Discovery of a potent, selective, and orally available EGFR C797S mutant inhibitor (DS06652923) with in vivo antitumor activity.

The C797S mutation is one of the major factors behind resistance to the third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs). Herein, we describe the discovery of DS06652923, a novel, potent, and orally available EGFR-triple-mutant inhibitor. Through scaffold hopping from the previously reported nicotinamide derivative, a novel biaryl scaffold was obtained. The potency was successfully enhanced by the introduction of basic substituents based on analysis of the docking study results. In addition, the difluoromethoxy group on the pyrazole ring improved the kinase selectivity by inducing steric clash with the other kinases. The most optimized compound, DS06652923, achieved tumor regression in the Ba/F3 allograft model upon its oral administration.

The Clinical Course and Treatment of a Case of Refractory Systemic Juvenile Myasthenia Gravis Successfully Treated with Thymectomy.

Juvenile myasthenia gravis (JMG) exhibits a more favorable response to glucocorticoids and has a better prognosis than adult myasthenia gravis. However, no established treatment exists for refractory JMG. Although thymectomy has been performed in several patients with refractory systemic JMG, there are few detailed clinical descriptions of patients who underwent thymectomy. Here, we present the case of a 10-year-old boy with refractory systemic JMG who was successfully treated with thymectomy. The patient developed symptoms, including dysphagia, malaise, diurnal ptosis, and weakness in the trunk muscles, and he was diagnosed with generalized JMG. Despite undergoing various treatments, including steroids, tacrolimus, steroid pulse therapy, intravenous immunoglobulin, azathioprine (AZT), and rituximab, his symptoms did not improve. Therefore, he underwent a thoracoscopic thymectomy 24 months after disease onset. Thymectomy led to remission, as demonstrated by a significant reduction in the quantitative myasthenia gravis score and anti-acetylcholine receptor antibody levels, which persisted for 43 months after surgery. Our case demonstrates the effectiveness of thymectomy in systemic JMG patients with positive anti-acetylcholine receptor antibodies, despite therapeutic failure with AZT and rituximab, within 2 years of disease onset.

Synthesis, activity, and their relationships of 2,4-diaminonicotinamide derivatives as EGFR inhibitors targeting C797S mutation.

The C797S mutation is one of the major factors behind resistance to the third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors. Herein, we describe the discovery of the 2,4-diaminonicotinamide derivative 5j, which shows potent inhibitory activity against EGFR del19/T790M/C797S and L858R/T790M/C797S. We also report the structure-activity relationship of the 2,4-diaminonicotinamide derivatives and the co-crystal structure of 5j and EGFR del19/T790M/C797S.

Discovery of EP300/CBP histone acetyltransferase inhibitors through scaffold hopping of 1,4-oxazepane ring.

EP300 and its paralog CBP play an important role in post-translational modification as histone acetyltransferases (HATs). EP300/CBP inhibition has been gaining attention as an anticancer treatment target in recent years. Herein, we describe the identification of a novel, highly selective EP300/CBP inhibitor, compound 11 (DS17701585), by scaffold hopping and structure-based optimization of a high-throughput screening hit 1. Compound 11 (DS17701585) shows dose-dependent inhibition of SRY-box transcription factor 2 (SOX2) mRNA expression in a human lung squamous cell carcinoma cell line LK2-xenografted mouse model.

Two Siblings with Cerebellar Ataxia, Mental Retardation, and Disequilibrium Syndrome 4 and a Novel Variant of ATP8A2.

Cerebellar ataxia, mental retardation, and disequilibrium syndrome 4 (CAMRQ4) is early onset neuromotor disorder and intellectual disabilities caused by variants of ATP8A2. We report sibling cases and systematically analyze previous literature to increase our understanding of CAMRQ4. Japanese siblings presented with athetotic movements at 1 and 2 months of age. They also had ptosis, ophthalmoplegia, feeding difficulty, hypotonia, and severely delayed development. One patient had retinal degeneration and optic atrophy. Flattening of the auditory brainstem responses and areflexia developed. At the last follow-up, neither patient could sit or achieve head control, although some nonverbal communication was preserved. Whole exome sequencing revealed compound heterozygous variants of ATP8A2: NM_016529.6:c.[1741C>T];[2158C>T] p.[(Arg581*)];[(Arg720*)]. The p.(Arg581*) variant has been reported, while the variant p.(Arg720*) was novel. The symptoms did not progress in the early period of development, which makes it difficult to distinguish from dyskinetic cerebral palsy, particularly in solitary cases. However, visual and hearing impairments associated with involuntary movements and severe developmental delay may be a clue to suspect CAMRQ4.

A patient with early-onset SMAX3 and a novel variant of ATP7A.

OBJECTIVE: To describe clinical and genetic studies on a patient with early-onset spinal muscular atrophyX3 (SMAX3) with novel variant of ATP7A. METHODS: Clinical, neurophysiological, neuroimaging and pathological examinations were performed. Whole exome sequencing was applied to search genetic bases of this patient. RESULTS: The patient had gait abnormality from early infantile period. Muscle imaging at 42 years old showed predominant involvement of proximal muscles as compared to the distal muscles. The patient had a novel variant of ATP7A, which was the fourth genotype of ATP7A exhibited as SMAX3. Contrary to previous reports of distal motor neuropathy, the clinical and neuroimaging findings in this case revealed dominant involvement in the proximal portion of the extremities and trunk, which is similar to patients with type III SMA. CONCLUSION: The dominant involvement of proximal motor system in this patient may expand the phenotypic variability of SMAX3. We need to be aware of this disorder in differential diagnosis of patients with type III SMA-like phenotype.

Prenatal clinical manifestations in individuals with COL4A1/2 variants.

BACKGROUND: Variants in the type IV collagen gene (COL4A1/2) cause early-onset cerebrovascular diseases. Most individuals are diagnosed postnatally, and the prenatal features of individuals with COL4A1/2 variants remain unclear. METHODS: We examined COL4A1/2 in 218 individuals with suspected COL4A1/2-related brain defects. Among those arising from COL4A1/2 variants, we focused on individuals showing prenatal abnormal ultrasound findings and validated their prenatal and postnatal clinical features in detail. RESULTS: Pathogenic COL4A1/2 variants were detected in 56 individuals (n=56/218, 25.7%) showing porencephaly (n=29), schizencephaly (n=12) and others (n=15). Thirty-four variants occurred de novo (n=34/56, 60.7%). Foetal information was available in 47 of 56 individuals, 32 of whom (n=32/47, 68.1%) had one or more foetal abnormalities. The median gestational age at the detection of initial prenatal abnormal features was 31 weeks of gestation. Only 14 individuals had specific prenatal findings that were strongly suggestive of features associated with COL4A1/2 variants. Foetal ventriculomegaly was the most common initial feature (n=20/32, 62.5%). Posterior fossa abnormalities, including Dandy-Walker malformation, were observed prenatally in four individuals. Regarding extrabrain features, foetal growth restriction was present in 16 individuals, including eight individuals with comorbid ventriculomegaly. CONCLUSIONS: Prenatal observation of ventriculomegaly with comorbid foetal growth restriction should prompt a thorough ultrasound examination and COL4A1/2 gene testing should be considered when pathogenic variants are strongly suspected.

Behavioral problems and family distress in tuberous sclerosis complex.

BACKGROUND: Tuberous sclerosis complex (TSC)-associated neuropsychiatric disorders (TAND) have a large impact on patients and their families. Improving intellectual ability outcomes using preventive vigabatrin (VGB) treatment has recently been reported. AIM: The aim of this study was to investigate the severity of behavioral problems and degree of distress among families of patients with TSC with and without a history of VGB treatment. METHOD: The study enrolled 21 children and adolescents who were patients with TSC from four hospitals: 14 in the VGB group and 7 in the no-VGB group. To evaluate patients' psychiatric and neurological symptoms, we used the TAND Checklist, Aberrant Behavior Checklist (ABC), Social Communication Questionnaire (SCQ), and Social Responsive Scale-2nd edition (SRS-2). RESULTS: All VGB-group patients were administered VGB after the onset of epileptic seizures. No obvious differences were observed between the VGB and no-VGB groups in behavioral problem scores on the TAND Checklist, or on the ABC, SCQ, and SRS-2 total scores. Behavioral problem scores were lower in patients with normal intelligence than in those with mild intellectual disability (ID; P = 0.042). Degrees of family distress assessed with the TAND Checklist were not correlated with the intelligence quotient/developmental quotient (IQ/DQ) or seizure frequency but were correlated with the total SRS-2 scores (P = 0.022). For several patients, there were large discrepancies between familial and physician ratings of the TAND impact score. CONCLUSION: Children and adolescents with TSC may present with significant behavioral difficulties and family distress, regardless of whether they were treated with VGB or not after the onset of seizures. Difficulties in social communication may have the strongest "TAND impact" on families.

Quizartinib, a selective FLT3 inhibitor, maintains antileukemic activity in preclinical models of RAS-mediated midostaurin-resistant acute myeloid leukemia cells.

FLT3 internal tandem duplication (ITD) mutations are associated with poor prognosis in patients with acute myeloid leukemia (AML). In this preclinical study, we characterized the binding affinity and selectivity of quizartinib, a small-molecule inhibitor of FLT3, and AC886, the active metabolite of quizartinib, compared with those of other FLT3 inhibitors. Selectivity profiling against >400 kinases showed that quizartinib and AC886 were highly selective against FLT3. Quizartinib and AC886 inhibited FLT3 signaling pathways in FLT3-ITD-mutated AML cells, leading to potent growth inhibition with IC50 values of <1 nM. When quizartinib was administered to mice bearing FLT3-ITD mutated tumors, AC886 was rapidly detected and tumor regression was observed at doses of ≥1 mg/kg without severe body weight loss. In addition, quizartinib inhibited the viability of midostaurin-resistant MOLM-14 cells and exerted potent antitumor activity in mouse xenograft models without severe body weight loss, while midostaurin and gilteritinib did not show significant antitumor effects. This is the first detailed characterization of quizartinib and AC886 in comparison with other FLT3 inhibitors under the same experimental conditions. Preclinical antileukemic activity in midostaurin-resistant FLT3-ITD-mutated AML cells suggests the potential value of quizartinib following midostaurin failure in patients with FLT3-ITD mutated AML.

Two males with sick sinus syndrome in a family with 0.6 kb deletions involving major domains in MECP2.

Mutations in methyl-CpG-binding protein 2 (MECP2) in males can lead to various phenotypes, ranging from neonatal encephalopathy to intellectual disability. In this study, using Nord's method of next-generation sequencing in three siblings, we identified a 0.6 kb deletion involving the transcriptional repression domain (TRD). Two males and one female had intellectual disability and apnea, but none met the criteria of Rett syndrome. Both males had sick sinus syndrome and severe tracheomalacia that resulted in early death. The mother, with skewed X-inactivation, had no symptoms. Therefore, this mutation is pathological for both males and females, resulting in sick sinus syndrome and severe tracheomalacia with strong reproducibility in males. Deletions involving major domains in MECP2 can result in a severe phenotype, and deletion of the TRD domain can cause severe autonomic nervous system dysregulation in males in these cases.

The new-generation selective ROS1/NTRK inhibitor DS-6051b overcomes crizotinib resistant ROS1-G2032R mutation in preclinical models.

ROS1 gene rearrangement was observed in around 1-2 % of NSCLC patients and in several other cancers such as cholangiocarcinoma, glioblastoma, or colorectal cancer. Crizotinib, an ALK/ROS1/MET inhibitor, is highly effective against ROS1-rearranged lung cancer and is used in clinic. However, crizotinib resistance is an emerging issue, and several resistance mechanisms, such as secondary kinase-domain mutations (e.g., ROS1-G2032R) have been identified in crizotinib-refractory patients. Here we characterize a new selective ROS1/NTRK inhibitor, DS-6051b, in preclinical models of ROS1- or NTRK-rearranged cancers. DS-6051b induces dramatic growth inhibition of both wild type and G2032R mutant ROS1-rearranged cancers or NTRK-rearranged cancers in vitro and in vivo. Here we report that DS-6051b is effective in treating ROS1- or NTRK-rearranged cancer in preclinical models, including crizotinib-resistant ROS1 positive cancer with secondary kinase domain mutations especially G2032R mutation which is highly resistant to crizotinib as well as lorlatinib and entrectinib, next generation ROS1 inhibitors.

Leucine-485 deletion variant of BRAF may exhibit the severe end of the clinical spectrum of CFC syndrome.

The genotype-phenotype correlation in BRAF variant in cardio-facio-cutaneous (CFC) syndrome is not clearly defined. Here we report a case with a severe clinical phenotype and a novel BRAF variant, p.Leu485del. The present case showed severe intellectual disability, impaired awareness, hyperekplexia, involuntary movements, early onset refractory seizures, and delayed myelination on brain magnetic resonance imaging as well as a polycystic and dysplastic kidney, which are previously unreported anomalies in CFC or RAS/mitogen-activated protein kinase syndromes related to BRAF variant. CFC syndrome, especially caused by BRAF variant, should be included in the differential diagnosis of patients with developmental and epileptic encephalopathies and hyperekplexia. Furthermore, we need to keep in mind that missense variants or the deletion of Leucine-485 may be associated with severe symptoms.

A case of new PCDH12 gene variants presented as dyskinetic cerebral palsy with epilepsy.

Here we report a Japanese patient with new compound heterozygous truncating variants in the PCDH12 gene. As compared to the previously reported families who had congenital microcephaly, intrauterine growth retardation, intracranial calcification, and neonatal seizure associated with dysplasia of the midbrain-hypothalamus-optic tract, the present patient showed no midbrain-hypothalamus dysplasia or congenital/postnatal microcephaly, but dyskinetic cerebral palsy and severe intellectual disability as well as multifocal epilepsy. To understand phenotypic spectrum associated with PCDH12 variants, more reports are needed.

Neuroepidemiology of Porencephaly, Schizencephaly, and Hydranencephaly in Miyagi Prefecture, Japan.

BACKGROUND: No population-based surveys of porencephaly, schizencephaly, and hydranencephaly have been conducted in Japan or other Asian countries. We performed a neuroepidemiologic analysis to elucidate the incidence of porencephaly, schizencephaly, and hydranencephaly in Miyagi prefecture, Japan, during 2007-2011. METHODS: We sent inquiry forms in February 2012 to three neonatal intensive care units, 25 divisions of orthopedic surgery in municipal hospitals, 33 divisions of pediatrics including one university hospital, municipal hospitals, pediatric practitioners, and institutions for physically handicapped children located in Miyagi prefecture. These covered all clinics related to pediatric neurology and orthopedic surgery in Miyagi prefecture. In the inquiry, diagnostic criteria for porencephaly, schizencephaly, and hydranencephaly were described and representative images of magnetic resonance imaging were shown. We obtained an 82% (27 of 33) response rate from the divisions of pediatrics, a 100% (3 of 3) response rate from the neonatal intensive care units, and a 68% (17 of 25) response rate from orthopedic surgery clinics. The magnetic resonance imaging scans of each patient were retrieved and inspected. RESULTS: Five, one, and two individuals developed porencephaly, schizencephaly, and hydranencephaly, respectively. The estimated incidence rates of porencephaly, schizencephaly, and hydranencephaly were 5.2 (95% confidence interval [CI], 0.6-9.8), 1.0 (95% CI, 0.0-3.1), and 2.1 (95% CI, 0.0-5.0) per 100,000 live births, respectively. CONCLUSIONS: The prevalence rates of porencephaly, schizencephaly, and hydranencephaly at birth reported herein are compatible with results reported previously in the United States and European countries. The overall prevalence rate of these three diseases was 8.3 (95% CI, 2.6-14.1) per 100,000 live births.

A girl with Cardio-facio-cutaneous syndrome complicated with status epilepticus and acute encephalopathy.

We report a six-year-old girl with Cardio-facio-cutaneous (CFC) syndrome who developed acute encephalopathy after the recurrence of status epilepticus. While epileptic encephalopathy and severe epilepsy have been mentioned as frequent complications of the CFC syndrome, no previous reports have shown a case of the CFC syndrome complicated with acute encephalopathy. Here we discuss the possibility for the linkage between the development of acute encephalopathy and CFC syndrome which is generally susceptible to seizures or epilepsy.

Unique discrepancy between cerebral blood flow and glucose metabolism in hemimegalencephaly.

Hemimegalencephaly (HME) presents as severe refractory seizures and requires early surgical treatment to prevent progression to catastrophic epilepsy. Single-photon emission computed tomography (SPECT) and positron emission tomography (PET) are useful imaging techniques for the presurgical evaluation of patients with intractable epilepsy. However, the results in HME are variable and no study has compared SPECT and PET performed at around the same time. We performed SPECT and PET for nine patients with HME, which was defined as a whole or part of affected hemisphere enlargement (three males, six females; age range 0.5-20 years). The ictal and interictal states were determined based on the presence or absence of clinical seizures during all PET examinations and majority of SPECT examinations. The perfusion pattern in the malformed hemisphere was increased or equal, despite the reduced glucose metabolism in six out of nine patients. Five of the six patients who underwent early surgical treatment showed this kind of perfusion/metabolism discrepancy. Importantly, even the non-affected hemisphere in early infantile cases already lacked the normal hypoperfusion and hypometabolism patterns of immature frontal lobes, which was most prominent in case with poor surgical prognosis. In all six surgical patients, epileptic seizures appeared before 4 months of age. By contrast, none of the non-surgical patients had seizures before 4 months of age. In conclusion, although the number of patients examined is small and the result is still preliminary, the perfusion/metabolism discrepancy found in this study may show potential characteristic aspect of HME and further study with simultaneous EEG recording will make clear if this finding can be useful indicator for early surgical treatment in HME.

Utility of subtraction ictal SPECT images in detecting focal leading activity and understanding the pathophysiology of spasms in patients with West syndrome.

PURPOSES: The aims of the study were to evaluate the detectability of focal leading activity in three cases of West syndrome having focal abnormal activity on EEG by comparing subtraction ictal images and raw ictal images, and to interpret the results in 16 cases. METHODS: Subtraction images were constructed using iNeurostat (revision 2). RESULTS: In three cases with focal abnormal activity on EEG, subtraction ictal images reflected the EEG findings; in contrast, raw ictal images did not. Diverse degrees of cortical hyperperfusion, ranging from zero to 10 sites, seen in the other 13 cases seemed to reflect spasm pathophysiology and rapid spasm propagation. Subtraction ictal images also allowed the ready detection of hyperperfusion of subcortical structures and of a tight cortico-subcortical relationship in a subset of cases. CONCLUSIONS: We showed the superiority of subtraction ictal images in detecting the focal epileptic region and in showing propagation pathways from the cortex to subcortical structures. A subset of spasms in WS may be focal cortical-onset secondarily generalized seizures. We believe that subtraction analysis is valuable in patients with complex WS who have partial seizures and spasms simultaneously along with focal epileptic EEG activity, as they will likely be candidates for epilepsy surgery.

Anti-tumour activity of CS-7017, a selective peroxisome proliferator-activated receptor gamma agonist of thiazolidinedione class, in human tumour xenografts and a syngeneic tumour implant model.

The anti-tumour activity of the novel thiazolidinedione class peroxisome proliferator-activated receptor gamma (PPARgamma) agonist CS-7017 was investigated. CS-7017 activated PPARgamma-mediated luciferase expression with an EC(50) of 0.20 nM. In addition, CS-7017 was shown to be highly selective for PPARgamma amongst other PPAR subfamilies. CS-7017 inhibited the proliferation of the human anaplastic thyroid tumour cell line DRO and the pancreatic tumour cell line AsPC-1 in vitro at concentrations as low as 10 nM. In xenograft studies, CS-7017 inhibited the growth of the human colorectal tumour cell line HT-29 in nude mice as well as DRO in nude rats in a dose-dependent manner. At the same dose, an increase in the levels of adiponectin, a surrogate marker for PPARgamma activation, was also observed. CS-7017 prolonged the survival of mice inoculated with murine colorectal tumour Colon 38 with marginal tumour growth inhibition. These preclinical results support the potential utility of CS-7017 in a clinical setting.

Effective treatment with levodopa and carbidopa for hypomyelination with atrophy of the basal ganglia and cerebellum.

Hypomyelination with atrophy of the basal ganglia and cerebellum (H-ABC) is a rare leukoencephalopathy presenting in the infantile period and characterized by diffuse cerebral hypomyelination, and atrophy of the basal ganglia and cerebellum. As patients with H-ABC lack remarkable laboratory findings, the diagnosis is based on brain magnetic resonance imaging findings alone. Only eight cases have been reported in the literature, and thus the natural course and treatment of this disease are not fully understood. We report a 35-month-old boy with H-ABC who had hemidystonia, hypomyelination, and cerebellar ataxia. We diagnosed H-ABC after considering a thorough differential diagnosis, excluding other diseases involving hemidystonia, hypomyelination, and cerebellar ataxia. Furthermore, technetium-99m ethyl cysteinate dimmer-single-photon emission computerized tomography (Tc-ECD-SPECT) and positron emission tomography with fluorodeoxyglucose (18)F (FDG-PET) revealed decreased blood flow and glucose metabolism in the bilateral lenticular nucleus, thalamus, and cerebellum. A peroral levodopa preparation containing carbidopa (levodopa-carbidopa) was effective at ameliorating and stopping the progression of the patient's dystonia (final effective doses: levodopa, 200 mg/day and carbidopa, 20 mg/day). This is the first case report of a Japanese patient with H-ABC and treatment for this disease. Levodopa-carbidopa may be an effective treatment for H-ABC.