AAPS Journal最新文献

Intravenous dosing of L- and D-eflornithine in a racemic mixture is a currently recommended late-stage gambiense human African trypanosomiasis (g-HAT) treatment, either as 14-day monotherapy or in combination with oral nifurtimox for seven days. However, an oral eflornithine treatment against late-stage g-HAT would be preferable. Pharmacokinetics of eflornithine are enantioselective with different oral absorption of the enantiomers. L-eflornithine has a greater in vitro antitrypanosomal potency than D-eflornithine. This study aimed to integrate knowledge about in vitro potency and literature data from the only clinical study with enantiospecific pharmacokinetic oral data to predict L-eflornithine concentrations in plasma and cerebrospinal fluid to estimate the probability of target attainment. L- and D-eflornithine concentrations in cerebrospinal fluid from the clinical study with enantiospecific data were described with a compartment model that was validated using external data with total eflornithine concentrations. Simulations were performed with oral L-eflornithine doses ranging between 125 to 1000 mg/kg/day administered twice to twelve times daily. The probability of target attainment analysis showed that oral L-eflornithine doses of 750 mg/kg/day administered four or twelve times daily (i.e., drinking a solution every 2nd hour) as monotherapy would be needed to acquire efficacious exposures. In combination with nifurtimox, L-eflornithine dosed at 375 mg/kg/day four or twelve times daily would give exposures over the threshold concentration in cerebrospinal fluid. The presented simulation framework may serve as a starting point to find a suitable oral dose regimen to assess the clinical potential for an oral L-eflornithine-based combination treatments against late-stage g-HAT.

A virtual bioequivalence (VBE) approach utilizing physiologically based pharmacokinetic (PBPK) modeling presents a compelling alternative for pharmaceutical industries. This method can significantly reduce the time and cost associated with clinical bioequivalence (BE) trials while minimizing the risk of detecting a type II error (a false negative), as well as a type I error (a false positive). Additionally, it aligns with ethical considerations by obviating the need to expose healthy volunteers to investigational drugs. To secure a biowaiver through the VBE approach, it is essential to translate compendial in vitro dissolution data into pharmacokinetic (PK) parameters using PBPK modeling to evaluate BE. This article reflects three concepts: compendial dissolution test, PBPK modeling, and BE, reviewing their historical development and current research. It highlights the gaps and challenges and discusses potential future opportunities to strengthen clear linkage among three concepts. A deeper understanding of the mechanisms and mathematical translation of dosage form disintegration and API particle dissolution can enhance the prediction of dosage form performance in both in vivo and in vitro settings. Future advancement of PBPK modeling should incorporate these developments to improve confidence in correlating compendial dissolution data with quantitative risk assessments of BE outcomes.

Accurate quantitation of circulating messenger RNA (mRNA) is critical for the quantitation of lipid nanoparticle-formulated mRNA (mRNA-LNP) drug products. This study evaluated the concordance between branched DNA (bDNA) and reverse transcription quantitative polymerase chain reaction (RT-qPCR) assays for quantifying mRNA in human serum from a phase 1 clinical trial. We compared analytical performance across bDNA and two RT-qPCR workflows-RNA purification and a simplified NP-40 detergent-based treatment. A total of 77 clinical serum samples were analyzed. Method performance was assessed using assay precision, accuracy, and total error, along with linear regression and Bland-Altman analyses to evaluate inter-platform concordance. Noncompartmental PK analysis was performed on a subset of samples from four subjects. Results showed that RT-qPCR methods yielded lower mRNA concentrations than bDNA, with a consistent negative bias more pronounced in NP-40-treated samples. The purification RT-qPCR method showed closer agreement with bDNA across the quantitative range (R² = 0.878) than NP-40 treated RT-qPCR (R² = 0.736). Despite quantitative differences, PK parameters derived from all methods were comparable, supporting RT-qPCR's suitability for clinical mRNA quantification. NP-40 treatment offered workflow efficiency and lower sample volume requirements, whereas mRNA purification had improved concordance with bDNA. These findings support the feasibility of adopting RT-qPCR as a viable alternative to bDNA method for mRNA quantification, with method selection guided by study phase, throughput needs, and available matrix volume. Cross-platform comparability ensures robust bioanalytical support for clinical development of mRNA drug candidates.

In vitro permeation testing (IVPT) is commonly used to assess dermal drug delivery, yet its utility can be challenged by high variability and the need for large sample sizes to achieve sufficient statistical power. Dermal physiologically based pharmacokinetic (PBPK) models provide a mechanistic approach to better interpret IVPT results and to extrapolate in vitro to in vivo. In the present work, a dermal PBPK model for caffeine was developed using a bottom-up approach with minimal parameter optimization. The model incorporated formulation characteristics, experimentally measured skin partition coefficients, and predicted diffusion coefficients, while explicitly accounting for the constraints associated with the analytical methods used in each IVPT, improving the model's predictive reliability compared to previous work. After validation against literature IVPT data for aqueous solutions, the model was extended to simulate permeation from ointments and emulsions. The model was used to extrapolate and predict in vivo skin concentrations following application of gel formulations containing a chemical penetration enhancer, propylene glycol. For the emulsion formulations, the model was utilised to explore virtual bioequivalence and define a preliminary "safe space" for bioequivalence, offering insights to support both drug product development and regulatory submissions.

Traditional validation methodologies - whether based on accuracy and precision or total analytical error (TAE) and risk - focus primarily on the intrinsic performance of an analytical procedure, largely disregarding its intended use environment. In contrast, this paper introduces a novel validation methodology that evaluates whether a procedure performs sufficiently well when integrated into its actual context of use. This approach aligns more closely with the intent of USP <1033> , where the Analytical Target Profile (ATP) is stated in terms of product and process requirements, rather than abstract analytical procedure requirements. By shifting the focus from theoretical performance to practical applicability, the proposed methodology ensures that analytical procedures meet quality requirements in practice - not just in principle. Although demonstrated here for potency assay validation in accordance with the USP <1033> guideline, the methodology is broadly applicable to other analytical procedures governed by ICH Q2(R2), with only minor adaptation. A freely accessible online application is provided to facilitate discussion and adoption of the novel methodology in practice.

The current gold standard of blood sample collection in clinical trials involves venous draws performed by trained phlebotomists in clinical settings. However, recent technological advancements have enabled the emergence of patient-centric sampling (PCS) methods, offering more flexible and accessible alternatives. This paper examines the motivation behind the pharmaceutical industry's growing interest in PCS devices and explores their application in drug development through seven case studies. The case studies highlight the benefits and practical challenges of PCS strategies, including remote (at-home) sample collection, use in pediatric populations, advantages during COVID-19 pandemic, and implementation across trials involving small molecules, biotherapeutics, biomarkers and vaccines. Several studies assess the concordance between traditional venous sampling and PCS methods, while also addressing logistical considerations for remote sampling with and without nurse support. A central theme across the case studies is the importance of designing trials that prioritize patient convenience and engagement. Examples such as an early-phase asthma trial exemplify how PCS can enhance study design. The findings underscore the clear advantages of PCS in improving trial recruitment, increasing participant diversity, minimizing discomfort, reducing sample volumes and enhancing operational efficiency. The paper provides practical insights and recent examples to guide the integration of PCS technologies into clinical trial protocols, emphasizing the value of early planning and strategic implementation.

Cytochrome P450 3A4 (CYP3A4) is a key target for time-dependent inhibition (TDI) assessment during drug development. However, translating in vitro TDI data to in vivo drug-drug interaction (DDI) risk remains challenging due to the acknowledged overestimation when incorporating in vitro kinetics in predictive models. We investigated different in vitro TDI assay conditions in human liver microsomes (HLM) and evaluated their impact on the predictive accuracy for CYP3A4-related DDI for 32 marketed drugs. Considering assay sensitivity and in vivo DDI prediction accuracy with mechanistic static modeling (MSM), optimal incubation parameters were identified as: a pre-incubation time of 40 min for precipitants and 10 min incubation time for CYP3A4 substrate midazolam (10 μM) at 0.1 mg/mL HLM. A tendency to overestimate the DDI magnitude (AFE = 4.83, AAFE = 4.87) was still observed in MSM when using the unbound drug inhibition constant (KI,_u) and maximum inactivation rate (k_inact), measured under optimized incubation conditions. Improved predictions were achieved when applying the same parameters in physiologically-based pharmacokinetic (PBPK) models (AFE = 1.94, AAFE = 2.13), with 60% of predicted AUCR falling in the twofold range. These findings highlighted the importance of optimizing in vitro TDI incubation conditions, together with evaluating the benefits and limitations of numerical prediction approaches for predicting clinically significant CYP3A4 TDI effects with mechanistic static and PBPK models.

Neutralizing antibodies (NAbs) to protein therapeutics have traditionally been assumed to be the most impactful subset of anti-drug-antibodies (ADA). NAbs can block the biotherapeutic from engaging its target impacting efficacy and may also cause serious safety events. Stand-alone NAb assays have been employed to detect neutralizing responses, often with reconfigured versions of other assays. These methods have historically been implemented in registrational trials for all molecules, and in early-stage studies for high risk biotherapeutics. However, data has demonstrated that NAb response and ADA magnitude are highly correlated. Additionally, the use of other markers to identify clinically relevant immunogenicity, such as apparent impact on pharmacokinetics (PK) or pharmacodynamics (PD), has been increasing. This manuscript reviews the available data on clinically meaningful immunogenic responses to biologics and proposes a risk-based strategy to determine if and when to employ a stand-alone NAb assay. For molecules with a high risk of safety consequences of immunogenicity (e.g., biological mimics) a NAb assay is recommended. However, for lower-safety risk molecules a stand-alone NAb assay does not enhance the interpretation of clinical data and is likely not needed. A combination of other assessments including ADA status, magnitude and persistence, PK, and PD (and efficacy) can be used as a surrogate for NAb assay data. Integration of data from all clinical evaluations is recommended by Health Authorities and can provide a more accurate overall assessment of neutralizing activity. This approach identifies clinically impactful downstream readouts of neutralizing activity without the need for a stand-alone NAb assay.

A clinical development program for follow-on locally acting intravitreal drug products typically includes a comparative efficacy study. Pharmacokinetic assessment is often considered of limited value because systemic exposure is low and/or not predictive of efficacy at the site of action. In this commentary, we evaluated the relevance of pharmacokinetics for locally acting intravitreal large molecule drug products. Our assessment showed that systemic pharmacokinetic information including the rate constant could provide valuable insights into estimating local exposure of intravitreally administered drugs. This information has the potential to introduce a novel approach to clinical development programs for follow-on locally acting intravitreal drug products.

Nintedanib (Nint) is a potent tyrosine kinase inhibitor recently approved by the US FDA to treat idiopathic pulmonary fibrosis (IPF). Delivery of Nint through available approaches is highly challenging because of its poor solubility and rapid metabolic degradation via hydrolytic ester cleavage, thereby reflecting poor oral bioavailability (< 5%). Hence, the current study was focused on formulating a Nint-loaded microemulsion (Nint-ME) and investigating its therapeutic potential in experimental animals to overcome the constraints of available therapies. Nint-ME was prepared via low-energy O/W emulsification aqueous titration techniques and optimized using QbD approach. Optimized ME subjected to screen for globule size, polydispersity index, encapsulation efficiency, transmittance, surface charge, and viscosity and were found to be 23.8 ± 1.4 nm, 0.18 ± 0.03, 99.8 ± 2.4%, 99.4 ± 0.1%, -0.7 ± 0.01 mV, and 1.5 ± 0.3 cP, respectively. Additionally, 94.5 ± 3.1% Nint was released from Nint-ME through the dialysis cassette within 72 h, demonstrating first-order kinetics with R² of 0.966. First-order and Higuchi release kinetic patterns support concentration-dependent release and Fickian diffusion from the matrix of Nint-ME. In-vitro permeation study of Nint across Caco2 colon epithelial cell monolayer depicted 48.1 ± 1.5 µg of cellular permeation out of 50 µg, ensuring the permeation potential of Nint-ME. Concurrently, an in-vivo pharmacokinetic study for optimized Nint-ME against Nint suspension reflected 41.0 ± 12.5% oral bioavailability, a 2-fold enhancement compared to plain Nint suspension. Existing work demonstrated the successful development of oral Nint-ME as a novel formulation for safe and effective delivery of Nint in IPF.