Using of deferasirox and deferoxamine in refractory iron overload thalassemia

BACKGROUND

Iron overload is a major complication of transfusion-dependent thalassemia (TDT) and requires iron chelation (IC) therapy. However, a combination therapy may be required for patients responding poorly to monotherapy.

METHODS

Nine TDT patients previously treated with IC were enrolled; five patients were previously treated with deferasirox (DFX) twice daily. The dose of DFX was 20-40 mg/kg/day, while the dose of deferoxamine (DFO) was 18-40 mg/kg/day for 3-6 days/week.

RESULTS

At the 6- and 12-month time points, six and eight patients demonstrated decreased serum ferritin levels, with median reductions of 707 ng/mL (range, 1,653-5,444 ng/mL) and 1,129 ng/mL (range, 1,781-7,725 ng/mL) compared to the baseline, respectively. Eight patients also had a reduced liver iron concentration (LIC), with a median reduction of 3.9 mg/g dry wt (range, 8.3-11.1 mg/g dry wt). Of the five patients treated with DFX twice daily, four responded to combination therapy. All responsive patients could finally stop DFO after the decline in LIC. Moreover, there were no treatment-related complications.

CONCLUSION

The combination of DFX and DFO proved to be effective and without significant toxicities for TDT patients who had been unresponsive to standard IC therapy. Further studies with a larger cohort size and long-term follow-up are warranted to elucidate the efficacy of the combination.

Changing patterns in the epidemiology of β-thalassemia

β‐thalassemia major is an inherited hemoglobinopathy that requires lifelong red blood cell transfusions and iron chelation therapy to prevent complications due to iron overload. Traditionally, β‐thalassemia has been more common in certain regions of the world such as the Mediterranean, Middle East, and Southeast Asia. However, the prevalence of β‐thalassemia is increasing in other regions, including Northern Europe and North America, primarily due to migration. This review summarizes the available data on the changing incidence and prevalence of β‐thalassemia as well as factors influencing disease frequency. The data suggest that the epidemiology of β‐thalassemia is changing: Migration has increased the prevalence of the disease in regions traditionally believed to have a low prevalence, while, at the same time, prevention and screening programs in endemic regions have reduced the number of affected individuals. Various approaches to prevention and screening have been used. Region‐specific prevention and treatment programs, customized to align with local healthcare resources and cultural values, have been effective in identifying patients and carriers and providing information and care. Significant challenges remain in universally implementing these programs.

Impact of splenectomy on outcomes of hematopoietic stem cell transplantation in pediatric patients with transfusion-dependent thalassemia

BACKGROUND

The role of splenectomy prior to hematopoietic stem cell transplantation (HSCT) is controversial. Only few studies compared the outcomes of splenectomized and nonsplenectomized children with transfusion-dependent thalassemia (TDT) undergoing allogeneic HSCTs.

METHODS

A retrospective analysis was undertaken on a transplantation cohort of TDT patients; August 1987-December 2014 to compare transplant outcomes between splenectomized and nonsplenectomized groups.

RESULTS

Ninety-six transplants in 86 TDT patients were analyzed. Sixteen patients were splenectomized before HSCTs. The splenectomized patients were significantly older (8.0 ± 1.9 vs 4.7 ± 0.6 years; P = 0.001), had larger livers and spleens (P = 0.001), and had a significantly shorter neutrophil engraftment time (absolute neutrophil count > 500/mm³ ; 15.0 ± 2.3 vs 19.2 ± 1.3 days; P = 0.004). Graft rejection occurred in 13.8% of the nonsplenectomized group, but not among the splenectomized patients. Though the splenectomized group's mortality rate was higher (25.0% vs 8.8%), this was not statistically significant (P = 0.491). The main causes of death in both groups were severe infections. The five-year overall survival (OS) rate was better for the nonsplenectomized group (91.78% vs 75.00%; P = 0.06).

CONCLUSIONS

Although splenectomies prior to HSCT for the TDT patients in our cohort were associated with faster neutrophil engraftments and lower rejection rates, they did not produce significantly better OS or affect the mortality. As the splenectomies did not provide any distinct advantages, this procedure should not be routinely performed as a pre-HSCT regimen for TDT patients with splenomegaly. Better pre-HSCT preparation for TDT patients, including early and adequate blood transfusions to avoid splenomegaly, is recommended.

Early development of decreased β-cell insulin secretion in children and adolescents with hemoglobin H disease and its relationship with levels of anemia

BACKGROUND

Diabetes mellitus (DM) associated with iron overload has been reported among adults with transfusion-dependent thalassemia and those with non-transfusion-dependent thalassemia (NTDT), especially in β-thalassemia disease. However, little is known about glucose metabolism and how early its dysregulation can develop in α-thalassemia hemoglobin H (Hb H) disease, which is one of the most common types of NTDT worldwide.

PROCEDURE

We prospectively calculated glucose metabolism index in 40 patients (aged 10-25 years) with Hb H disease. Glucose metabolism data were compared between patients with deletional versus nondeletional Hb H, and between patients with normal versus abnormal insulin secretion/sensitivity.

RESULTS

Despite normal glucose tolerance in all patients, 52.5% had abnormal insulinogenic index indicating decreased β-cell insulin secretion. Patients with functional hemoglobin < 8 g/dL had significantly higher percentages of abnormal insulinogenic index. There was no significant difference in abnormal insulinogenic index between deletional and nondeletional Hb H.

CONCLUSION

Decreased β-cell insulin secretion is highly prevalent among children and adolescents with Hb H disease, and it is associated with levels of functional anemia at baseline, but not with the type of Hb H disease. This result warrants heightened awareness among hematologists due to potentially increased risk of DM later in life.

A Phase 3 Trial of Luspatercept in Patients with Transfusion-Dependent β-Thalassemia

BACKGROUND

Patients with transfusion-dependent β-thalassemia need regular red-cell transfusions. Luspatercept, a recombinant fusion protein that binds to select transforming growth factor β superfamily ligands, may enhance erythroid maturation and reduce the transfusion burden (the total number of red-cell units transfused) in such patients.

METHODS

In this randomized, double-blind, phase 3 trial, we assigned, in a 2:1 ratio, adults with transfusion-dependent β-thalassemia to receive best supportive care plus luspatercept (at a dose of 1.00 to 1.25 mg per kilogram of body weight) or placebo for at least 48 weeks. The primary end point was the percentage of patients who had a reduction in the transfusion burden of at least 33% from baseline during weeks 13 through 24 plus a reduction of at least 2 red-cell units over this 12-week interval. Other efficacy end points included reductions in the transfusion burden during any 12-week interval and results of iron studies.

RESULTS

A total of 224 patients were assigned to the luspatercept group and 112 to the placebo group. Luspatercept or placebo was administered for a median of approximately 64 weeks in both groups. The percentage of patients who had a reduction in the transfusion burden of at least 33% from baseline during weeks 13 through 24 plus a reduction of at least 2 red-cell units over this 12-week interval was significantly greater in the luspatercept group than in the placebo group (21.4% vs. 4.5%, P<0.001). During any 12-week interval, the percentage of patients who had a reduction in transfusion burden of at least 33% was greater in the luspatercept group than in the placebo group (70.5% vs. 29.5%), as was the percentage of those who had a reduction of at least 50% (40.2% vs. 6.3%). The least-squares mean difference between the groups in serum ferritin levels at week 48 was -348 μg per liter (95% confidence interval, -517 to -179) in favor of luspatercept. Adverse events of transient bone pain, arthralgia, dizziness, hypertension, and hyperuricemia were more common with luspatercept than placebo.

CONCLUSIONS

The percentage of patients with transfusion-dependent β-thalassemia who had a reduction in transfusion burden was significantly greater in the luspatercept group than in the placebo group, and few adverse events led to the discontinuation of treatment. (Funded by Celgene and Acceleron Pharma; BELIEVE ClinicalTrials.gov number, NCT02604433; EudraCT number, 2015-003224-31.).

Paper-based microchip electrophoresis for point-of-care hemoglobin testing

Nearly 7% of the world's population live with a hemoglobin variant. Hemoglobins S, C, and E are the most common and significant hemoglobin variants worldwide. Sickle cell disease, caused by hemoglobin S, is highly prevalent in sub-Saharan Africa and in tribal populations of Central India. Hemoglobin C is common in West Africa, and hemoglobin E is common in Southeast Asia. Screening for significant hemoglobin disorders is not currently feasible in many low-income countries with the high disease burden. Lack of early diagnosis leads to preventable high morbidity and mortality in children born with hemoglobin variants in low-resource settings. Here, we describe HemeChip, the first miniaturized, paper-based, microchip electrophoresis platform for identifying the most common hemoglobin variants easily and affordably at the point-of-care in low-resource settings. HemeChip test works with a drop of blood. HemeChip system guides the user step-by-step through the test procedure with animated on-screen instructions. Hemoglobin identification and quantification is automatically performed, and hemoglobin types and percentages are displayed in an easily understandable, objective way. We show the feasibility and high accuracy of HemeChip via testing 768 subjects by clinical sites in the United States, Central India, sub-Saharan Africa, and Southeast Asia. Validation studies include hemoglobin E testing in Bangkok, Thailand, and hemoglobin S testing in Chhattisgarh, India, and in Kano, Nigeria, where the sickle cell disease burden is the highest in the world. Tests were performed by local users, including healthcare workers and clinical laboratory personnel. Study design, methods, and results are presented according to the Standards for Reporting Diagnostic Accuracy (STARD). HemeChip correctly identified all subjects with hemoglobin S, C, and E variants with 100% sensitivity, and displayed an overall diagnostic accuracy of 98.4% in comparison to reference standard methods. HemeChip is a versatile, mass-producible microchip electrophoresis platform that addresses a major unmet need of decentralized hemoglobin analysis in resource-limited settings.

Estimating the burden of α-thalassaemia in Thailand using a comprehensive prevalence database for Southeast Asia

Severe forms of α-thalassaemia, haemoglobin H disease and haemoglobin Bart’s hydrops fetalis, are an important public health concern in Southeast Asia. Yet information on the prevalence, genetic diversity and health burden of α-thalassaemia in the region remains limited. We compiled a geodatabase of α-thalassaemia prevalence and genetic diversity surveys and, using geostatistical modelling methods, generated the first continuous maps of α-thalassaemia mutations in Thailand and sub-national estimates of the number of newborns with severe forms in 2020. We also summarised the current evidence-base for α-thalassaemia prevalence and diversity for the region. We estimate that 3595 (95% credible interval 1,717–6,199) newborns will be born with severe α-thalassaemia in Thailand in 2020, which is considerably higher than previous estimates. Accurate, fine-scale epidemiological data are necessary to guide sustainable national and regional health policies for α-thalassaemia management. Our maps and newborn estimates are an important first step towards this aim.

Editorial note: This article has been through an editorial process in which the authors decide how to respond to the issues raised during peer review. The Reviewing Editor's assessment is that all the issues have been addressed (see decision letter).

Validation of a patient-reported outcomes symptom measure for patients with nontransfusion-dependent thalassemia (NTDT-PRO© )

This study demonstrates the quantitative characteristics of the first patient‐reported outcome (PRO) tool developed for patients with nontransfusion‐dependent β‐thalassemia (NTDT), the NTDT‐PRO^©. A multicenter validation study was performed over 24 weeks, involving 48 patients from Italy, Lebanon, Greece, and Thailand. Most patients were female (68.8%), with a median age of 34.5 years (range, 18‐52); 66.7% were diagnosed with β‐thalassemia intermedia, and median time since diagnosis was 22 years (range, 0‐43). The NTDT‐PRO comprises 6 items across 2 domains (Tiredness/Weakness and Shortness of Breath [SoB]), and was valid and reliable, with good consistency. At baseline, most patients reported symptoms as present via the NTDT‐PRO, and were highly compliant, ≥90% completing the NTDT‐PRO tool. In a pairwise correlation analysis, all items were positively correlated. Correlations between NTDT‐PRO and existing tools—36‐Item Short Form Health Survey version 2 (SF‐36v2) and Functional Assessment of Cancer Therapy‐Anemia (FACT‐An)—were assessed at weeks 1, 3, and 12; robust correlations were seen between SoB and SF‐36v2‐Vitality (r_s = −0.53), and between SoB and Fact‐An‐Fatigue Experience (r_s = −0.66) at week 1. Internal consistency was high for both Tiredness/Weakness (Cronbach alpha, 0.91) and SoB (Spearman‐Brown coefficient, 0.78); intraclass correlation coefficients were high (Tiredness/Weakness, 0.88 and 0.97; SoB, 0.92 and 0.98), demonstrating stability. Further studies are required to fully support the validity of this tool, this study demonstrated the usefulness of the NTDT‐PRO in the clinical setting and for longitudinal clinical research, particularly in trials where patient health‐related quality of life is expected to change.

Development of a patient-reported outcomes symptom measure for patients with nontransfusion-dependent thalassemia (NTDT-PRO© )

β‐Thalassemia, a hereditary blood disorder caused by reduced or absent synthesis of the β‐globin chain of hemoglobin, is characterized by ineffective erythropoiesis, and can manifest as nontransfusion‐dependent thalassemia (NTDT) or transfusion‐dependent thalassemia (TDT). Many patients with NTDT develop a wide range of serious complications that affect survival and quality of life (QoL). Patient‐reported outcomes (PRO), including health‐related QoL (HRQoL), are important tools for determining patient health impairment and selecting appropriate treatment. However, there are currently no disease‐specific PRO tools available to assess symptoms related to chronic anemia experienced by patients with NTDT. This study aimed to develop a new, US Food and Drug Administration (FDA)‐compliant PRO of chronic anemia symptoms, the NTDT‐PRO^© tool, for use in patients with NTDT. Participants had a median age of 36 years (range, 18‐47) and 60% were female. The initial development of the NTDT‐PRO tool involved concept‐elicitation interviews with 25 patients from 3 centers (in Lebanon, Greece, and Canada); subsequent interview discussions and clinical input resulted in the generation of 9 items for inclusion in the draft NTDT‐PRO. Following a round of cognitive interviews involving 21 patients from 2 centers (in Lebanon and Greece), 4 items (Pain, Headaches, Ability to Concentrate, and Paleness) were removed from the draft NTDT‐PRO. The final NTDT‐PRO comprises 6 items that measure Tiredness, Weakness, and Shortness of Breath, with or without Physical Activity. The NTDT‐PRO is a new disease‐specific HRQoL tool for patients with NTDT, developed using a thorough methodology based on FDA 2009 PRO development guidelines.

An integration-free iPSC line (MUSIi008-A) derived from a patient with severe hemolytic anemia carrying compound heterozygote mutations in KLF1 gene for disease modeling

We generated an induced pluripotent stem cell (iPSC) line from peripheral blood mononuclear cells (PBMNCs) isolated from a 1-year old female carrying compound heterozygote for KLF1 mutations (G176RfsX179 and A298P mutations). Non-integrating Sendai viral (SeV) vectors containing KOS, hc-MYC and hKLF4 were used for reprogramming. The established MUSIi008-A cell line contained the same mutations found in the patient, expressed pluripotent markers, differentiated into cells of three embryonic germ layers both in vitro and in vivo, and exhibited normal karyotype. This cell line may provide an alternative renewable source of cells for in vitro disease modeling of severe transfusion-dependent hemolytic anemia.

Clinical Classification, Screening and Diagnosis for Thalassemia

At present, thalassemia diseases are classified into transfusion-dependent thalassemia and non-transfusion-dependent thalassemia. This classification is based on the clinical severity of patients determining whether they do require regular blood transfusions to survive (transfusion-dependent thalassemia) or not (non-transfusion-dependent thalassemia). In addition to the previous terminology of "thalassemia major" or "thalassemia intermedia," this classification has embraced all other forms of thalassemia syndromes such as α-thalassemia, hemoglobin E/β-thalassemia and combined α- and β-thalassemias. Definitive diagnosis of thalassemia and hemoglobinopathies requires a comprehensive workup from complete blood count, hemoglobin analysis, and molecular studies to identify mutations of globin genes.

A prospective analysis for prevalence of complications in Thai nontransfusion-dependent Hb E/β-thalassemia and α-thalassemia (Hb H disease)

Recently, complications in patients with nontransfusion-dependent thalassemia (NTDT), in particular those with β-thalassemia intermedia (β-TI), were found to be significantly different from those in patients with transfusion dependent thalassemia (TDT), mainly β-thalassemia major (β-TM). However, this information is rather limited in other forms of NTDT. In this prospective study, adult Thai NTDT patients were interviewed and clinically evaluated for thalassemia related complications. Fifty-seven NTDT patients (age 18-74 years), 59.6% Hb E/β-thalassemia and 40.4% Hb H disease, were recruited; 26.4% were splenectomized. The most common complications were gallstones (68.4%), osteoporosis (26.3%), and pulmonary hypertension (15.8%). Splenectomy was associated with higher rate of gallstones and serious infection (P = .001 and .052, respectively), consistent with a multivariate analysis (RR = 9.5, P = .044, and RR = 15.1, P = .043, respectively). In addition, a higher hemoglobin level was inversely associated with gallstones in both univariate and multivariate analyses (P = .01 and .022, respectively). Serum ferritin was associated with abnormal liver function (P = .002). In contrast to the previous study, the prevalence of thrombosis was less common in our population (1.7%), probably due to differences in transfusion therapy, ethnicity, and underlying genotypes. For the first time, this prospective study provided the current prevalence of NTDT related complications in a Southeast Asian population with a different underlying genetic basis compared with previous studies. Although individual prevalence of each complication might differ from other studies, several important clinical factors such as splenectomy, degree of anemia, and iron overload seem to be determining risks of developing these complications consistently across different ethnicities.

An Automated Segmentation of R2* Iron-Overloaded Liver Images Using a Fuzzy C-Mean Clustering Scheme

OBJECTIVES

The objectives of this study were to develop and test an automated segmentation of R2* iron-overloaded liver images using fuzzy c-mean (FCM) clustering and to evaluate the observer variations.

MATERIALS AND METHODS

Liver R2* images and liver iron concentration (LIC) maps of 660 thalassemia examinations were randomly separated into training (70%) and testing (30%) cohorts for development and evaluation purposes, respectively. Two-dimensional FCM used R2* images, and the LIC map was implemented to segment vessels from the parenchyma. Two automated FCM variables were investigated using new echo time and membership threshold selection criteria based on the FCM centroid distance and LIC levels, respectively. The new method was developed on a training cohort and compared with manual segmentation for segmentation accuracy and to a previous semiautomated method, and a semiautomated scheme was suggested to improve unsuccessful results. The automated variables found from the training cohort were assessed for their effectiveness in the testing cohort, both quantitatively and qualitatively (the latter by 2 abdominal radiologists using a grading method, with evaluations of observer variations). A segmentation error of less than 30% was considered to be a successful result in both cohorts, whereas, in the testing cohort, a good grade obtained from satisfactory automated results was considered a success.

RESULTS

The centroid distance method has a segmentation accuracy comparable with the previous-best, semiautomated method. About 94% and 90% of the examinations in the training and testing cohorts were automatically segmented out successfully, respectively. The failed examinations were successfully segmented out with thresholding adjustment (3% and 8%) or by using alternative results from the previous 1-dimensional FCM method (3% and 2%) in the training and testing cohorts, respectively. There were no failed segmentation examinations in either cohort. The intraobserver and interobserver variabilities were found to be in substantial agreement.

CONCLUSIONS

Our new method provided a robust automated segmentation outcome with a high ease of use for routine clinical application.

Prevalence of low bone mass among adolescents with nontransfusion-dependent hemoglobin E/β-thalassemia and its relationship with anemia severity

BACKGROUND

Low bone mass is common among adolescents with transfusion-dependent β-thalassemia despite adequate transfusion and iron chelation. However, there are few reports regarding bone mineral density (BMD) among adolescents with nontransfusion-dependent thalassemia (NTDT). Indeed, only BMD data in patients with nontransfusion-dependent (NTD) β-thalassemia intermedia have been reported. No previous study has investigated BMD among adolescents with NTD hemoglobin (Hb) E/β-thalassemia.

OBJECTIVE

To determine the prevalence of low bone mass among adolescents with NTD Hb E/β-thalassemia and factors relating to low bone mass.

METHODS

We investigated BMD of lumbar spine (L2-L4; BMDLS) and total body (BMDTB), as measured by dual-energy X-ray absorptiometry, in 22 adolescents (aged 13.2-20 years) with NTD Hb E/β-thalassemia.

RESULTS

Low bone mass was found to be 18.2% and 22.7% at the lumbar spine (BMDLS Z-score adjusted for bone age and height age) and 13.6% and 9.1% at the total body (BMDTB Z-score adjusted for bone age and height age). Patients with mean Hb level <8 g/dl were more likely to have low bone mass (BMDLS and BMDTB Z-scores adjusted for bone age) compared to those with Hb level ≥ 8 g/dl. Mean Hb level correlated with BMDLS and BMDTB Z-scores adjusted for bone age.

CONCLUSION

We demonstrated that a low Hb level was associated with low bone mass among adolescents with NTD Hb E/β-thalassemia. A significant proportion of low bone mass among these patients highlights the importance of appropriate management, including red cell transfusion, vitamin D and calcium supplementation for improved long-term bone health.

Safety and pharmacokinetics of the oral iron chelator SP-420 in β-thalassemia

Our phase I, open-label, multi-center, dose-escalation study evaluated the pharmacokinetics (PK) of SP-420, a tridentate oral iron chelating agent of the desferrithiocin class, in patients with transfusion dependent β-thalassemia. SP-420 was administered as a single dose of 1.5 (n = 3), 3 (n = 3), 6 (n = 3), 12 (n = 3), and 24 (n = 6) mg/kg or as a twice-daily dose of 9 mg/kg (n = 6) over 14-28 days. There was a near dose-linear increase in the mean plasma SP-420 concentrations and in the mean values for C_max and AUC_0-τ over the dose range evaluated. The median t_max ranged from 0.5 to 2.25 h and was not dose dependent. The study was prematurely terminated by the sponsor due to renal adverse events (AE) including proteinuria, increase in serum creatinine, and one case of Fanconi syndrome. Other adverse effects included hypersensitivity reactions and gastrointestinal disturbances. Based on current dose administration, the renal AE observed outweighed the possible benefits from chelation therapy. However, additional studies assessing efficacy and safety of lower doses or less frequent dosing of SP-420 over longer durations with close monitoring would be necessary to better explain the findings of our study and characterize the safety of the study drug.

Prevalence and predictors of cardiac and liver iron overload in patients with thalassemia: A multicenter study based on real-world data

Prevalence of cardiac and liver iron overload in patients with thalassemia in real-world practice may vary among different regions especially in the era of widely-used iron chelation therapy. The aim of this study was to determine the prevalence of cardiac and liver iron overload in and the management patterns of patients with thalassemia in real-world practice in Thailand. We established a multicenter registry for patients with thalassemia who underwent magnetic resonance imaging (MRI) as part of their clinical evaluation. All enrolled patients underwent cardiac and liver MRI for assessment of iron overload. There were a total of 405 patients enrolled in this study. The mean age of patients was 18.8±12.5years and 46.7% were male. Two hundred ninety-six (73.1%) of patients received regular blood transfusion. Prevalence of cardiac iron overload (CIO) and liver iron overload (LIO) was 5.2% and 56.8%, respectively. Independent predictors for iron overload from laboratory information were serum ferritin and transaminase for both CIO and LIO. Serum ferritin can be used as a screening tool to rule-out CIO and to diagnose LIO. Iron chelation therapy was given in 74.6%; 15.3% as a combination therapy.

Interaction between Hb E and Hb Yala (HBB:c.129delT); a novel frameshift beta globin gene mutation, resulting in Hemoglobin E/β0 thalassemia

OBJECTIVES

There are more than 200 known mutations found in patients with β-thalassemia, a possibility to identify an unknown or novel mutation becomes less possible. Here, we report a novel mutation in a patient from Thailand who presented with chronic hemolytic anemia.

METHODS

A comprehensive hematology and DNA analysis was applied in the index patient and her mother.

RESULTS

Hematological and hemoglobin analyses were consistent with the clinical diagnosis of Hb E/β⁰-thalassemia. However, we could find only Hb E heterozygous mutation using our common polymerase chain reaction-based mutation detection of the β-globin genes. Furthermore, the molecular analysis demonstrated a novel T-deletion at codon 42 of the second exon of the β-globin gene which we named 'Hb Yala' according to the origin of this index family.

DISCUSSION

This mutation was assumed to generate a truncated β-globin chain terminating at codon 60 with possible unstable variant leading to a 'null' or β⁰-thalassemia. However, the clinical phenotype was surprisingly mild and no other ameliorating genetic factors, including co-inheritance of α-thalassemia and high propensity of Hb F by Xmn I polymorphism, were found.

CONCLUSION

This report has provided evidence that genotype-phenotype correlation in thalassemia syndromes is highly complex and a correct clinical severity classification of thalassemia should be mainly based on clinical evaluation.