Comprehensive Nonclinical Safety Assessment of Nirmatrelvir Supporting Timely Development of the SARS-COV-2 Antiviral Therapeutic, Paxlovid™.

COVID-19 is a potentially fatal infection caused by the SARS-CoV-2 virus. The SARS-CoV-2 3CL protease (Mpro) is a viral enzyme essential for replication and is the target for nirmatrelvir. Paxlovid (nirmatrelvir co-administered with the pharmacokinetic enhancer ritonavir) showed efficacy in COVID-19 patients at high risk of progressing to hospitalization and/or death. Nonclinical safety studies with nirmatrelvir are essential in informing benefit-risk of Paxlovid and were conducted to support clinical development. In vivo safety pharmacology assessments included a nervous system/pulmonary study in rats and a cardiovascular study in telemetered monkeys. Potential toxicities were assessed in repeat dose studies of up to 1 month in rats and monkeys. Nirmatrelvir administration (1,000 mg/kg, p.o.) to male rats produced transient increases in locomotor activity and respiratory rate but did not affect behavioral endpoints in the functional observational battery. Cardiovascular effects in monkeys were limited to transient increases in blood pressure and decreases in heart rate, observed only at the highest dose tested (75 mg/kg per dose b.i.d; p.o.). Nirmatrelvir did not prolong QTc-interval or induce arrhythmias. There were no adverse findings in repeat dose toxicity studies up to 1 month in rats (up to 1,000 mg/kg daily, p.o.) or monkeys (up to 600 mg/kg daily, p.o.). Nonadverse, reversible clinical pathology findings without clinical or microscopic correlates included prolonged coagulation times at ≥60 mg/kg in rats and increases in transaminases at 600 mg/kg in monkeys. The safety pharmacology and nonclinical toxicity profiles of nirmatrelvir support clinical development and use of Paxlovid for treatment of COVID-19.

Current nonclinical testing paradigm enables safe entry to First-In-Human clinical trials: The IQ consortium nonclinical to clinical translational database.

The contribution of animal testing in drug development has been widely debated and challenged. An industry-wide nonclinical to clinical translational database was created to determine how safety assessments in animal models translate to First-In-Human clinical risk. The blinded database was composed of 182 molecules and contained animal toxicology data coupled with clinical observations from phase I human studies. Animal and clinical data were categorized by organ system and correlations determined. The 2×2 contingency table (true positive, false positive, true negative, false negative) was used for statistical analysis. Sensitivity was 48% with a 43% positive predictive value (PPV). The nonhuman primate had the strongest performance in predicting adverse effects, especially for gastrointestinal and nervous system categories. When the same target organ was identified in both the rodent and nonrodent, the PPV increased. Specificity was 84% with an 86% negative predictive value (NPV). The beagle dog had the strongest performance in predicting an absence of clinical adverse effects. If no target organ toxicity was observed in either test species, the NPV increased. While nonclinical studies can demonstrate great value in the PPV for certain species and organ categories, the NPV was the stronger predictive performance measure across test species and target organs indicating that an absence of toxicity in animal studies strongly predicts a similar outcome in the clinic. These results support the current regulatory paradigm of animal testing in supporting safe entry to clinical trials and provide context for emerging alternate models.

Impact of genetic modulation of SULT1A enzymes on DNA adduct formation by aristolochic acids and 3-nitrobenzanthrone.

Exposure to aristolochic acid (AA) causes aristolochic acid nephropathy (AAN) and Balkan endemic nephropathy (BEN). Conflicting results have been found for the role of human sulfotransferase 1A1 (SULT1A1) contributing to the metabolic activation of aristolochic acid I (AAI) in vitro. We evaluated the role of human SULT1A1 in AA bioactivation in vivo after treatment of transgenic mice carrying a functional human SULT1A1-SULT1A2 gene cluster (i.e. hSULT1A1/2 mice) and Sult1a1(-/-) mice with AAI and aristolochic acid II (AAII). Both compounds formed characteristic DNA adducts in the intact mouse and in cytosolic incubations in vitro. However, we did not find differences in AAI-/AAII-DNA adduct levels between hSULT1A1/2 and wild-type (WT) mice in all tissues analysed including kidney and liver despite strong enhancement of sulfotransferase activity in both kidney and liver of hSULT1A1/2 mice relative to WT, kidney and liver being major organs involved in AA metabolism. In contrast, DNA adduct formation was strongly increased in hSULT1A1/2 mice compared to WT after treatment with 3-nitrobenzanthrone (3-NBA), another carcinogenic aromatic nitro compound where human SULT1A1/2 is known to contribute to genotoxicity. We found no differences in AAI-/AAII-DNA adduct formation in Sult1a1(-/-) and WT mice in vivo. Using renal and hepatic cytosolic fractions of hSULT1A1/2, Sult1a1(-/-) and WT mice, we investigated AAI-DNA adduct formation in vitro but failed to find a contribution of human SULT1A1/2 or murine Sult1a1 to AAI bioactivation. Our results indicate that sulfo-conjugation catalysed by human SULT1A1 does not play a role in the activation pathways of AAI and AAII in vivo, but is important in 3-NBA bioactivation.

Evaluation of Therapeutics for Severely Debilitating or Life-Threatening Diseases or Conditions: Defining Scope to Enable Global Guidance Development.

A significant regulatory gap exists to facilitate global development of therapeutics for nononcology severely debilitating or life-threatening diseases or conditions (SDLTs). In a 2017 publication, a streamlined approach to the development of treatments for SDLTs was proposed to facilitate earlier and continued patient access to new, potentially beneficial therapeutics.1 However, a major hindrance to broad adoption of this streamlined approach has been the lack of universally accepted, objective criteria to define SDLTs. This article serves to extend the 2017 publication by further addressing the challenge of defining SDLT scope in order to stimulate broader discussion and facilitate development of regional and ultimately international guidelines on the development of therapeutics for SDLTs. Using case examples, we describe key attributes of SDLTs and provide criteria for consideration of an SDLT scope definition.

The Progressive Multifocal Leukoencephalopathy Consortium as a Model for Advancing Research and Dialogue on Rare Severe Adverse Drug Reactions.

Progressive multifocal leukoencephalopathy (PML) is a rare but serious disease. Caused by the JC virus (JCV), it occurs in individuals with weakened immune systems and is a potential adverse reaction for certain immunomodulatory drugs. The PML Consortium was created to find better methods to predict, prevent, and treat PML. The Consortium brought together the pharmaceutical industry with academic, regulatory, and patient communities to advance research and dialogue on PML through a not-for-profit, collaborative approach involving a grant program, scientific workshops and conferences, and disease awareness efforts. Over nearly a decade, the Consortium contributed to the PML and JCV fields by advancing research, scientific exchange, and awareness of PML. In addition to advancing knowledge and helping to build cross-sector consensus on research priorities, the Consortium's grant program filled a funding gap and brought new investigators into PML and JCV research. Additionally, the Consortium's workshops and conferences created platforms for exchange that drove dialogue on knowledge gaps and future research directions. The Consortium also contributed to the scientific knowledge base with two literature reviews, one on PML treatment studies and a second on T cell deficiencies as a risk factor for PML and the brain as a site for conversion of harmless JCV into a pathogenic virus. Finally, the Consortium addressed a significant information gap with its disease awareness website for healthcare professionals, patients, and caregivers. Beyond its impact on the PML and JCV fields, the PML Consortium is important because it provides a precedent for how the pharmaceutical industry, academic researchers, patient organizations, and government can work together to address rare diseases, in particular rare adverse events. This kind of collaboration could be replicated to speed progress in addressing other rare diseases and adverse events, with significant potential benefits for the scientific, medical, and patient communities. FUNDING: PML Consortium (PML Consortium, Washington, DC).

The Role of the Face Itself in the Face Effect: Sensitivity, Expressiveness, and Anticipated Feedback in Individual Compliance.

Face-to-face interactions are central to many individual choices and decision-making issues, such as customer services, sales, promotions, and negotiations. While the face effect, that is, face-to-face interactions are more effective in inducing compliance than other forms of interactions, has been noted in the literature, its mechanism has rarely been explored. This research helps to fill the theoretical void and provides new insights into the face effect with two lab experiments and one field experiment. Study 1, a field experiment conducted in a beauty salon, and Study 2, a lab experiment, show that the face effect is largely attributable to anticipated facial feedback and that the face effect is stronger when individuals are sensitive to face and when the requester's face is expressive. Study 3, using video-simulated face-to-face interactions, demonstrates that anticipated facial feedback, not necessarily actual feedback, is enough to drive the face effect. In so doing, this research furthers our understanding of factors that affect individual compliance in face-to-face interactions in both the "sending" and "receiving" stages. We discuss the theoretical and empirical implications, limitations, and future avenues of research.

Ingestible roasted barley for contrast-enhanced photoacoustic imaging in animal and human subjects.

Photoacoustic computed tomography (PACT) is an emerging imaging modality. While many contrast agents have been developed for PACT, these typically cannot immediately be used in humans due to the lengthy regulatory process. We screened two hundred types of ingestible foodstuff samples for photoacoustic contrast with 1064 nm pulse laser excitation, and identified roasted barley as a promising candidate. Twenty brands of roasted barley were further screened to identify the one with the strongest contrast, presumably based on complex chemical modifications incurred during the roasting process. Individual roasted barley particles could be detected through 3.5 cm of chicken-breast tissue and through the whole hand of healthy human volunteers. With PACT, but not ultrasound imaging, a single grain of roasted barley was detected in a field of hundreds of non-roasted particles. Upon oral administration, roasted barley enabled imaging of the gut and peristalsis in mice. Prepared roasted barley tea could be detected through 2.5 cm chicken breast tissue. When barley tea was administered to humans, photoacoustic imaging visualized swallowing dynamics in healthy volunteers. Thus, roasted barley represents an edible foodstuff that should be considered for photoacoustic contrast imaging of swallowing and gut processes, with immediate potential for clinical translation.

Nanomedicines: From Bench to Bedside and Beyond.

Advancing nanomedicines from concept to clinic requires integration of new science with traditional pharmaceutical development. The medical and commercial success of nanomedicines is greatly facilitated when those charged with developing nanomedicines are cognizant of the unique opportunities and technical challenges that these products present. These individuals must also be knowledgeable about the processes of clinical and product development, including regulatory considerations, to maximize the odds for successful product registration. This article outlines these topics with a goal to accelerate the combination of academic innovation with collaborative industrial scientists who understand pharmaceutical development and regulatory approval requirements-only together can they realize the full potential of nanomedicines for patients.

Progressive multifocal leukoencephalopathy: current treatment options and future perspectives.

Progressive multifocal leukoencephalopathy (PML) is a rare but debilitating and frequently fatal viral disease of the central nervous system, primarily affecting individuals with chronically and severely suppressed immune systems. The disease was relatively obscure until the outbreak of HIV/AIDS, when it presented as one of the more frequent opportunistic infections in this immune deficiency syndrome. It attracted additional attention from the medical and scientific community following the discovery of significant PML risk associated with natalizumab, a monoclonal antibody used for treatment of relapsing-remitting multiple sclerosis. This was followed by association of PML with other immunosuppressive or immunomodulating drugs. PML is currently untreatable disease with poor outcomes, so it is a significant concern when developing new immunotherapies. Current prophylaxis and treatment of PML are focused on immune reconstitution, restoration of immune responses to JC virus infection, and eventual suppression of immune reconstitution inflammatory syndrome. This approach was successful in reducing the incidence of PML and improved survival of PML patients with HIV infection. However, the outcome for the majority of PML patients, regardless of their medical history, is still relatively poor. There is a high unmet need for both prophylaxis and treatment of PML. The aim of this review is to discuss potential drug candidates for prophylaxis and treatment of PML with a critical review of previously conducted and completed PML treatment studies as well as to provide perspectives for future therapies.

Therapeutic protein drug-drug interactions: navigating the knowledge gaps-highlights from the 2012 AAPS NBC Roundtable and IQ Consortium/FDA workshop.

The investigation of therapeutic protein drug-drug interactions has proven to be challenging. In May 2012, a roundtable was held at the American Association of Pharmaceutical Scientists National Biotechnology Conference to discuss the challenges of preclinical assessment and in vitro to in vivo extrapolation of these interactions. Several weeks later, a 2-day workshop co-sponsored by the U.S. Food and Drug Administration and the International Consortium for Innovation and Quality in Pharmaceutical Development was held to facilitate better understanding of the current science, investigative approaches and knowledge gaps in this field. Both meetings focused primarily on drug interactions involving therapeutic proteins that are pro-inflammatory cytokines or cytokine modulators. In this meeting synopsis, we provide highlights from both meetings and summarize observations and recommendations that were developed to reflect the current state of the art thinking, including a four-step risk assessment that could be used to determine the need (or not) for a dedicated clinical pharmacokinetic interaction study.