Effects of AFQ056 on language learning in fragile X syndrome.

BACKGROUNDFXLEARN, the first-ever large multisite trial of effects of disease-targeted pharmacotherapy on learning, was designed to explore a paradigm for measuring effects of mechanism-targeted treatment in fragile X syndrome (FXS). In FXLEARN, the effects of metabotropic glutamate receptor type 5 (mGluR5) negative allosteric modulator (NAM) AFQ056 on language learning were evaluated in 3- to 6-year-old children with FXS, expected to have more learning plasticity than adults, for whom prior trials of mGluR5 NAMs have failed.METHODSAfter a 4-month single-blind placebo lead-in, participants were randomized 1:1 to AFQ056 or placebo, with 2 months of dose optimization to the maximum tolerated dose, then 6 months of treatment during which a language-learning intervention was implemented for both groups. The primary outcome was a centrally scored videotaped communication measure, the Weighted Communication Scale (WCS). Secondary outcomes were objective performance-based and parent-reported cognitive and language measures.RESULTSFXLEARN enrolled 110 participants, randomized 99, and had 91 who completed the placebo-controlled period. Although both groups made language progress and there were no safety issues, the change in WCS score during the placebo-controlled period was not significantly different between the AFQ056 and placebo-treated groups, nor were there any significant between-group differences in change in any secondary measures.CONCLUSIONDespite the large body of evidence supporting use of mGluR5 NAMs in animal models of FXS, this study suggests that this mechanism of action does not translate into benefit for the human FXS population and that better strategies are needed to determine which mechanisms will translate from preclinical models to humans in genetic neurodevelopmental disorders.TRIAL REGISTRATIONClincalTrials.gov NCT02920892.FUNDING SOURCESNeuroNEXT network NIH grants U01NS096767, U24NS107200, U24NS107209, U01NS077323, U24NS107183, U24NS107168, U24NS107128, U24NS107199, U24NS107198, U24NS107166, U10NS077368, U01NS077366, U24NS107205, U01NS077179, and U01NS077352; NIH grant P50HD103526; and Novartis IIT grant AFQ056X2201T for provision of AFQ056.

Low Risk Profile of Long-Term Repeated Lumbar Puncture for Intrathecal Delivery of 2-Hydroxypropyl-Beta-Cyclodextrin in Patients With Niemann-Pick Type C.

BACKGROUND: Intrathecal delivery of 2-hydroxypropyl-beta-cyclodextrin (VTS-270, adrabetadex) by lumbar puncture (LP) has been performed on a biweekly schedule for over nine years for the treatment of Niemann-Pick type C1 (NPC1) at Rush University Medical Center. METHODS: Over this time 59 patients with NPC1 have been treated with 2935 infusions, performed with either a 22-G 3-inch Whitacre or a 22-G 2-inch Gertie Marx atraumatic needles, with or without general anesthesia. Adverse events potentially related to the LP infusion were collected from records for all patients treated for NPC. The NPC1 cohort ranged in age from one to 31 years at the initiation of treatment. RESULTS: Of the 59 patients treated 33 (55.9%) had no adverse events ever after an LP and 26 (44.1%) had adverse effects at some time. Of the 2935 LPs, adverse events occurred after 3.3% of LPs. Adverse events most observed were headache (1.2% of LPs), nausea (0.3%), vomiting (1.0%), and back pain (1.3%). CONCLUSIONS: This study shows that frequent repeated LPs are possible for delivery of intrathecal therapy and can be accomplished with a very low rate of post-LP adverse events.

Consistently High Agreement Between Independent Raters of Niemann-Pick Type C1 Clinical Severity Scale in Phase 2/3 Trial.

BACKGROUND: Niemann-Pick disease, type C1 (NPC1) is a rare neurodegenerative genetic disorder characterized by impaired intracellular transport of cholesterol and other lipids. The Niemann-Pick Disease, type C1 Severity Scale (NPC-SS) was developed to quantify neurological progression of NPC; it is used to monitor the natural history of disease progression and assess response to treatment. The objective of the study was to examine the interrater reliability of the NPC-SS in a phase 2/3 trial. METHODS: Study data were from a multicenter, prospective, randomized, double-blind trial of adrabetadex in 56 subjects with NPC1. Clinical data recorded at each study site were distributed to two independent blinded central raters to generate a severity score. A composite four-item score was utilized as the primary clinical study end point, whereas a five-item focused score has been utilized in other NPC1 trials. Interrater reliability was assessed using two-way mixed models for instrument stability, Cohen kappa, weighted kappa, and percent agreement for the four- and five-item scores. RESULTS: The frequency distribution and mean (S.D.) of the NPC-SS domain assessments by the raters were almost identical. Evaluation at the patient visit level showed wide variability between visits; however, weighted kappa calculation provided a lower variability between visits. The average kappa coefficients ranged between 0.69 and 0.89, indicating good to very good agreement between raters. CONCLUSIONS: These results support the NPC-SS, including derived four- and five-item composite scores, as reliable measures for use in a clinical trial setting.

Long-Term Treatment of Niemann-Pick Type C1 Disease With Intrathecal 2-Hydroxypropyl-ß-Cyclodextrin.

BACKGROUND: Intrathecal 2-hydoxypropyl-ß-cyclodextrin has been found to mobilize cholesterol, extend life, reduce cerebellar pathology, and delay onset of ataxia in the mouse and cat models of Niemann-Pick disease, type C1, a clinically variable progressive and ultimately fatal neurodegenerative storage disorder characterized by endolysosomal accumulation of unesterified cholesterol. OBJECTIVE: In this study, the long-term effects of intrathecal 2-hydoxypropyl-ß-cyclodextrin treatment for 2.5 to three years in humans with Niemann-Pick disease, type C, were evaluated. METHODS: Three patients with Niemann-Pick disease, type C, in different stages of progression and displaying varying disease manifestations were treated with intrathecal 2-hydoxypropyl-ß-cyclodextrin (VTS-270) delivered by lumbar puncture infusion through an intermediate-size patient population investigational new drug application for expanded access. Disease progression was monitored with the Niemann-Pick disease, type C, Neurological Severity Scale and numerous objective measures of function in five neurological domains typically impacted by the disease: cognitive/language, gait/balance, fine motor, swallowing, and eye movement. RESULTS: No worsening in any domain except eye movements (vertical pursuit gain) was seen for any of the three patients, and in the other domains, improved scores on measures were seen over time for one or more patients. The Niemann-Pick disease type C (NPC) Neurological Severity Scale (NSS) showed stable to slightly improved ratings. CONCLUSIONS: These trajectories are not consistent with the typical trajectory of the disease and suggest that intrathecal 2-hydoxypropyl-ß-cyclodextrin has stabilized the disease over an extended period of time, supporting the current phase 2/3 controlled registration trial with VTS-270.

Pharmacotherapy for Fragile X Syndrome: Progress to Date.

To date, no drug is approved for the treatment of Fragile X Syndrome (FXS) although many drugs are used to manage challenging behaviors from a symptomatic perspective in this population. While our understanding of FXS pathophysiology is expanding, efforts to devise targeted FXS-specific treatments have had limited success in placebo-controlled trials. Compounds aimed at rectifying excessive glutamate and deficient gamma-aminobutyric acid (GABA) neurotransmission, as well as other signaling pathways known to be affected by Fragile X Mental Retardation Protein (FMRP) are under various phases of development in FXS. With the failure of several metabotropic glutamate receptor subtype 5 (mGlur5) selective antagonists under clinical investigation, no clear single treatment appears to be greatly effective. These recent challenges call into question various aspects of clinical study design in FXS. More objective outcome measures are under development and validation. Future trials will likely be aimed at correcting multiple pathways known to be disrupted by the loss of FMRP. This review offers a brief summary of the prevalence, phenotypic characteristics, genetic causes and molecular functions of FMRP in the brain (as these have been extensively reviewed elsewhere), discusses the most recent finding in FXS drug development, and summarizes FXS trials utilizing symptomatic treatment.