Tasimelteon for non-24-hour sleep-wake disorder in totally blind people (SET and RESET): two multicentre, randomised, double-masked, placebo-controlled phase 3 trials

BACKGROUND

Most totally blind people have non-24-hour sleep-wake disorder (non-24), a rare circadian rhythm disorder caused by an inability of light to reset their circadian pacemaker. In two consecutive placebo-controlled trials (SET and RESET), we assessed safety and efficacy (in terms of circadian entrainment and maintenance) of once-daily tasimelteon, a novel dual-melatonin receptor agonist.

METHODS

We undertook the placebo-controlled, randomised, double-masked trials in 27 US and six German clinical research centres and sleep centres. We screened totally blind adults (18-75 years of age), who were eligible for the randomisation phase of SET if they had a non-24-hour circadian period (τ) of 24·25 h or longer (95% CI greater than 24·0 and up to 24·9 h), as calculated from measurements of urinary 6-sulphatoxymelatonin rhythms. For SET, we used block randomisation to assign patients (1:1) to receive tasimelteon (20 mg) or placebo every 24 h at a fixed clock time 1 h before target bedtime for 26 weeks. Patients who entered the open-label group receiving tasimelteon in SET or who did not meet the SET inclusion criteria but did meet the RESET inclusion criteria were screened for RESET. A subset of the patients who entered the open-label group before the RESET study and who had eligible τ values were screened for RESET after completing the open-label treatment. In RESET, we withdrew tasimelteon in a randomised manner (1:1) in patients who responded (ie, entrained) after a tasimelteon run-in period. Entrainment was defined as having τ of 24·1 h or less and a 95% CI that included 24·0 h. In SET, the primary endpoint was the proportion of entrained patients, assessed in the intention-to-treat population. The planned step-down primary endpoint assessed the proportion of patients who had a clinical response (entrainment at month 1 or month 7 plus clinical improvement, measured by the Non-24 Clinical Response Scale). In RESET, the primary endpoint was the proportion of non-entrained patients, assessed in the intention-to-treat population. Safety assessments included adverse events and clinical laboratory measures, assessed in all treated patients. These trials are registered with ClinicalTrials.gov, numbers NCT01163032 and NCT01430754.

FINDINGS

Between Aug 25, 2010, and July 5, 2012, we screened 391 totally blind patients for SET, of whom 84 (22%) were assigned to receive tasimelteon (n=42) or placebo (n=42). Two patients in the tasimelteon group and four in the placebo group discontinued the study before τ was measured, due to adverse events, withdrawal of consent, and a protocol deviation. Circadian entrainment occurred in eight (20%) of 40 patients in the tasimelteon group compared with one (3%) of 38 patients in the placebo group at month 1 (difference 17%, 95% CI 3·2-31·6; p=0·0171). Nine (24%) of 38 patients showed a clinical response, compared with none of 34 in the placebo group (difference 24%, 95% CI 8·4-39·0; p=0·0028). Between Sept 15, 2011, and Oct 4, 2012, we screened 58 patients for eligibility in RESET, 48 (83%) of whom had τ assessed and entered the open-label tasimelteon run-in phase. 24 (50%) patients entrained, and 20 (34%) were enrolled in the randomisation phase. Two (20%) of ten patients who were withdrawn to placebo remained entrained compared with nine (90%) of ten who continued to receive tasimelteon (difference 70%, 95% CI 26·4-100·0; p=0·0026). No deaths were reported in either study, and discontinuation rates due to adverse events were comparable between the tasimelteon (3 [6%] of 52 patients) and placebo (2 [4%] of 52 patients) treatment courses. The most common side-effects associated with tasimelteon in SET were headache (7 [17%] of 42 patients given tasimelteon vs 3 [7%] of 42 patients given placebo), elevated liver enzymes (4 [10%] vs 2 [5%]), nightmares or abnormal dreams (4 [10%] vs none), upper respiratory tract infection (3 [7%] vs none], and urinary tract infections (3 [7%] vs 1 [2%]).

INTERPRETATION

Once-daily tasimelteon can entrain totally blind people with non-24; however, continued tasimelteon treatment is necessary to maintain these improvements.

FUNDING

Vanda Pharmaceuticals.

Absence of weight gain association with the HTR2C -759C/T polymorphism in patients with schizophrenia treated with iloperidone

Weight gain is a common side effect of antipsychotics, contributing to poor treatment adherence, and previously linked to the -759C/T polymorphism near the serotonin receptor 2C gene. The effect of this polymorphism was analyzed in schizophrenia patients treated with iloperidone for up to 7 months. No association was detected with the modest weight changes observed in these patients.

Association of the NPAS3 gene and five other loci with response to the antipsychotic iloperidone identified in a whole genome association study

A whole genome association study was performed in a phase 3 clinical trial conducted to evaluate a novel antipsychotic, iloperidone, administered to treat patients with schizophrenia. Genotypes of 407 patients were analyzed for 334,563 single nucleotide polymorphisms (SNPs). SNPs associated with iloperidone efficacy were identified within the neuronal PAS domain protein 3 gene (NPAS3), close to a translocation breakpoint site previously observed in a family with schizophrenia. Five other loci were identified that include the XK, Kell blood group complex subunit-related family, member 4 gene (XKR4), the tenascin-R gene (TNR), the glutamate receptor, inotropic, AMPA 4 gene (GRIA4), the glial cell line-derived neurotrophic factor receptor-alpha2 gene (GFRA2), and the NUDT9P1 pseudogene located in the chromosomal region of the serotonin receptor 7 gene (HTR7). The study of these polymorphisms and genes may lead to a better understanding of the etiology of schizophrenia and of its treatment. These results provide new insight into response to iloperidone, developed with the ultimate goal of directing therapy to patients with the highest benefit-to-risk ratio.

Applicability of a genetic signature for enhanced iloperidone efficacy in the treatment of schizophrenia

OBJECTIVE

To demonstrate how several polymorphisms previously associated with the efficacy of the novel antipsychotic iloperidone could be used together to predict clinical response and provide practical information for individualized treatment.

METHOD

This inpatient randomized, double-blind, placebo- and ziprasidone-controlled, 28-day study of the efficacy of iloperidone was conducted from November 2005 to September 2006. Likelihood ratios, predicted probabilities of response, and number needed to treat were calculated for patients with schizophrenia (DSM-IV criteria) using 6 genetic markers of iloperidone response as measured by change in the Positive and Negative Syndrome Scale-Total (PANSS-T) score. Data analysis was performed on 409 patients of various ethnic origins.

RESULTS

The 6-marker genotype combinations defined 4 groups of patients with distinct probabilities of response. More than 75% of iloperidone-treated patients in the group with the optimal genotype combinations showed a 20% or greater improvement, compared with 37% for patients with other genotypes. These patients had a significant response by the first week of treatment, which was earlier than for patients with other genotype combinations. The odds of responding to iloperidone treatment with at least 20% improvement ranged from 2.4 to 3.6 for patients with 1 of the 6 favorable single-marker genotypes. The odds increased to 9.5 or greater for patients with the most favorable 6-marker combinations. The difference in PANSS-T score improvement observed between the genotype groups was also seen for the positive, negative, and general psychopathology PANSS subscales. The relationship between treatment efficacy and genotype combinations was not observed for patients treated with ziprasidone.

CONCLUSION

These results illustrate the combined use of genetic markers to predict enhanced response to iloperidone and support the application of pharmacogenetics to differentiate medication options and improve individualized treatments for schizophrenia.

TRIAL REGISTRATION

(ClinicalTrials.gov) Identifier: NCT00254202.

Common effect of antipsychotics on the biosynthesis and regulation of fatty acids and cholesterol supports a key role of lipid homeostasis in schizophrenia

For decades, the dopamine hypothesis has gained the most attention in an attempt to explain the origin and the symptoms of schizophrenia. While this hypothesis offers an explanation for the relationship between psychotic symptoms and dopamine kinetics, it does not provide a direct explanation of the etiology of schizophrenia which remains poorly understood. Consequently, current antipsychotics that target neurotransmitter receptors, have limited and inconsistent efficacy. To gain insights into the mechanism of action of these drugs, we studied the expression profile of 12,490 human genes in a cell line treated with 18 antipsychotics, and compared it to that of a library of 448 other compounds used in a variety of disorders. Analysis reveals a common effect of antipsychotics on the biosynthesis and regulation of fatty acids and cholesterol, which is discussed in the context of a lipid hypothesis where alterations in lipid homeostasis might underlie the pathogenesis of schizophrenia. This finding may help research aimed at the development of novel treatments for this devastating disease.

Effect of a ciliary neurotrophic factor polymorphism on schizophrenia symptom improvement in an iloperidone clinical trial

AIMS

Presence of the null FS63TER allele of the rs1800169 polymorphism in the gene encoding the ciliary neurotrophic factor (CNTF) may increase the risk of schizophrenia. This study prospectively evaluated the CNTF rs1800169 genotype (G/G vs non-G/G) effects on response to iloperidone.

PATIENTS & METHODS

Iloperidone 24 mg/day was evaluated in a study of patients with schizophrenia. Efficacy measurements included Positive and Negative Syndrome Scale total (PANSS-T), Brief Psychiatric Rating Scale (BPRS) and Clinical, Global, Impression (CGI) scores. The step-down primary end point was the difference in PANSS-T scores based on CNTF rs1800169 G/G genotype.

RESULTS

This study genotyped 417 patients (279 iloperidone and 138 placebo) for the rs1800169 polymorphism. Iloperidone significantly improved PANSS-T, PANSS positive subscale (PANSS-P), PANSS negative subscale (PANSS-N), BPRS, Clinical Global Impression of Change (CGI-C) and Clinical Global Impression of Severity (CGI-S) scores versus placebo. G/G versus non-G/G patients had greater improvement with iloperidone versus placebo in PANSS, BPRS and CGI scores.

CONCLUSIONS

The relative treatment benefit of iloperidone compared with placebo in patients with schizophrenia is enhanced in patients homozygous G/G for the rs1800169 polymorphism.

Genes that co-cluster with estrogen receptor alpha in microarray analysis of breast biopsies

The estrogen receptor plays a critical role in the pathogenesis and clinical behavior of breast cancer. To better understand the molecular basis of estrogen-dependent forms of this disease we studied gene expression profiles from 53 primary breast cancer biopsies. Gene expression data for more than 7000 genes were generated from each tumor sample with oligo microarrays. A standard correlation-clustering algorithm identified 18 genes that co-clustered with estrogen receptor alpha. Eleven of these genes had previously been associated with estrogen regulation or breast tumorigenesis including trefoil factor 1 and estrogen regulated LIV-1. Additional study of these 18 genes may further delineate the role of estrogen receptor in breast cancer, generate new predictive biomarkers for response to endocrine therapies and identify novel therapeutic targets.

A mutation in the human neurofilament M gene in Parkinson's disease that suggests a role for the cytoskeleton in neuronal degeneration

Parkinson's disease (PD) is a common neurodegenerative movement disorder characterized by the destruction of dopaminergic neurons of the substantia nigra. We have identified a new mutation (Gly336Ser) in the medium neurofilament subunit in a patient of French-Canadian origin with early onset severe PD. This finding suggests, for the first time, that aberrations in neuronal molecules involved in the cytoskeleton could lead to the development of the pathology seen in PD.

Genomic organization and expression of the human beta-synuclein gene (SNCB)

The beta-synuclein protein is highly homologous to the alpha-synuclein protein for which two mutations were reported in some familial cases of Parkinson disease. It has been shown that both alpha- and beta-synucleins may be able to inhibit phospholipase D2 selectively. We have observed that the beta-synuclein gene (HGMW-approved symbol, SNCB) is highly expressed in brain including the substantia nigra, the main region of neuronal degeneration in patients with Parkinson disease. We have determined the intron-exon structure of the beta-synuclein gene and established sequencing assays that will facilitate the search for mutations in the beta-synuclein gene in patients with Parkinson disease or other neurodegenerative disorders.

Deletions in the Parkin gene and genetic heterogeneity in a Greek family with early onset Parkinson's disease

Parkinson's disease is the second most common neurodegenerative disease after Alzheimer's disease and is manifested as a movement disorder. A positive family history is the second most important risk factor for developing the illness, after age. Both autosomal dominant and recessive forms of the illness have been described. Recently deletions in a novel gene, parkin, have been associated with the autosomal recessive form of the illness in Japanese families. In this study, we demonstrate that deletions of exons 5, 6 and 7 of the parkin gene are present in two affected individuals of a Greek pedigree with early onset Parkinson's disease. However, no deletions were identified in a different branch of the same pedigree with three affected individuals. These results suggest that deletions in the parkin gene will be found in other families besides those of Japanese origin and that there must be at least one additional locus responsible for early onset autosomal recessive Parkinson's disease.

The synuclein family

The synuclein gene family recently came into the spotlight, when one of its members, alpha-synuclein, was found to be mutated in several families with autosomal dominant Parkinson's disease (PD). A peptide of the alpha-synuclein protein had been characterized previously as a major component of amyloid plaques in brains of patients with Alzheimer's disease (AD). The mechanism by which this presynaptic protein is involved in the two most common neurodegenerative disorders, AD and PD, remains unclear. Remarkably, another member of this gene family, gamma-synuclein, has been shown to be overexpressed in breast carcinomas and may also be overexpressed in ovarian cancer. The possible involvement of the synuclein proteins in the etiology of common human diseases has raised exciting questions and is the subject of intense investigation. Details of the properties of any member of the synuclein family may provide useful information for understanding the characteristics and function of other family members. The present review offers a synopsis of the current state of knowledge of all synuclein family members in different species.

Identification, localization and characterization of the human gamma-synuclein gene

We have identified and characterized a new member of the human synuclein gene family, gamma-synuclein (SNCG). This gene is composed of five exons, which encode a 127 amino acid protein that is highly homologous to alpha-synuclein, which is mutated in some Parkinson's disease families, and to beta-synuclein. The gamma-synuclein gene is localized to chromosome 10q23 and is principally expressed in the brain, particularly in the substantia nigra. We have determined its genomic sequence, and established conditions for sequence analysis of each of the exons. The gamma-synuclein gene, also known as BCSG1, was recently found to be overexpressed in advanced infiltrating carcinoma of the breast. Our survey of the EST database indicated that it might also be overexpressed in an ovarian tumor.

Long uninterrupted CGG repeats within the first exon of the human FMR1 gene are not intrinsically unstable in transgenic mice

Despite the increasing number of disorders known to result from trinucleotide repeat amplification, the molecular mechanism underlying these dynamic mutations is still unknown. In an attempt to create a mouse model for the CGG repeat instability seen in Fragile X syndrome, we constructed transgenes corresponding to FMR1 premutation alleles. While in humans these alleles would expand to full mutation with almost 100% certainty upon maternal transmission, they remain stable in our transgenic mice. Therefore, the presence of a large number of uninterrupted CGGs is not sufficient to cause instability in mice, even in the context of flanking human FMR1 sequences.

Contig map of the Parkinson's disease region on 4q21-q23

We have constructed a yeast artificial chromosome contig (YAC) map of human chromosome 4q21-q23 across the Parkinson's disease region by combining molecular and fluorescence in situ hybridization techniques. This map contains 55 YACs and 51 molecular markers, including 23 polymorphic markers. We have also isolated one P1 and 33 bacterial artificial chromosomes located within this contig. Plasmid libraries were generated from 11 of these BAC and P1 clones, and 614 random plasmid clones were sequenced for a total of about 200 kb. This contig allowed us to precisely determine the location of 18 transcripts within the D4S2460-D4S2986 interval, including the alpha-synuclein gene found to be mutated in some families with Parkinson's disease.

Mutation in the alpha-synuclein gene identified in families with Parkinson's disease

Parkinson's disease (PD) is a common neurodegenerative disorder with a lifetime incidence of approximately 2 percent. A pattern of familial aggregation has been documented for the disorder, and it was recently reported that a PD susceptibility gene in a large Italian kindred is located on the long arm of human chromosome 4. A mutation was identified in the alpha-synuclein gene, which codes for a presynaptic protein thought to be involved in neuronal plasticity, in the Italian kindred and in three unrelated families of Greek origin with autosomal dominant inheritance for the PD phenotype. This finding of a specific molecular alteration associated with PD will facilitate the detailed understanding of the pathophysiology of the disorder.

Mutation in the alpha-synuclein gene identified in families with Parkinson's disease

Parkinson's disease (PD) is a common neurodegenerative disorder with a lifetime incidence of approximately 2 percent. A pattern of familial aggregation has been documented for the disorder, and it was recently reported that a PD susceptibility gene in a large Italian kindred is located on the long arm of human chromosome 4. A mutation was identified in the alpha-synuclein gene, which codes for a presynaptic protein thought to be involved in neuronal plasticity, in the Italian kindred and in three unrelated families of Greek origin with autosomal dominant inheritance for the PD phenotype. This finding of a specific molecular alteration associated with PD will facilitate the detailed understanding of the pathophysiology of the disorder.

Mutations in American families with spinocerebellar ataxia (SCA) type 3: SCA3 is allelic to Machado-Joseph disease

We identified an expansion of the CAG trinucleotide repeat in the coding region of the Machado-Joseph disease gene in 7 of 24 American families diagnosed with autosomal dominant ataxia. All affected individuals were heterozygous for an expanded allele that ranged from 67 to more than 200 CAG repeats, whereas the normal allele had 14 to 33 repeats. In contrast to the Azorean-Portuguese origins of Machado-Joseph disease, the two largest American families were of German and Dutch-African descent. Clinical, pathologic, and genetic evaluations suggest that American families with spinocerebellar ataxia type 3 differ from those with Machado-Joseph disease by their ethnic origins, predominant spinopontine atrophy, lack of dystonic features, and larger CAG repeat expansion.

French myotonic dystrophy families show expansion of a CTG repeat in complete linkage disequilibrium with an intragenic 1 kb insertion

The molecular basis of myotonic dystrophy (DM) has been characterised. All DM mutations characterised to date appear as an unstable elongation of a fragment containing a tandem repeat of a CTG motif, which can be visualised in both EcoRI and BamHI digests. It has been shown that the fragment is polymorphic in the normal population. Another 1 kb insertion/deletion polymorphism located near the unstable CTG repeat region has been identified. The 1 kb insertion allele is present in all DM patients. These different polymorphic systems can be distinguished using cDNA25 and BamHI, because this enzyme cuts between the site of the 1 kb insertion and the CTG repeat. We thus haplotyped DM patients from 72 French families and clearly showed that all chromosomes (100%) with the DM mutation carried the 1 kb insertion as well. In addition to this association, we detected significant linkage disequilibrium between the DM locus and D19S63 for which allelic frequencies were different from other European populations. Our results in the French DM population are thus in agreement with the hypothesis that the CTG expansion occurred on one or a few ancestral chromosomes carrying the large 1 kb insertion allele.

Myotonic dystrophy: absence of CTG enlarged transcript in congenital forms, and low expression of the normal allele

Myotonic dystrophy (DM) is an autosomal dominant neuromuscular disease. The mutation has been identified as an unstable trinucleotide CTG repeat in a sequence encoding a putative cAMP-dependent protein kinase. The CTG repeat varies in length between affected siblings, and generally increases through generations in parallel with increasing severity of the disease. Congenital myotonic dystrophy, which represents the most severe phenotype, is exclusively maternally inherited. In this report, we show, by Northern blot analysis, that no mutated enlarged transcript is detectable in a 20-week-old DM fetus and in two congenitally affected infants. Furthermore, in skeletal and cardiac muscle of the DM fetus, we observed by RNA analysis, including Northern blot and RT-PCR, an unexpectedly low expression of the paternal wild type allele. Varying degrees of expression of the mutant and/or the normal allele might therefore account for the characteristic features of the congenital form and the extreme variability of the disease.

Myotonic dystrophy: size- and sex-dependent dynamics of CTG meiotic instability, and somatic mosaicism

Myotonic dystrophy (DM) is a progressive neuromuscular disorder which results from elongations of an unstable (CTG)n repeat, located in the 3' untranslated region of the DM gene. A correlation has been demonstrated between the increase in the repeat number of this sequence and the severity of the disease. However, the clinical status of patients cannot be unambiguously ascertained solely on the basis of the number of CTG repeats. Moreover, the exclusive maternal inheritance of the congenital form remains unexplained. Our observation of differently sized repeats in various DM tissues from the same individual may explain why the size of the mutation observed in lymphocytes does not necessarily correlate with the severity and nature of symptoms. Through a molecular and genetic study of 142 families including 418 DM patients, we have investigated the dynamics of the CTG repeat meiotic instability. A positive correlation between the size of the repeat and the intergenerational enlargement was observed similarly through male and female meioses for < or = 0.5-kb CTG sequences. Beyond 0.5 kb, the intergenerational variation was more important through female meioses, whereas a tendency to compression was observed almost exclusively in male meioses, for > or = 1.5-kb fragments. This implies a size- and sex-dependent meiotic instability. Moreover, segregation analysis supports the hypothesis of a maternal as well as a familial predisposition for the occurrence of the congenital form. Finally, this analysis reveals a significant excess of transmitting grandfathers partially accounted for by increased fertility in affected males.

Prenatal diagnosis of myotonic dystrophy using closely linked flanking markers

We report on two cases of prenatal diagnosis of myotonic dystrophy (DM), using flanking markers APOC2 or CKMM on the proximal side and D19S51 on the distal side. By double digestion (TaqI and NcoI) of PCR amplified CKMM, the informativeness was increased from a PIC value of 0.57 to 0.69. Altogether, with a PIC value of 0.64 for APOC2, 0.69 for CKMM, and 0.27 for D19S51 (BglI), presymptomatic and prenatal diagnosis can thus be offered to approximately 24% of persons with a risk between 0.0004 and 0.0008 using these flanking markers.

[Antioncogenes: models for tumors in children]

The chromosomal assignment of genes responsible for malformation syndromes associated with increased susceptibility to malignancy could be determined owing to specific constitutional chromosomal abnormalities or to family studies. For certain types of tumors, somatic chromosomal rearrangements (loss of alleles) occur at the same locus indicating the presence of a recessive suppressor gene or an antioncogène. For other types of tumors chromosomal rearrangements involving regions different from the locus for predisposition suggest genetic heterogeneity and/or implication of genes for tumor progression. These genes which are also involved in development and regulation of differentiation and cell growth, may undergo a differential genomic imprinting.

Constitutional and somatic deletions of two different regions of maternal chromosome 11 in Wilms tumor

Loss of heterozygosity for 11p markers and preferential loss of maternal alleles have been described in Wilms tumor. In this report we describe the molecular characterization of the constitutional and somatic 11p rearrangements in a del(11p13) WAGR patient with Wilms tumor. Both rearrangements led to loss of maternal alleles for two different regions of 11p, namely, 11p13 and 11p14----p15. This result clearly suggests that Knudson's hypothesis of two hits at the same locus does not necessarily apply to Wilms tumor. Moreover, the loss of 11p15 maternal alleles in the tumor is not incompatible with maternal inheritance of predisposition at 11p13. The putative roles of these two loci are discussed.

Molecular definition of de novo and genetically transmitted WAGR-associated rearrangements of 11p13

We describe a family in whom the phenotypically normal father carries a balanced insertional translocation, ins(14;11)(q23;p12p14). This individual fathered three mentally retarded children, two with a del(11)(p13) and one with a dup(11)(p13). Two other cases of a de novo del(11)(p13) are also described. All four del(11)(p13) cases presented with WAGR, a complex syndrome associated with a predisposition to Wilms' tumor (WT), aniridia (A), genitourinary abnormalities (G), and mental retardation (R). Using an approach combining karyotype analysis, determination of the gene copy number, and RFLP studies employing five 11p13 DNA markers, we were able to define the chromosomal rearrangement involved in each case. Analysis of these WAGR deletions provides further subdivision of band p13 on chromosome 11.