Using physiologically-based pharmacokinetic modeling for predicting the effects of hepatic impairment on the pharmacokinetics of olanzapine and samidorphan given as a combination tablet

Dose Optimization Informed by PBPK Modeling: State-of-the Art and Future

Model-informed drug development (MIDD) is a powerful quantitative approach that plays an integral role in drug development and regulatory review. While applied throughout the life cycle of the development of new drugs, a key application of MIDD is to inform clinical trial design including dose selection and optimization. To date, physiologically-based pharmacokinetic (PBPK) modeling, an established component of the MIDD toolkit, has mainly been used for assessment of drug-drug interactions (DDIs) and consequential dose adjustments in regulatory submissions. As a result of recent scientific advances and growing confidence in the utility of the approach, PBPK models are being increasingly applied to provide dose recommendations for subjects with differing ages, genetics, and disease states. In this review, we present our perspective on the current landscape of regulatory acceptance of PBPK applications supported by relevant case studies. We also discuss the recent progress and future challenges associated with expanding the utility of PBPK models into emerging areas for regulatory decision making, especially dose optimization in highly vulnerable and understudied populations and facilitating diversity in clinical trials.

Combining samidorphan with olanzapine to mitigate weight gain as a side effect in schizophrenia treatment

Purpose

This article analyzes clinical trials that provide evidence for the positive effects of using samidorphan to mitigate undesirable weight gain in patients diagnosed with schizophrenia who are undergoing treatment with olanzapine.

Views

Weight gain is a prevalent and problematic side effect of antipsychotic drug therapy, particularly in patients with schizophrenia. To address this issue, extensive research is being conducted to explore new drug therapies that can effectively counteract psychotic symptoms while minimizing the occurrence of unwanted side effects. One promising approach involves the addition of weight-loss substances to existing medications. Studies have indicated that opioid receptor antagonists, such as samidorphan, have the potential to facilitate weight loss. Consequently, a novel therapy combining samidorphan and olanzapine has been developed and is discussed in detail in this article.

Conclusions

The combination of samidorphan and olanzapine has demonstrated its ability to effectively reduce weight gain in patients with schizophrenia, without compromising the drug's primary function of alleviating psychotic symptoms. Moreover, the inclusion of samidorphan in the treatment regimen may contribute to a lower risk of cardiovascular events, though it is worth noting that it could also lead to an increase in digestive side effects. Despite this potential drawback, the introduction of this innovative therapy represents a significant advancement in the management of obesity among individuals with schizophrenia.

Physiologically Based Pharmacokinetic Modeling of Extracellular Vesicles

Extracellular vesicles (EVs) are lipid membrane bound-cell-derived structures that are a key player in intercellular communication and facilitate numerous cellular functions such as tumor growth, metastasis, immunosuppression, and angiogenesis. They can be used as a drug delivery platform because they can protect drugs from degradation and target specific cells or tissues. With the advancement in the technologies and methods in EV research, EV-therapeutics are one of the fast-growing domains in the human health sector. Therapeutic translation of EVs in clinics requires assessing the quality, safety, and efficacy of the EVs, in which pharmacokinetics is very crucial. We report here the application of physiologically based pharmacokinetic (PBPK) modeling as a principal tool for the prediction of absorption, distribution, metabolism, and excretion of EVs. To create a PBPK model of EVs, researchers would need to gather data on the size, shape, and composition of the EVs, as well as the physiological processes that affect their behavior in the body. The PBPK model would then be used to predict the pharmacokinetics of drugs delivered via EVs, such as the rate at which the drug is absorbed and distributed throughout the body, the rate at which it is metabolized and eliminated, and the maximum concentration of the drug in the body. This information can be used to optimize the design of EV-based drug delivery systems, including the size and composition of the EVs, the route of administration, and the dose of the drug. There has not been any dedicated review article that describes the PBPK modeling of EV. This review provides an overview of the absorption, distribution, metabolism, and excretion (ADME) phenomena of EVs. In addition, we will briefly describe the different computer-based modeling approaches that may help in the future of EV-based therapeutic research.

Application of physiologically-based pharmacokinetic models for therapeutic proteins and other novel modalities

The past two decades have seen diversification of drug development pipelines and approvals from traditional small molecule therapies to alternative modalities including monoclonal antibodies, engineered proteins, antibody drug conjugates (ADCs), oligonucleotides and gene therapies. At the same time, physiologically-based pharmacokinetic (PBPK) models for small molecules have seen increased industry and regulatory acceptance.This review focusses on the current status of the application of PBPK models to these newer modalities and give a perspective on the successes, challenges and future directions of this field.There is greatest experience in the development of PBPK models for therapeutic proteins, and PBPK models for ADCs benefit from prior experience for both therapeutic proteins and small molecules. For other modalities, the application of PBPK models is in its infancy.Challenges are discussed and a common theme is lack of availability of physiological and experimental data to characterise systems and drug parameters to enable a priori prediction of pharmacokinetics. Furthermore, sufficient clinical data are required to build confidence in developed models.The PBPK modelling approach provides a quantitative framework for integrating knowledge and data from multiple sources and can be built on as more data becomes available.

Olanzapine-samidorphan combination tablets for the treatment of schizophrenia and bipolar I disorder - what is it, and will it be used?

INTRODUCTION

: Although olanzapine remains one of the most efficacious antipsychotic medications for the treatment of schizophrenia, there are significant tolerability concerns related to its weight and metabolic profile. Olanzapine-samidorphan combination tablets (OLZ/SAM), branded as Lybalvi, is a newly FDA approved formulation aimed at attenuating antipsychotic induced weight gain via modulation of the endogenous opioid system with samidorphan, while retaining the robust antipsychotic efficacy of olanzapine.

AREAS COVERED

: We reviewed the published literature of OLZ/SAM for the management of schizophrenia using the US National Library of Medicine's PubMed.gov resource. Topics covered in this narrative review include the pharmacokinetics, pharmacodynamics, tolerability, and efficacy of OLZ/SAM.

EXPERT OPINION

: OLZ/SAM is an effective and well tolerated pharmacologic option in mitigating olanzapine induced weight gain while retaining olanzapine's efficacy. It has a limited effect on metabolic laboratory parameters and cumulatively tends to limit weight gain rather than promote weight loss. Additional research will be needed to determine its effectiveness compared to alternative strategies to attenuate antipsychotic induced weight gain.

Olanzapine/Samidorphan: New Drug Approved for Treating Bipolar I Disorder and Schizophrenia

OBJECTIVE

To describe the approval of olanzapine/samidorphan, compare the clinical trial data, and summarize key findings, with a focus on impact to clinical practice.

DATA SOURCES

A literature search of PubMed was performed (March 2006 to November 2021) using the following search terms: Lybalvi, olanzapine/samidorphan, olanzapine, antipsychotic, bipolar disorder, and schizophrenia. Product monographs, review articles, and randomized control trials were reviewed.

STUDY SELECTION AND DATA EXTRACTION

Relevant English-language studies conducted in humans were considered. Primary use of Phase III clinical drug approval trials preferred; supplementary trial analysis evaluated to provide context.

DATA SYNTHESIS

In June 2021, the Food and Drug Administration (FDA) approved Lybalvi^® (olanzapine/samidorphan) for indications including treatment of adults with schizophrenia and/or bipolar I disorder (acute manic episodes or acute episodes with mixed features) through the multi-stage ENLIGHTEN clinical trials. Participants were enrolled in 4-week, 24-week, and 52-week studies to evaluate the safety and efficacy of olanzapine/samidorphan. Subsequent secondary analysis evaluated metabolic effects.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

This review details the pharmacologic, pharmacokinetic, associated dosing and indications, and adverse effects for the drug combination olanzapine/samidorphan. Better understanding of novel drug mechanisms will help to expand on the potential role and place for use in clinical practice.

CONCLUSION

When treating complex patients with schizophrenia, the olanzapine/samidorphan combination has limited effect on medication-induced weight gain often associated with antipsychotic olanzapine monotherapy. Additional studies are needed to further define the role of olanzapine/samidorphan in bipolar I disorder and clinical practice.