Pain and other non‐neurological adverse events in children with sickle cell anemia and previous stroke who received hydroxyurea and phlebotomy or chronic transfusions and chelation: Results from the SWiTCH clinical trial

To compare the non‐neurological events in children with sickle cell anemia (SCA) and previous stroke enrolled in SWiTCH. The NHLBI‐sponsored Phase III multicenter randomized clinical trial stroke with transfusions changing to hydroxyurea (SWiTCH) ( ClinicalTrials.gov NCT00122980) compared continuation of chronic blood transfusion/iron chelation to switching to hydroxyurea/phlebotomy for secondary stroke prevention and management of iron overload. All randomized children were included in the analysis (intention to treat). The Fisher's Exact test was used to compare the frequency of subjects who experienced at least one SCA‐related adverse event (AE) or serious adverse event (SAE) in each arm and to compare event rates. One hundred and thirty three subjects, mean age 13 ± 3.9 years (range 5.2–19.0 years) and mean time of 7 years on chronic transfusion at study entry, were randomized and treated. Numbers of subjects experiencing non‐neurological AEs were similar in the two treatment arms, including SCA‐related events, SCA pain events, and low rates of acute chest syndrome and infection. However, fewer children continuing transfusion/chelation experienced SAEs (P = 0.012), SCA‐related SAEs (P = 0.003), and SCA pain SAEs (P = 0.016) as compared to children on the hydroxyurea/phlebotomy arm. The timing of phlebotomy did not influence SAEs. Older age at baseline predicted having at least 1 SCA pain event. Patients with recurrent neurological events during SWiTCH were not more likely to experience pain. In children with SCA and prior stroke, monthly transfusions and daily iron chelation provided superior protection against acute vaso‐occlusive pain SAEs when compared to hydroxyurea and monthly phlebotomy. Am. J. Heamtol. 88:932–938, 2013. © 2013 Wiley Periodicals, Inc.     

To SWiTCH or not to SWiTCH?

In this issue of Blood, Ware and Helms report results from the Stroke With Transfusions Changing To Hydroxyurea (SWiTCH) study designed to determine whether hydroxyurea is as effective as transfusions in preventing recurrent strokes in children with sickle cell anemia. The finding of strokes in 7 of 67 children receiving hydroxyurea but none in 66 children who received transfusions led the authors to conclude that hydroxyurea is not effective in mitigating strokes.1     

Long-term results using hydroxyurea/phlebotomy for reducing secondary stroke risk in children with sickle cell anemia and iron overload

Children with sickle cell anemia (SCA) and a primary overt stroke are at high risk of recurrent (secondary) stroke. Chronic transfusion therapy dramatically reduces but does not eliminate this high risk, and inevitably results in transfusion-related hemosiderosis. We previously reported the use of hydroxyurea/phlebotomy as an alternative to transfusions to reduce the risk of secondary stroke and improve management of iron overload in 35 children with SCA. To report long-term results, we retrospectively reviewed clinical and laboratory data through October 2008. With a median of 5.6 years and total of 219 patient-years of follow-up, 10 of 35 patients (29%) had recurrent stroke after switching to hydroxyurea; seven were previously reported and three new strokes occurred during extended follow-up. The overall secondary stroke event rate was 4.6 per 100 patient-years. Children on hydroxyurea received serial phlebotomy and had lower mean serum ferritin values than children on transfusions (591 ng/mL vs. 3410 ng/mL, P = 0.02). In this cohort, long-term hydroxyurea treatment reduced but did not eliminate the risk of stroke recurrence and, uniquely, allowed phlebotomy to reduce iron overload. Long-term assessments of this therapy should evaluate risk factors for secondary stroke and assessments of hemosiderosis, neurocognitive outcome, and health-related quality of life.     

Chronic transfusion practice for children with sickle cell anaemia and stroke

Chronic transfusions to maintain haemoglobin S (HbS) ≤30% are the mainstay of treatment for children with sickle cell anaemia (SCA) and previous stroke. This HbS target is often hard to maintain, however, and values achieved in current practice are unknown. In preparation for the Phase III Stroke With Transfusions Changing to Hydroxyurea (SWiTCH) trial, we collected data on 295 children with SCA and stroke who received transfusions at 23 institutions. The overall average pre-transfusion %HbS was 35 ± 11% (institutional range 22–51%). Receiving scheduled transfusions on time was the most predictive variable for maintaining HbS at the ≤30% goal.     

Therapeutic phlebotomy is safe in children with sickle cell anaemia and can be effective treatment for transfusional iron overload

Serial phlebotomy was performed on sixty children with sickle cell anaemia, stroke and transfusional iron overload randomized to hydroxycarbamide in the Stroke With Transfusions Changing to Hydroxyurea trial. There were 927 phlebotomy procedures with only 33 adverse events, all of which were grade 2. Among 23 children completing 30 months of study treatment, the net iron balance was favourable (?8·7 mg Fe/kg) with significant decrease in ferritin, although liver iron concentration remained unchanged. Therapeutic phlebotomy was safe and well‐tolerated, with net iron removal in most children who completed 30 months of protocol‐directed treatment.     

Hydroxyurea as an alternative to blood transfusions for the prevention of recurrent stroke in children with sickle cell disease.

Children with sickle cell disease (SCD) and stroke receive chronic transfusions to prevent stroke recurrence. Transfusion risks including infection, erythrocyte allosensitization, and iron overload suggest a need for alternative therapies. We previously used hydroxyurea (HU) and phlebotomy in two young adults with SCD and stroke as an alternative to transfusions. We have now prospectively discontinued transfusions in 16 pediatric patients with SCD and stroke. Reasons to discontinue transfusions included erythrocyte alloantibodies or autoantibodies, recurrent stroke on transfusions, iron overload, noncompliance, and deferoxamine allergy. HU was started at 15 mg/kg/d and escalated to 30 mg/kg/d based on hematologic toxicity. Patients with iron overload underwent phlebotomy. The children have been off transfusions 22 months, (range, 3 to 52 months). Their average HU dose is 24.9 +/- 4.2 mg/kg/d, hemoglobin concentration is 9.4 +/- 1.3 g/dL, and mean corpuscular volume (MCV) is 112 +/- 9 fL. Maximum percentage fetal hemoglobin (%HbF) is 20.6% +/- 8.0% and percentage HbF-containing erythrocytes (%F cells) is 79.3% +/- 14.7%. Fourteen patients underwent phlebotomy with an average of 8,993 mL (267 mL/kg) removed. Serum ferritin has decreased from 2,630 to 424 ng/mL, and 4 children have normal ferritin values. Three patients (19%) had neurological events considered recurrent stroke, each 3 to 4 months after discontinuing transfusions, but before maximal HU effects. These preliminary data suggest some children with SCD and stroke may discontinue chronic transfusions and use HU therapy to prevent stroke recurrence. Phlebotomy is well-tolerated and significantly reduces iron overload. Modifications in HU therapy to raise HbF more rapidly might increase protection against stroke recurrence.     

Iron status and treatment modalities in transfusion-dependent patients with myelodysplastic syndromes

Transfusion dependency and iron overload are common among patients with myelodysplastic syndromes (MDS) treated with red blood cell (RBC) transfusions. Transfusion dependency is associated with leukemic progression and shorter survival. Guidelines recommend iron chelation therapy to manage iron overload, however little is known about the chelation patterns in daily clinical practice. The objective of this multicenter, retrospective, cross-sectional, observational study was to evaluate iron status and its management in transfusion-dependent MDS patients. A total of 193 patient records from 29 centers were eligible for inclusion. Median patient age was 76, and median age at diagnosis of MDS was 74. Patients had received an average of 13.4?±?7.6 RBC units in the past 4?months; 44% had received more than 50 units since their MDS diagnosis. Medium serum ferritin was 1,550???g/L. Ninety patients (46.6%) received iron chelation therapy with either deferoxamine (41%), deferasirox (36%), and deferoxamine followed by deferasirox (23%). There were no statistically significant differences between chelated and nonchelated patients in terms of International Prognostic Scoring System (IPSS), French-American-British (FAB), and/or World Health Organization (WHO) status, though chelated patients had received more RBC transfusions (p?=?0.014). Iron chelation therapy may be underutilized in transfusion-dependent patients. Undertreatment can be reduced by complementing sound clinical judgment with the generally accepted guidelines of a serum ferritin level >1,000???g/L and/or two or more RBC transfusions per month for the past year; considering patients on the basis of their IPSS, FAB, and/or WHO status; and individually tailored treatment regimens. Prospective randomized trials are necessary to establish causally the efficacy of iron chelation therapy in MDS.     

Deferasirox reduces iron overload significantly in nontransfusion-dependent thalassemia: 1-year results from a prospective, randomized, double-blind, placebo-controlled study

Nontransfusion-dependent thalassemia (NTDT) patients may develop iron overload and its associated complications despite receiving only occasional or no transfusions. The present 1-year, randomized, double-blind, placebo-controlled THALASSA (Assessment of Exjade in Nontransfusion-Dependent Thalassemia) trial assessed the efficacy and safety of deferasirox in iron-overloaded NTDT patients. A total of 166 patients were randomized in a 2:1:2:1 ratio to starting doses of 5 or 10 mg/kg/d of deferasirox or placebo. The means ± SD of the actual deferasirox doses received over the duration of the study in the 5 and 10 mg/kg/d starting dose cohorts were 5.7 ± 1.4 and 11.5 ± 2.9 mg/kg/d, respectively. At 1 year, the liver iron concentration (LIC) decreased significantly compared with placebo (least-squares mean [LSM] ± SEM, -2.33 ± 0.7 mg Fe/g dry weight [dw], P = .001, and -4.18 ± 0.69 mg Fe/g dw, P < .001) for the 5 and 10 mg/kg/d deferasirox groups, respectively (baseline values [means ± SD], 13.11 ± 7.29 and 14.56 ± 7.92 mg Fe/g dw, respectively). Similarly, serum ferritin decreased significantly compared with placebo by LSM -235 and -337 ng/mL for the deferasirox 5 and 10 mg/kg/d groups, respectively (P < .001). In the placebo patients, LIC and serum ferritin increased from baseline by 0.38 mg Fe/g dw and 115 ng/mL (LSM), respectively. The most common drug-related adverse events were nausea (n = 11; 6.6%), rash (n = 8; 4.8%), and diarrhea (n = 6; 3.6%). This is the first randomized study showing that iron chelation with deferasirox significantly reduces iron overload in NTDT patients with a frequency of overall adverse events similar to placebo.     

Two-year analysis of efficacy and safety of deferasirox treatment for transfusional iron overload in sickle cell anemia patients

The efficacy and safety of a 2-year treatment with deferasirox was evaluated in 31 patients with sickle cell anemia and transfusional iron overload. At 24 months, there were significant decreases from baseline in mean serum ferritin (from 2,344.6 to 1,986.3 μg/l; p = 0.040) and in mean liver iron concentration (from 13.0 ± 5.4 to 9.3 ± 5.7 mg Fe/g dry weight; p < 0.001). Myocardial T2* values were normal (>20 ms) in all patients at baseline and did not change significantly over the course of the study. However, there was a significant improvement from baseline in left ventricular ejection fraction at 24 months (62.2-64.6%; p = 0.02). Deferasirox was generally well tolerated with no progressive increases in serum creatinine or renal failure observed. These data confirm that deferasirox is effective in reducing body iron burden in patients with sickle cell anemia and transfusional iron overload.     

Organ iron accumulation in chronically transfused children with sickle cell anaemia: baseline results from the TWiTCH trial

Transcranial Doppler (TCD) With Transfusions Changing to Hydroxyurea (TWiTCH) trial is a randomized, open‐label comparison of hydroxycarbamide (also termed hydroxyurea) versus continued chronic transfusion therapy for primary stroke prevention in patients with sickle cell anaemia (SCA) and abnormal TCD. Severity and location of iron overload is an important secondary outcome measure. We report the baseline findings of abdominal organ iron burden in 121 participants. At enrollment, patients were young (9·8 ± 2·9 years), predominantly female (60:40), and previously treated with transfusions (4·1 ± 2·4 years) and iron chelation (3·1 ± 2·1 years). Liver iron concentration (LIC; 9·0 ± 6·6 mg/g dry weight) and serum ferritin were moderately elevated (2696 ± 1678 μg/l), but transferrin was incompletely saturated (47·2 ± 23·6%). Spleen R2* was 509 ± 399 Hz (splenic iron ~13·9 mg/g) and correlated with LIC (r² = 0·14, P = 0·0008). Pancreas R2* was increased in 38·3% of patients but not to levels associated with endocrine toxicity. Kidney R2* was increased in 80·7% of patients; renal iron correlated with markers of intravascular haemolysis and was elevated in patients with increased urine albumin‐creatinine ratios. Extra‐hepatic iron deposition is common among children with SCA who receive chronic transfusions, and could potentiate oxidative stress caused by reperfusion injury and decellularized haemoglobin.     

Hydroxyurea therapy lowers transcranial Doppler flow velocities in children with sickle cell anemia

Hydroxyurea has hematologic and clinical efficacy in sickle cell anemia (SCA), but its effects on transcranial Doppler (TCD) flow velocities remain undefined. Fifty-nine children initiating hydroxyurea therapy for clinical severity had pretreatment baseline TCD measurements; 37 with increased flow velocities (> or = 140 cm/s) were then enrolled in an institutional review board (IRB)-approved prospective phase 2 trial with TCD velocities measured at maximum tolerated dose (MTD) and one year later. At hydroxyurea MTD (mean +/- 1 SD = 27.9 +/- 2.7 mg/kg per day), significant decreases were observed in the right middle cerebral artery (MCA) (166 +/- 27 cm/s to 135 +/- 27 cm/s, P < .001) and left (MCA) (168 +/- 26 cm/s to 142 +/- 27 cm/s, P < .001) velocities. The magnitude of TCD velocity decline was significantly correlated with the maximal baseline TCD value. At hydroxyurea MTD, 14 of 15 children with conditional baseline TCD values improved, while 5 of 6 with abnormal TCD velocities whose families refused transfusions became less than 200 cm/s. TCD changes were sustained at follow-up. These prospective data indicate that hydroxyurea can significantly decrease elevated TCD flow velocities, often into the normal range. A multicenter trial is warranted to determine the efficacy of hydroxyurea for the management of increased TCD values, and ultimately for primary stroke prevention in children with SCA.     

Red cell transfusion and alloimmunization in sickle cell disease

Red cell transfusion remains a critical component of care for acute and chronic complications of sickle cell disease. Randomized clinical trials demonstrated the benefits of transfusion therapy for prevention of primary and secondary strokes and postoperative acute chest syndrome. Transfusion for splenic sequestration, acute chest syndrome, and acute stroke are guided by expert consensus recommendations. Despite overall improvements in blood inventory safety, adverse effects of transfusion are prevalent among patients with sickle cell disease and include alloimmunization, acute and delayed hemolytic transfusion reactions, and iron overload. Judicious use of red cell transfusions, optimization of red cell antigen matching, and the use of erythrocytapheresis and iron chelation can minimize adverse effects. Early recognition and management of hemolytic transfusion reactions can avert poor clinical outcomes. In this review, we discuss transfusion methods, indications, and complications in sickle cell disease with an emphasis on alloimmunization.     

Iron chelation with deferasirox in adult and pediatric patients with thalassemia major: efficacy and safety during 5 years' follow-up

Patients with β-thalassemia require lifelong iron chelation therapy from early childhood to prevent complications associated with transfusional iron overload. To evaluate long-term efficacy and safety of once-daily oral iron chelation with deferasirox, patients aged ≥ 2 years who completed a 1-year, phase 3, randomized trial entered a 4-year extension study, either continuing on deferasirox (deferasirox cohort) or switching from deferoxamine to deferasirox (crossover cohort). Of 555 patients who received ≥ 1 deferasirox dose, 66.8% completed the study; 43 patients (7.7%) discontinued because of adverse events. In patients with ≥ 4 years' deferasirox exposure who had liver biopsy, mean liver iron concentration significantly decreased by 7.8 ± 11.2 mg Fe/g dry weight (dw; n = 103; P < .001) and 3.1 ± 7.9 mg Fe/g dw (n = 68; P < .001) in the deferasirox and crossover cohorts, respectively. Median serum ferritin significantly decreased by 706 ng/mL (n = 196; P < .001) and 371 ng/mL (n = 147; P < .001), respectively, after ≥ 4 years' exposure. Investigator-assessed, drug-related adverse events, including increased blood creatinine (11.2%), abdominal pain (9.0%), and nausea (7.4%), were generally mild to moderate, transient, and reduced in frequency over time. No adverse effect was observed on pediatric growth or adolescent sexual development. This first prospective study of long-term deferasirox use in pediatric and adult patients with β-thalassemia suggests treatment for ≤ 5 years is generally well tolerated and effectively reduces iron burden. This trial was registered at www.clinicaltrials.gov as #NCT00171210.     

Pharmacokinetics, pharmacodynamics, and pharmacogenetics of hydroxyurea treatment for children with sickle cell anemia

Hydroxyurea therapy has proven laboratory and clinical efficacies for children with sickle cell anemia (SCA). When administered at maximum tolerated dose (MTD), hydroxyurea increases fetal hemoglobin (HbF) to levels ranging from 10% to 40%. However, interpatient variability of percentage of HbF (%HbF) response is high, MTD itself is variable, and accurate predictors of hydroxyurea responses do not currently exist. HUSTLE (NCT00305175) was designed to provide first-dose pharmacokinetics (PK) data for children with SCA initiating hydroxyurea therapy, to investigate pharmacodynamics (PD) parameters, including HbF response and MTD after standardized dose escalation, and to evaluate pharmacogenetics influences on PK and PD parameters. For 87 children with first-dose PK studies, substantial interpatient variability was observed, plus a novel oral absorption phenotype (rapid or slow) that influenced serum hydroxyurea levels and total hydroxyurea exposure. PD responses in 174 subjects were robust and similar to previous cohorts; %HbF at MTD was best predicted by 5 variables, including baseline %HbF, whereas MTD was best predicted by 5 variables, including serum creatinine. Pharmacogenetics analysis showed single nucleotide polymorphisms influencing baseline %HbF, including 5 within BCL11A, but none influencing MTD %HbF or dose. Accurate prediction of hydroxyurea treatment responses for SCA remains a worthy but elusive goal.     

Efficacy and safety of oral deferasirox treatment in the posttransplant period for patients who have undergone allogeneic hematopoietic stem cell transplantation (alloHSCT)

Iron overload is considered to be associated with various complications in patients who undergo both allogeneic (allo) and autologous hematopoietic stem cell transplantation (HSCT). A total of 23 alloHSCT recipients who started deferasirox treatment due to hyperferritinemia (ferritin ≥1,000?ng/mL) were analyzed retrospectively. The demographic characteristics, data about deferasirox treatment, and history of phlebotomy were obtained from the patients' files. The reduction in posttreatment ferritin levels was found statistically significant compared with pretreatment ferritin levels in both def+phlebotomy and def+nonphlebotomy groups (p?=?0.025 and 0.017, respectively). The liver enzymes, especially ALT and bilirubins, were significantly reduced after the treatment (p?相似文献   

Prevention and management of strokes in patients with sickle cell disease

Overt strokes occur in about 11% of children with sickle cell disease, and many more develop silent infarcts. Until recently, the only available management intervention was the use of chronic transfusions to prevent stroke recurrence. The stroke prevention trial in sickle cell anemia (STOP) demonstrated that children at risk for strokes can be identified by transcranial Doppler (TCD) ultrasonography. In high-risk patients, the risk of first stroke can be decreased by 90% if patients are placed on chronic transfusion regimens. However, transfusing all patients with abnormal TCD is also problematic; as many as 60% do not seem to develop a stroke. At this time, a more precise stratification of stroke risk based on imaging studies, genetic studies, and neuropsychological testing is needed. Moreover, the development of alternatives to chronic transfusions, such as hydroxyurea and other pharmacologic therapies, may also improve the outlook for patients at high risk for stroke.     

Hydroxyurea (HU) for prevention of recurrent stroke in sickle cell anemia (SCA)

Cerebrovascular accident (CVA) is a major cause of morbidity and death in sickle cell anemia (SCA). Transfusion of packed erythrocytes is widely used to prevent this complication. However, chronic transfusion may lead to iron overload, alloimmunization, or infections. Cost and compliance may compromise transfusion therapy. A possible alternative, the prophylactic use of hydroxyurea (HU), has not been tried to determine whether it may prevent recurrent stroke. We used HU in five children with SCA who had suffered stroke, in three of them after a first episode and in the other two after a second CVA. Four had infarctive stroke and one a transient ischemic attack (TIA). Four patients took HU at a dose of 40 mg/kg/d, one patient at 30 mg/kg/d. None of the patients had recurrent stroke during 42-112 months of observation. None experienced pain crises. In all, HbF increased significantly and was maintained above 14.7% during treatment. The total Hb concentration increased 19.5 g/L (median) above the value before treatment. HU was well tolerated. None of the five children had leukopenia or thrombocytopenia during therapy. HU appears to prevent recurrence of stroke in SCA without risk of major toxicity.     

Japanese epidemiological survey with consensus statement on Japanese guidelines for treatment of iron overload in bone marrow failure syndromes

Many patients with bone marrow failure syndromes need frequent transfusions of red blood cells, and most of them eventually suffer from organ dysfunction induced by excessively accumulated iron. The only way to treat transfusion-induced iron overload is iron chelating therapy. However, most patients have not been treated effectively because daily/continuous administration of deferoxamine is difficult for outpatients. Recently, a novel oral iron chelator, deferasirox, has been developed, and introduction of the drug may help many patients benefit from iron chelation therapy. In this review, we will discuss the current status of iron overload in transfusion-dependent patients, and the development of Japanese guidelines for the treatment of iron overload in Japan, which were established by the National Research Group on Idiopathic Bone Marrow Failure Syndromes in Japan.     

Toward optimizing the use of deferasirox: potential benefits of combined use with deferoxamine

Patients with β-thalassemia require iron chelation therapy to protect against progressive iron overload and non-transferrin-bound iron. Some patients fail to respond adequately to deferoxamine and deferasirox monotherapy while others have side effects which limit their use of these drugs. Since combining deferiprone and deferoxamine has an additive effect, placing all patients into net negative iron balance, we investigated the possibility that combining deferasirox and deferoxamine would lead to similar results. We conducted 34-day metabolic iron balance studies in six patients in whom the relative effectiveness of deferasirox (30 mg/kg/day) and deferoxamine (40 mg/kg/day) was compared, alone and in combination. Patients consumed fixed low-iron diets; daily urinary and stool iron excretion were determined by atomic absorption. Red blood cell transfusions were given prior to each drug treatment to minimize the effects of ineffective erythropoiesis. Serial safety measures, hematologic parameters, serum chemistries, ferritin levels and urinalyses were determined. All patients were in negative iron balance when treated with deferoxamine alone while four of six patients remained in positive balance when deferasirox monotherapy was evaluated. Daily use of both drugs had a synergistic effect in two patients and an additive effect in three others. Five of six patients would be in negative iron balance if they used the combination of drugs just 3 days a week. No significant or drug-related changes were observed in the blood work-ups or urinalyses performed. We conclude that supplementing the daily use of deferasirox with 2 – 3 days of deferoxamine therapy would place all patients into net negative iron balance thereby providing a convenient way to tailor chelation therapy to the individual needs of each patient.     

Efficacy and safety of deferasirox compared with deferoxamine in sickle cell disease: Two‐year results including pharmacokinetics and concomitant hydroxyurea

We report a prospective, randomized, Phase II study of deferasirox and deferoxamine (DFO) in sickle cell disease patients with transfusional iron overload, with all patients continuing on deferasirox after 24 weeks, for up to 2 years. The primary objective was to evaluate deferasirox safety compared with DFO; long‐term efficacy and safety of deferasirox was also assessed. We also report, for the first time, the safety and pharmacokinetics of deferasirox in patients concomitantly receiving hydroxyurea. Deferasirox (n = 135) and DFO (n = 68) had comparable safety profiles over 24 weeks. Adverse events (AEs) secondary to drug administration were reported in 26.7% of patients in the deferasirox cohort and 28.6% in the DFO cohort. Gastrointestinal disorders were more common with deferasirox, including diarrhea (10.4% versus 3.6%) and nausea (5.2% versus 3.6%). The most common AE in the DFO group was injection‐site pain irritation, which occurred in 7% of patients. Acute renal failure occurred in one patient on deferasirox who was continued on medication despite progressive impairment of renal function parameters. Serum ferritin levels were reduced in both treatment groups. Patients continuing on deferasirox for up to 2 years demonstrated an absolute median serum ferritin decrease of ?614 ng/mL (n = 96). Increasing deferasirox dose was associated with improved response and a continued manageable safety profile. Concomitant hydroxyurea administration (n = 28) did not appear to influence the efficacy, safety (including liver and kidney function), and pharmacokinetic parameters of deferasirox. Am. J. Hematol. 88:1068–1073, 2013. © 2013 Wiley Periodicals, Inc.