Changing Body Weight-Based Dosing to a Flat Dose for Avelumab in Metastatic Merkel Cell and Advanced Urothelial Carcinoma

Population pharmacokinetics of adebrelimab - Support of alternative flat dose regimen in extensive-stage small-cell lung cancer

Adebrelimab, a novel anti-PD-L1 antibody, has been approved by the National Medical Products Administration of China as an intravenous infusion for use in combination with carboplatin and etoposide as first-line treatment for extensive-stage small-cell lung cancer in 2023. A two-compartment model with empirical time-varying CL for adebrelimab was established based on data from 263 patients receiving body weight-based doses from two clinical studies. Significant covariate effects of baseline body weight, albumin levels, tumor size, neutrophil counts, and presence of anti-drug antibodies were identified on CL of debrelimab, none of which were clinically significant or warranted dose adjustment. The degree of decrease in CL was higher in patients who responded to treatment with adebrelimab than in non-responders. Adebrelimab exposures (AUC, Ctrough, or Cmax) were not identified as a statistically significant factor related to efficacy or safety endpoint in the exposure-response analysis. Distribution of simulated exposure metrics from the flat dose regimen (1200 mg q3w) was similar to the marketed weight-based dosing regimen (20 mg/kg q3w), supporting the alternative flat dose regimen in the clinic.

First-line Avelumab plus Chemotherapy in Patients with Advanced Solid Tumors: Results from the Phase Ib/II JAVELIN Chemotherapy Medley Study

PURPOSE

Chemotherapy can potentially enhance the activity of immune checkpoint inhibitors by promoting immune priming. The phase Ib/II JAVELIN Chemotherapy Medley trial (NCT03317496) evaluated first-line avelumab + concurrent chemotherapy in patients with advanced urothelial carcinoma or non-small cell lung cancer (NSCLC).

MATERIALS AND METHODS

Avelumab 800 or 1,200 mg was administered continuously every 3 weeks with standard doses of cisplatin + gemcitabine in patients with urothelial carcinoma, or carboplatin + pemetrexed in patients with nonsquamous NSCLC. Dual primary endpoints were dose-limiting toxicity (DLT; phase Ib) and confirmed objective response (phase Ib/II).

RESULTS

In phase Ib, urothelial carcinoma and NSCLC cohorts received avelumab 800 mg (n = 13 and n = 6, respectively) or 1,200 mg (n = 6 each) + chemotherapy. In evaluable patients with urothelial carcinoma treated with avelumab 800 or 1,200 mg + chemotherapy, DLT occurred in 1/12 (8.3%) and 1/6 (16.7%), respectively; no DLT occurred in the NSCLC cohort. In phase II, 35 additional patients with urothelial carcinoma received avelumab 1,200 mg + chemotherapy. Across all treated patients, safety profiles were similar irrespective of avelumab dose. Objective response rates (95% confidence internal) with avelumab 800 or 1,200 mg + chemotherapy, respectively, across phase Ib/II, were 53.8% (25.1-80.8) and 39.0% (24.2-55.5) in urothelial carcinoma, and 50.0% (11.8-88.2) and 33.3% (4.3-77.7) in NSCLC.

CONCLUSIONS

Preliminary efficacy and safety findings with avelumab + chemotherapy in urothelial carcinoma and NSCLC were consistent with previous studies of similar combination regimens. Conclusions about clinical activity are limited by small patient numbers.

SIGNIFICANCE

This phase Ib/II trial evaluated avelumab (immune checkpoint inhibitor) administered concurrently with standard first-line chemotherapy in patients with advanced urothelial carcinoma or advanced nonsquamous NSCLC without actionable mutations. Efficacy and safety appeared consistent with previous studies of similar combinations, although patient numbers were small.

A phase II open-label trial of avelumab plus axitinib in previously treated non-small-cell lung cancer or treatment-naïve, cisplatin-ineligible urothelial cancer

BACKGROUND

We hypothesized that avelumab plus axitinib could improve clinical outcomes in patients with advanced non-small-cell lung cancer (NSCLC) or urothelial carcinoma (UC).

PATIENTS AND METHODS

We enrolled previously treated patients with advanced or metastatic NSCLC, or untreated, cisplatin-ineligible patients with advanced or metastatic UC. Patients received avelumab 800 mg every 2 weeks (Q2W) and axitinib 5 mg orally two times daily. The primary endpoint was objective response rate (ORR). Immunohistochemistry was used to assess programmed death-ligand 1 (PD-L1) expression (SP263 assay) and the presence of CD8+ T cells (clone C8/144B). Tumor mutational burden (TMB) was assessed by whole-exome sequencing.

RESULTS

A total of 61 patients were enrolled and treated (NSCLC, n = 41; UC, n = 20); 5 remained on treatment at data cut-off (26 February 2021). The confirmed ORR was 31.7% in the NSCLC cohort and 10.0% in the UC cohort (all partial responses). Antitumor activity was observed irrespective of PD-L1 expression. In exploratory subgroups, ORRs were higher in patients with higher (≥median) CD8+ T cells in the tumor. ORRs were higher in patients with lower TMB (<median) in the NSCLC cohort and higher TMB (≥median) in the UC cohort. Treatment-related adverse events (TRAEs) occurred in 93.4% of patients, including grade ≥3 TRAEs in 55.7%. Avelumab exposures with 800 mg Q2W dosing were similar to those observed with 10 mg/kg Q2W dosing.

CONCLUSIONS

In previously treated patients with advanced/metastatic NSCLC, ORR appeared to be superior to anti-PD-L1 or anti-programmed cell death protein 1 monotherapy, irrespective of PD-L1 status, whereas in untreated, cisplatin-ineligible patients with advanced/metastatic UC, ORR was lower than expected, potentially limited by small patient numbers.

TRIAL REGISTRATION

Clinicaltrial.gov NCT03472560; https://clinicaltrials.gov/ct2/show/NCT03472560.

Optimizing benefit/risk in oncology: Review of post-marketing dose optimization and reflections on the road ahead

Oncology therapies shifted from chemotherapy to molecularly targeted agents and finally to the era of immune-oncology agents. In contrast to cytotoxic agents, molecularly targeted agents are more selective, exhibit a wider therapeutic window, and may maximally modulate tumor growth at doses lower than the maximum tolerated dose (MTD). However, first-in-patient oncology studies for molecularly targeted agents continued to evaluate escalating doses using limited number of patients per dose cohort assessing dose-limiting toxicities to identify the MTD which is commonly selected for further development adopting a 'more is better' approach that led to several post-marketing requirement (PMR) studies to evaluate alternative, typically lower, doses or dosing frequencies to optimize the benefit-risk profile. In this review, post-marketing dose optimization efforts were reviewed including those required by a regulatory pathway or voluntarily conducted by the sponsor to improve efficacy, safety, or method of administration. Lessons learned and future implications from this deep dive review are discussed considering the evolving regulatory landscape on dose optimization for oncology compounds.

Avelumab Maintenance Treatment After First-line Chemotherapy in Advanced Urothelial Carcinoma-A Cost-Effectiveness Analysis

BACKGROUND

Recently, a clinical trial (NCT02603432) showed that avelumab maintenance treatment, post first-line chemotherapy, can significantly prolong the overall survival of patients with advanced urothelial carcinoma (UC), however, the treatment was very expensive. This study aimed to determine the cost-effectiveness of avelumab maintenance therapy in advanced or metastatic UC from the US taxpayer perspective.

METHODS

Based on the data of the JAVELIN Bladder 100 clinical trial (NCT02603432), a Markov multi-state model was constructed to investigate the costs and clinical outcomes of avelumab maintenance after platinum-based chemotherapy versus best supportive care (BSC) for advanced or metastatic UC. Parameters of the model came from the 2020 Average Sales Price Drug Pricing Files and published literature. The main outputs were costs, life years (LYs), quality-adjusted life years (QALYs), and incremental cost-effectiveness ratio (ICER). Robustness was tested by deterministic and probabilistic sensitivity analyses. The analysis was stratified to include both the overall population and a subset of programmed death-ligand 1 (PD-L1)-positive patients.

RESULTS

Avelumab maintenance therapy was estimated to generate an additional 0.26 QALYs (1.46 vs. 1.20 QALYs) and costs $183,271 ($278,323 vs. $95,052) more compared to BSC alone in the overall population, yielding an ICER of $699,065/QALY. For the PD-L1-positive population, avelumab produced a 0.42 increase in QALYs (1.74 vs. 1.32 QALYs) and raised costs to $223,238 ($320,355 vs. $97,117), resulting in an ICER of $521,850/QALY for this population. Both ICERs were above the willingness-to-pay (WTP) threshold of $200,000/QALY. Sensitivity analyses manifested that the model was robust.

CONCLUSION

From the perspective of the US taxpayer, avelumab maintenance therapy is considered cost-ineffective for patients with advanced or metastatic UC at a WTP threshold of $200,000/QALY in the overall population as well as in PD-L1-positive population.

Advances in pharmacokinetics and pharmacodynamics of PD-1/PD-L1 inhibitors

Immune checkpoint inhibitors (ICIs) are a group of drugs designed to improve the therapeutic effects on various types of malignant tumors. Irrespective of monotherapy or combinational therapies as first-line and later-line therapy, ICIs have achieved benefits for various tumors. Programmed cell death protein-1 (PD-1) / ligand 1 (PD-L1) is an immune checkpoint that suppresses antitumor immunity, especially in the tumor microenvironment (TME). PD-1/PD-L1 immune checkpoint inhibitors block tumor-related downregulation of the immune system, thereby enhancing antitumor immunity. In comparison with traditional small-molecule drugs, ICIs exhibit pharmacokinetic characteristics owing to their high molecular weight. Furthermore, different types of ICIs exhibit different pharmacodynamic characteristics. Hence, ICIs have been approved for different indications by the Food and Drug Administration (FDA) and National Medical Products Administration (NMPA). This review summarizes pharmacokinetic and pharmacodynamic studies of PD-1/ PD-L1 inhibitors to provide a reference for rational clinical application.

The emerging landscape of novel 4-1BB (CD137) agonistic drugs for cancer immunotherapy

The clinical development of 4-1BB agonists for cancer immunotherapy has raised substantial interest during the past decade. The first generation of 4-1BB agonistic antibodies entering the clinic, urelumab (BMS-663513) and utomilumab (PF-05082566), failed due to (liver) toxicity or lack of efficacy, respectively. The two antibodies display differences in the affinity and the 4-1BB receptor epitope recognition, as well as the isotype, which determines the Fc-gamma-receptor (FcγR) crosslinking activity. Based on this experience a very diverse landscape of second-generation 4-1BB agonists addressing the liabilities of first-generation agonists has recently been developed, with many entering clinical Phase 1 and 2 studies. This review provides an overview focusing on differences and their scientific rationale, as well as challenges foreseen during the clinical development of these molecules.

Avelumab in paediatric patients with refractory or relapsed solid tumours: dose-escalation results from an open-label, single-arm, phase 1/2 trial

BACKGROUND

We report dose-escalation results from an open-label, phase 1/2 trial evaluating avelumab (anti-PD-L1) in paediatric patients with refractory/relapsed solid tumours.

METHODS

In phase 1, patients aged < 18 years with solid (including central nervous system [CNS]) tumours for which standard therapy did not exist or had failed were enrolled in sequential cohorts of 3-6 patients. Patients received avelumab 10 or 20 mg/kg intravenously every 2 weeks. Primary endpoints were dose-limiting toxicities (DLTs) and grade ≥ 3 treatment-emergent adverse events (AEs).

RESULTS

At data cut-off (27 July 2021), 21 patients aged 3-17 years had received avelumab 10 mg/kg (n = 6) or 20 mg/kg (n = 15). One patient had three events that were classified as a DLT (fatigue with hemiparesis and muscular weakness associated with pseudoprogression; 20 mg/kg cohort). Grade ≥ 3 AEs occurred in five (83%) and 11 (73%) patients in the 10 and 20 mg/kg cohorts, respectively, and were treatment-related in one patient (7%; grade 3 [DLT]) in the 20 mg/kg cohort. Avelumab exposure in paediatric patients receiving 20 mg/kg dosing, but not 10 mg/kg, was comparable or higher compared with approved adult dosing (10 mg/kg or 800 mg flat dose). No objective responses were observed. Four patients with CNS tumours (20 mg/kg cohort) achieved stable disease, which was ongoing in two patients with astrocytoma at cut-off (for 24.7 and 30.3 months).

CONCLUSION

In paediatric patients with refractory/relapsed solid tumours, avelumab monotherapy showed a safety profile consistent with previous adult studies, but clinical benefits were limited.

A Profile of Avelumab Plus Axitinib in the Treatment of Renal Cell Carcinoma

Until recently, the approved first-line treatment for metastatic RCC (mRCC) consisted of tyrosine kinase inhibitors (TKI) targeting the vascular endothelial growth factor receptors (VEGFR) monotherapy. The landscape of first-line treatment has been transformed in the last few years with the advent of immune checkpoint inhibitors (ICI) or VEGFR TKI plus ICI combinations. This article focuses on the profile of one of these ICI plus VEGFR TKI combination, avelumab plus axitinib. We detail the characteristics of each drug separately, and then we explore the rationale for their association, its efficacy and the resulting toxicity. Finally, we examine the factors associated with avelumab plus axitinib outcomes, and their impact on therapeutic strategy.

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.

Avelumab First-Line Maintenance Treatment in Advanced Bladder Cancer: Practical Implementation Steps for Infusion Nurses

Immune checkpoint inhibitors, such as programmed cell death ligand 1 inhibitors pembrolizumab, nivolumab, atezolizumab, and avelumab, are used to treat patients with advanced urothelial carcinoma (UC). Based on data from the phase 3 JAVELIN Bladder 100 trial, avelumab first-line (1L) maintenance is now considered the standard-of-care treatment for patients with locally advanced or metastatic UC who responded or experienced disease stabilization after 1L platinum-containing chemotherapy, and it is the only category 1 preferred checkpoint inhibitor maintenance option in the National Comprehensive Cancer Network Clinical Practice Guidelines in Oncology for patients with cisplatin-eligible and cisplatin-ineligible locally advanced or metastatic UC. This article reviews key considerations related to avelumab 1L maintenance therapy that infusion nurses should be familiar with, including dosing, administration, and immune-related adverse event recognition and management, to ensure safe and appropriate use of this important and impactful therapy.

Model-informed drug development supporting the approval of the avelumab flat-dose regimen in patients with advanced renal cell carcinoma

Avelumab is an anti–PD‐L1 monoclonal antibody approved as monotherapy for Merkel cell carcinoma (MCC) and urothelial carcinoma (UC), and in combination with axitinib for advanced renal cell carcinoma (aRCC). Although initially approved with weight‐based dosing (10 mg/kg intravenously [IV] every 2 weeks [Q2W]), avelumab was subsequently approved for flat dosing (800 mg IV Q2W) based on population pharmacokinetic (PopPK), exposure‐efficacy, and exposure‐safety modeling in MCC and UC. Here, through modeling and simulation, we provide justification for a flat‐dose regimen of avelumab plus axitinib in aRCC. Simulated exposure metrics from the previous monotherapy PopPK model (1827 patients) for both weight‐based and flat‐dose regimens were compared with exposure metrics from treatment‐naive patients with aRCC who received avelumab plus axitinib (488 patients). The aRCC population exposures were derived from a fit‐for‐purpose PopPK model developed using data from monotherapy and combination studies and the existing base structural PopPK model. Exposure‐response relationships for safety were analyzed, including grade ≥3 treatment‐emergent adverse events (TEAEs), any‐grade infusion‐related reactions, and TEAE any‐grade immune‐related adverse events (irAEs). Weight‐based dosing of avelumab in the aRCC population yielded similar PK exposures to the flat‐dose regimen reference exposures in the monotherapy population. Increased avelumab exposure was not associated with increased probabilities of grade ≥3 TEAEs or any‐grade IRRs, although there was a weak association with an increased probability of any‐grade irAEs. Overall, models in aRCC suggest that the avelumab 800‐mg Q2W flat‐dose regimen would provide similar benefits compared with weight‐based dosing with no meaningful change in the probability of AEs.

Immune checkpoint-targeted antibodies: a room for dose and schedule optimization?

Anti-CTLA-4 and anti-PD-1/PD-L1 immune checkpoint inhibitors are therapeutic monoclonal antibodies that do not target cancer cells but are designed to reactivate or promote antitumor immunity. Dosing and scheduling of these biologics were established according to conventional drug development models, even though the determination of a maximum tolerated dose in the clinic could only be defined for anti-CTLA-4. Given the pharmacology of these monoclonal antibodies, their high interpatient pharmacokinetic variability, the actual clinical benefit as monotherapy that is observed only in a specific subset of patients, and the substantial cost of these treatments, a number of questions arise regarding the selected dose and the dosing interval. This review aims to outline the development of these immunotherapies and considers optimization options that could be used in clinical practice.

Two Clinical Cases of Metastatic Merkel Cell Carcinoma Illustrating Avelumab Tolerability in Elderly Patients

We present two cases of primary cutaneous Merkel cell carcinoma in a 80-year and a 95-year old patient. Both patients had a wide local excision, but early recurrences occurred. Case 1 required palliative radiotherapy. He did not receive chemotherapy but case 2 did. They then proceeded to have immunotherapy with sustained responses lasting greater than 2 and 3 years. This report highlights an important new class of drug for the treatment of advanced Merkel cell carcinoma. Furthermore, our case report demonstrates that avelumab immunotherapy can be safely delivered to elderly patients, including 80- and 95-year-old patients. This report parallels the high and durable response rates to avelumab (including complete responses) that were shown in the JAVELIN phase II trials.

Biological Therapeutic Advances for the Treatment of Advanced Urothelial Cancers

In recent years, diagnostic and therapeutic advances have contributed to a reduction in mortality rates of patients with metastatic urothelial carcinoma (mUC). Immune checkpoint inhibitors have demonstrated efficacy and safety as both first-line and first-line switch maintenance therapy for mUC. For platinum-refractory patients, in addition to immunotherapy, other targeted agents (antibody-drug conjugates and fibroblast growth factor receptor inhibitors) have been approved after demonstrating a clinically relevant advantage in overall response rate, progression-free survival, and overall survival compared to standard of care. Sequential treatment strategies are finally feasible for patients with advanced urothelial carcinoma. This review will summarize the results of the most important phase II-III clinical trials for first-line, switch maintenance, second-line, and subsequent lines of therapy, and describe the most promising clinical trials currently ongoing in these treatment scenarios.

Advances and Controversies With Checkpoint Inhibitors in Bladder Cancer

Immune checkpoint inhibitors have revolutionized the treatment of bladder urothelial cancers and have wide application in almost all disease states. Although several drugs have initially been shown to be beneficial in the second-line metastatic setting, there are still ongoing controversies and debate, including voluntary withdrawals of durvalumab and atezolizumab, along with the approval of agents in the first-line setting in the cisplatin-ineligible state based on inconsistent confirmatory phase III trials. As novel immunotherapy drugs are discovered and studied in various phases of clinical trials, these agents will continue to change the treatment landscape for bladder cancer patients. This review will discuss current available evidence and information and key pivotal trials using checkpoint inhibitors in bladder cancer.

Immunotherapy using PD-1/PDL-1 inhibitors in metastatic triple-negative breast cancer: A systematic review

Breast cancer is the most commonly diagnosed cancer in women and is one of the leading causes of death from cancer in women worldwide. Despite the significant benefits of using conventional chemotherapy in the treatment of breast cancer, one of its subtypes, the triple-negative breast cancer, is still a challenge in clinical practice. Recent studies have been investigating the role of the immune system in breast cancer and the development of immunotherapy. Although recently the use of atezolizumab, an anti-PD-L1 monoclonal antibody, combined with chemotherapy was approved, an important step in the treatment of patients with triple-negative metastatic breast cancer, the use of immunotherapy to treat breast tumors remains a major challenge. In this systematic literature review, following PRISMA guidelines, we searched for clinical trials using immunotherapy in the treatment of metastatic triple-negative breast cancer published until March 2020 in the databases EMBASE, PubMed and Cochrane Central Register of Controlled Trials (CENTRAL), with no language restrictions. We did not contact the authors of the clinical trials to obtain additional information. Two researchers independently collected the data and assessed the quality of this study. The literature shows that immunotherapy with anti-PD-1/PD-L1 agents is emerging as a new treatment option in breast cancer. On the other hand, when compared to other types of cancer in which several agents have already been approved, the research is still in its infancy. The use of anti-PD-1/PD-L1 agents as monotherapy revealed encouraging results in the metastatic setting, especially when administered in the early course of the disease, although combination strategies with chemotherapy appear to increase its efficacy. The main limitation of this study is the approach of cancer only in advanced stages.

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.

Avelumab first-line maintenance in locally advanced or metastatic urothelial carcinoma: Applying clinical trial findings to clinical practice

Although urothelial carcinoma (UC) is considered a chemotherapy-sensitive tumor, progression-free survival and overall survival (OS) are typically short following standard first-line (1L) platinum-containing chemotherapy in patients with locally advanced or metastatic disease. Immune checkpoint inhibitors (ICIs) have antitumor activity in UC and favorable safety profiles compared with chemotherapy; however, trials of 1L ICI monotherapy or chemotherapy + ICI combinations have not yet shown improved OS vs chemotherapy alone. In addition to direct cytotoxicity, chemotherapy has potential immunogenic effects, providing a rationale for assessing ICIs as switch-maintenance therapy. In the JAVELIN Bladder 100 phase 3 trial, avelumab administered as 1L maintenance with best supportive care (BSC) significantly prolonged OS vs BSC alone in patients with locally advanced or metastatic UC that had not progressed with 1L platinum-containing chemotherapy (median OS, 21.4 vs 14.3 months; hazard ratio, 0.69 [95% CI, 0.56-0.86]; P = 0.001). Efficacy benefits were seen across various subgroups, including recipients of 1L cisplatin- or carboplatin-based chemotherapy, patients with PD-L1+ or PD-L1- tumors, and patients with diverse characteristics. Results from JAVELIN Bladder 100 led to the approval of avelumab as 1L maintenance therapy for patients with locally advanced or metastatic UC that has not progressed with platinum-containing chemotherapy. Avelumab 1L maintenance is also included as a standard of care in treatment guidelines for advanced UC with level 1 evidence. This review summarizes the data that supported these developments and discusses practical considerations for administering avelumab maintenance in clinical practice, including patient selection and treatment management.

Cancer Immunotherapy Dosing: A Pharmacokinetic/Pharmacodynamic Perspective

Immune check-point inhibitors are drugs that are markedly different from other anticancer drugs because of their indirect mechanisms of antitumoral action and their apparently random effect in terms of efficacy and toxicity. This marked pharmacodynamics variability in patients calls for reconsidering to what extent approved dosing used in clinical practice are optimal or whether they should require efforts for customization in outlier patients. To better understand whether or not dosing could be an actionable item in oncology, in this review, preclinical and clinical development of immune checkpoint inhibitors are described, particularly from the angle of dose finding studies. Other issues in connection with dosing issues are developed, such as the flat dosing alternative, the putative role therapeutic drug monitoring could play, the rise of combinatorial strategies, and pharmaco-economic aspects.

Opportunities for using in silico-based extended dosing regimens for monoclonal antibody immune checkpoint inhibitors

Therapeutic drug monitoring (TDM) involves frequent measurements of drug concentrations to ensure levels remain within a therapeutic window, and it is especially useful for drugs with narrow therapeutic indices or extensive interindividual pharmacokinetic variability. This technique has never been applied to immuno-oncology drugs, but, given recent examinations of clinical data (both exposure and response) on a number of these drugs, further investigations into TDM may be justified to reduce costs as well as potentially reducing the severity and/or duration of immune-related adverse events. Specifically, all but one of the approved PD-1 and PD-L1 inhibitors (pembrolizumab, nivolumab, cemiplimab-rwlc, atezolizumab, avelumab, durvalumab) have been shown to exhibit a plateaued exposure-response (E-R) curve at doses evaluated extensively to date, as well as time-dependent changes in drug exposure. Furthermore, responders have a greater decrease in drug clearance over time and would, therefore, have supratherapeutic serum concentrations. With frequent trough measurements, it is possible to use pharmacokinetic modelling and simulation to estimate drug clearance via Bayesian methods. Based on patient-specific estimates for clearance, optimal alternative dosing strategies can be simulated to lower drug and cost burden yet maintain therapeutic levels, especially as the clearance of the drug decreases over time. This review will comprehensively discuss each of the FDA approved PD-1, PD-L1/2 and CTLA-4 inhibitors regarding their indications and current recommended dosing, with evidence supporting the investigation of these types of TDM strategies.

Mechanism-based treatment of cancer with immune checkpoint inhibitor therapies

Immune checkpoints are cell surface molecules that initiate regulatory pathways which have powerful control of CD8+ cytolytic T cell activity. Antagonistic and agonistic antibodies engaging these molecules have demonstrated profound impact on immune activation and have entered clinical use for the treatment of a variety of diseases. Over the past decade, antagonistic antibodies known as immune checkpoint inhibitors have become a new pillar of cancer treatment and have reshaped the therapeutic landscape in oncology. These agents differ in their mechanism of action and toxicity profiles compared to more traditional systemic cancer treatments such as chemo- and targeted therapies. This article reviews the pharmacology of this new class of agents.

Model-based simulation to support the extended dosing regimens of atezolizumab

PURPOSE

The currently recommended dosages of atezolizumab for patients with non-small cell lung cancer (NSCLC) and urothelial carcinoma (UC) is 840 mg every 2 weeks, 1200 mg every 3 weeks (q3w), and 1680 mg every 4 weeks (q4w). However, it has been argued that these dosages may not be optimal. This study aimed to explore the feasibility of extended dosing regimens by population pharmacokinetics (PK) simulations and exposure-response (E-R) relationships.

METHODS

All simulations were conducted based on the established population PK and E-R model for safety (i.e., adverse events of special interest, AESI) and efficacy (i.e., objective response rate, ORR) for patients with NSCLC or UC. The PK, AESI, and ORR profiles of the following dosing regimens were simulated: (i) 840 mg q4w, (ii) 1200 mg every 6 weeks (q6w), and (iii) 1680 mg q8w. These regimens were compared with those of the 1200 mg q3w standard regimen.

RESULTS

The simulation revealed that the ranking of efficacy for different extended dosing regimens were 1680 mg q8w ≅ 1200 mg q3w ≅ 1200 mg q6w > 840 mg q4w based on the predicted probability of ORR in patients with NSCLC and UC, and this ranking order was similar to that of the safety outcome of the AESI. The minimum serum concentration at steady-state (C_min,ss) values for all dosing regimens was all higher than the target effective concentration of 6 μg/mL.

CONCLUSION

The findings from this simulation suggest that extended dosing regimens are unlikely to significantly impair clinical outcomes and may provide more therapeutic benefits to patients in terms of safety.

Structure and Optimization of Checkpoint Inhibitors

With the advent of checkpoint inhibitor treatment for various cancer types, the optimization of drug selection, pharmacokinetics and biomarker assays is an urgent and as yet unresolved dilemma for clinicians, pharmaceutical companies and researchers. Drugs which inhibit cytotoxic T-lymphocyte associated protein-4 (CTLA-4), such as ipilimumab and tremelimumab, programmed cell death protein-1 (PD-1), such as nivolumab and pembrolizumab, and programmed cell death ligand-1 (PD-L1), such as atezolizumab, durvalumab and avelumab, each appear to have varying pharmacokinetics and clinical activity in different cancer types. Each drug differs in terms of dosing, which becomes an issue when drug comparisons are attempted. Here, we examine the various checkpoint inhibitors currently used and in development. We discuss the antibodies and their protein targets, their pharmacokinetics as measured in various tumor types, and their binding affinities to their respective antigens. We also examine the various dosing regimens for these drugs and how they differ. Finally, we examine new developments and methods to optimize delivery and efficacy in the field of checkpoint inhibitors, including non-fucosylation, prodrug formations, bispecific antibodies, and newer small molecule and peptide checkpoint inhibitors.