Intracerebral Gene Therapy in Four Children with Sanfilippo B Syndrome: 5.5-Year Follow-Up Results.

We report the safety (primary endpoint) and efficacy (secondary endpoint) of a novel intracerebral gene therapy at 5.5 years of follow-up in children with Sanfilippo B. An uncontrolled, phase 1/2 clinical trial was performed in four patients aged 20, 26, 30, and 53 months. Treatment consisted of 16 intracerebral and cerebellar deposits of a recombinant adeno-associated viral vector encoding human α-N-acetylglucosaminidase (rAAV2/5-hNAGLU) plus immunosuppression. An intermediate report at 30 months was previously published. Thirty treatment-emergent adverse events were reported between 30 and 66 months after surgery, including three classified as severe with no serious drug reactions. At 5.5 years, NAGLU activity was persistently detected in the lumbar cerebrospinal fluid (18% of unaffected control level). Circulating T cells reacting against NAGLU peptides were present, indicating a lack of acquired tolerance. Patients 2, 3, and 4 showed progressive brain atrophy and neurocognitive evolution that did not differ from untreated Sanfilippo A/B children. Patient 1, enrolled at 20 months of age, had a milder disease with normal brain imaging and a significantly better cognitive outcome than the three other patients and untreated patients, although not equivalent to normal children. After 5.5 years, the primary endpoint of this study was achieved with a good safety profile of the proposed treatment. We have also observed sustained enzyme production in the brain and absence of immunological tolerance. Cognitive benefit was not confirmed in the three oldest patients. Milder disease in the youngest patient supports further investigations of adeno-associated vector-mediated intracerebral gene therapy in Sanfilippo B.

Intracerebral gene therapy in children with mucopolysaccharidosis type IIIB syndrome: an uncontrolled phase 1/2 clinical trial.

BACKGROUND: Mucopolysaccharidosis type IIIB syndrome (also known as Sanfilippo type B syndrome) is a lysosomal storage disease resulting in progressive deterioration of cognitive acquisition after age 2-4 years. No treatment is available for the neurological manifestations of the disease. We sought to assess the safety and efficacy of a novel intracerebral gene therapy. METHODS: Local regulatory authorities in France allowed inclusion of up to four children in this phase 1/2 study. Treatment was 16 intraparenchymal deposits (four in the cerebellum) of a recombinant adenoassociated viral vector serotype 2/5 (rAAV2/5) encoding human α-N-acetylglucosaminidase (NAGLU) plus immunosuppressive therapy. We assessed tolerance, neurocognitive progression, brain growth, NAGLU enzymatic activity in CSF, and specific anti-NAGLU immune response for 30 months after surgery. This trial is registered with EudraCT, number 2012-000856-33, and the International Standard Clinical Trial Registry, number ISRCTN19853672. FINDINGS: Of seven eligible children, the four youngest, from France (n=2), Italy (n=1), and Greece (n=1), aged 20, 26, 30, and 53 months, were included between February, 2012, and February, 2014. 125 adverse events were recorded, of which 117 were treatment emergent and included six classified as severe, but no suspected unexpected serious adverse drug reactions were seen. Vector genomes were detected in blood for 2 days after surgery. Compared with the natural history of mucopolysaccharidosis type III syndromes, neurocognitive progression was improved in all patients, with the youngest patient having function close to that in healthy children. Decrease in developmental quotient was -11·0 points in patient one, -23·0 in patient two, -29·0 in patient three, and -17·0 in patient four, compared with -37·7 in the natural history of the disease. NAGLU activity was detected in lumbar CSF and was 15-20% of that in unaffected children. Circulating T lymphocytes that proliferated and produced tumour necrosis factor α upon ex-vivo exposure to NAGLU antigens were detectable at 1-12 months and 3-12 months, respectively, but not at 30 months in three of four patients. INTERPRETATION: Intracerebral rAVV2/5 was well tolerated and induced sustained enzyme production in the brain. The initial specific anti-NAGLU immune response that later subsided suggested acquired immunological tolerance. The best results being obtained in the youngest patient implies a potential window of opportunity. Longer follow-up is needed to further assess safety outcomes and persistence of improved cognitive development. FUNDING: Association Française Contre les Myopathies, Vaincre les Maladies Lysosomales, Institut Pasteur, and UniQure.

Intracerebral administration of adeno-associated viral vector serotype rh.10 carrying human SGSH and SUMF1 cDNAs in children with mucopolysaccharidosis type IIIA disease: results of a phase I/II trial.

Mucopolysaccharidosis type IIIA is a severe degenerative disease caused by an autosomal recessive defect of a gene encoding a lysosomal heparan-N-sulfamidase, the N-sulfoglycosamine sulfohydrolase (SGSH), the catalytic site of which is activated by a sulfatase-modifying factor (SUMF1). Four children (Patients 1-3, aged between 5.5 and 6 years; Patient 4 aged 2 years 8 months) received intracerebral injections of an adeno-associated viral vector serotype rh.10-SGSH-IRES-SUMF1 vector in a phase I/II clinical trial. All children were able to walk, but their cognitive abilities were abnormal and had declined (Patients 1-3). Patients 1-3 presented with brain atrophy. The therapeutic vector was delivered in a frameless stereotaxic device, at a dose of 7.2×10(11) viral genomes/patient simultaneously via 12 needles as deposits of 60 µl over a period of 2 hr. The vector was delivered bilaterally to the white matter anterior, medial, and posterior to the basal ganglia. Immunosuppressive treatment (mycophenolate mofetil and tacrolimus) was initiated 15 days before surgery and maintained for 8 weeks (mycophenolate mofetil) or throughout follow-up (tacrolimus, with progressive dose reduction) to prevent elimination of transduced cells. Safety data collected from inclusion, during the neurosurgery period and over the year of follow-up, showed good tolerance, absence of adverse events related to the injected product, no increase in the number of infectious events, and no biological sign of toxicity related to immunosuppressive drugs. Efficacy analysis was necessarily preliminary in this phase I/II trial on four children, in the absence of validated surrogate markers. Brain atrophy evaluated by magnetic resonance imaging seemed to be stable in Patients 1 and 3 but tended to increase in Patients 2 and 4. Neuropsychological evaluations suggested a possible although moderate improvement in behavior, attention, and sleep in Patients 1-3. The youngest patient was the most likely to display neurocognitive benefit.

Impaired inhibition of proactive interference in abstinent individuals with alcoholism.

Cognitive impairment has been associated with higher risk of alcoholism and relapse. Recent theoretical refinements have separated inhibition of dominant response and inhibition of proactive interference. We assessed the latter using a directed-forgetting procedure in 38 recently detoxified individuals with alcoholism and in 26 controls. On this task, memory performance of letter trigrams was compared when presented alone, followed by a second trigram to be recalled, then a second trigram to be forgotten (directed-forgetting condition). Individuals with alcoholism recalled more letters to be forgotten and performed worse than controls in the directed-forgetting condition, which significantly correlated with the duration of alcoholism.