BRIEF OBSERVATION

Amlodipine Reduces Cardiac Iron Overload in Patientswith Thalassemia Major: A Pilot TrialJuliano Lara Fernandes, MD, PhD,a Erika Fontana Sampaio, MD,a Kleber Fertrin, MD, PhD,a Otavio Rizzi Coelho, MD, PhD,a

Sandra Loggetto, MD,b Antonio Piga, MD,c Monica Verissimo, MD,d Sara T. Saad, MD, PhDaaInternal Medicine Department, University of Campinas (Unicamp), Brazil; bCentro de Hematologia São Paulo, Brazil; cUniversity ofTorino, Italy; dCentro Infantil Boldrini, Brazil.

Funding: PubEstado de São Pau

Conflict of InAuthorship: A

manuscript.Requests for re

PhD, Internal Med13025-292, Brazil

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0002-9343/$ -seehttp://dx.doi.org/1

ABSTRACT

BACKGROUND: Iron chelation therapy in patients with thalassemia major may not prevent iron overload inall organs, especially those in which iron enters cells through specific calcium channels. We designed acontrolled pilot study to assess the potential of the calcium channel blocker amlodipine in strengthening theefficacy of iron chelation.METHODS: Fifteen patients with thalassemia major undergoing chelation therapy were randomized toreceive amlodipine added to standard treatment in a 1:2 allocation for 12 months. T2* values for assessmentof iron overload in the liver and heart using magnetic resonance imaging were obtained at baseline and at6 and 12 months.RESULTS: In the amlodipine-treated group, heart T2* increased significantly in comparison to baseline at6 and 12 months (21.7 � 7.2 ms to 28.2 � 7.9 ms and 28.3 � 8.0 ms, with P ¼ .007 and .03, respectively),while no differences were observed in the control group (25.1 � 8.8 ms to 24.7 � 7.8 ms and 26.2 � 11.4ms; P ¼ .99 and 0.95, respectively); significant differences between groups were observed at 6 months(28.2� 7.9 ms vs 24.7� 7.8 ms in the control group, P¼ .03). A significant reduction in ferritin levels alsowas observed in the treated group at 12 months.CONCLUSIONS: The use of amlodipine in conjunction with standard chelation therapy may suggest a newstrategy in preventing and treating iron overload in patients with thalassemia major, especially in organswhere iron absorption depends on active uptake by calcium channels like the heart.� 2013 Elsevier Inc. All rights reserved. � The American Journal of Medicine (2013) 126, 834-837

KEYWORDS: Iron overload; Magnetic resonance imaging; Thalassemia

Iron overload in thalassemia major is one of the main prog-nostic factors in the management of the disease, leading toreduced quality of life and long-term chelation therapy,which is associated with multiple side effects.1 All chelationstrategies in thalassemia major have been limited so far to theremoval of iron from different organs, but because ironmoves in and out of cells through distinct mechanisms, someiron chelators might not be so effective in removing

lic funding agency Fundaçao de Amparo a Pesquisa dolo, Brazil.terest: The authors report no conflict of interest.ll authors had access to the data and a role in writing the

prints should be addressed to Juliano L. Fernandes, MD,icine Department, R. Antonio Lapa 1032, Campinas, SP.: jlaraf@fcm.unicamp.br

front matter � 2013 Elsevier Inc. All rights reserved.0.1016/j.amjmed.2013.05.002

previously stored iron, with the need for higher doses orcombination therapy, and worsening of potential side ef-fects.2 Therefore, lowering cellular iron uptake may be apotential complementary treatment to standard iron chelation.

Previous in vitro studies showed that L-type calciumchannels provide a major pathway for iron entry into car-diomyocytes3-5 and, in mice, calcium channel blockersreduce myocardial iron overload. Thus, we investigated in apilot study the use of the calcium channel blocker amlodipinein reducing iron overload in patients with thalassemia major.

METHODS

PatientsThe pilot study was designed as an open-label, controlledtrial. From a group of 60 patients who had repeatedly un-dergone a magnetic resonance (MR) examination since

Fernandes et al Amlodipine in Thalassemia Major 835

2003, 15 patients were included in the study based on thecriteria of at least 7 years of age (for compliance with theMR examination), regular transfusions, and iron overloadwith no perspective of changing the chelation therapy inthe following 6 months. Exclusion criteria were patientswith significant left ventricular dysfunction (ejection frac-

CLINICAL SIGNIFICANCE

� Iron chelation may not prevent uptakeof iron in all organs, especially in thosein which iron enters cells through spe-cific ion channels.

� Calcium channel blockade with amlodi-pine in patients with thalassemia majorreduced iron overload in the heart inassociation with standard chelation.

� Amlodipine might serve as a newcomplementary treatment to standardchelation regimens in patients withthalassemia major, without the burdenof significant costs or side effects.

tion < 35%), renal insufficiency,advanced atrioventricular conduc-tion disturbances, and formalcontraindications to MR exami-nations. To minimize an impactfrom changes in chelation duringthe study, patients chosen had aprevious history of good compli-ance, and it was not plannedto alter their current chelation re-gimen in the short run. Samplesize was chosen based on the 45%reduction of myocardial iron ob-served in studies with mice, con-sidering an initial mean cardiacT2* of 20 ms with a standard de-viation of 5 ms, power of 0.8, andan alpha error of 0.05 (PASS 11;NCSS LLC, Kaysville, Utah).3

The study was approved by the

local Ethics Committee and all patients provided writteninformed consent. The study is registered at www.ClinicalTrials.gov as NCT01125254.

Study DesignAt baseline, patients were assessed for clinical characteris-tics as well as laboratory data, including ferritin levels. Allpatients also underwent an MR scan (1.5T Siemens Sym-phony; Siemens Medical Solutions, Erlangen, Germany) forevaluation of left ventricular volumes and function as wellas both heart and liver T2* iron quantification according topreviously published standards, using the truncation model.6

Heart and liver T2* values were calculated using CMR42software (Circle Cardiovascular Imaging Inc., Calgary, AB,Canada) in batch and random order by 2 readers (JLF andEFS) with the mean of the 2 readings used. Liver ironconcentrations were calculated using previous publisheddata by Wood et al and quoted in dry weight.7

After baseline measurements, patients were randomizedto receive amlodipine 5 mg/d for 12 months in a 1:2 allo-cation. Attending physicians were allowed to change theinitial dose if blood pressure was lower than 90 � 60 mmHg or if symptoms or side effects were important. All pa-tients repeated laboratory and MR evaluation at 6 and 12months. Although the drug was given open label, the readersof the MR images were blinded to treatment allocation.

Outcomes and Statistical AnalysisThe primary outcome of the study was the difference in heartT2* values betweengroups at 12months. Secondaryoutcomes

included myocardium T2* changes at 6 months as well asserum ferritin and liver iron concentration at both time points.

Ferritin, heart T2*, and liver iron concentration were nor-mally distributed, so parametric tests were used. Baseline dif-ferences between treatment and control groups were comparedusing Student’s t test or chi-squared. Changes within the same

group were analyzed using analysisof variance for repeated measureswith Bonferroni correction forpairwise comparisons. Comparisonbetween groups at different timepoints was done with analysis ofcovariance with group as the factorand baseline values as covariate toaccount for potential differences inthe baseline values.

RESULTSBaseline characteristics of patientsare shown in the Table. No sig-nificant differences were foundamong the participants, includingthe type of chelation therapy,although ferritin and hemoglobinlevels had a trend to be higher inthe control group. One patient in

the treatment group died at 10 months of follow-up due toliver failure secondary to advanced cirrhosis already presentat baseline. All analysis that included 12-month data did notinclude this patient. All treated patients used 5 mg/d ofamlodipine initially, with one patient having to reduce thedose to 2.5 mg/d due to lower extremities edema. No seriousadverse events related to amlodipine were detected. Nosignificant reductions in systemic blood pressure wereobserved and no significant changes in chelation therapywere made during the trial in the patient or control group(type of medication or dosing).

At 6 and 12 months, heart T2* in the treatment groupsignificantly increased from 21.7 � 7.2 ms to 28.2 � 7.9 msand 28.3 � 8.0 ms (P ¼ .007 and .03, respectively), with nosignificant changes in the control group (25.1 � 8.8 ms to24.7 � 7.8 ms and 26.2 � 11.4 ms; P ¼ .99 and .95,respectively) (Figure). Compared with controls, treatedpatients at 6 months had significantly higher heart T2*values (P ¼ .03), although this difference was not significantat 12 months (P ¼ .3).

A reduction in ferritin levels also was observed in treatedpatients compared with controls at 12 months (P ¼ .017).Compared with baseline, ferritin levels for treated patientsfell nonsignificantly from 1110 � 837 ng/mL to 545 � 198ng/mL and 453 � 285 ng/mL at 6 and 12 months (P ¼ .42and P ¼ .66, respectively). Control patients did not showsignificant changes from baseline (1602 � 1084 ng/mL to1673 � 1194 ng/mL and 1608 � 842 ng/mL; P ¼ .97 and.99, respectively).

Liver iron concentration did not change significantly inboth groups along the 12 months of follow-up from

Table Baseline Characteristics

Variable Amlodipine Group (n = 5) Control Group (n = 10) P Value

Age, y (range) 31.2 � 3.9 (25-35) 26.8 � 4.8 (17-32) .6Males, n (%) 3 (60) 6 (60) 1Height (m) 1.68 � 0.06 1.61 � 0.08 .4Weight (kg) 65.4 � 15.5 59.1 � 10.3 .4BSA (m2) 1.73 � 0.22 1.62 � 0.17 .5Chelation therapy .3

DFO, n (%) 2 (40) 2 (20)DFP, n (%) 1 (20) 4 (40)DFX, n (%) 0 (0) 3 (30)DFO þ DFP, n (%) 2 (40) 1 (10)

Ferritin, ng/mL 1110 � 837 1602 � 1084 .3Hemoglobin g/dL 9.4 � 0.65 9.8 � 0.29 .06Splenectomy (%) 2 (40) 7 (70) .3Hepatitis C (%) 3 (60) 4 (40) .6Heart T2* (ms) 21.7 � 7.2 25.1 � 8.8 .56Liver iron concentration (mg/g dry weight) 6.5 � 4.3 9.5 � 7.9 .45Left ventricular ejection fraction (%) (range) 66.5 � 9.2 (55.2-78.0) 66.6 � 6.7 (61.8-71.4) .99Indexed diastolic left ventricular volume (mL/m2) 83.2 � 23.2 74.2 � 15.7 .39Indexed systolic left ventricular volume (mL/m2) 29.1 � 15.5 25.2 � 8.7 .54

BSA ¼ body surface area; DFO ¼ deferoxamine; DFP ¼ deferiprone; DFX ¼ deferasirox.*Data are presented as means � SD.

836 The American Journal of Medicine, Vol 126, No 9, September 2013

baseline, and no significant differences were found betweengroups at 6 or 12 months.

DISCUSSIONWe showed that calcium channel blockade with amlodipinemay represent a novel and complementary treatment for ironoverload in patients with thalassemia major. Our results arein accordance with previous data in mice that showed a 50%reduction of myocardial iron levels after a 3-month treat-ment with verapamil.3 While an improvement of onlyapproximately 30% in heart T2* was observed after 12months, this increase is still significant compared with in-creases in heart T2* of 40%-50% observed with intensivechelation therapy8,9 or of 15%-31% with chelation

Figure Mean values and 95% confidence interval limits for ferritinmonths in the control group (triangles, dashed line) and in patients treatgroups; †P <.05 comparing changes from baseline at 6 and 12 month

monotherapy, also at 1 year.10,11 As expected, liver ironconcentrations did not change because iron uptake in theliver is less dependent on calcium channels compared withthe myocardium.4 The decrease in ferritin was quite unex-pected; we speculate that other factors, such as a reductionin inflammation, may be responsible for these changes.Another explanation might be the increased extracellularavailability of iron for the chelators once these atoms areaverted from entering sites blocked by amlodipine, althoughone might expect a reduction in liver iron concentration aswell in this case.12 Finally, we cannot exclude the possibilitythat increased urinary iron excretion played a role in theelimination of iron in treated patients, as amlodipine pro-longs the opening of divalent metal transporter-1 in thekidneys.13

, heart T2*, and liver iron concentration at baseline, 6, and 12ed with amlodipine (open circles, solid line). *P <.05 comparings.

837

The choice of amlodipine over other calcium channelblockers resides on its safety profile (including pediatricpopulations),14 as well as its negligible effect on inotropismand atrioventricular conduction at normal doses.15,16 Thiscould extend the use of the drug in patients with left ven-tricular dysfunction, a condition in thalassemia major pa-tients where cardiac iron overload is usually moresignificant.

Our small study had limitations inherent with itsexploratory nature. We were unable to assess whether theobserved changes in surrogate end points might correspondto clinical benefits or heart function improvement, especiallychanges in left ventricular ejection fraction. We also did notexplore other organs that also may suffer from calciumchannel-mediated iron overload. Finally, we decided not tocontinue with the originally planned cross-over study after12 months, as the results of the interim analysis suggestedthe need to proceed to a more robust randomized, blindedstudy that is currently ongoing (www.ClinicalTrials.govNCT01395199). The lack of significant differences be-tween groups at 12 months despite the significant findings at6 months and the differences observed within groups for theamlodipine arm, also point to the need of a larger cohort.

In conclusion, the addition of a calcium channel blockerto standard chelation in patients with thalassemia major mayimprove the efficacy of heart iron removal and reduce serumlevels of ferritin, with further testing for assessment of safetyand clinical benefits still needed.

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