Lentiviral haematopoietic stem-cell gene therapy for early-onset metachromatic leukodystrophy: long-term results from a non-randomised, open-label, phase 1/2 trial and expanded access

BACKGROUND

Effective treatment for metachromatic leukodystrophy (MLD) remains a substantial unmet medical need. In this study we investigated the safety and efficacy of atidarsagene autotemcel (arsa-cel) in patients with MLD.

METHODS

This study is an integrated analysis of results from a prospective, non-randomised, phase 1/2 clinical study and expanded-access frameworks. 29 paediatric patients with pre-symptomatic or early-symptomatic early-onset MLD with biochemical and molecular confirmation of diagnosis were treated with arsa-cel, a gene therapy containing an autologous haematopoietic stem and progenitor cell (HSPC) population transduced ex vivo with a lentiviral vector encoding human arylsulfatase A (ARSA) cDNA, and compared with an untreated natural history (NHx) cohort of 31 patients with early-onset MLD, matched by age and disease subtype. Patients were treated and followed up at Ospedale San Raffaele, Milan, Italy. The coprimary efficacy endpoints were an improvement of more than 10% in total gross motor function measure score at 2 years after treatment in treated patients compared with controls, and change from baseline of total peripheral blood mononuclear cell (PBMC) ARSA activity at 2 years after treatment compared with values before treatment. This phase 1/2 study is registered with ClinicalTrials.gov, NCT01560182.

FINDINGS

At the time of analyses, 26 patients treated with arsa-cel were alive with median follow-up of 3·16 years (range 0·64-7·51). Two patients died due to disease progression and one due to a sudden event deemed unlikely to be related to treatment. After busulfan conditioning, all arsa-cel treated patients showed sustained multilineage engraftment of genetically modified HSPCs. ARSA activity in PBMCs was significantly increased above baseline 2 years after treatment by a mean 18·7-fold (95% CI 8·3-42·2; p<0·0001) in patients with the late-infantile variant and 5·7-fold (2·6-12·4; p<0·0001) in patients with the early-juvenile variant. Mean differences in total scores for gross motor function measure between treated patients and age-matched and disease subtype-matched NHx patients 2 years after treatment were significant for both patients with late-infantile MLD (66% [95% CI 48·9-82·3]) and early-juvenile MLD (42% [12·3-71·8]). Most treated patients progressively acquired motor skills within the predicted range of healthy children or had stabilised motor performance (maintaining the ability to walk). Further, most displayed normal cognitive development and prevention or delay of central and peripheral demyelination and brain atrophy throughout follow-up; treatment benefits were particularly apparent in patients treated before symptom onset. The infusion was well tolerated and there was no evidence of abnormal clonal proliferation or replication-competent lentivirus. All patients had at least one grade 3 or higher adverse event; most were related to conditioning or to background disease. The only adverse event related to arsa-cel was the transient development of anti-ARSA antibodies in four patients, which did not affect clinical outcomes.

INTERPRETATION

Treatment with arsa-cel resulted in sustained, clinically relevant benefits in children with early-onset MLD by preserving cognitive function and motor development in most patients, and slowing demyelination and brain atrophy.

FUNDING

Orchard Therapeutics, Fondazione Telethon, and GlaxoSmithKline.

Hematopoietic Stem- and Progenitor-Cell Gene Therapy for Hurler Syndrome

BACKGROUND

Allogeneic hematopoietic stem-cell transplantation is the standard of care for Hurler syndrome (mucopolysaccharidosis type I, Hurler variant [MPSIH]). However, this treatment is only partially curative and is associated with complications.

METHODS

We are conducting an ongoing study involving eight children with MPSIH. At enrollment, the children lacked a suitable allogeneic donor and had a Developmental Quotient or Intelligence Quotient score above 70 (i.e., none had moderate or severe cognitive impairment). The children received autologous hematopoietic stem and progenitor cells (HSPCs) transduced ex vivo with an α-L-iduronidase (IDUA)-encoding lentiviral vector after myeloablative conditioning. Safety and correction of blood IDUA activity up to supraphysiologic levels were the primary end points. Clearance of lysosomal storage material as well as skeletal and neurophysiological development were assessed as secondary and exploratory end points. The planned duration of the study is 5 years.

RESULTS

We now report interim results. The children's mean (±SD) age at the time of HSPC gene therapy was 1.9±0.5 years. At a median follow-up of 2.10 years, the procedure had a safety profile similar to that known for autologous hematopoietic stem-cell transplantation. All the patients showed prompt and sustained engraftment of gene-corrected cells and had supraphysiologic blood IDUA activity within a month, which was maintained up to the latest follow-up. Urinary glycosaminoglycan (GAG) excretion decreased steeply, reaching normal levels at 12 months in four of five patients who could be evaluated. Previously undetectable levels of IDUA activity in the cerebrospinal fluid became detectable after gene therapy and were associated with local clearance of GAGs. Patients showed stable cognitive performance, stable motor skills corresponding to continued motor development, improved or stable findings on magnetic resonance imaging of the brain and spine, reduced joint stiffness, and normal growth in line with World Health Organization growth charts.

CONCLUSIONS

The delivery of HSPC gene therapy in patients with MPSIH resulted in extensive metabolic correction in peripheral tissues and the central nervous system. (Funded by Fondazione Telethon and others; ClinicalTrials.gov number, NCT03488394; EudraCT number, 2017-002430-23.).

Metachromatic leukodystrophy: A single-center longitudinal study of 45 patients

In this study, we characterize the natural course of metachromatic leukodystrophy (MLD), explore intra/inter group differences, and identify biomarkers to monitor disease progression. This is a longitudinal observational study. Genotype and characteristics at disease onset were recorded. Time-to-event analyses were performed to assess time to major disease-related milestones in different subgroups. Longitudinal trajectories of nerve conduction velocities (NCV), brain MRI score, and brainstem auditory evoked responses (BAERs) were described. We recruited 22 late-infantile, 14 early-juvenile, 5 late-juvenile, and 4 adult MLD patients. Thirty-four were prospectively evaluated (median FU time 43 months). In late-infantile patients, the attainment of independent walking was associated with a later age at dysphagia. In early-juvenile, the presence of isolated cognitive impairment at onset was not a favorable prognostic factor. Late-infantile and early-juvenile subjects showed similar rapid loss of ambulation and onset of seizures, but late-infantile displayed earlier loss of trunk control, dysphagia, and death. We found significant differences in all major disease-related milestones (except death) between early-juvenile and late-juvenile patients. Late-juvenile and adult patients both presented with a predominant cognitive impairment, mild/no peripheral neuropathy, lower brain MRI score at plateau compared to LI/EJ, and later cerebellar involvement. NCV and BAER were consistently severely abnormal in late-infantile but not in older subjects, in whom both NCV and BAER were variably affected, with no deterioration over time in some cases. This study clarifies intra/inter group differences between MLD subtypes and provides additional indications regarding reliable clinical and instrumental tools to monitor disease progression and to serve as areference to evaluate the efficacy of future therapeutic interventions inthe different MLD variants.

Intra-arterial transplantation of HLA-matched donor mesoangioblasts in Duchenne muscular dystrophy

Intra‐arterial transplantation of mesoangioblasts proved safe and partially efficacious in preclinical models of muscular dystrophy. We now report the first‐in‐human, exploratory, non‐randomized open‐label phase I–IIa clinical trial of intra‐arterial HLA‐matched donor cell transplantation in 5 Duchenne patients. We administered escalating doses of donor‐derived mesoangioblasts in limb arteries under immunosuppressive therapy (tacrolimus). Four consecutive infusions were performed at 2‐month intervals, preceded and followed by clinical, laboratory, and muscular MRI analyses. Two months after the last infusion, a muscle biopsy was performed. Safety was the primary endpoint. The study was relatively safe: One patient developed a thalamic stroke with no clinical consequences and whose correlation with mesoangioblast infusion remained unclear. MRI documented the progression of the disease in 4/5 patients. Functional measures were transiently stabilized in 2/3 ambulant patients, but no functional improvements were observed. Low level of donor DNA was detected in muscle biopsies of 4/5 patients and donor‐derived dystrophin in 1. Intra‐arterial transplantation of donor mesoangioblasts in human proved to be feasible and relatively safe. Future implementation of the protocol, together with a younger age of patients, will be needed to approach efficacy.

Health related quality of life in Middle Eastern children with beta-thalassemia

Background

Thalassemia is a common disorder worldwide with a predominant incidence in Mediterranean countries, North Africa, the Middle East, India, Central Asia, and Southeast Asia. Whilst substantial progress has been made towards the improvement of Health related quality of life (HRQoL) in western countries, scarce evidence-based data exists on HRQol of thalassemia children and adolescents living in developing countries.

Methods

We studied 60 thalassemia children from Middle Eastern countries with a median age of 10 years (range 5 to 17 years). HRQoL was assessed with the Pediatric Quality of Life Inventory (PedsQL) 4.0. The Questionnaire was completed at baseline by all patients and their parents. The agreement between child-self and parent-proxy HRQoL reports and the relationship between HRQoL profiles and socio-demographic and clinical factors were investigated.

Results

The scores of parents were generally lower than those of their children for Emotional Functioning (mean 75 vs 85; p = 0.002), Psychosocial Health Summary (mean 70.3 vs 79.1; p = 0.015) and the Total Summary Score (mean 74.3 vs 77.7 p = 0.047). HRQoL was not associated with ferritin levels, hepatomegaly or frequency of transfusions or iron chelation therapy. Multivariate analysis showed that a delayed start of iron chelation had a negative impact on total PedsQL scores of both children (p = 0.046) and their parents (p = 0.007).

Conclusions

The PedsQL 4.0 is a useful tool for the measurement of HRQoL in pediatric thalassemia patients. This study shows that delayed start of iron chelation has a negative impact on children’s HRQoL.

[Injuries in childhood: a study on emergency department admissions of pediatric population in an Emilia-Romagna USL]

A study of childhood injuries of 0-14 year-olds children based on emergency room records of the five hospitals was conducted in USL 39 of Emilia-Romagna during 1988. The incidence of visits was 164, 14/1000 child-years with 95% confidence intervals (CI = 163, 28-165). The rate was 198, 93/1000 child-years (CI = 195, 36-202, 51) among the 0-4 year-olds, 140, 65/1000 child-years (CI = 139, 17-142, 13) in the 5-9 age group and 170, 86/1000 child-years (CI = 169, 77-171, 95) among 10-14 year-olds. The male to female ratio was 1.4 for the 0-4 year-olds, 1.7 for the 5-9 year-olds and for the 10-14 year-olds. The most frequent causes of injuries were falls (49.52%), being road accidents (22.1%) and bites-stings (17.4%); 4.8% of the injured children were admitted to hospital and 0.044% dead.

[Neurologic risks caused by perinatal and neonatal problems in a provincial hospital]

The study intends to value results of follow-up of risk neonates hospitalized for the period 1980-88 at Neonatal Intensive Care Unit of Bufalini Hospital Cesena and the course with time of neurologic and neuropsychological alterations, reported to the birth-rate of territory in which operates the Neonatal Intensive Care Unit. The survivor infants attended in follow up have been 419: 63 of neonatal weight less than or equal to 1500 g (group A), 117 of weight 1501-2000 g (group B), 239 of weight greater than 2000 g (group C). The follow-up provided at first 12 months of life a pediatric examination together with motoscopic examination to Milani-Comparetti every two months, at 3 years--4 years and 6 months, 7 years a pediatric examination with evaluation of Intelligence Quotient (N.E.M.I.), at last two months of 1st Primary School evaluation of acquired scholastic learning capacities by reading test of Inizan and calculation test of Meljac. Diagnosis of cerebral palsy (C.P.) has been always placed at first 12 months of life. All the survivors have been executed pediatric checks as foreseen at first 12 months of life. The subjects with CP are 26 (%); of these 13 have an I.Q. less than or equal to 70. The risk to develop CP seems to depend strictly by hypoxic perinatal stress (21/26 infants). The type of CP seems to be conditioned by neonatal weight, in particular as regards spastic paraplegia (10/12 infants of weight less than or equal to 2000 g), but hemiplegia and tetraplegia are with equality distributed (7/14 infants of weight less than or equal to 2000 g).(ABSTRACT TRUNCATED AT 250 WORDS)

[The diagnostic value of the intelligence quotient in learning disabilities]

In 1983-88 period, 206 subjects with a average age of 9 years and 6 months, referred [correction of envoied] to our service for learning disabilities, have been submitted to neuropsychiatric visit with a psychometric evaluation, I.Q. included, by which a neuropsychological diagnosis has been expressed. The distribution curves of I.Q. of different diagnostic groups (neurosis, psychosis, specific learning disability with and without sociocultural deprivation, central neuromotor damage, psychomotor delay, Down syndrome, mental retardation) have been examined. The analysis shows that only subjects with central neuromotor damage, psychomotor delay, Down syndrome, mental retardation have an I.Q. less than or equal to 70. The anamnesis and clinical evaluation consent to assert an "organic" etiopathogenesis in 9 of 20 subjects with mental retardation. Therefore for diagnostic evaluation of children with learning disabilities seems useful to perform always an I.Q. and, when I.Q. less than or equal to 70, to execute an instrumental examination to exclude an "organic" etiopathogenesis.

[Epidemiology and etiopathogenesis of school accidents]

The study purpose to take a contribution to the Knowledge of circumstance and of consequences in which happen the scholastic incidents. Have been taken into consideration 92 scholastic incidents happened during the school year 83/84 at nursery, primary and secondary schools of the Municipality of Cesena, for a total of 11,856 children and have been compared with 1,185 incidents not scholastic of children with same age, happened in Municipality of Cesena and registered at first aid of the "Bufalini" Hospital of Cesena in months of November-December '83 and March, April, July, August 1984. The frequency of such scholastic and not scholastic incidents results superior at male child and of age more low. The seat of damage of scholastic and not scholastic is prevalently the head for children in age 3-6 years and the limbs for those in age 7-11 and 12-14 years. The type of damage of scholastic and not scholastic incidents are prevalently the wounds-abrasions for children in age 3-6 years and the bruises-luxations-stretchings-distortions for those in age 7-11 and 12-14 years. The 77% of scholastic incidents applies to treatment of first aid, the prognostic opinions of which are not significantly different from those emitted for not scholastic incidents. The scholastic incidents at nursery school happen prevalently in court on the occasion of recreation activities for falling from a play equipment, at primary school in schoolroom or in corridor on the occasion of recreation for push of schoolfellow, at secondary school in palaestra during time of physical education for falling or traumatic contact with the ball.(ABSTRACT TRUNCATED AT 250 WORDS)

[Partial agenesis of the corpus callosum associated with characteristic fascies, ocular anomalies, hypotonia and mental retardation (description of 2 cases in the female sex)]

Two children of female sex with partial agenesis of corpus callosum, ocular anomalies, hypotonia and intellectual retardation are described. It is discussed if this clinical picture can be a new syndrome.

[Long-term subacute sclerosing panencephalitis with sensorial transcortical aphasia. Description of a case]

A 16 year boy with subacute sclerosing panencephalitis in stage 4 is described. Neuropsychological analysis reveal a transcortical sensorial aphasia. Behavior therapies of shaping and fading are proposed.

[Fat necrosis in the newborn infant associated with hypercalcemia and dyslipidemia (description of a case)]

A case of subcutaneous fat necrosis (S.F.N.) with hypercalcemia and hyperlipemia in a newborn infant is reported. On the basis of previous reports it is impossible to definite the pathogenesis of hypercalcemia and hyperlipemia in subcutaneous fat necrosis. Moreover the Authors point out that in a newborn with S.F.N. plasma levels of calcium and lipids and, if it is possible, urinary prostaglandin E and serum PTH and 250HD3 should be determined.