Changes of liver transaminases levels during one year follow up of Deferasirox treatment in children with β-thalassemia major

Objectives: Abnormal liver function tests lead to interruptions of Deferasirox therapy. The aim of this study is to determine the changes in liver transaminases levels in pediatric patients with β -thalassemia major during one year follow up of Deferasirox treatment. Material and methods: This study was conducted at Ibn Al Atheer center of thalassemia, Mosul city, Iraq during the period from 3rd of February 2013 till 2nd of February 2014. Seventy one pediatric patients with β -thalassemia major were included in the study. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were measured every 4 weeks after starting Deferasirox therapy dose of 30 mg /kg/day for one year. Results: In comparison to mean baseline ALT values, there were significant elevations of mean ALT values in each of the subsequent 4-weekly interval readingsafter Deferasirox therapy. There was nearly eleven times relative risk of having ALT ≥ 5 upper normal level (UNL) in patient with abnormal baseline ALT (Odd ratio 10.96,95% Confidence Interval: lower 2.05, upper 58.58). During a year of study, Deferasirox therapy was associated withALT readings of ≥ 5UNL in 22(31%) of pediatric β-thalassemia patients and that elevation lasted for 4 weeks in 95.5% of patients. Conclusions: Elevated ALT of ≥ 5UNL after Deferasirox therapy was shortlived, and lasted for 4 weeks in 95.5% of patients. It is advisable to start Deferasirox therapy at a dose of 30 mg /kg / day when baseline ALT level is normal.


Introduction
Patients with β-thalassemia demand permanent iron chelation therapy to prevent complications relatedtotransfusional iron overload [1,3] .During recent years, Deferasiroxhas been widely used as efficaciousiron chelation treatmentfor patients at least 2 years of age. [4,5] . Thalassemia patients frequently have abnormal liver function tests due either to iron overload or concomitant viral hepatitis, moreover among the most common side effects of Deferasirox was increased liver enzyme [6][7][8][9][10][11][12][13][14][15] . Adverse events that led to discontinuations of Deferasirox included abnormal liver function tests and drug-induced hepatitis [9,16] . The aims of the present one year, follow-up study is to determine the changes in Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in Deferasirox treated children with β -thalassemia major, also to identify the effects of age, sex and baseline level of transaminase on subsequent measured transaminase levels.

Material and methods
This follow up study was conducted in Nineveh governorate, located in north of Iraq. It included registered patients in Ibn Al Atheer center of thalassemia in Mosul city, which is the only center in the governorate that provide medical care and management of patients with thalassemia. Since 2/11/2012 upon availability of the oral chelator drug Deferasirox (Exjade, Novartis) in Nineveh governorate and regardless of presence or absence of previous administration ofchelator therapy, patients aged ≥ 2 years with serum ferritin of 1000-2000 ng/ ml were selected to start Deferasirox (Exjade ®) monotherapy. Inagreement with Deferasiroxdrug manufacture prescribing information, all patients should start Deferasiroxtreatment at initial dose of 20 mg ⁄kg ⁄ day, increasing after 3 months to 30 mg /kg/day. All enrolled patients for this study should have their ALT and AST baseline values ≤ 2 × upper normal level (UNL) just prior to administration of Deferasirox dose of 30 mg /kg/day.In order to eliminate other causes of elevated liver transaminase, all patients were tested initially and every 6 months of study for Hepatitis B and C; any seropositive patients were excluded from the study.A total of 71 patients, 39 (54.9%) males and 32 (45.1%) females with mean age of 4.8 years and age range between 2-9 years, were eligible to be analyzed in this one year follow upresearch. The study started after a first dose of 30 mg /kg/day of Deferasirox is administered to each patient and it is dated from 3 rd of February 2013 till 2 nd of February 2014. Each patient was investigated thirteen times in the study year, at 4weekly intervals for measurements of ALT and AST and serum ferritin. Deferasirox dose of 30 mg /kg/ day is discontinued if patient displayed elevated transaminases levels ≥ 5 × UNL and reinstalled at a lower dose of 20 mg/kg/day upon decline of transaminase level below 5 folds duringsubsequent 4 weekly interval transaminase level assessment. A dose of 30 mg /kg /day is resumed when ALT level of < 5 UNL was maintained for another 4 weeks. Liver transaminase levels were measured using ChemWell-T automated chemistry analyzer device (USA) and utilizingPointe Scientific kit (USA) which had upper normal value of 34U/L for ALT and AST. Serum ferritin was analyzed by minividas 69280 (Biomeriux, Italy) using VIDAS ® Ferritin kit (Biomeriux, France). This study was approved by local research authority in Ninevah College of medicine, Ninevah University. Chi-square test was used to compare the categorical variables, Paired sample T test was used to evaluate differences between means of continuous variables, P value < 0.05 was considered to be statistically significant. Data analysis was executed using version 17 SPSS program.

Results
Throughout a year of follow up, ALT levels were not increased in all of thirteen readings in 17(23.9%) patients, whereas 22(31%) of studied patients had one or more than one readings out of the 13 assessments of each patient displayed ≥ 5UNL ALT level. Elevation of >1-<5 folds ALT level were displayed in the remaining 32 (45.1%) of patients. In comparison to mean baseline ALT values, there was significant elevation of mean ALT value in each of 4-weekly readings afterDeferasirox therapy in all compared pairs, nevertheless the differences between assessed mean ALT values compared to mean baseline ALT value ranged between 6.18 ± 2.31 -30.41 ± 4.63 U/L (Table 1). Single time ALT elevation of ≥ 5 UNL among the thirteen readings throughout a year of follow upensued in 15 (21.1 %) of 71 patients   * P-value: value less than 0.05 is considered significant.
Among 22 patients with ALT ≥ 5 UNL; Majority 21 (95.5 %) of patient's ALT decline to a lower level after 4 weeks. About two third (63.6 %) of them dropped to < 2 UNL of ALT. Only one (4.5 %) of patients had ALT ≥ 5 UNL at 2 consecutive post baseline visits. Timing of first ALT elevation is almost comparable in first and second half of follow up year (Table 3). Only one patient (4.5 %) had ALT of ≥ 10 UNL.

Discussion
Of the adverse events that led toDeferasirox discontinuation, the most common were increased alanine aminotransferase [1] . Studied patients receiving Deferasirox chelation therapy for one year displayed deranged ALT in 54/71 (83%) of them. Almost one third (30.9 %) of studied patients had one or more than one readings displayed ≥ 5UNL increase in ALT level , nevertheless , that elevation occurred single time in 15 (68.1%) of those patients, it was shortlived and returning to below fivefold level in the succeeding 4 weeks in 95.5 % of analyzed patients. These finding supported that Deferasirox adverse events generally are mostly transient and there were no progressive increases liver transaminase levels [17,18] . Albeit there were significant elevation of studied mean ALT values in comparison to mean baseline ALT values, however the assessed mean ALT paired differences ranged between 6.18 ± 2.31 -30.41 ± 4.63 U/L,a value of only about one fold ALT increment. Mean ALT levels were mildlyelevated during the first 2 years of Deferasiroxtreatment [11] . Only one (4.5 %) of studied patient had ALT levels >10 UNL which is comparable to other studies [4] . Only one (4.5 %) of investigated patients had ALT ≥ 5 UNL at 2 consecutive post baseline visits. Minority of patients experienced two consecutive increases in ALT [1,4,17] . In accordance with results of this research majority of patients who had ALT levels above UNL at baseline had higher ALT in their follow up [4,17] . AST increased less frequently than ALT among investigated patients, similar finding was obtained by other study [2] .Elevated serum ALT levels indicate a high specificity and a reasonable sensitivityof liverinjury [17] . Analyzed ≥ 5 UNL of AST values has sensitivity of 81.8 % in relation to ≥ 5 UNLof ALT values, implying that ALT was the determinant of Deferasirox dose interruptions and modification The measurement of serum ferritin provides a relatively strong marker of iron burden [ 18] . There was no significant difference between means of analyzed serum ferritin during first time changes of ALT above versus those below 5 folds, denoting that iron overload was not the reason for the studied ALT elevations.

Conclusions
In the view of this study results, it is reasonable to start Deferasirox therapy at a dose of 30 mg /kg / day whenbaseline ALT level is normal, since there is nearly eleven times relative risk of having ALT ≥ 5 UNL in patient with abnormal baseline ALT. It is not necessary to test for AST taking into consideration that ALT was the determinant ofDeferasirox dose modification.