Leslie Raffini

Age-dependent effects of RPE65 gene therapy for Leber's congenital amaurosis: a phase 1 dose-escalation trial

BACKGROUND Gene therapy has the potential to reverse disease or prevent further deterioration of vision in patients with incurable inherited retinal degeneration. We therefore did a phase 1 trial to assess the effect of gene therapy on retinal and visual function in children and adults with Lebers congenital amaurosis. METHODS We assessed the retinal and visual function in 12 patients (aged 8-44 years) with RPE65-associated Lebers congenital amaurosis given one subretinal injection of adeno-associated virus (AAV) containing a gene encoding a protein needed for the isomerohydrolase activity of the retinal pigment epithelium (AAV2-hRPE65v2) in the worst eye at low (1.5 x 10(10) vector genomes), medium (4.8 x 10(10) vector genomes), or high dose (1.5 x 10(11) vector genomes) for up to 2 years. FINDINGS AAV2-hRPE65v2 was well tolerated and all patients showed sustained improvement in subjective and objective measurements of vision (ie, dark adaptometry, pupillometry, electroretinography, nystagmus, and ambulatory behaviour). Patients had at least a 2 log unit increase in pupillary light responses, and an 8-year-old child had nearly the same level of light sensitivity as that in age-matched normal-sighted individuals. The greatest improvement was noted in children, all of whom gained ambulatory vision. The study is registered with ClinicalTrials.gov, number NCT00516477. INTERPRETATION The safety, extent, and stability of improvement in vision in all patients support the use of AAV-mediated gene therapy for treatment of inherited retinal diseases, with early intervention resulting in the best potential gain. FUNDING Center for Cellular and Molecular Therapeutics at the Childrens Hospital of Philadelphia, Foundation Fighting Blindness, Telethon, Research to Prevent Blindness, F M Kirby Foundation, Mackall Foundation Trust, Regione Campania Convenzione, European Union, Associazione Italiana Amaurosi Congenita di Leber, Fund for Scientific Research, Fund for Research in Ophthalmology, and National Center for Research Resources.

Dramatic increase in venous thromboembolism in children's hospitals in the United States from 2001 to 2007.

OBJECTIVES: The goals were to determine whether there has been an increase in the rate of venous thromboembolism (VTE) in pediatric tertiary care hospitals and to evaluate the use of anticoagulants in the treatment of hospitalized pediatric patients with VTE. METHODS: A retrospective cohort study of patients <18 years of age who were discharged from 35 to 40 childrens hospitals (depending on the year) across the United States in 2001–2007 was performed. By using the Pediatric Health Information System administrative database, cases were assessed for discharge diagnosis codes for VTE; the use of anticoagulants was assessed by using patient-specific pharmacy files. RESULTS: During the 7-year study period, in which 11337 hospitalized patients were diagnosed with VTE, the annual rate of VTE increased by 70%, from 34 to 58 cases per 10000 hospital admissions (P < .001). This increase was observed in neonates, infants, children, and adolescents. The majority (63%) of children with VTE had ≥1 coexisting chronic complex medical condition. Pediatric malignancy was the medical comorbid condition associated most strongly with recurrent VTE (P < .001). The proportion of children with VTE who were treated with enoxaparin increased from 29% to 49% during this time period (P < .001); the use of warfarin decreased slightly from 11.4% to 9.6% (P = .02). Increasing age was associated with increased likelihood of patients with VTE being treated with either enoxaparin or warfarin. CONCLUSION: This multicenter study demonstrates a dramatic increase in the diagnosis of VTE at childrens hospitals from 2001 to 2007.

Impact of Thrombophilia on Risk of Arterial Ischemic Stroke or Cerebral Sinovenous Thrombosis in Neonates and Children A Systematic Review and Meta-Analysis of Observational Studies

Background— The aim of this study was to estimate the impact of thrombophilia on risk of first childhood stroke through a meta-analysis of published observational studies. Methods and Results— A systematic search of electronic databases (Medline via PubMed, EMBASE, OVID, Web of Science, The Cochrane Library) for studies published from 1970 to 2009 was conducted. Data on year of publication, study design, country of origin, number of patients/control subjects, ethnicity, stroke type (arterial ischemic stroke [AIS], cerebral venous sinus thrombosis [CSVT]) were abstracted. Publication bias indicator and heterogeneity across studies were evaluated, and summary odds ratios (ORs) and 95% confidence intervals (CIs) were calculated with fixed-effects or random-effects models. Twenty-two of 185 references met inclusion criteria. Thus, 1764 patients (arterial ischemic stroke [AIS], 1526; cerebral sinus venous thrombosis [CSVT], 238) and 2799 control subjects (neonate to 18 years of age) were enrolled. No significant heterogeneity was discerned across studies, and no publication bias was detected. A statistically significant association with first stroke was demonstrated for each thrombophilia trait evaluated, with no difference found between AIS and CSVT. Summary ORs (fixed-effects model) were as follows: antithrombin deficiency, 7.06 (95% CI, 2.44 to 22.42); protein C deficiency, 8.76 (95% CI, 4.53 to 16.96); protein S deficiency, 3.20 (95% CI, 1.22 to 8.40), factor V G1691A, 3.26 (95% CI, 2.59 to 4.10); factor II G20210A, 2.43 (95% CI, 1.67 to 3.51); MTHFR C677T (AIS), 1.58 (95% CI, 1.20 to 2.08); antiphospholipid antibodies (AIS), 6.95 (95% CI, 3.67 to 13.14); elevated lipoprotein(a), 6.27 (95% CI, 4.52 to 8.69), and combined thrombophilias, 11.86 (95% CI, 5.93 to 23.73). In the 6 exclusively perinatal AIS studies, summary ORs were as follows: factor V, 3.56 (95% CI, 2.29 to 5.53); and factor II, 2.02 (95% CI, 1.02 to 3.99). Conclusions— The present meta-analysis indicates that thrombophilias serve as risk factors for incident stroke. However, the impact of thrombophilias on outcome and recurrence risk needs to be further investigated.

Efficacy and safety of voretigene neparvovec (AAV2-hRPE65v2) in patients with RPE65-mediated inherited retinal dystrophy: a randomised, controlled, open-label, phase 3 trial

BACKGROUND Phase 1 studies have shown potential benefit of gene replacement in RPE65-mediated inherited retinal dystrophy. This phase 3 study assessed the efficacy and safety of voretigene neparvovec in participants whose inherited retinal dystrophy would otherwise progress to complete blindness. METHODS In this open-label, randomised, controlled phase 3 trial done at two sites in the USA, individuals aged 3 years or older with, in each eye, best corrected visual acuity of 20/60 or worse, or visual field less than 20 degrees in any meridian, or both, with confirmed genetic diagnosis of biallelic RPE65 mutations, sufficient viable retina, and ability to perform standardised multi-luminance mobility testing (MLMT) within the luminance range evaluated, were eligible. Participants were randomly assigned (2:1) to intervention or control using a permuted block design, stratified by age (<10 years and ≥10 years) and baseline mobility testing passing level (pass at ≥125 lux vs <125 lux). Graders assessing primary outcome were masked to treatment group. Intervention was bilateral, subretinal injection of 1·5 × 1011 vector genomes of voretigene neparvovec in 0·3 mL total volume. The primary efficacy endpoint was 1-year change in MLMT performance, measuring functional vision at specified light levels. The intention-to-treat (ITT) and modified ITT populations were included in primary and safety analyses. This trial is registered with ClinicalTrials.gov, number NCT00999609, and enrolment is complete. FINDINGS Between Nov 15, 2012, and Nov 21, 2013, 31 individuals were enrolled and randomly assigned to intervention (n=21) or control (n=10). One participant from each group withdrew after consent, before intervention, leaving an mITT population of 20 intervention and nine control participants. At 1 year, mean bilateral MLMT change score was 1·8 (SD 1·1) light levels in the intervention group versus 0·2 (1·0) in the control group (difference of 1·6, 95% CI 0·72-2·41, p=0·0013). 13 (65%) of 20 intervention participants, but no control participants, passed MLMT at the lowest luminance level tested (1 lux), demonstrating maximum possible improvement. No product-related serious adverse events or deleterious immune responses occurred. Two intervention participants, one with a pre-existing complex seizure disorder and another who experienced oral surgery complications, had serious adverse events unrelated to study participation. Most ocular events were mild in severity. INTERPRETATION Voretigene neparvovec gene replacement improved functional vision in RPE65-mediated inherited retinal dystrophy previously medically untreatable. FUNDING Spark Therapeutics.

Modern management of haemophilic arthropathy

Currently available factor concentrates for treatment of patients with haemophilia are virally inactivated or are made by recombinant technology and their broad use in developed nations has resulted in the dramatic elimination of the treatment‐related viral illnesses that decimated the haemophilia community in the late 20th century. The major morbidity experienced by patients with haemophilia today is joint disease, a result of repeated bleeding episodes into joint spaces. Although administration of factor concentrates to prevent bleeding has been demonstrated to prevent haemophilic joint disease when applied assiduously, repeated bleeding episodes induce synovitis that is irreversible and may progress despite subsequent prophylaxis. Surgical and nuclear medicine interventions are available to reduce the pain of haemophilic arthropathy and to reduce further bleeding episodes. Patients with high titre inhibitors are at great risk for the development of joint disease and present the greatest therapeutic challenges when joint surgery is needed.

Associations between intracranial haemorrhage and prescribed prophylaxis in a large cohort of haemophilia patients in the United States.

Intracranial haemorrhage (ICH) is the most serious type of bleeding for patients with haemophilia. Prior published reports regarding ICH predate the widespread provision of prophylaxis. Our study objectives were to determine risk factors for ICH and whether prophylaxis reduces ICH occurrence. We performed a nested case‐control study of persons with haemophilia, ≥2 years of age enrolled in the Centers for Disease Control and Prevention Universal Data Collection project. Of 10 262 patients 199 (1·9%) experienced an ICH for an incidence rate of 390/105 patient years. Head trauma was reported in 44% (88/199). ICH mortality was 19·6% (39/199). Significant risk factors for ICH included a high titre inhibitor [odds ratio (OR) = 4·01, 95% confidence interval (2·40–6·71)], prior ICH [OR = 3·62 (2·66–4·92)] and severe haemophilia [OR = 3·25 (2·01–5·25)]. Prophylaxis was associated with a significant risk reduction for ICH occurrence in patients with severe haemophilia who were negative for human immunodeficiency virus or an inhibitor, with an OR of 0·52 (0·34–0·81) and 0·50 (0·32–0·77) respectively. The most significant risk factors for ICH included the presence of an inhibitor, prior ICH, severity of haemophilia and reported head trauma. This is the first study to demonstrate that prescribed prophylaxis conferred a protective effect against ICH in patients with uncomplicated severe disease.

Thromboprophylaxis in a Pediatric Hospital: A Patient-Safety and Quality-Improvement Initiative

OBJECTIVES: Venous thromboembolism (VTE) prophylaxis for patients at risk is often overlooked in pediatric health care institutions, which provides an opportunity to improve patient care. The objectives of this study were to review our current hospital practice, identify a population at high risk, and formulate institutional guidelines for thromboprophylaxis. METHODS: This was a prospective patient-safety and quality-improvement project performed at a large pediatric tertiary care hospital. We developed criteria for assessing risk and selecting prophylactic intervention through analysis of the age distribution and underlying medical conditions of patients with VTE at our center, literature review of adult recommendations for thromboprophylaxis, and consensus opinion of multiple specialists at our institution. A patient-care policy was developed to assess VTE risk and prescribe the appropriate thromboprophylaxis regimen. The primary outcome measure was compliance with thromboprophylaxis guidelines in patients at risk for VTE. RESULTS: Over the 4-year study period, the observed rate of VTE prophylaxis in patients at risk increased from a baseline of 22% to an average rate of 82%, and there were intermittent improvements up to 100%. CONCLUSIONS: Although some of the details may vary from center to center, many of the discussed principles and practices involved in instituting a VTE-prevention program are applicable to other pediatric institutions. Despite the fact that the risk of VTE in hospitalized children is much lower than that in adults, there are patients in pediatric hospitals who deserve systematic screening and thoughtful application of preventative measures.

Off-label recombinant factor VIIa use and thrombosis in children: a multi-center cohort study.

OBJECTIVE To describe the off-label use of recombinant factor VIIa (rFVIIa) in tertiary care pediatric hospitals across the United States and to assess thrombotic events. STUDY DESIGN A retrospective multi-center cohort study using the Pediatric Health Information System administrative database. Children 18 years of age or younger who received rFVIIa between 2000 and 2007 were included. A label admission was defined as an admission with an International Classification of Diseases diagnostic code for hemophilia or factor VII deficiency; admissions without these codes were classified as off-label. RESULTS There were 4942 rFVIIa admissions, representing 3764 individual subjects; 74% (3655) of the admissions were off-label. There was a 10-fold increase in the annual rate of off-label admissions from 2000 to 2007 (from 2 to 20.8 per 10 000 hospital admissions, P < .001). The mortality rate in the off-label group was 34% (1258/3655). Thrombotic events occurred in 10.9% (399/3655) of the off-label admissions. CONCLUSIONS The off-label use of rFVIIa in hospitalized children is increasing rapidly despite the absence of adequate clinical trials demonstrating safety and efficacy. Thrombotic events are common and mortality is high among patients receiving off-label rFVIIa. Further studies are warranted to determine whether these adverse events are attributable to rFVIIa.

Argatroban therapy in pediatric patients requiring nonheparin anticoagulation: An open-label, safety, efficacy, and pharmacokinetic study†

An increasing number of pediatric patients suffer from thrombotic events necessitating anticoagulation therapy including heparins. Some such patients develop heparin‐induced thrombocytopenia (HIT) and thus require alternative anticoagulation. As such, studies evaluating the safety, efficacy, and dosing of alternative anticoagulants are required.

Survey of current prophylaxis practices and bleeding characteristics of children with severe haemophilia A in US haemophilia treatment centres

Summary.  Every other day (qod) factor VIII prophylaxis prevents joint bleeds in children with severe haemophilia A. Although three times weekly or qod prophylaxis is recommended by the National Hemophilia Foundation (NHF), how widely these practices have been adopted is not known. We sought to define current prophylaxis practices at US haemophilia treatment centres (HTCs). An email survey was distributed to US HTCs, utilizing web‐based membership rosters of the Centers for Disease Control (CDC) and the Hemostasis Thrombosis Research Society (HTRS). Of 62 HTCs responding, prophylaxis is initiated on a three times weekly schedule in 29 (46.8%), twice weekly in 13 HTCs (21.0%) and once weekly in 20 HTCs (32.2%). Central venous catheters are used to infuse factor prophylactically at 55 HTCs (88.7%), including in 100% of children initiating prophylaxis at 19 HTCs (30.6%) and in 50% of those at 41 HTCs (66.1%), but avoided altogether at seven HTCs (11.3%). Prophylaxis is initiated after one or more bleeds in 56 HTCs (90.3%), but after the first bleed in only 28 HTCs (25.2%). Among 226 newborns with severe haemophilia A in 62 HTCs, 1.82 births/HTC/year, the median age at first bleed, excluding circumcision, is 7 months. Of the 113 (53.5%) newborns who underwent circumcision, 62 (54.9%) bled. Despite a recommended standard of three times weekly prophylaxis, over half of surveyed HTCs do not follow these guidelines, and nearly one‐third begin prophylaxis on a once weekly schedule to delay or avoid the need for central venous access.