Preclinical development of an automated injection device for intradermal delivery of a cell-based therapy.

Current methods for intradermal delivery of therapeutic products in clinical use include manual injection via the Mantoux technique and the use of injection devices, primarily developed for the delivery of vaccines and small molecules. A novel automated injection device is presented specifically designed for accurate delivery of multiple doses of product through a number of adjustable injection parameters, including injection depth, dose volume and needle insertion speed. The device was originally conceived for the delivery of a cell-based therapy to patients with skin wounds caused by epidermolysis bullosa. A series of preclinical studies was conducted (i) to evaluate the performance of the pre-production model (PreCTCDV01) and optimise the final design, (ii) to confirm that a cell therapy product can be effectively delivered through the injection system and (iii) to test whether the device can be safely and effectively operated by potential end-users. Results from these studies confirmed that the device is able to consistently deliver repeated doses of a liquid to the intradermal layer in an ex vivo skin model. In addition, the device can support delivery of a cell therapy product through a customised microbore tubing without compromising cell viability. Finally, the device was shown to be safe and easy to use as evidenced by usability testing. The clinical device has since been granted European market access and plans for clinical use are currently underway. The device is expected to find use in the emerging area of cell therapies and a broad spectrum of traditional parenteral drug delivery applications.

Cell-based therapy technology classifications and translational challenges.

Cell therapies offer the promise of treating and altering the course of diseases which cannot be addressed adequately by existing pharmaceuticals. Cell therapies are a diverse group across cell types and therapeutic indications and have been an active area of research for many years but are now strongly emerging through translation and towards successful commercial development and patient access. In this article, we present a description of a classification of cell therapies on the basis of their underlying technologies rather than the more commonly used classification by cell type because the regulatory path and manufacturing solutions are often similar within a technology area due to the nature of the methods used. We analyse the progress of new cell therapies towards clinical translation, examine how they are addressing the clinical, regulatory, manufacturing and reimbursement requirements, describe some of the remaining challenges and provide perspectives on how the field may progress for the future.

Genetically modified T cells in cancer therapy: opportunities and challenges.

Tumours use many strategies to evade the host immune response, including downregulation or weak immunogenicity of target antigens and creation of an immune-suppressive tumour environment. T cells play a key role in cell-mediated immunity and, recently, strategies to genetically modify T cells either through altering the specificity of the T cell receptor (TCR) or through introducing antibody-like recognition in chimeric antigen receptors (CARs) have made substantial advances. The potential of these approaches has been demonstrated in particular by the successful use of genetically modified T cells to treat B cell haematological malignancies in clinical trials. This clinical success is reflected in the growing number of strategic partnerships in this area that have attracted a high level of investment and involve large pharmaceutical organisations. Although our understanding of the factors that influence the safety and efficacy of these therapies has increased, challenges for bringing genetically modified T-cell immunotherapy to many patients with different tumour types remain. These challenges range from the selection of antigen targets and dealing with regulatory and safety issues to successfully navigating the routes to commercial development. However, the encouraging clinical data, the progress in the scientific understanding of tumour immunology and the improvements in the manufacture of cell products are all advancing the clinical translation of these important cellular immunotherapies.

Landscape of current and emerging cell therapy clinical trials in the UK: current status, comparison to global trends and future perspectives.

Cell Therapy Clinical Trial and Preclinical Research databases have been established by the Cell Therapy Catapult to document current and future cell therapy clinical trials in the UK. We identified 41 ongoing trials in April 2014, an increase of seven trials from April 2013. In addition, we identified 45 late-stage preclinical research projects. The majority of the clinical trials are early phase, primarily led by academic groups. The leading therapeutic areas are cancer, cardiology and neurology. The trends in the UK are also seen globally. As the field matures, more later phase and commercial studies will emerge and the challenges will likely evolve into how to manufacture sufficient cell quantities, manage complex logistics for multi-center trials and control cost.

Proceedings: international regulatory considerations on development pathways for cell therapies.

Regenerative medicine is a rapidly evolving field that faces novel scientific and regulatory challenges. In September 2013, the International Workshop on Regulatory Pathways for Cell Therapies was convened to discuss the nature of these challenges and potential solutions and to highlight opportunities for potential convergence between different regulatory bodies that might assist the field's development. The workshop discussions generated potentially actionable steps in five main areas that could mitigate cell therapy development pathway risk and accelerate moving promising therapies to patients. These included the need for convergence of regulatory guidelines on donor eligibility and suitability of lines for use in clinical trials and subsequent commercialization for cell therapies to move forward on a global basis; the need to challenge and encourage investigators in the regenerative medicine field to share information and provide examples of comparability studies related to master cell banks; the need for convergence of guidelines across regulatory jurisdictions on requirements for tumorigenicity studies, based on particular cell types and on biodistribution studies; the need to increase transparency in sharing clinical trial information more broadly and disseminating results more rapidly; and the need to establish a forum for sharing the experiences of various approaches being developed to expedite regulatory approvals and access for patients to innovative cell and regenerative therapies in the different regulatory jurisdictions and to assess their potential strengths and weaknesses.

The translational efficacy of a nonsteroidal progesterone receptor antagonist, 4-[3-cyclopropyl-1-(mesylmethyl)-5-methyl-1H-pyrazol-4-yl]oxy,-2,6-dimethylbenzonitrile (PF-02413873), on endometrial growth in macaque and human.

There is considerable ongoing investment in the research and development of selective progesterone receptor (PR) modulators for the treatment of gynecological conditions such as endometriosis. Here, we provide the first report on the clinical evaluation of a nonsteroidal progesterone receptor antagonist 4-[3-cyclopropyl-1-(mesylmethyl)-5-methyl-1H-pyrazol-4-yl]oxy,-2,6-dimethylbenzonitrile (PF-02413873) in healthy female subjects. In in vitro assays, PF-02413873 behaved as a selective and fully competitive PR antagonist, blocking progesterone binding and PR nuclear translocation. The pharmacological mode of action of PF-02413873 seems to differ from the founding member of the class of steroidal PR antagonists, 11ß-4-dimethylaminophenyl-17ß-hydroxy-17α-propinyl-4,9-estradiene-3-one (RU-486; mifepristone). Exposure-effect data from studies in the cynomolgus macaque, however, demonstrated that PF-02413873 reduced endometrial functionalis thickness to a comparable degree to RU-486 and this effect was accompanied by a decrease in proliferation rate (as measured by bromodeoxyuridine incorporation) for both RU-486 and high-dose PF-02413873. These data were used to underwrite a clinical assessment of PF-02413873 in a randomized, double-blinded, third-party open, placebo-controlled, dose-escalation study in healthy female volunteers with dosing for 14 days. PF-02413873 blocked the follicular phase increase in endometrial thickness, the midcycle lutenizing hormone surge, and elevation in estradiol in a dose-dependent fashion compared with placebo. This is the first report of translational efficacy data with a nonsteroidal PR antagonist in cynomolgus macaque and human subjects.

Preclinical and clinical pharmacokinetics of PF-02413873, a nonsteroidal progesterone receptor antagonist.

The recently discovered selective nonsteroidal progesterone receptor (PR) antagonist 4-[3-cyclopropyl-1-(methylsulfonylmethyl)-5-methyl-1H-pyrazol-4-yl]oxy-2,6-dimethylbenzonitrile (PF-02413873) was characterized in metabolism studies in vitro, in preclinical pharmacokinetics in rat and dog, and in an initial pharmacokinetic study in human volunteers. Clearance (CL) of PF-02413873 was found to be high in rat (84 ml · min(-1) · kg(-1)) and low in dog (3.8 ml · min(-1) · kg(-1)), consistent with metabolic stability determined in liver microsomes and hepatocytes in these species. In human, CL was low in relation to hepatic blood flow, consistent with metabolic stability in human in vitro systems, where identified metabolites suggested predominant cytochrome P450 (P450)-catalyzed oxidative metabolism. Prediction of CL using intrinsic CL determined in human liver microsomes (HLM), recombinant human P450 enzymes, and single species scaling (SSS) from pharmacokinetic studies showed that dog SSS and HLM scaling provided the closest estimates of CL of PF-02413873 in human. These CL estimates were combined with a physiologically based pharmacokinetic (PBPK) model to predict pharmacokinetic profiles after oral suspension administration of PF-02413873 in fasted and fed states in human. Predicted plasma concentration versus time profiles were found to be similar to those observed in human over the PF-02413873 dose range 50 to 500 mg and captured the enhanced exposure in fed subjects. This case study of a novel nonsteroidal PR antagonist underlines the utility of PBPK modeling techniques in guiding prediction confidence and design of early clinical trials of novel chemical agents.

Discovery of a selective small-molecule melanocortin-4 receptor agonist with efficacy in a pilot study of sexual dysfunction in humans.

The relevance of the melanocortin system to sexual activity is well established, and nonselective peptide agonists of the melanocortin receptors have shown evidence of efficacy in human sexual dysfunction. The role of the MC4 receptor subtype has received particular scrutiny, but the sufficiency of its selective activation in potentiating sexual response has remained uncertain owing to conflicting data from studies in preclinical species. We describe here the discovery of a novel series of small-molecule MC4 receptor agonists derived from library hit 2. The addition of methyl substituents at C3 and C5 of the 4-phenylpiperidin-4-ol ring was found to be markedly potency-enhancing, enabling the combination of low nanomolar potencies with full rule-of-five compliance. In general, the series shows only micromolar activity at other melanocortin receptors. Our preferred compound 40a provided significant systemic exposure in humans on both sublingual and oral administration and was safe and well tolerated up to the maximum tested dose. In a pilot clinical study of male erectile dysfunction, the highest dose of 40a tested (200 mg) provided a similar level of efficacy to sildenafil.

A novel series of potent and selective PDE5 inhibitors with potential for high and dose-independent oral bioavailability.

Sildenafil (5-[2-ethoxy-5-(4-methyl-1-piperazinylsulfonyl)phenyl]-1-methyl-3-n-propyl-1,6-dihydro-7H-pyrazolo[4,3-d]pyrimidin-7-one), a potent and selective phosphodiesterase type 5 (PDE5) inhibitor, provided the first oral treatment for male erectile dysfunction. The objective of the work reported in this paper was to combine high levels of PDE5 potency and selectivity with high and dose-independent oral bioavailability, to minimize the impact on the C(max) of any interactions with coadministered drugs in the clinic. This goal was achieved through identification of a lower clearance series with a high absorption profile, by replacing the 5'-piperazine sulfonamide in the sildenafil template with a 5'-methyl ketone. This novel series provided compounds with low metabolism in human hepatocytes, excellent caco-2 flux, and the potential for good aqueous solubility. The in vivo oral and iv pharmacokinetic profiles of example compounds confirmed the high oral bioavailability predicted from these in vitro screens. 5-(5-Acetyl-2-butoxy-3-pyridinyl)-3-ethyl-2-(1-ethyl-3-azetidinyl)-2,6-dihydro-7H-pyrazolo[4,3-d]pyrimidin-7-one (2) was selected for progression into the clinic.