the
      L/M signal ratio is linear over only a small concentration of tissue iron.

      The accuracy of the MRI technique was subsequently verified by Alustiza et al. (13). They
      measured hepatic iron concentration in 112 patients with iron levels that varied from normal
      (n=68) to abnormal in patients with hereditary hemochromatosis (n=21) and transfusional
      hemosiderosis (n=23). The correlation coefficient between iron measured by MRI compared to
      tissue biopsy in this series was 0.957. This positive correlation verifies the Gandon
      technique.

      Serum samples will also be collected at baseline to screen for the most common mutations of
      the HFE gene (C282Y mutation and H63D mutation) as hereditary hemochromatosis is common in
      the general population and may contribute to iron overload in HSCT recipients. The patient
      and family physician will be informed about the results of hemochromatosis testing and
      standard practice will be followed.

      Determination of end organ function The effect of iron overload will be studied in three
      principal areas: liver, heart and endocrine organs. All measurements will be performed at
      baseline and at 6 and 12 months following the start of the series of 12 phlebotomies. Hepatic
      function will be determined by measurement of liver enzymes (alkaline phosphatase, aspartate
      aminotransferase and alanine aminotransferase) and liver function testing including total
      bilirubin, albumin and INR. Cardiac function will be determined by magnetic resonance imaging
      and serum brain natriuretic peptide and troponin. Endocrine function will be determined by
      measurement of serum LH, FSH, TSH, free T4, testosterone (males) and fasting glucose.

      Follow-up After completion of the trial, patients will continue to be followed by their
      hematologist. If the phlebotomy is safe and feasible, their physician may choose to continue
      with phlebotomy but this would not be standard practice and there is not evidence to support
      the intervention at this time.

      Analysis The analysis of the results of this study will be descriptive. A screening log will
      be kept and the number of patients screened for this study will be recorded. Patients who are
      eligible to participate and who give informed consent will be described according to the
      following parameters: age, gender, underlying indication for transplant, type of transplant,
      number of red cell transfusions received prior to transplant, number of red cell transfusions
      from the start of conditioning until study enrollment and ECOG performance status at time of
      study entry. The feasibility of the intervention will be recorded by describing the
      proportion of patients who complete the planned series of 12 phlebotomies. In order to
      consider the patients who are unable to complete all 12 phlebotomies, the total number of
      actual phlebotomies conducted in the trial will also be recorded and expressed as a
      proportion of the total number of planned phlebotomies. The number of phlebotomies per
      patient per time period will also be reported. The efficacy of the intervention will be
      recorded by describing the changes in serum ferritin and transferrin saturation, liver
      enzymes and liver function, endocrine parameters and liver and cardiac iron stores as
      determined by liver MRI. Cardiac function will also be determined at study entry and 6 and 12
      months following the start of the series of 12 planned phlebotomies. The safety of the
      intervention will be recorded by evaluating the number of patients who had adverse and/or
      serious adverse events.
    

Intervention name(s): monthly phlebotomy x 12 months
Intervention type(s): Procedure
Intervention description(s): All patients will receive monthly phlebotomies.
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: iron reduction; iron overload; phlebotomy; hematopoietic stem cell transplant