Role of Modeling and Simulation in Preclinical and Clinical Long-Acting Injectable Drug Development

Lenacapavir: Playing the Long Game in the New Era of Antiretrovirals

The mainstay of antiretroviral therapy (ART) has been combination oral therapy. While oral ART is highly effective, nonadherence remains a chief concern. Addressing this concern in recent years is the emergence of long-acting antiretrovirals for the treatment and prevention of HIV-1 infection. The most recently approved long-acting antiretroviral is the first-in-class capsid inhibitor lenacapavir (LEN) for heavily treatment-experienced adults with multidrug-resistant HIV-1 infection. Due to its biannual subcutaneous dosing scheme to inhibit the HIV-1 capsid, LEN exhibits unique pharmacokinetics and reinforces an evolving era of ART. In this review, we evaluate published and accepted research articles, conference proceedings, and clinical trial records to provide a comprehensive overview of LEN for treatment and preliminary data for the prevention of HIV-1 infection. These data include clinical trials outcomes, in vitro and in vivo resistance profiles, and preclinical data supporting downstream indications. We also discuss the unique clinical pharmacology of LEN with the goal of serving as a resource toward subsequent physiologically based, population-based, and other miscellaneous pharmacometric-focused analyses. Given the dynamic nature of the HIV treatment and prevention research fields, we also discuss ongoing studies related to LEN for treatment-naïve adults and for prevention. Lastly, we discuss important pharmacologic gaps in special populations, drug-drug interactions, and at the sites of action germane to HIV treatment and prevention. The information discussed in this review will provide knowledge and understanding of the unique pharmacologic properties of LEN to assist clinicians and researchers as they navigate the dynamic HIV research landscape.

Novel omeprazole delayed release orally disintegrating tablets for enhanced patient compliance: a case of model informed formulation development

The advanced in silico simulation tools, such as physiologically based biopharmaceutics models (PBBM) or physiologically based pharmacokinetic models (PBPK), play critical role in model informed formulation development. This approach has been successfully implemented in the present case for development of novel omeprazole delayed-release orally disintegrating tablets (ODT) formulation, aimed to enhance patient compliance.PBBM was developed using physicochemical, biopharmaceutical, and dissolution data. The dissolution studies for pilot formulations were conducted in biopredictive media in fasting (0.1 N HCl followed by pH 6.8) and fed (pH 5 followed by pH 6.8) conditions. The model was extensively validated in three stages: pilot fasted, pilot fed virtual bioequivalence and food effect assessments. Impressively, the model was able to predict both passed and failed batches appropriately.Based on insights from the pilot study, a higher scale pivotal formulation was optimised. Prospective predictions were made for pivotal formulations using validated model and bio results were found to be in line with model predictions in fasting condition.Overall, a rationale and patient compliant formulation was developed using innovative modelling approach and filed to regulatory agency. The novel omeprazole formulation enhanced patient compliance through ease of administration thereby circumventing challenges of conventional formulation.

In vitro modelling of intramuscular injection site events

INTRODUCTION

Intramuscular (IM) injections deliver a plethora of drugs. The majority of IM-related literature details dissolution and/or pharmacokinetic (PK) studies, using methods with limited assessments of post-injection events that can impact drug fate, and absorption parameters. Food and Drug Association guidelines no longer require preclinical in vivo modeling in the U.S.A. Preclinical animal models fail to correlate with clinical outcomes, highlighting the need to study, and understand, IM drug fate in vitro using bespoke models emulating human IM sites. Post-IM injection events, i.e. underlying processes that influence PK outcomes, remain unacknowledged, complicating the application of in vitro methods in preclinical drug development. Understanding such events could guide approaches to predict and modulate IM drug fate in humans.

AREAS COVERED

This article reviews challenges in biorelevant IM site modeling (i.e. modeling drug fate outcomes), the value of technologies available for developing IM injectables, methods for studying drug fate, and technologies for training in performing IM administrations. PubMed, Web-of-Science, and Lens databases provided papers published between 2014 and 2024.

EXPERT OPINION

IM drug research is expanding what injectable therapeutics can achieve. However, post-injection events that influence PK outcomes remain poorly understood. Until addressed, advances in IM drug development will not realize their full potential.

Accelerated and Biopredictive In Vitro Release Testing Strategy for Single Agent and Combination Long-Acting Injectables

The purpose of this study was to develop an in vitro release testing (IVRT) strategy to predict the pre-clinical performance of single agent and combination long acting injectable (LAI) suspension products. Two accelerated IVRT methods were developed using USP apparatus 2 to characterize initial, intermediate, and terminal phases of drug release. Initial and intermediate phases were captured using a suspension cup with moderate agitation to ensure a constant, low surface area exposure of the LAI suspension to the release media. The terminal phase was obtained by exposing the LAI suspension to a high initial paddle speed. This resulted in smaller suspension particulates with high cumulative surface area that were dispersed throughout the release media, enabling rapid drug release. The in vitro release profiles obtained with these two methods in 48 h or less were independently time scaled to reflect the in vivo time scale of approximately 1800 h. Level-A in vitro in vivo correlations (IVIVCs) were separately developed for each method and active pharmaceutical ingredient (API) using in vivo absorption profiles obtained by deconvolution of rat plasma concentration-time profiles. The IVIVCs were successfully validated for each API. This work provides a framework for evaluating individual phases of drug release of complex LAIs to ultimately predict their in vivo performance.

Development of Mechanistic In Vitro-In Vivo Extrapolation to Support Bioequivalence Assessment of Long-Acting Injectables

Long-acting injectable (LAI) formulations provide sustained drug release over an extended period ranging from weeks to several months to improve efficacy, safety, and compliance. Nevertheless, many challenges arise in the development and regulatory assessment of LAI drug products due to a limited understanding of the tissue response to injected particles (e.g., inflammation) impacting in vivo performance. Mechanism-based in silico methods may support the understanding of LAI-physiology interactions. The objectives of this study were as follows: (1) to use a mechanistic modeling approach to delineate the in vivo performance of DepoSubQ Provera® and formulation variants in preclinical species; (2) to predict human exposure based on the knowledge gained from the animal model. The PBPK model evaluated different elements involved in LAI administration and showed that (1) the effective in vivo particle size is potentially larger than the measured in vitro particle size, which could be due to particle aggregation at the injection site, and (2) local inflammation is a key process at the injection site that results in a transient increase in depot volume. This work highlights how a mechanistic modeling approach can identify critical physiological events and product attributes that may affect the in vivo performance of LAIs.