Oligonucleotides (ONs) are an emerging class of drugs being developed for the treatment of a wide... more Oligonucleotides (ONs) are an emerging class of drugs being developed for the treatment of a wide variety of diseases including the treatment of respiratory diseases by the inhalation route. As a class, their toxicity on human lungs has not been fully characterized, and predictive toxicity biomarkers have not been identified. To that end, identification of sensitive methods and biomarkers that can detect toxicity in humans before any long term and/or irreversible side effects occur would be helpful. In light of the public's greater interests, the Inhalation Subcommittee of the Oligonucleotide Safety Working Group (OSWG) held expert panel discussions focusing on the potential toxicity of inhaled ONs and assessing the strengths and weaknesses of different monitoring techniques for use during the clinical evaluation of inhaled ON candidates. This white paper summarizes the key discussions and captures the panelists' perspectives and recommendations which, we propose, could be u...
Monoclonal antibodies (mAbs) are improving the quality of life for patients suffering from seriou... more Monoclonal antibodies (mAbs) are improving the quality of life for patients suffering from serious diseases due to their high specificity for their target and low potential for off-target toxicity. The toxicity of mAbs is primarily driven by their pharmacological activity, and therefore safety testing of these drugs prior to clinical testing is performed in species in which the mAb binds and engages the target to a similar extent to that anticipated in humans. For highly human-specific mAbs, this testing often requires the use of non-human primates (NHPs) as relevant species. It has been argued that the value of these NHP studies is limited because most of the adverse events can be predicted from the knowledge of the target, data from transgenic rodents or target-deficient humans, and other sources. However, many of the mAbs currently in development target novel pathways and may comprise novel scaffolds with multi-functional domains; hence, the pharmacological effects and potential ...
A series of acute and multiple dose toxicology studies were performed to support the clinical dos... more A series of acute and multiple dose toxicology studies were performed to support the clinical dose and to evaluate the systemic toxicity of an immunotoxin, H65-RTA. H65-RTA consists of a murine anti-CD5 monoclonal antibody and ricin A chain (RTA). The LD50 of H65-RTA was estimated to be between 60 and 62.5 mg/kg in the rat. H65-RTA was administered to the rat and the monkey as a bolus injection at doses of 0.1, 0.5, and 2 mg/kg and over 1-hr infusion at 0.2 and 2 mg/kg, respectively. Two to three weeks of postdosing recovery was included in the study design. Following repeated doses of H65-RTA, the following findings were demonstrated: peripheral edema, decreased body weight, decreased body temperature (monkey only) in addition to a general inflammatory reaction evidenced by changes in hematology, clinical chemistry, and urinalysis parameters. Histopathologically, chronic inflammation in the nonarticular soft tissue was found in the rat at doses of 0.1 mg/kg and higher and monkeys developed much more severe toxicity when compared to the rat at the same doses. Inflammation, hemorrhage, and/or edema were evident in a variety of tissues. Myeloid hyperplasia was also evident. Additional findings resulting from the drug-related stress involved adrenals, spleen, thymus, and lymph nodes. All toxicity was reversible. The antibody response was evident in rats at doses of 0.5 mg/kg and higher and in all monkeys at doses of 0.2 and 2 mg/kg. In conclusion, since H65 antibody does not cross-react with the T cells from either the rat or the cynomolgus monkey, the toxicity observed in the studies described above was not related to T lymphocytes and was probably due to a series of acute to subacute inflammatory reactions caused largely by the RTA moiety of H65-RTA.
This article provides an overview of the discussions held by the Immunomodulatory Subcommittee of... more This article provides an overview of the discussions held by the Immunomodulatory Subcommittee of the Oligonucleotide Safety Working Group on complement activation induced by oligonucleotides, most notably the phosphorothioate-containing oligonucleotides. Alternative complement pathway activation in monkeys is a common effect of single-stranded phosphorothioate backbone oligonucleotides in toxicology studies. This article discusses the mechanism for activation, general investigational strategy, and the impact of various chemical modifications. The goal is to provide the best practice approach to characterizing this effect, understanding the implication of the species specificity, and the interpretation of clinical relevance.
ABSTRACT Since the first description of human pluripotent stem cells (PSCs) in 1998, there has be... more ABSTRACT Since the first description of human pluripotent stem cells (PSCs) in 1998, there has been tremendous excitement surrounding their potential to transform our understanding of cell and molecular biology, and to develop treatments for a wide array of diseases with unmet medical needs. The scientific significance of human PSCs was recently recognized with the Nobel Prize in Physiology or Medicine in 2012 [1]. This chapter is intended to provide an overview of key considerations for the preclinical development of PSC-based therapeutics. PSCs are defined as cells that are capable of differentiating into derivatives of all three primary germ layers—endoderm, mesoderm, and ectoderm—and maintain pluripotency through multiple passages or cell divisions [2]. They can be differentiated into virtually any cell type in the body, although they only give rise to a limited range of extraembryonic tissues and do not form placenta. Since PSCs can be differentiated into a multitude of cell types they have the potential to be applied to a virtually unlimited number of disease and injured states. There are two main types of PSCs, human embryonic stem cells (hESCs) and induced pluripotent stem cells (iPSCs). PSCs are expected to restore function or ameliorate disease by two main mechanisms: (1) secretion of factors that support the endogenous environment and /or (2) replacement of diseased cells/tissues. Theoretically, PSCs can be used at various points in maturation, from an early precursor state, to a progenitor state, or to a terminally differentiated state. Adult stem cells have been used therapeutically for decades, starting with hematopoietic transplants in the 1960s [3–6]. Numerous types of adult stem cells, such as hematopoietic and more recently mesenchymal stem cells (MSCs), have been identified and are used clinically due to their regenerative properties, paracrine regulatory effects and immune-modulatory activity [7]. However, adult stem cells are multipotent and can only give rise to tissues of the embryonic germ layer from which they originate (ectoderm, mesoderm, or endoderm). They also exhibit limited proliferative capacity, diminished differentiation potential and progressive loss of function upon in vitro expansion and with increasing donor age, thus limiting their use in clinical applications [8–12]. Conversely, PSC exhibit unlimited proliferation and differentiation potential. The characteristics that make PSCs such a promising and powerful resource also present the biggest challenges for preclinical development and clinical translation. Researchers must develop new methods to appropriately direct or control cell fate to assure pluripotency is extinguished, eliminating the risk for potential tumorigenicty. See Table 15.1 for a comparison of the product attributes of different stem cell-based therapies.
Receptor tyrosine kinase-like orphan receptor 1 (ROR1) is an oncoembryonic antigen. Because of it... more Receptor tyrosine kinase-like orphan receptor 1 (ROR1) is an oncoembryonic antigen. Because of its expression on the cell surface of leukemia cells from patients with chronic lymphocytic leukemia (CLL), but not on normal B-cells or other postpartum tissues, ROR1 is an attractive candidate for targeted therapies. UC-961 is a first-in-class humanized monoclonal antibody that binds the extracellular domain of ROR1. In this article we outline some of the preclinical studies leading to an investigational new drug designation, enabling clinical studies in patients with CLL.
PEGylation (the covalent binding of one or more polyethylene glycol molecules to another molecule... more PEGylation (the covalent binding of one or more polyethylene glycol molecules to another molecule) is a technology frequently used to improve the half-life and other pharmaceutical or pharmacological properties of proteins, peptides, and aptamers. To date, 11 PEGylated biopharmaceuticals have been approved and there is indication that many more are in nonclinical or clinical development. Adverse effects seen with those in toxicology studies are mostly related to the active part of the drug molecule and not to polyethylene glycol (PEG). In 5 of the 11 approved and 10 of the 17 PEGylated biopharmaceuticals in a 2013 industry survey presented here, cellular vacuolation is histologically observed in toxicology studies in certain organs and tissues. No other effects attributed to PEG alone have been reported. Importantly, vacuolation, which occurs mainly in phagocytes, has not been linked with changes in organ function in these toxicology studies. This article was authored through collab...
Oligonucleotides (ONs) are an emerging class of drugs being developed for the treatment of a wide... more Oligonucleotides (ONs) are an emerging class of drugs being developed for the treatment of a wide variety of diseases including the treatment of respiratory diseases by the inhalation route. As a class, their toxicity on human lungs has not been fully characterized, and predictive toxicity biomarkers have not been identified. To that end, identification of sensitive methods and biomarkers that can detect toxicity in humans before any long term and/or irreversible side effects occur would be helpful. In light of the public's greater interests, the Inhalation Subcommittee of the Oligonucleotide Safety Working Group (OSWG) held expert panel discussions focusing on the potential toxicity of inhaled ONs and assessing the strengths and weaknesses of different monitoring techniques for use during the clinical evaluation of inhaled ON candidates. This white paper summarizes the key discussions and captures the panelists' perspectives and recommendations which, we propose, could be u...
Monoclonal antibodies (mAbs) are improving the quality of life for patients suffering from seriou... more Monoclonal antibodies (mAbs) are improving the quality of life for patients suffering from serious diseases due to their high specificity for their target and low potential for off-target toxicity. The toxicity of mAbs is primarily driven by their pharmacological activity, and therefore safety testing of these drugs prior to clinical testing is performed in species in which the mAb binds and engages the target to a similar extent to that anticipated in humans. For highly human-specific mAbs, this testing often requires the use of non-human primates (NHPs) as relevant species. It has been argued that the value of these NHP studies is limited because most of the adverse events can be predicted from the knowledge of the target, data from transgenic rodents or target-deficient humans, and other sources. However, many of the mAbs currently in development target novel pathways and may comprise novel scaffolds with multi-functional domains; hence, the pharmacological effects and potential ...
A series of acute and multiple dose toxicology studies were performed to support the clinical dos... more A series of acute and multiple dose toxicology studies were performed to support the clinical dose and to evaluate the systemic toxicity of an immunotoxin, H65-RTA. H65-RTA consists of a murine anti-CD5 monoclonal antibody and ricin A chain (RTA). The LD50 of H65-RTA was estimated to be between 60 and 62.5 mg/kg in the rat. H65-RTA was administered to the rat and the monkey as a bolus injection at doses of 0.1, 0.5, and 2 mg/kg and over 1-hr infusion at 0.2 and 2 mg/kg, respectively. Two to three weeks of postdosing recovery was included in the study design. Following repeated doses of H65-RTA, the following findings were demonstrated: peripheral edema, decreased body weight, decreased body temperature (monkey only) in addition to a general inflammatory reaction evidenced by changes in hematology, clinical chemistry, and urinalysis parameters. Histopathologically, chronic inflammation in the nonarticular soft tissue was found in the rat at doses of 0.1 mg/kg and higher and monkeys developed much more severe toxicity when compared to the rat at the same doses. Inflammation, hemorrhage, and/or edema were evident in a variety of tissues. Myeloid hyperplasia was also evident. Additional findings resulting from the drug-related stress involved adrenals, spleen, thymus, and lymph nodes. All toxicity was reversible. The antibody response was evident in rats at doses of 0.5 mg/kg and higher and in all monkeys at doses of 0.2 and 2 mg/kg. In conclusion, since H65 antibody does not cross-react with the T cells from either the rat or the cynomolgus monkey, the toxicity observed in the studies described above was not related to T lymphocytes and was probably due to a series of acute to subacute inflammatory reactions caused largely by the RTA moiety of H65-RTA.
This article provides an overview of the discussions held by the Immunomodulatory Subcommittee of... more This article provides an overview of the discussions held by the Immunomodulatory Subcommittee of the Oligonucleotide Safety Working Group on complement activation induced by oligonucleotides, most notably the phosphorothioate-containing oligonucleotides. Alternative complement pathway activation in monkeys is a common effect of single-stranded phosphorothioate backbone oligonucleotides in toxicology studies. This article discusses the mechanism for activation, general investigational strategy, and the impact of various chemical modifications. The goal is to provide the best practice approach to characterizing this effect, understanding the implication of the species specificity, and the interpretation of clinical relevance.
ABSTRACT Since the first description of human pluripotent stem cells (PSCs) in 1998, there has be... more ABSTRACT Since the first description of human pluripotent stem cells (PSCs) in 1998, there has been tremendous excitement surrounding their potential to transform our understanding of cell and molecular biology, and to develop treatments for a wide array of diseases with unmet medical needs. The scientific significance of human PSCs was recently recognized with the Nobel Prize in Physiology or Medicine in 2012 [1]. This chapter is intended to provide an overview of key considerations for the preclinical development of PSC-based therapeutics. PSCs are defined as cells that are capable of differentiating into derivatives of all three primary germ layers—endoderm, mesoderm, and ectoderm—and maintain pluripotency through multiple passages or cell divisions [2]. They can be differentiated into virtually any cell type in the body, although they only give rise to a limited range of extraembryonic tissues and do not form placenta. Since PSCs can be differentiated into a multitude of cell types they have the potential to be applied to a virtually unlimited number of disease and injured states. There are two main types of PSCs, human embryonic stem cells (hESCs) and induced pluripotent stem cells (iPSCs). PSCs are expected to restore function or ameliorate disease by two main mechanisms: (1) secretion of factors that support the endogenous environment and /or (2) replacement of diseased cells/tissues. Theoretically, PSCs can be used at various points in maturation, from an early precursor state, to a progenitor state, or to a terminally differentiated state. Adult stem cells have been used therapeutically for decades, starting with hematopoietic transplants in the 1960s [3–6]. Numerous types of adult stem cells, such as hematopoietic and more recently mesenchymal stem cells (MSCs), have been identified and are used clinically due to their regenerative properties, paracrine regulatory effects and immune-modulatory activity [7]. However, adult stem cells are multipotent and can only give rise to tissues of the embryonic germ layer from which they originate (ectoderm, mesoderm, or endoderm). They also exhibit limited proliferative capacity, diminished differentiation potential and progressive loss of function upon in vitro expansion and with increasing donor age, thus limiting their use in clinical applications [8–12]. Conversely, PSC exhibit unlimited proliferation and differentiation potential. The characteristics that make PSCs such a promising and powerful resource also present the biggest challenges for preclinical development and clinical translation. Researchers must develop new methods to appropriately direct or control cell fate to assure pluripotency is extinguished, eliminating the risk for potential tumorigenicty. See Table 15.1 for a comparison of the product attributes of different stem cell-based therapies.
Receptor tyrosine kinase-like orphan receptor 1 (ROR1) is an oncoembryonic antigen. Because of it... more Receptor tyrosine kinase-like orphan receptor 1 (ROR1) is an oncoembryonic antigen. Because of its expression on the cell surface of leukemia cells from patients with chronic lymphocytic leukemia (CLL), but not on normal B-cells or other postpartum tissues, ROR1 is an attractive candidate for targeted therapies. UC-961 is a first-in-class humanized monoclonal antibody that binds the extracellular domain of ROR1. In this article we outline some of the preclinical studies leading to an investigational new drug designation, enabling clinical studies in patients with CLL.
PEGylation (the covalent binding of one or more polyethylene glycol molecules to another molecule... more PEGylation (the covalent binding of one or more polyethylene glycol molecules to another molecule) is a technology frequently used to improve the half-life and other pharmaceutical or pharmacological properties of proteins, peptides, and aptamers. To date, 11 PEGylated biopharmaceuticals have been approved and there is indication that many more are in nonclinical or clinical development. Adverse effects seen with those in toxicology studies are mostly related to the active part of the drug molecule and not to polyethylene glycol (PEG). In 5 of the 11 approved and 10 of the 17 PEGylated biopharmaceuticals in a 2013 industry survey presented here, cellular vacuolation is histologically observed in toxicology studies in certain organs and tissues. No other effects attributed to PEG alone have been reported. Importantly, vacuolation, which occurs mainly in phagocytes, has not been linked with changes in organ function in these toxicology studies. This article was authored through collab...
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