Comparison of different promoters to improve AAV vector-mediated gene therapy for neuronopathic Gaucher disease

Gaucher Disease (GD) is an inherited metabolic disorder caused by mutations in the GBA1 gene. It can manifest with severe neurodegeneration and visceral pathology. The most acute neuronopathic form (nGD), for which there are no curative therapeutic options, is characterised by devastating neuropathology and death during infancy. In this study, we investigated the therapeutic benefit of systemically delivered AAV9 vectors expressing the human GBA1 gene at two different doses comparing a neuronal-selective promoter with ubiquitous promoters. Our results highlight the importance of a careful evaluation of the promoter sequence used in gene delivery vectors, suggesting a neuron-targeted therapy leading to high levels of enzymatic activity in the brain but lower GCase expression in the viscera, might be the optimal therapeutic strategy for nGD.

Observations on presumptive lumpy skin disease in native cattle and Asian water buffaloes around the tiger reserves of the central Indian highlands

CASE HISTORY

Between August and October 2020, following the monsoon, signs of lumpy skin disease (LSD) were recorded and described in 154 oxen, 34 cows, 13 calves (Bos indicus) and two Asian water buffalo (Bubalus bubalis) cows belonging to smallholder farmers in 32 villages located around the Kanha and Bandhavgarh tiger reserves in the state of Madhya Pradesh, central India. Affected animals were subjected to a full clinical examination and detailed findings were recorded in a clinical register. A semi-structured questionnaire was attached to the existing clinical register format to gather information on the clinical disease history and animal husbandry practices relevant to the spread of LSD virus.

CLINICAL FINDINGS

The affected animals were between 4 months and 14 years of age (mean 6.4 (SD 2.5) years). Persistent high temperature, depression, anorexia, and characteristic round nodules (lumps) on the skin were reported. The nodules were 2-5 cm in diameter and spread over the face, ears, neck, back, perineum, scrotum, legs, tail, udder, and nasal and oral mucosa. Secondary complications of myiasis (n = 39), mastitis (n = 16) and ulcerative lesions on legs were noticed. Death was reported for one animal (0.5%). The affected animals' recovery times were variable (mean 18.4 (SD 2.7) days). There was a significant positive correlation between delay in initiating treatment and the duration of sickness. Reduction in milk yield of 30-55% was reported in Bos indicus cows.

DIAGNOSIS

Clinical findings and treatment responses consistent with lumpy skin disease and its sequelae.

CLINICAL RELEVANCE

The presumptive LSD outbreak caused serious economic loss to the animal keepers. LSD is a new disease for India and in the absence of active immunisation, efficient vector control, animal movement control and stall-feeding practice, it will inevitably become endemic in the country. The severe impacts resulting from the introduction of a new disease to a previously unaffected country highlight the need for iterative improvements in global transboundary disease surveillance. The value of clinical examination and recording of findings is demonstrated in the context of smallholder farming systems with limited access to laboratory diagnosis, which are common around the world. The description of an LSD outbreak in naïve populations of cattle and buffalo illustrates the need for increased awareness of the associated clinical signs and maintenance of high levels of biosecurity in hitherto disease-free countries.

Phenotypic and Functional Characterization of Müller Glia Isolated from Induced Pluripotent Stem Cell-Derived Retinal Organoids: Improvement of Retinal Ganglion Cell Function upon Transplantation

Glaucoma is one of the leading causes of blindness, and there is an ongoing need for new therapies. Recent studies indicate that cell transplantation using Müller glia may be beneficial, but there is a need for novel sources of cells to provide therapeutic benefit. In this study, we have isolated Müller glia from retinal organoids formed by human induced pluripotent stem cells (hiPSCs) in vitro and have shown their ability to partially restore visual function in rats depleted of retinal ganglion cells by NMDA. Based on the present results, we suggest that Müller glia derived from retinal organoids formed by hiPSC may provide an attractive source of cells for human retinal therapies, to prevent and treat vision loss caused by retinal degenerative conditions. Stem Cells Translational Medicine 2019;8:775&784.

Data Standardization, Pharmaceutical Drug Development, and the 3Rs

Despite the efforts, cost, and extensive use of animals for nonclinical research, only a small number of studies have methodically compared findings from animal toxicology studies to those from human clinical trials. Impediments to understanding the translation of nonclinical safety have included the lack of easy access to data and the need for extensive data curation given the diverse terminologies, formats, and data platforms in use. SEND and SDTM study data standards, developed by CDISC and about to become mandated by FDA, can address this and other drug development issues by facilitating access to data in ways that are not currently feasible. A consistent data standard across clinical and nonclinical will discourage the development of data silos, which easily become obstacles to data sharing and maximizing the value of animal and human data. The confluence of rapid scientific advances, increasingly larger quantities of diverse data, technological advances in data mining, and the FDA's requirements for standardized study data create new opportunities for the advancement of drug development and for refinement in the way we use animals.

Demonstration of an anti-hyperalgesic effect of a novel pan-Trk inhibitor PF-06273340 in a battery of human evoked pain models

AIM

Inhibitors of nerve growth factor (NGF) reduce pain in several chronic pain indications. NGF signals through tyrosine kinase receptors of the tropomyosin-related kinase (Trk) family and the unrelated p75 receptor. PF-06273340 is a small molecule inhibitor of Trks A, B and C that reduces pain in nonclinical models, and the present study aimed to investigate the pharmacodynamics of this first-in-class molecule in humans.

METHODS

A randomized, double-blind, single-dose, placebo- and active-controlled five-period crossover study was conducted in healthy human subjects (NCT02260947). Subjects received five treatments: PF-06273340 50 mg, PF-06273340 400 mg, pregabalin 300 mg, ibuprofen 600 mg and placebo. The five primary endpoints were the pain detection threshold for the thermal pain tests and the pain tolerance threshold for the cold pressor, electrical stair and pressure pain tests. The trial had predefined decision rules based on 95% confidence that the PF-06273340 effect was better than that of placebo.

RESULTS

Twenty subjects entered the study, with 18 completing all five periods. The high dose of PF-06273340 met the decision rules on the ultraviolet (UV) B skin thermal pain endpoint [least squares (LS) mean vs. placebo: 1.13, 95% confidence interval: 0.64-1.61], but not on the other four primary endpoints. The low dose did not meet the decision criteria for any of the five primary endpoints. Pregabalin (cold pressor and electrical stair tests) and ibuprofen (UVB thermal pain) showed significant analgesic effects on expected endpoints.

CONCLUSIONS

The study demonstrated, for the first time, the translation of nonclinical effects into man in an inflammatory pain analgesic pharmacodynamic endpoint using a pan-Trk inhibitor.

Helping to drive the robustness of preclinical research - the assay capability tool

Numerous articles in Nature, Science, Pharmacology Research and Perspectives, and other biomedical research journals over the past decade have highlighted that research is plagued by findings that are not reliable and cannot be reproduced. Poor experiments can occur, in part, as a consequence of inadequate statistical thinking in the experimental design, conduct and analysis. As it is not feasible for statisticians to be involved in every preclinical experiment many of the same journals have published guidelines on good statistical practice. Here, we outline a tool that addresses the root causes of irreproducibility in preclinical research in the pharmaceutical industry. The Assay Capability Tool uses 13 questions to guide scientists and statisticians during the development of in vitro and in vivo assays. It promotes the absolutely essential experimental design and analysis strategies and documents the strengths, weaknesses, and precision of an assay. However, what differentiates it from other proposed solutions is the emphasis on how the resulting data will be used. An assay can be assigned a low, medium, or high rating to indicate the level of confidence that can be afforded when making important decisions using data from that assay. This provides transparency on the appropriate interpretation of the assay's results in the light of its current capability. We suggest that following a well-defined process during assay development and use such as that laid out within the Assay Capability Tool means that whatever the results, positive or negative, a researcher can have confidence to make decisions upon and publish their findings.

Inhibition of TRPM8 channels reduces pain in the cold pressor test in humans

The transient receptor potential (subfamily M, member 8; TRPM8) is a nonselective cation channel localized in primary sensory neurons, and is a candidate for cold thermosensing, mediation of cold pain, and bladder overactivity. Studies with TRPM8 knockout mice and selective TRPM8 channel blockers demonstrate a lack of cold sensitivity and reduced cold pain in various rodent models. Furthermore, TRPM8 blockers significantly lower body temperature. We have identified a moderately potent (IC50 = 103 nM), selective TRPM8 antagonist, PF-05105679 [(R)-3-[(1-(4-fluorophenyl)ethyl)(quinolin-3-ylcarbonyl)amino]methylbenzoic acid]. It demonstrated activity in vivo in the guinea pig bladder ice water and menthol challenge tests with an IC50 of 200 nM and reduced core body temperature in the rat (at concentrations >1219 nM). PF-05105679 was suitable for acute administration to humans and was evaluated for effects on core body temperature and experimentally induced cold pain, using the cold pressor test. Unbound plasma concentrations greater than the IC50 were achieved with 600- and 900-mg doses. The compound displayed a significant inhibition of pain in the cold pressor test, with efficacy equivalent to oxycodone (20 mg) at 1.5 hours postdose. No effect on core body temperature was observed. An unexpected adverse event (hot feeling) was reported, predominantly periorally, in 23 and 36% of volunteers (600- and 900-mg dose, respectively), which in two volunteers was nontolerable. In conclusion, this study supports a role for TRPM8 in acute cold pain signaling at doses that do not cause hypothermia.

Characterization of resistance to the nonnucleoside NS5B inhibitor filibuvir in hepatitis C virus-infected patients

Filibuvir (PF-00868554) is an investigational nonnucleoside inhibitor of the hepatitis C virus (HCV) nonstructural 5B (NS5B) RNA-dependent RNA polymerase currently in development for treating chronic HCV infection. The aim of this study was to characterize the selection of filibuvir-resistant variants in HCV-infected individuals receiving filibuvir as short (3- to 10-day) monotherapy. We identified amino acid M423 as the primary site of mutation arising upon filibuvir dosing. Through bulk cloning of clinical NS5B sequences into a transient-replicon system, and supported by site-directed mutagenesis of the Con1 replicon, we confirmed that mutations M423I/T/V mediate phenotypic resistance. Selection in patients of an NS5B mutation at M423 was associated with a reduced replicative capacity in vitro relative to the pretherapy sequence; consistent with this, reversion to wild-type M423 was observed in the majority of patients following therapy cessation. Mutations at NS5B residues R422 and M426 were detected in a small number of patients at baseline or the end of therapy and also mediate reductions in filibuvir susceptibility, suggesting these are rare but clinically relevant alternative resistance pathways. Amino acid variants at position M423 in HCV NS5B polymerase are the preferred pathway for selection of viral resistance to filibuvir in vivo.