Estimation of acceptable daily intake values based on modeling and in vivo mutagenicity of NDSRIs of fluoxetine, duloxetine and atomoxetine.

Nitrosamine drug substance related impurities or NDSRIs can be formed if an active pharmaceutical ingredient (API) has an intrinsic secondary amine that can undergo nitrosation. This is a concern as 1) nitrosamines are potentially highly potent carcinogens, 2) secondary amines in API are common, and 3) NDSRIs that might form from such secondary amines will be of unknown carcinogenic potency. Approaches for evaluating NDSRIs include read across, quantum mechanical modeling of reactivity, in vitro mutation data, and transgenic in vivo mutation data. These approaches were used here to assess NDSRIs that could potentially form from the drugs fluoxetine, duloxetine and atomoxetine. Based on a read across informed by modeling of physicochemical properties and mechanistic activation from quantum mechanical modeling, NDSRIs of fluoxetine, duloxetine, and atomoxetine were 10-100-fold less potent compared with highly potent nitrosamines such as NDMA or NDEA. While the NDSRIs were all confirmed to be mutagenic in vitro (Ames assay) and in vivo (TGR) studies, the latter data indicated that the potency of the mutation response was ≥4400 ng/day for all compounds-an order of magnitude higher than published regulatory limits for these NDSRIs. The approaches described herein can be used qualitatively to better categorize NDSRIs with respect to potency and inform whether they are in the ICH M7 (R2) designated Cohort of Concern.

Pharmaceutical Industry Perspective on the Non-Clinical Evaluation of Novel Excipients: Results From an Industry Survey Conducted by the IQ Novel Excipient Working Group.

Excipients are essential components within drug products that contribute significantly to their overall quality, effectiveness, and safety. There is a lack of global, harmonized guidance relating to the non-clinical testing of novel excipients which is perceived to create uncertainty and strategic risk, potentially hindering innovation and disincentivizing their use. To test these perceptions, the IQ Novel Excipient Working Group surveyed member companies regarding their main concerns and prior experience regarding the non-clinical evaluation of excipients. Of the 19 respondents, 13 provided, collectively, 33 non-clinical program examples supporting the development of novel excipients. Programs were distributed across a range of therapeutic areas and included a variety of drug modalities and administration routes. Package designs were variable, but where possible, employed the use of existing data, supplemented with new toxicology studies as appropriate. Of the programs which had submitted data to regional health authorities, only three received feedback requesting additional studies or that demonstrated differences in regional opinion. In addition, companies provided recommendations on how the current (or new) guidance related to non-clinical excipient evaluation (and other areas, such as Chemistry, Manufacturing, and Controls and databases) may be improved.

A cross-industry survey on photosafety evaluation of pharmaceuticals after implementation of ICH S10.

A cross-industry survey was conducted by EFPIA/IQ DruSafe in 2018 to provide information on photosafety evaluation of pharmaceuticals after implementation of ICH S10. This survey focused on the strategy utilized for photosafety risk assessment, the design of nonclinical (in vitro and in vivo) and clinical evaluations, the use of exposure margins in risk assessment, and regulatory interactions. The survey results indicated that a staged approach for phototoxicity assessment has been widely accepted by regulatory authorities globally. The OECD-based 3T3 NRU Phototoxicity Test is the most frequently used in vitro approach. Modifications to this assay suggested by ICH S10 are commonly applied. For in-vitro-positives, substantial margins from in vitro IC50 values under irradiation to Cmax (clinical) have enabled further development without the need for additional photosafety data. In vivo phototoxicity studies typically involve dosing rodents and exposing skin and eyes to simulated sunlight, and subsequently evaluating at least the skin for erythema and edema. However, no formal guidelines exist and protocols are less standardized across companies. A margin-of-safety approach (based on Cmax at NOAEL) has been successfully applied to support clinical development. Experience with dedicated clinical phototoxicity studies was limited, perhaps due to effective de-risking approaches employed based on ICH S10.

Drug Development 101: A Primer.

Drug development is a term used to define the entire process of bringing a new drug or device to market. It is an integrated, multidisciplinary endeavor that includes drug discovery, chemistry and pharmacology, nonclinical safety testing, manufacturing, clinical trials, and regulatory submissions. This report summarizes presentations of a workshop entitled "Drug Development 101," held at the 39th Annual Meeting of the American College of Toxicology in West Palm Beach, Florida. The workshop was designed to provide an introductory overview of drug development. Experienced scientists from industry and government provided overviews of each area, with a focus on safety assessment, and described some of the challenges that can arise. The role of chemistry and manufacturing was discussed in the context of early- and late-stage product development and approaches to assess, control, and limit impurities. The toxicologic assessment was emphasized in early-phase development, from the selection of a candidate drug through the determination of a first-in-human starting dose. Clinical trial development was discussed in the context of regulatory requirements and expectations. The final topic of issues and considerations in the review processes of different types of submissions to Food and Drug Administration included advice for best practices in authoring good Investigational New Drug and New Drug Application/Biologic License Application submissions and interacting effectively with regulatory reviewers.

Pharmaceutical industry perspective on combination toxicity studies: Results from an intra-industry survey conducted by IQ DruSafe Leadership Group.

Interest in developing combination products to overcome drug resistance and treat complex diseases is growing. However, ambiguity remains around the value of combination toxicity studies to support combination products. Therefore, the IQ* DruSafe Leadership Group surveyed member companies to evaluate industry experience with combination toxicity strategies, study designs and their impact on clinical development. Twenty companies responded, representing 79 combination programs. Combination toxicity studies were performed based on scientific rationale, regulatory agency request, or expected regulatory requirement. Combination toxicity study designs were varied (eg, group numbers, dose selection rationale and endpoints assessed) with no evidence that any one study design was superior. Studies were perceived as adding value when they fulfilled a regulatory requirement; avoided potential development delays; or when new or exaggerated toxicity or pharmacokinetic interactions were identified. Twelve percent of combination toxicity studies impacted clinical trial designs. The decision to conduct and the design of nonclinical combination toxicity studies should be based on sound scientific judgement with proactive engagement with regulatory agencies. Studies are not warranted when sufficient knowledge (eg, expected pharmacology, known mechanism of action, drug disposition, toxicity profile) is available to proceed safely in clinical development.

Challenges and strategies to facilitate formulation development of pediatric drug products: Safety qualification of excipients.

A public workshop entitled "Challenges and strategies to facilitate formulation development of pediatric drug products" focused on current status and gaps as well as recommendations for risk-based strategies to support the development of pediatric age-appropriate drug products. Representatives from industry, academia, and regulatory agencies discussed the issues within plenary, panel, and case-study breakout sessions. By enabling practical and meaningful discussion between scientists representing the diversity of involved disciplines (formulators, nonclinical scientists, clinicians, and regulators) and geographies (eg, US, EU), the Excipients Safety workshop session was successful in providing specific and key recommendations for defining paths forward. Leveraging orthogonal sources of data (eg. food industry, agro science), collaborative data sharing, and increased awareness of the existing sources such as the Safety and Toxicity of Excipients for Paediatrics (STEP) database will be important to address the gap in excipients knowledge needed for risk assessment. The importance of defining risk-based approaches to safety assessments for excipients vital to pediatric formulations was emphasized, as was the need for meaningful stakeholder (eg, patient, caregiver) engagement.

Nonclinical assessment of carcinogenic risk and tumor growth enhancement potential of prasugrel, a platelet-inhibiting therapeutic agent.

Prasugrel, a thienopyridine ADP receptor antagonist, is an orally administered prodrug requiring in vivo metabolism to form the active metabolite that irreversibly inhibits platelet activation and aggregation mediated by the P2Y12[sub 12] receptor. A comprehensive nonclinical safety assessment including genotoxicity and carcinogenicity studies supported the chronic use of prasugrel in patients with atherothrombotic disease. In addition, a special assessment of the potential for prasugrel to enhance tumor growth was undertaken to address regulatory concerns relating to increases in human cancers. Prasugrel demonstrated no evidence of genotoxicity and was not oncogenic in a 2-year rat carcinogenicity study. In the 2-year mouse study, an increase in hepatocellular adenomas was considered secondary to enzyme induction and not relevant to human safety. Further, the absence of any increase in common background tumors at any other organ site in either rodent study indicated a lack of tumor promoting activity (apart from the CYP450 induction-related increase in mouse liver tumors). Cell culture studies with 3 human tumor cell lines (lung, colon, prostate) demonstrated that exposure of serum-starved cells to prasugrel's active and major circulating human metabolites does not increase cell proliferation relative to starved cells stimulated to proliferate by addition of 10% FBS. Prasugrel also did not increase tumor growth relative to vehicle controls in nude mice implanted with 3 human tumor cell lines. Thus, traditional genotoxicity and 2-year bioassays as well as specially designed tumor growth enhancement studies in human tumor cell lines and mouse xenograft models clearly demonstrated prasugrel's lack of tumorigenic potential.

The Toxicology Education Summit: building the future of toxicology through education.

Toxicology and careers in toxicology, as well as many other scientific disciplines, are undergoing rapid and dramatic changes as new discoveries, technologies, and hazards advance at a blinding rate. There are new and ever increasing demands on toxicologists to keep pace with expanding global economies, highly fluid policy debates, and increasingly complex global threats to public health. These demands must be met with new paradigms for multidisciplinary, technologically complex, and collaborative approaches that require advanced and continuing education in toxicology and associated disciplines. This requires paradigm shifts in educational programs that support recruitment, development, and training of the modern toxicologist, as well as continued education and retraining of the midcareer professional to keep pace and sustain careers in industry, government, and academia. The Society of Toxicology convened the Toxicology Educational Summit to discuss the state of toxicology education and to strategically address educational needs and the sustained advancement of toxicology as a profession. The Summit focused on core issues of: building for the future of toxicology through educational programs; defining education and training needs; developing the "Total Toxicologist"; continued training and retraining toxicologists to sustain their careers; and, finally, supporting toxicology education and professional development. This report summarizes the outcomes of the Summit, presents examples of successful programs that advance toxicology education, and concludes with strategies that will insure the future of toxicology through advanced educational initiatives.

The design of chronic toxicology studies of monoclonal antibodies: implications for the reduction in use of non-human primates.

The changing environment of monoclonal antibody (mAb) development is impacting on the cost of drug development and the use of experimental animals, particularly non-human primates (NHPs). The drive to reduce these costs is huge and involves rethinking and improving nonclinical studies to make them more efficient and more predictive of man. While NHP use might be unavoidable in many cases because of the exquisite specificity and consequent species selectivity of mAbs, our increasing knowledge base can be used to improve drug development and maximise the output of experimental data. Data on GLP regulatory toxicology studies for 58mAbs were obtained from 10 companies across a wide range of therapeutic indications. These data have been used to investigate current practice and identify study designs that minimise NHP use. Our analysis shows that there is variation in the number of animals used for similar studies. This information has been used to develop practical guidance and make recommendations on the use of science-based rationale to design studies using fewer animals taking into account the current regulatory guidance. There are eight recommendations intended to highlight areas for consideration. They include guidance on the main group size, the inclusion of recovery groups and the number of dose groups used in short and long term chronic toxicology studies.

Considerations regarding nonhuman primate use in safety assessment of biopharmaceuticals.

Selection of a pharmacologically responsive species can represent a major challenge in designing nonclinical safety assessment programs for many biopharmaceuticals (eg, monoclonal antibodies (mAbs)). Frequently, the only relevant species for nonclinical testing of mAbs is the non-human primate (NHP). This situation, coupled with a rapidly increasing number of mAb drugs in development, has resulted in a significant increase in the number of NHPs used in nonclinical safety assessment. Apart from ethical considerations related to responsible animal use, there is a clear need for more efficient and innovative approaches to drug discovery and development; these factors drive the need to investigate alternative approaches and strategies for the safety assessment. This review summarizes important scientific and regulatory perspectives derived from presentations and audience discussions in an educational forum at the 2010 annual American College of Toxicology meeting regarding opportunities for employing alternative approaches to minimize NHP use in mAb drug development.

High dose selection in general toxicity studies for drug development: A pharmaceutical industry perspective.

The choice of an appropriate high dose for nonclinical toxicology studies continues to generate significant discussion and debate. Typically, use of the term "high dose" reflects a consideration of a Maximum Tolerated Dose (MTD) or a Maximum Feasible Dose (MFD), inexact terms applied to the design of nonclinical studies conducted to support human clinical trials for experimental new drugs. A pharmaceutical industry perspective on appropriate considerations for high doses in nonclinical studies is provided herein, however, the basic principles applied to the design of toxicology studies translate across the areas of Regulatory, Academic, and Industrial toxicology. Dose selection approaches for nonclinical studies of safety assessment for pharmaceuticals should consider the need to demonstrate the full range of the dose-response continuum (e.g., NOAEL through a toxic dose), however, should also take into account relevance to human therapeutic doses and incorporate clinical indication- and phase-specific considerations.

Toxicology testing in drug discovery and development.

The primary objective of toxicology studies in the drug discovery process is to evaluate the safety of potential drug candidates. This is accomplished using relevant animal models and validated procedures. The ultimate goal is to translate the animal responses into an understanding of the risk for human subjects. To this end the toxicologist must be aware of the international guidelines for safety evaluation as well as traditional and nontraditional toxicology models. As described in this unit, the typical toxicology profile consists of safety pharmacology, genetic toxicology, acute and subchronic toxicology, absorption, distribution, metabolism, and excretion (ADME) studies, reproductive and developmental toxicity, and an evaluation of carcinogenic potential.

Toxicology in the drug discovery and development process.

The primary objective of toxicology studies in the drug development process is to evaluate the safety of potential drug candidates. This is accomplished using relevant animal models and validated procedures. The ultimate goal is to translate the animal model responses into an understanding of the risk for human subjects. To this end, the toxicologist must be aware of the international guidelines for safety evaluation, as well as traditional and nontraditional toxicology models. As described in this unit, the typical toxicology profile consists of safety pharmacology, genetic toxicology, acute and subchronic toxicology, chronic toxicology, absorption, distribution, metabolism, and excretion (ADME) studies, reproductive and developmental toxicology, and an evaluation of carcinogenic potential.