Population pharmacokinetics, exposure-safety, and immunogenicity of atezolizumab in pediatric and young adult patients with cancer

Advances on immunotherapy for osteosarcoma

Osteosarcoma is the most common primary bone cancer in children and young adults. Limited progress has been made in improving the survival outcomes in patients with osteosarcoma over the past four decades. Especially in metastatic or recurrent osteosarcoma, the survival rate is extremely unsatisfactory. The treatment of osteosarcoma urgently needs breakthroughs. In recent years, immunotherapy has achieved good therapeutic effects in various solid tumors. Due to the low immunogenicity and immunosuppressive microenvironment of osteosarcoma, immunotherapy has not yet been approved in osteosarcoma patients. However, immune-based therapies, including immune checkpoint inhibitors, chimeric antigen receptor T cells, and bispecfic antibodies are in active clinical development. In addition, other immunotherapy strategies including modified-NK cells/macrophages, DC vaccines, and cytokines are still in the early stages of research, but they will be hot topics for future study. In this review, we showed the functions of cell components including tumor-promoting and tumor-suppressing cells in the tumor microenvironment of osteosarcoma, and summarized the preclinical and clinical research results of various immunotherapy strategies in osteosarcoma, hoping to provide new ideas for future research in this field.

Unlocking the Potential: A Systematic Review of Master Protocol in Pediatrics

The use of master protocols allows for innovative approaches to clinical trial designs, potentially enabling new approaches to operations and analytics and creating value for patients and drug developers. Pediatric research has been conducted for many decades, but the use of novel designs such as master protocols in pediatric research is not well understood. This study aims to provide a systematic review on the utilization of master protocols in pediatric drug development. A search was performed in September 2022 using two data sources (PubMed and ClinicalTrials.gov) and included studies conducted in the past10 years. General study information was extracted such as study type, study status, therapeutic area, and clinical trial phase. Study characteristics that are specific to pediatric studies (such as age of the participants and pediatric drug dosing) and important study design elements (such as number of test drug arms and whether randomization and/or concurrent control was used) were also collected. Our results suggest that master protocol studies are being used in pediatrics, with platform and basket trials more common than umbrella trials. Most of this experience is in oncology and early phase studies. There is a rise in the use starting in 2020, largely in oncology and COVID-19 trials. However, adoption of master protocols in pediatric clinical research is still on a small scale and could be substantially expanded. Work is required to further understand the barriers in implementing pediatric master protocols, from setting up infrastructure to interpreting study findings.

Therapeutic drug monitoring guidelines in oncology: what do we know and how to move forward? Insights from a systematic review

Background

Compared with anti-infective drugs, immunosuppressants and other fields, the application of therapeutic drug monitoring (TDM) in oncology is somewhat limited.

Objective

We aimed to provide a comprehensive understanding of TDM guidelines for antineoplastic drugs and to promote the development of individualized drug therapy in oncology.

Design

This study type is a systematic review.

Data sources and methods

This study was performed and reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 statement. Databases including PubMed, Embase, the official websites of TDM-related associations and Chinese databases were comprehensively searched up to March 2023. Two investigators independently screened the literature and extracted data. The methodological and reporting quality was evaluated using the Appraisal of Guidelines for Research and Evaluation II (AGREE II) and the Reporting Items for Practice Guidelines in Healthcare (RIGHT), respectively. Recommendations and quality evaluation results were presented by visual plots. This study was registered in PROSPERO (No. CRD42022325661).

Results

A total of eight studies were included, with publication years ranging from 2014 to 2022. From the perspective of guideline development, two guidelines were developed using evidence-based methods. Among the included guidelines, four guidelines were for cytotoxic antineoplastic drugs, three for small molecule kinase inhibitors, and one for antineoplastic biosimilars. Currently available guidelines and clinical practice provided recommendations of individualized medication in oncology based on TDM, as well as influencing factors. With regard to methodological quality based on AGREE II, the average overall quality score was 55.21%. As for the reporting quality by RIGHT evaluation, the average reporting rate was 53.57%.

Conclusion

From the perspective of current guidelines, TDM in oncology is now being expanded from cytotoxic antineoplastic drugs to newer targeted treatments. Whereas, the types of antineoplastic drugs involved are still small, and there is still room for quality improvement. Furthermore, the reflected gaps warrant future studies into the exposure-response relationships and population pharmacokinetics models.

Atezolizumab as the First Systemic Therapy Approved for Alveolar Soft Part Sarcoma

OBJECTIVE

The objective was to review the pharmacology, efficacy, and safety of atezolizumab (Tecentriq) for the treatment of adult and pediatric patients aged 2 years and older with unresectable or metastatic alveolar soft part sarcoma (ASPS).

DATA SOURCES

A literature search was conducted using PubMed and MEDLINE databases, published abstracts, and ongoing studies from ClinicalTrials.gov between January 1, 1981, and May 31, 2023. Keywords included atezolizumab, Tecentriq, MPDL3280, immunotherapy, PD-L1, PD-1, pediatrics, sarcoma, and ASPS.

STUDY SELECTION AND DATA EXTRACTION

All English-language studies involving atezolizumab for ASPS were included and discussed.

DATA SYNTHESIS

Atezolizumab is an anti-programmed death-ligand 1 (PD-L1) monoclonal antibody designed to block the interaction between PD-L1 and the programmed cell death protein 1 (PD-1) receptor. Atezolizumab was granted approval by the FDA specifically for ASPS based on a phase II clinical trial in adult and pediatric patients (n = 49), which reported an overall response rate of 24% and a durable response rate at 6 and 12 months of 67% and 42%, respectively. Common grade 3/4 adverse reactions include musculoskeletal pain (8%), followed by hypertension (6%), weight gain (6%), headache (4%), and dizziness (4%).

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE IN COMPARISON WITH EXISTING DRUGS

Advanced ASPS is a high-risk disease with limited treatment options. Atezolizumab appears to be a viable treatment option in ASPS demonstrating clinical efficacy and a manageable toxicity profile.

CONCLUSIONS

With no other treatments that are FDA approved specifically for ASPS, and few demonstrating efficacy in the advanced setting, the approval of atezolizumab, including the first approval for pediatric patients, represents a landmark improvement to the therapeutic arsenal against this rare disease.

Antibody Drug Clearance: An Underexplored Marker of Outcomes with Checkpoint Inhibitors

Immune-checkpoint inhibitor (ICI) therapy has dramatically changed the clinical landscape for several cancers, and ICI use continues to expand across many cancer types. Low baseline clearance (CL) and/or a large reduction of CL during treatment correlates with better clinical response and longer survival. Similar phenomena have also been reported with other monoclonal antibodies (mAb) in cancer and other diseases, highlighting a characteristic of mAb clinical pharmacology that is potentially shared among various mAbs and diseases. Though tempting to attribute poor outcomes to low drug exposure and arguably low target engagement due to high CL, such speculation is not supported by the relatively flat exposure-response relationship of most ICIs, where a higher dose or exposure is not likely to provide additional benefit. Instead, an elevated and/or increasing CL could be a surrogate marker of the inherent resistant phenotype that cannot be reversed by maximizing drug exposure. The mechanisms connecting ICI clearance, therapeutic efficacy, and resistance are unclear and likely to be multifactorial. Therefore, to explore the potential of ICI CL as an early marker for efficacy, this review highlights the similarities and differences of CL characteristics and CL-response relationships for all FDA-approved ICIs, and we compare and contrast these to selected non-ICI mAbs. We also discuss underlying mechanisms that potentially link mAb CL with efficacy and highlight existing knowledge gaps and future directions where more clinical and preclinical investigations are warranted to clearly understand the value of baseline and/or time-varying CL in predicting response to ICI-based therapeutics.

Nivolumab and ipilimumab population pharmacokinetics in support of pediatric dose recommendations-Going beyond the body-size effect

Body size has historically been considered the primary source of difference in the pharmacokinetics (PKs) of monoclonal antibodies (mAbs) between children aged greater than or equal to 2 years and adults. The contribution of age-associated differences (e.g., ontogeny) beyond body-size differences in the pediatric PKs of mAbs has not been comprehensively evaluated. In this study, the population PK of two mAbs (nivolumab and ipilimumab) in pediatric oncology patients were characterized. The effects of age-related covariates on nivolumab or ipilimumab PKs were assessed using data from 13 and 10 clinical studies, respectively, across multiple tumor types, including melanoma, lymphoma, central nervous system tumors (CNSTs), and other solid tumors. Clearance was lower in pediatric patients (aged 1-17 years) with solid tumors or CNST than in adults after adjusting for other covariates, including the effect of body size. In contrast, clearance was similar in pediatric patients with lymphoma to that in adults with lymphoma. The pediatric effects characterized have increased the accuracy of the predictions of the model, facilitating its use in subsequent exposure comparisons between pediatric and adult patients, as well as for exposure-response analyses to inform pediatric dosing. This study approach may be applicable to the optimization of pediatric dosing of other mAbs and possibly other biologics.

Treatment-emergent antidrug antibodies related to PD-1, PD-L1, or CTLA-4 inhibitors across tumor types: a systematic review

BACKGROUND

Increased understanding of how the immune system regulates tumor growth has innovated the use of immunotherapeutics to treat various cancers. The impact of such therapies, including programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) inhibitors, on the production of antidrug antibodies (ADAs) and their impact on outcomes, is poorly understood. This study aims to evaluate the clinical trial evidence on ADA incidence associated with PD-1, PD-L1, and CTLA-4 inhibitors in the treatment of cancer and to assess associations between treatment administered, ADA incidence, and treatment outcomes.

METHODS

Embase®, Medline®, and EBM Reviews were searched via the OVID® platform on February 15, 2022. Conference proceedings, clinical trial registries, and global regulatory and reimbursement body websites were also searched. Eligible publications included clinical trials enrolling patients receiving cancer treatment with either PD-1, PD-L1, or CTLA-4 reporting outcomes including incidence or prevalence of ADAs and the impact of immunogenicity on treatment safety and efficacy. Reference lists of eligible publications were also searched. The review was conducted and reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses and evidence quality assessment was conducted using the appropriate Joanna Briggs Institute Critical Appraisal tool.

RESULTS

After screening 4160 records and reviewing 97 full publications, a total of 34 publications reporting on 68 trials were included. A further 41 relevant clinical trials were identified on ClinicalTrials.gov and a further 32 from searches of packaging inserts. In total, 141 relevant trials covering 15 different checkpoint inhibitors and 16 different tumor types were included. Across the included trials, atezolizumab was associated with the highest incidence of ADAs (29.6% of 639 patients), followed by nivolumab (11.2% of 2,085 patients). Combination checkpoint inhibitor treatment appeared to increase the rate of ADAs versus monotherapy. Only 17 trials reported on the impact of ADAs on treatment outcomes with mixed results for the impact of ADAs on treatment efficacy, safety, and pharmacokinetics.

CONCLUSIONS

Checkpoint inhibitors for the treatment of cancer are immunogenic, with the incidence of treatment-emergent ADAs varying between individual therapies. It remains unclear what impact ADAs have on treatment outcomes.

Advancing drug development in pediatric oncology, a focus on cancer biology and targeted therapies: iMATRIX platform

With the development of novel treatment therapies as well as evolving and innovative approaches to conduct clinical trials, the landscape of pediatric oncology drug development has dramatically changed in recent years. Despite this change, approvals for new drugs and labeling updates to ensure availability of proper treatment for pediatric patients with cancer remain slow. The context of drug development in pediatric tumors has also changed with regulatory initiatives in the US and Europe, creating a great need for faster development of novel drugs. Today, conventional study designs have been replaced or complemented by novel clinical trial designs, such as master protocols and platform trials, to optimize cancer drug development and enable faster regulatory approval. The iMATRIX platform is a mechanism-of-action (MOA)-based phase 1/2 trial framework for concurrently studying multiple molecules across a range of relevant pediatric tumor types, taking into account the biology of each pediatric tumor type. Six studies have been conducted, ongoing, or planned on the iMATRIX platform - investigating atezolizumab, cobimetinib, entrectinib, idasanutlin, alectinib, and glofitamab. A brief overview of study designs and characteristics are shared in this article, along with learnings from them.

Current advances in immunotherapy for atypical teratoid rhabdoid tumor (ATRT)

Atypical teratoid rhabdoid tumors (ATRT) are rare and aggressive embryonal tumors of central nervous system that typically affect children younger than 3 years of age. Given the generally poor outcomes of patients with ATRT and the significant toxicities associated with conventional multi-modal therapies, there is an urgent need for more novel approaches to treat ATRT, one such approach being immunotherapy. The recent rise of large-scale, multicenter interdisciplinary studies has delineated several molecular and genetic characteristics unique to ATRT. This review aims to describe currently available data on the tumor immune microenvironment of ATRT and its specific subtypes and to summarize the emerging clinical and preclinical results of immunotherapy-based approaches. It will also highlight the evolving knowledge of epigenetics on immunomodulation in this epigenetically influenced tumor, which may help guide the development of effective immunotherapeutic approaches in the future.

Therapeutic drug monitoring of immune checkpoint inhibitors: based on their pharmacokinetic properties and biomarkers

As a new means of oncology treatment, immune checkpoint inhibitors (ICIs) can improve survival rates in patients with resistant or refractory tumors. However, there are obvious inter-individual differences in the unsatisfactory response rate, drug resistance rate and the occurrence of immune-related adverse events (irAE). These questions have sparked interest in researchers looking for a way to screen sensitive populations and predict efficacy and safety. Therapeutic drug monitoring (TDM) is a way to ensure the safety and effectiveness of medication by measuring the concentration of drugs in body fluids and adjusting the medication regimen. It has the potential to be an adjunctive means of predicting the safety and efficacy of ICIs treatment. In this review, the author outlined the pharmacokinetic (PK) characteristics of ICIs in patients. The feasibility and limitations of TDM of ICIs were discussed by summarizing the relationships between the pharmacokinetic parameters and the efficacy, toxicity and biomarkers.

A Simple Method for the Prediction of Therapeutic Proteins (Monoclonal and Polyclonal Antibodies and Non-Antibody Proteins) for First-in-Pediatric Dose Selection: Application of Salisbury Rule

In order to conduct a pediatric clinical trial, it is important to optimize pediatric dose as accurately as possible. In this study, a simple weight-based method known as ‘Salisbury Rule’ was used to predict pediatric dose for therapeutic proteins and was then compared with the observed pediatric dose. The observed dose was obtained mainly from the FDA package insert and if dosing information was not available from the FDA package insert then the observed dose was based on the dose given to an age group in a particular study. It was noted that the recommended doses of most of the therapeutic proteins were extrapolated to pediatrics from adult dose based on per kilogram (kg) body weight basis. Since it is widely believed that pediatric dose should be selected based on the pediatric clearance (CL), a CL based pediatric dose was projected from the following equation: Dose in children = Adult dose × (Observed CL in children/Observed adult CL). In this study, this dose was also considered observed pediatric dose for comparison. A ±30% prediction error (predicted vs. observed) was considered acceptable. There were 21 monoclonal antibodies, 5 polyclonal antibodies in children ≥ 2 years of age, 4 polyclonal antibodies in preterm and term neonates, and 11 therapeutic proteins (non-antibodies) in the study. In children < 30 kg body weight, the predicted doses were within 0.5−1.5-fold prediction error for 87% (monoclonal antibody), 100% (polyclonal antibody), and 92% (non-antibodies) observations. In children > 30 kg body weight, the predicted doses were within 0.5−1.5-fold prediction error for 96% (monoclonal antibody), 100% (polyclonal antibody), and 100% (non-antibodies) observations. The Salisbury Rule mimics more to CL-based dose rather than per kg body weight-based extrapolated dose from adults. The Salisbury Rule for the pediatric dose prediction can be used to select first-in-children dose in pediatric clinical trials and may be in clinical settings.

Development of a pediatric physiologically-based pharmacokinetic model to support recommended dosing of atezolizumab in children with solid tumors

Background: Atezolizumab has been studied in multiple indications for both pediatric and adult patient populations. Generally, clinical studies enrolling pediatric patients may not collect sufficient pharmacokinetic data to characterize the drug exposure and disposition because of operational, ethical, and logistical challenges including burden to children and blood sample volume limitations. Therefore, mechanistic modeling and simulation may serve as a tool to predict and understand the drug exposure in pediatric patients.

Objective: To use mechanistic physiologically-based pharmacokinetic (PBPK) modeling to predict atezolizumab exposure at a dose of 15 mg/kg (max 1,200 mg) in pediatric patients to support dose rationalization and label recommendations.

Methods: A minimal mechanistic PBPK model was used which incorporated age-dependent changes in physiology and biochemistry that are related to atezolizumab disposition such as endogenous IgG concentration and lymph flow. The PBPK model was developed using both in vitro data and clinically observed data in adults and was verified across dose levels obtained from a phase I and multiple phase III studies in both pediatric patients and adults. The verified model was then used to generate PK predictions for pediatric and adult subjects ranging from 2- to 29-year-old.

Results: Individualized verification in children and in adults showed that the simulated concentrations of atezolizumab were comparable (76% within two-fold and 90% within three-fold, respectively) to the observed data with no bias for either over- or under-prediction. Applying the verified model, the predicted exposure metrics including C_min, C_max, and AUC_tau were consistent between pediatric and adult patients with a geometric mean of pediatric exposure metrics between 0.8- to 1.25-fold of the values in adults.

Conclusion: The results show that a 15 mg/kg (max 1,200 mg) atezolizumab dose administered intravenously in pediatric patients provides comparable atezolizumab exposure to a dose of 1,200 mg in adults. This suggests that a dose of 15 mg/kg will provide adequate and effective atezolizumab exposure in pediatric patients from 2- to 18-year-old.

The Role of Master Protocols in Pediatric Drug Development

Master protocols are innovative clinical trial designs that enable new approaches to analytics and operations, creating value for patients and drug developers. To date, the use of master protocols in pediatric drug development has been limited, focused primarily on pediatric oncology with limited experience in rare and ultra-rare pediatric diseases. This article explores the application of master protocols to pediatric programs required by FDA and EMA based on adult developmental programs. These required programs involve multiple assets developed in limited pediatric populations for registrational purposes. However, these required programs include the possibility for extrapolation of efficacy and safety from the adult population. The use of master protocols is a potential solution to the challenge of conducting clinical trials in small pediatric populations provided that such use would improve enrollment or reduce the required sample size. Toward that end, Janssen and Lilly have been working on a collaborative cross-company pediatric platform trial in pediatric Crohn's disease using an innovative Bayesian analysis. We describe how two competing companies can work together to design and execute the proposed platform, focusing on selected aspects-the usefulness of a single infrastructure, the regulatory submission process, the choice of control group, and the use of pediatric extrapolation. Master protocols offer the potential for great benefit in pediatrics by streamlining clinical development, with the goal of reducing the delay in pediatric marketing approvals when compared to adults so that children have timelier access to safe and effective medications.

Avelumab Dose Selection for Clinical Studies in Pediatric Patients with Solid Tumors

BACKGROUND AND OBJECTIVE

A phase I/II trial evaluated the safety, antitumor activity, and pharmacokinetics of avelumab (anti-PD-L1 antibody) in pediatric patients with refractory/relapsed solid tumors (NCT03451825). This study aimed to inform avelumab dose selection in pediatric populations using population pharmacokinetic modeling and simulations.

METHODS

Patients aged < 18 years with refractory/relapsed solid tumors enrolled in phase I received avelumab 10 or 20 mg/kg intravenously every 2 weeks. A pediatric population pharmacokinetic model was developed via the frequentist prior approach.

RESULTS

Pharmacokinetic parameters from 21 patients who received avelumab 10 mg/kg (n = 6) or 20 mg/kg (n = 15) were analyzed. Patients had a wide range of weights and ages (medians, 37.3 kg and 12 years). Exposures with 10-mg/kg dosing were lower vs adult dosing, particularly in patients weighing < 40 kg, whereas 20-mg/kg dosing achieved or exceeded adult exposures, irrespective of body weight. A two-compartment linear model with time-varying clearance using body weight as a covariate, with the frequentist prior approach, best described pediatric data. In this model, optimal overlap in exposure with adult data was achieved with 800 mg every 2 weeks for patients aged ≥ 12 years and weighing ≥ 40 kg, and 15 mg/kg every 2 weeks for patients aged < 12 years or weighing < 40 kg.

CONCLUSIONS

Based on exposure matching, the recommended doses for further avelumab studies, including combination studies, are 15 mg/kg every 2 weeks for pediatric patients aged < 12 years or weighing < 40 kg and the adult flat dose of 800 mg every 2 weeks for pediatric patients aged ≥ 12 years and weighing ≥ 40 kg.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov NCT03451825.

Evolution of Preclinical Characterization and Insights into Clinical Pharmacology of Checkpoint Inhibitors Approved for Cancer Immunotherapy

Cancer immunotherapy has significantly advanced the treatment paradigm in oncology, with approvals of immuno‐oncology agents for over 16 indications, many of them first line. Checkpoint inhibitors (CPIs) are recognized as an essential backbone for a successful anticancer therapy regimen. This review focuses on the US Food and Drug Administration (FDA) regulatory approvals of major CPIs and the evolution of translational advances since their first approval close to a decade ago. In addition, critical preclinical and clinical pharmacology considerations, an overview of the pharmacokinetic and dose/regimen aspects, and a discussion of the future of CPI translational and clinical pharmacology as combination therapy becomes a mainstay of industrial immunotherapy development and in clinical practice are also discussed.

A Physiologically Based Pharmacokinetic Framework for Quantifying Antibody Distribution Gradients from Tumors to Tumor-Draining Lymph Nodes

Immune checkpoint blockades prescribed in the neoadjuvant setting are now under active investigation for many types of tumors, and many have shown early success. The primary tumor (PT) and tumor-draining lymph node (TDLN) immune factors, along with adequate therapeutic antibody distributions to the PT and TDLN, are critical for optimal immune activation and anti-tumor efficacy in neoadjuvant immunotherapy. However, it remains largely unknown how much of the antibody can be distributed into the PT-TDLN axis at different clinical scenarios. The goal of the current work is to build a physiologically based pharmacokinetic (PBPK) model framework capable of characterizing antibody distribution gradients in the PT-TDLN axis across various clinical and pathophysiological scenarios. The model was calibrated using clinical data from immuno-PET antibody-imaging studies quantifying antibody pharmacokinetics (PK) in the blood, PTs, and TDLNs. The effects of metastatic lesion location, tumor-induced compression, and inflammation, as well as surgery, on antibody concentration gradients in the PT-TDLN axis were characterized. The PBPK model serves as a valuable tool to predict antibody exposures in various types of tumors, metastases, and the associated lymph node, supporting effective immunotherapy.

The current knowledge concerning solid cancer and therapy

Solid cancers comprise a large number of new cases and deaths from cancer each year globally. There are a number of strategies for addressing tumors raised from solid organs including surgery, chemotherapy, radiotherapy, targeted therapy, immunotherapy, combinational therapy, and stem cell and extracellular vesicle (EV) therapy. Surgery, radiotherapy, and chemotherapy are the dominant cures, but are not always effective, in which even in a localized tumor there is a possibility of tumor relapse after surgical resection. Over half of the cancer patients will receive radiotherapy as a part of their therapeutic schedule. Radiotherapy can cause an abscopal response for boosting the activity of the immune system outside the local field of radiation, but it may also cause an unwanted bystander effect, predisposing nonradiated cells into carcinogenesis. In the context of immunotherapy, immune checkpoint inhibition is known as the standard-of-care, but the major concern is in regard with cold cancers that show low responses to such therapy. Stem-cell therapy can be used to send prodrugs toward the tumor area; this strategy, however, has its own predicaments, such as unwanted attraction toward the other sites including healthy tissues and its instability. A substitute to such therapy and quite a novel strategy is to use EVs, by virtue of their stability and potential to cross biological barriers and long-term storage of contents. Combination therapy is the current focus. Despite advances in the field, there are still unmet concerns in the area of effective cancer therapy, raising challenges and opportunities for future investigations.

Population pharmacokinetics of the anti-PD-1 antibody camrelizumab in patients with multiple tumor types and model-informed dosing strategy

Camrelizumab, a programmed cell death 1 (PD-1) inhibitor, has been approved for the treatment of patients with relapsed or refractory classical Hodgkin lymphoma, nasopharyngeal cancer and non-small cell lung cancer. The aim of this study was to perform a population pharmacokinetic (PK) analysis of camrelizumab to quantify the impact of patient characteristics and to investigate the appropriateness of a flat dose in the dosing regimen. A total of 3092 camrelizumab concentrations from 133 patients in four clinical trials with advanced melanoma, relapsed or refractory classical Hodgkin lymphoma and other solid tumor types were analyzed using nonlinear mixed effects modeling. The PKs of camrelizumab were properly described using a two-compartment model with parallel linear and nonlinear clearance. Then, covariate model building was conducted using stepwise forward addition and backward elimination. The results showed that baseline albumin had significant effects on linear clearance, while actual body weight affected intercompartmental clearance. However, their impacts were limited, and no dose adjustments were required. The final model was further evaluated by goodness-of-fit plots, bootstrap procedures, and visual predictive checks and showed satisfactory model performance. Moreover, dosing regimens of 200 mg every 2 weeks and 3 mg/kg every 2 weeks provided similar exposure distributions by model-based Monte Carlo simulation. The population analyses demonstrated that patient characteristics have no clinically meaningful impact on the PKs of camrelizumab and present evidence for no advantage of either the flat dose or weight-based dose regimen for most patients with advanced solid tumors.

Physiologically Based Pharmacokinetic Modeling and Allometric Scaling in Pediatric Drug Development: Where Do We Draw the Line?

Developing medicines for children is now established in legislation in both the United States and Europe; new drugs require pediatric study or investigation plans as part of their development. Particularly in early age groups, many developmental processes are not reflected by simple scalars such as body weight or body surface area, and even projecting doses based on simple allometric scaling can lead to significant overdoses in certain age groups. Modeling and simulation methodology, including physiologically based modeling, has evolved as part of the drug development toolkit and is being increasingly applied to various aspects of pediatric drug development. Pediatric physiologically based pharmacokinetic (PBPK) models account for the development of organs and the ontogeny of specific enzymes and transporters that determine the age-related pharmacokinetic profiles. However, when should this approach be used, and when will simpler methods such as allometric scaling suffice in answering specific problems? The aim of this review article is to illustrate the application of allometric scaling and PBPK in pediatric drug development and explore the optimal application of the latter approach with reference to case examples. In reality, allometric scaling included as part of population pharmacokinetic and PBPK approaches are all part of a model-informed drug development toolkit helping with decision making during the process of drug discovery and development; to that end, they should be viewed as complementary.

Atezolizumab and Bevacizumab in Patients with Unresectable Hepatocellular Carcinoma: Pharmacokinetic and Safety Assessments Based on Hepatic Impairment Status and Geographic Region

INTRODUCTION

Phase 1b GO30140 and phase 3 IMbrave150 studies evaluated first-line atezolizumab + bevacizumab for unresectable hepatocellular carcinoma (HCC). Here, we evaluated pharmacokinetics (PK) and safety by hepatic impairment status and geographic region.

METHODS

Patients received atezolizumab 1,200 mg + bevacizumab 15 mg/kg IV every 3 weeks. Drug concentrations were evaluated by descriptive statistics and population PK. PK and adverse event frequencies were evaluated by hepatic impairment status and region.

RESULTS

323 IMbrave150 patients and 162 GO30140 patients were PK evaluable. Compared with IMbrave150 patients who had normal hepatic function per the National Cancer Institute Organ Dysfunction Working Group (NCI-ODWG) criteria (n = 123), patients with mild impairment (n = 171) had a geometric mean ratio (GMR) of 0.92 for cycle 1 atezolizumab area under the concentration-time curve (AUC); patients with moderate impairment (n = 27) had a GMR of 0.88. Patients in Asia ([n = 162] vs. outside [n = 161]) had a GMR of 1.25 for cycle 1 atezolizumab AUC. Compared with GO30140 patients who had normal hepatic function (NCI-ODWG [n = 61]), patients with mild impairment (n = 92) had a GMR of 0.97 for cycle 1 peak bevacizumab concentrations; those with moderate impairment (n = 9) had a GMR of 0.94. Patients in Asia (n = 111) versus outside Asia (n = 51) had a GMR of 0.94 for cycle 1 peak bevacizumab concentration. PK results were generally comparable when evaluated based on additional hepatic functional definitions (Child-Pugh or albumin/bilirubin criteria) or study enrollment in Japan. No associations between atezolizumab PK and HCC etiology were seen. Adverse event frequencies were similar across evaluated groups.

CONCLUSIONS

IMbrave150 and GO30140 patients with unresectable HCC had varying baseline hepatic impairment and high enrollment from Asia. PK data demonstrated considerable exposure overlap across groups. Treatment was tolerable across groups. No need for dose adjustment based on mild or moderate hepatic impairment or region is recommended based on this analysis.

Pediatric Dose Selection for Therapeutic Proteins

In selecting optimal dosing regimens in support of the clinical use of monoclonal antibodies and other therapeutic proteins in pediatric indications, the unique pharmacokinetic properties of this class of biologics, as well as the underlying physiologic and pathophysiologic processes and their modulation by childhood growth and development, needs to be appreciated. During drug development, first-in-pediatric dose selection is a capstone event in the pediatric investigation plan that relies heavily on extrapolation of pharmacokinetic and pharmacodynamic data from adult to pediatric populations. It is facilitated by combinations of pharmacometric approaches, including allometry, physiologically based pharmacokinetic modeling, and population pharmacokinetic analyses, although data on reliability and qualification of some of these tools in the context of therapeutic proteins are still limited but emerging. Presented data suggest nonlinear relationships between body weight and both clearance and volume of distribution for therapeutic proteins in pediatric populations, with allometric exponents of 0.75 and 0.8, respectively. For newborns and infants (<1 year), even higher nonlinearity seems to occur. Translation of the quantitative characterization of the pediatric pharmacokinetics of therapeutic proteins into dosing regimens for the drug label requires compromising between precision dosing and clinical practicability, with tiered dosing algorithms based on size or age strata being the currently most frequently applied methodology.

Evaluating the efficacy and safety of immune checkpoint inhibitors by detecting the exposure-response: An inductive review

Immune checkpoint inhibitors (ICIs) have been demonstrated an effective treatment in multiple tumor type, which restore the immune response to against cancer cell. Currently, approved ICIs include anti-cytotoxic T-lymphocyte antigen-4 (CTLA-4); anti-programmed cell death 1 (PD-1) and anti-programmed cell death ligand 1 (PD-L1) monoclonal antibodies (mAbs). In most these drugs, unique pharmacokinetic (PK) and pharmacodynamics (PD) have shown significant influence on clinical outcomes, which occurred by target-mediated drug concentration and time-varying drug clearance. An exposure-response (E-R) relationship has been used to describe the safety and efficacy of ICIs, and shown a plateaued E-R and time dependent changes in exposure. Using an enzyme linked immunosorbent assay (ELISA) or LC-MS/MS method to measure the peak concentration, trough concentration or area under the curve (AUC) of ICIs to assess the drug exposure. There are lots of covariates that have an influence on exposure, such as sex, clearance, body weight and tumor burden. In this review, we pooled data from studies of concentration or other pharmacokinetics parameter of mAbs to assess E-R in efficacy and safety.

Results of a Dose-Finding Phase 1b Study of Subcutaneous Atezolizumab in Patients With Locally Advanced or Metastatic Non-Small Cell Lung Cancer

Intravenous (IV) atezolizumab is approved for non-small cell lung and other cancers. Subcutaneous (SC) atezolizumab coformulated with recombinant human hyaluronidase, a permeation enhancer for SC dispersion and absorption, is being developed to improve treatment options, reduce burden, and increase efficiency for patients and practitioners. IMscin001 (NCT03735121), a 2-part, open-label, global, multicenter, phase 1b/3 study, is evaluating the pharmacokinetics (PK), safety, and efficacy of SC atezolizumab. The part 1 (phase 1b) objective was determination of an SC atezolizumab dose yielding a serum trough concentration (C_trough ) comparable with IV. Patients enrolled in 3 cohorts received SC atezolizumab 1800 mg (thigh) once (cohort 1), 1200 mg (thigh) every 2 weeks for 3 cycles (cohort 2), or 1800 mg (abdomen) every 3 weeks cycle 1, then cycles 2 and 3 (thigh) every 3 weeks (cohort 3). In subsequent cycles, IV atezolizumab 1200 mg every 3 weeks was administered until loss of clinical benefit. SC atezolizumab 1800 mg every 3 weeks and 1200 mg every 2 weeks provided similar C_trough and area under the curve values in cycle 1 to the corresponding IV atezolizumab reference, was well tolerated, and exhibited a safety profile consistent with the established IV formulation. Exposure following SC injection in the abdomen was lower (20%, 28%, and 27% for C_trough , maximum concentration, and area under the concentration-time curve from time 0 to day 21, respectively) than in the thigh. Part 1 SC and IV PK data were analyzed using a population PK modeling approach, followed by simulations. Part 2 (phase 3) will now be initiated to demonstrate that SC atezolizumab PK exposure is not lower than that of IV.

Pharmacokinetic implications of dosing emicizumab based on vial size: A simulation study

INTRODUCTION

Emicizumab is dosed as mg/kg and, according to the label, any unused drug left in the vial(s) must be discarded, thereby wasting expensive resources. The aim of this study was to use population pharmacokinetics to illustrate the implications of changing the dosing interval to avoid wastage.

METHODS

We used a previously published emicizumab PopPK model after extending its validation to children. We simulated PK parameters for labelled dosing regimens and for regimens using full vials with infusion frequency varied to keep the steady-state drug concentration unchanged. Cost and drug savings were calculated.

RESULTS

The model evaluation was successful. When rounding up, the average individual below 53, 47 and 39 has a time-to-trough increase of up to 5.7, 7.9 and 5.8 days for the QW, Q2 W and Q4 W regimen, respectively. This resulted in an annual cost reduction of up to $173,136, $75,747 and $61,319 USD per patient. At higher body weights, rounding down the dose to the nearest vial resulted in negligible changes in the steady state concentration and cost savings of up to $93,781, $46,891 and $23,446 USD per patient, respectively.

CONCLUSION

Individuals with a lower body weight may benefit from increasing dose intervals and rounding up dose up to the nearest vial, and individuals with a higher body weight from maintaining the injection frequency and rounding dose down to the nearest vial without significant change in emicizumab levels. Administering the entire vial may result in a reduction of vials used annually and potential cost savings.

Allometric scaling of therapeutic monoclonal antibodies in preclinical and clinical settings

Constant technological advancement enabled the production of therapeutic monoclonal antibodies (mAbs) and will continue to contribute to their rapid expansion. Compared to small-molecule drugs, mAbs have favorable characteristics, but also more complex pharmacokinetics (PK), e.g., target-mediated nonlinear elimination and recycling by neonatal Fc-receptor. This review briefly discusses mAb biology, similarities and differences in PK processes across species and within human, and provides a detailed overview of allometric scaling approaches for translating mAb PK from preclinical species to human and extrapolating from adults to children. The approaches described here will remain vital in mAb drug development, although more data are needed, for example, from very young patients and mAbs with nonlinear PK, to allow for more confident conclusions and contribute to further growth of this field. Improving mAb PK predictions will facilitate better planning of (pediatric) clinical studies and enable progression toward the ultimate goal of expediting drug development.

Recent advances in understanding osteosarcoma and emerging therapies

Osteosarcoma is the most common bone cancer in adolescents and young adults, but it is a rare cancer with no improvement in patient survival in the last four decades. The main problem of this bone tumor is its evolution toward lung metastatic disease, despite the current treatment strategy (chemotherapy and surgery). To further improve survival, there is a strong need for new therapies that control osteosarcoma cells with metastatic potential and their favoring tumor microenvironment (ME) from the diagnosis. However, the complexity and heterogeneity of those tumor cell genomic/epigenetic and biology, the diversity of tumor ME where it develops, the sparsity of appropriate preclinical models, and the heterogeneity of therapeutic trials have rendered the task difficult. No tumor- or ME-targeted drugs are routinely available in front-line treatment. This article presents up-to-date information from preclinical and clinical studies that were recently published or presented in recent meetings which we hope might help change the osteosarcoma treatment landscape and patient survival in the near future.

A drug safety evaluation of atezolizumab in locally advanced or metastatic urothelial carcinoma

INTRODUCTION

Immune checkpoint inhibitors (ICIs) have rapidly changed the treatment landscape, demonstrating dramatic clinical efficacy in various cancers.

AREAS COVERED

In urothelial cancer (UC), several ICIs have been approved in platinum refractory disease and also as first-line therapy in patients that fulfill the criteria for cisplatin ineligibility. Atezolizumab is a monoclonal antibody that targets the immune checkpoint Programmed Cell Death Ligand-1 (PD-L1) and has been currently approved for advanced UC, non-small cell lung cancer, small cell lung cancer, and triple-negative breast cancer. Herein, we provide a summary of the mechanism of action, safety, and clinical efficacy of atezolizumab in UC.

EXPERT OPINION

Atezolizumab is a drug with a favorable toxicity profile and will obtain more indications in the future in UC and other cancers. Treating physicians should be aware of treatment-related and immune-related adverse events associated with the drug.

Immunotherapy in sarcoma: combinations or single agents? In whom?

PURPOSE OF REVIEW

First clinical trials investigating immune check point (ICP) inhibitors in patients with sarcoma, regardless histological or molecular subtypes did not demonstrate any prolonged benefit. To maximize the chance of benefit from immunotherapy, recent strategies explore the combination of treatments and aim to improve identification of responsive histological subtypes.

RECENT FINDINGS

Combination of several ICP inhibitors tends to increase toxicity and efficacy. Mechanisms of synergistic action remain unclear. Combination of ICP blockade with tyrosine kinase inhibitor increases efficacy in specific histological subtypes already identified as sensitive to each drug separately. The role of the combination is not established yet. Several ongoing trials assess the combination of ICP blockade with chemotherapy or radiotherapy. ICP blockade seems highly effective in some selected histological subtypes like alveolar soft part sarcoma, chordoma, malignant rhabdoid tumor, and angiosarcoma. Encouraging preliminary results need to be confirmed in larger cohorts and biological mechanisms that sustain this efficacy should be further explored. Adoptive cell therapy seems very promising in synovialosarcoma.

SUMMARY

Significant efforts are underway to efficiently develop immunotherapy in patients with sarcoma and better characterize patients who would benefit the most from it.

Effect of age on pharmacokinetics, efficacy, and safety of galcanezumab treatment in adult patients with migraine: results from six phase 2 and phase 3 randomized clinical trials

Background

Migraine clinical profile may change with age, making it necessary to verify that migraine treatments are equally safe and effective in older patients. These analyses evaluated the effects of patient age on the pharmacokinetics (PK), efficacy, and safety of galcanezumab for prevention of migraine.

Methods

Analyses included efficacy data from three double-blind phase 3 clinical trials: two 6-month studies in episodic migraine (EVOLVE-1, EVOLVE-2: N = 1773) and one 3-month study in chronic migraine (REGAIN:N = 1113). Patients were randomized 2:1:1 to placebo, galcanezumab 120 mg, or galcanezumab 240 mg. Safety and PK data included additional phase 2 and phase 3 trials for a larger sample size of patients > 60 years (range = 18–65 for all studies). Subgroup analyses assessed efficacy measures, adverse event (AE) occurrence, and cardiovascular measurement changes by patient age group. Galcanezumab PK were evaluated using a population analysis approach, where age was examined as a potential covariate on apparent clearance (CL/F) and apparent volume of distribution (V/F) of galcanezumab.

Results

Numbers of baseline monthly migraine headache days were similar across age groups. There were no statistically significant treatment-by-age group interactions for any efficacy measures, except in episodic migraine studies where older patients appeared to have a larger reduction than younger patients in the number of monthly migraine headache days with acute medication use. Age (18–65) had a minimal effect on CL/F, and no effect on V/F. Galcanezumab-treated patients ≥60 years experienced no clinically meaningful increases in blood pressure and no increased frequency in treatment-emergent AEs, discontinuations due to AEs, serious adverse events (SAEs) overall, or cardiovascular SAEs, compared to age-matched placebo-treated patients.

Conclusions

Age (up to 65 years) does not affect efficacy in migraine prevention and has no clinically meaningful influence on galcanezumab PK to warrant dose adjustment. Furthermore, older galcanezumab-treated patients experienced no increases in frequency of AEs or increases in blood pressure compared with age-matched placebo-treated patients.

Trial registrations

EVOLVE-1 (NCT02614183, registered 23 November 2015), EVOLVE-2 (NCT02614196, 23 November 2015), REGAIN (NCT02614261, 23 November 2015), ART-01 (NCT01625988, 20 June 2012, ), I5Q-MC-CGAB (NCT02163993, 12 June 2014, ), I5Q-MC-CGAJ (NCT02614287, 23 November 2015, ), all retrospectively registered.