Rationale for fixed dosing of pertuzumab in cancer patients based on population pharmacokinetic analysis

High-throughput, low-cost quantification of 11 therapeutic antibodies using caprylic acid precipitation and LC-MS/MS

BACKGROUND

Therapeutic drug monitoring of treatment with therapeutic antibodies is hampered by the application of a wide range of different methods in the quantification of serum levels. LC-MS based methods could significantly improve comparability of results from different laboratories, but such methods are often considered complicated and costly. We developed a method for LC-MS/MS based quantification of 11 therapeutic antibodies concomitantly measured in a single run, with emphasis on simplicity in sample preparation and low cost.

RESULTS

After a single-step sample purification using caprylic acid precipitation to remove interfering proteins, the sample underwent proteolysis followed by LC-MS/MS analysis. Infliximab is used as internal standard for sample preparation while isotope-labeled signature peptides identified for each analyte are internal standards for the LC-MS/MS normalization. The method was validated according to recognized guidelines, and pipetting steps can be performed by automated liquid handling systems. The total precision of the method ranged between 2.7 and 7.3 % (5.1 % average) across the quantification range of 4-256 μg/ml for all 11 drugs, with an average accuracy of 96.3 %. Matrix effects were xamined in 55 individual patient samples instead of the recommended 6, and 147 individual patient samples were screened for interfering compounds.

SIGNIFICANCE AND NOVELTY

Our method for simultaneous quantification of 11 t-mAb in human serum allows an unprecedented integration of robustness, speed and reduced complexity, which could pave the way for uniform use in research projects and clinical settings alike. In addition, the first LC-MS protocol for signature peptide-based quantification of durvalumab is described. This high throughput method can be readily adapted to a drug panel of choice.

Monoclonal Antibodies and Antibody-drug Conjugates as Emerging Therapeutics for Breast Cancer Treatment

When breast cells divide and multiply out of control, it is called breast cancer. Symptoms include lump formation in the breast, a change in the texture or color of the breast, or a discharge from the nipple. Local or systemic therapy is frequently used to treat breast cancer. Surgical and radiation procedures limited to the affected area are examples of local management. There has been significant worldwide progress in the development of monoclonal antibodies (mAbs) since 1986, when the first therapeutic mAb, Orthoclone OKT3, became commercially available. mAbs can resist the expansion of cancer cells by inducing the destruction of cellular membranes, blocking immune system inhibitors, and preventing the formation of new blood vessels. mAbs can also target growth factor receptors. Understanding the molecular pathways involved in tumor growth and its microenvironment is crucial for developing effective targeted cancer therapeutics. Due to their unique properties, mAbs have a wide range of clinical applications. Antibody-drug conjugates (ADCs) are drugs that improve the therapeutic index by combining an antigen-specific antibody with a payload. This review focuses on the therapeutic applications, mechanistic insights, characteristics, safety aspects, and adverse events of mAbs like trastuzumab, bevacizumab, pertuzumab, ertumaxomab, and atezolizumab in breast cancer treatment. The creation of novel technologies utilizing modified antibodies, such as fragments, conjugates, and multi-specific antibodies, must be a central focus of future studies. This review will help scientists working on developing mAbs to treat cancers more effectively.

Pharmacokinetic serum concentrations of VRC01 correlate with prevention of HIV-1 acquisition

BACKGROUND

The phase 2b proof-of-concept Antibody Mediated Prevention (AMP) trials showed that VRC01, an anti-HIV-1 broadly neutralising antibody (bnAb), prevented acquisition of HIV-1 sensitive to VRC01. To inform future study design and dosing regimen selection of candidate bnAbs, we investigated the association of VRC01 serum concentration with HIV-1 acquisition using AMP trial data.

METHODS

The case-control sample included 107 VRC01 recipients who acquired HIV-1 and 82 VRC01 recipients who remained without HIV-1 during the study. We measured VRC01 serum concentrations with a qualified pharmacokinetic (PK) Binding Antibody Multiplex Assay. We employed nonlinear mixed effects PK modelling to estimate daily-grid VRC01 concentrations. Cox regression models were used to assess the association of VRC01 concentration at exposure and baseline body weight, with the hazard of HIV-1 acquisition and prevention efficacy as a function of VRC01 concentration. We also compared fixed dosing vs. body weight-based dosing via simulations.

FINDINGS

Estimated VRC01 concentrations in VRC01 recipients without HIV-1 were higher than those in VRC01 recipients who acquired HIV-1. Body weight was inversely associated with HIV-1 acquisition among both placebo and VRC01 recipients but did not modify the prevention efficacy of VRC01. VRC01 concentration was inversely correlated with HIV-1 acquisition, and positively correlated with prevention efficacy of VRC01. Simulation studies suggest that fixed dosing may be comparable to weight-based dosing in overall predicted prevention efficacy.

INTERPRETATION

These findings suggest that bnAb serum concentration may be a useful marker for dosing regimen selection, and operationally efficient fixed dosing regimens could be considered for future trials of HIV-1 bnAbs.

FUNDING

Was provided by the National Institutes of Health, National Institute of Allergy and Infectious Diseases (NIAID) (UM1 AI068614, to the HIV Vaccine Trials Network [HVTN]; UM1 AI068635, to the HVTN Statistical Data and Management Center [SDMC], Fred Hutchinson Cancer Center [FHCC]; 2R37 054165 to the FHCC; UM1 AI068618, to HVTN Laboratory Center, FHCC; UM1 AI068619, to the HPTN Leadership and Operations Center; UM1 AI068613, to the HIV Prevention Trials Network [HPTN] Laboratory Center; UM1 AI068617, to the HPTN SDMC; and P30 AI027757, to the Center for AIDS Research, Duke University (AI P30 AI064518) and University of Washington (P30 AI027757) Centers for AIDS Research; R37AI054165 from NIAID to the FHCC; and OPP1032144 CA-VIMC Bill & Melinda Gates Foundation.

HLX22, an anti-HER-2 monoclonal antibody, in patients with advanced solid tumors overexpressing human epidermal growth factor receptor 2: an open-label, dose-escalation, phase 1 trial

HLX22 is a novel monoclonal antibody targeting human epidermal growth factor receptor 2 (HER2). This first-in-human, phase 1 dose-escalation study aimed to evaluate the safety, pharmacokinetics, pharmacodynamics, and preliminary efficacy of HLX22 in patients with advanced solid tumors who had failed or were intolerant to standard therapies. Enrolled patients aged 18 to 75 years with histologically confirmed HER2-overexpressing advanced or metastatic solid tumors received intravenous HLX22 once every 3 weeks at 3, 10, and 25 mg/kg. Primary endpoints were safety and the maximum tolerated dose (MTD). Secondary endpoints included pharmacokinetics, pharmacodynamics, immunogenicity, and efficacy. Between July 31, 2019, and December 27, 2021, 11 patients were enrolled to receive HLX22 at 3 (n = 5), 10 (n = 3), and 25 (n = 3) mg/kg doses. The most common treatment-emergent adverse events were lymphocyte count decreased (45.5%), white blood cell count decreased (36.4%), and hypokalemia (36.4%). No serious adverse events or dose-limiting toxicities occurred during the treatment period, and the MTD was determined at 25 mg/kg once every 3 weeks. Systemic exposure of HLX22 increased with escalating dose levels. No patients achieved a complete or partial response, and four (36.4%) had stable disease. The disease control rate and median progression-free survival were 36.4% (95% confidence interval [CI], 7.9-64.8) and 44.0 days (95% CI, 41.0-170.0), respectively. HLX22 was well tolerated in patients with advanced solid tumors overexpressing HER2 after failure of standard therapies. The study results support further investigation of HLX22 in combination with trastuzumab and chemotherapy.

Pharmacokinetics and pharmacodynamics of MEDI0680, a fully human anti-PD-1 monoclonal antibody, in patients with advanced malignancies

MEDI0680 is a humanized immunoglobulin monoclonal antibody that targets human programmed cell death protein 1 (PD-1) for the treatment of cancer. A population two-compartmental pharmacokinetic (PK) model and a sequential direct maximal effective drug concentration receptor occupancy (RO) model with baseline parameters were developed to quantify PK variability, identify significant covariates, and characterize the relationship between the PK and the RO of MEDI0680. A total of 58 patients with advanced malignancies received MEDI0680 by intravenous infusion at a dose of 0.1-20 mg/kg in a phase 1 study. The clearance was 0.27 L per day and the central volume of distribution (V₁) was 3.14 L, with a modest between-subject variability of 30 and 19%, respectively. None of the evaluated covariates showed any impact on PK parameters except for a nonclinically meaningful relevant impact of body weight on V₁. The estimated half-maximal effective concentration for MEDI0680 binding to the PD-1 antigen was approximately 1.88 µg/mL. Visual predictive check results demonstrated good predictability of the final population PK-RO model. PK-RO simulations demonstrated that > 90% RO could be maintained in all subjects after a 20-mg/kg dose every 2 weeks (Q2W). Therefore, 20 mg/kg Q2W and an equivalently fixed dose of 1500 mg was recommended for phase 2 studies.

Breast Cancer Treatments: Updates and New Challenges

Breast cancer (BC) is the most frequent cancer diagnosed in women worldwide. This heterogeneous disease can be classified into four molecular subtypes (luminal A, luminal B, HER2 and triple-negative breast cancer (TNBC)) according to the expression of the estrogen receptor (ER) and the progesterone receptor (PR), and the overexpression of the human epidermal growth factor receptor 2 (HER2). Current BC treatments target these receptors (endocrine and anti-HER2 therapies) as a personalized treatment. Along with chemotherapy and radiotherapy, these therapies can have severe adverse effects and patients can develop resistance to these agents. Moreover, TNBC do not have standardized treatments. Hence, a deeper understanding of the development of new treatments that are more specific and effective in treating each BC subgroup is key. New approaches have recently emerged such as immunotherapy, conjugated antibodies, and targeting other metabolic pathways. This review summarizes current BC treatments and explores the new treatment strategies from a personalized therapy perspective and the resulting challenges.

Unraveling the complexity of therapeutic drug monitoring for monoclonal antibody therapies to individualize dose in oncology

Monoclonal antibodies (Mabs) have become key drugs in cancer treatment, either as targeted therapies or more recently as immune checkpoint inhibitors (ICIs). The fact that only some patients benefit from these drugs poses the usual question in the field of onco-hematology: that of the benefit of individual dosing and the potential of therapeutic drug monitoring (TDM) to carry out this individualization. However, Mabs present unique pharmacological characteristics for TDM, and the pharmacokinetic-pharmacodynamic relationship observed should be interpreted differently than that observed for conventional drugs and small molecules. This pharmacology practice review has been summarized from a public debate between the authors at the International TDM and Clinical Toxicology meeting in Banff, 2020, regarding the potential roles of TDM in the Mab/ICI setting.

Nuances to precision dosing strategies of targeted cancer medicines

Selecting the dose of a targeted cancer medicine that is most appropriate for a specific individual is a rational approach to maximize therapeutic outcomes and minimize toxicity. There are many different options for optimizing the dose of targeted cancer medicines and the purpose of this review is to provide a comprehensive comparison of the main options explored in prospective studies. Precision initial dose selection of targeted cancer therapies has been minimally explored to date; however, concentration, toxicity, and therapeutic outcome markers are used to guide on-therapy dose adaption of targeted cancer therapies across several medicines and cancers. While a specific concentration, toxicity, or therapeutic outcome marker commonly dominates an investigated precision on-therapy dose adaption strategy, greater attention to simultaneously account for exposure, toxicity, therapeutic outcomes, disease status, time since treatment initiation and patient preferences are required for optimal patient outcomes. To enable successful implementation of precision dosing strategies for targeted cancer medicines into clinical practice, future prospective studies aiming to develop strategies should consider these elements in their design.

Understanding Inter-Individual Variability in Monoclonal Antibody Disposition

Monoclonal antibodies (mAbs) are currently the largest and most dominant class of therapeutic proteins. Inter-individual variability has been observed for several mAbs; however, an understanding of the underlying mechanisms and factors contributing to inter-subject differences in mAb disposition is still lacking. In this review, we analyze the mechanisms of antibody disposition and the putative mechanistic determinants of inter-individual variability. Results from in vitro, preclinical, and clinical studies were reviewed evaluate the role of the neonatal Fc receptor and Fc gamma receptors (expression and polymorphism), target properties (expression, shedding, turnover, internalization, heterogeneity, polymorphism), and the influence of anti-drug antibodies. Particular attention is given to the influence of co-administered drugs and disease, and to the physiological relevance of covariates identified by population pharmacokinetic modeling, as determinants of variability in mAb pharmacokinetics.

The impact of body composition parameters on severe toxicity of nivolumab

BACKGROUND

The occurrence of severe, acute limiting toxicity in patients receiving anti-programmed cell death receptor-1 monoclonal antibodies, such as nivolumab, is largely unpredictable. Sarcopenia was found to be associated with anti-cytotoxic T-lymphocyte-associated protein 4 acute toxicity. We explore the clinical and pharmacological parameters influencing nivolumab toxicity, including body composition.

METHODS

From June 2015 to January 2017, all consecutive patients treated with nivolumab in our institution were prospectively included. We studied the relationship between muscle mass assessed by computed tomography, nivolumab trough level (C_min) at day 14 assessed using the enzyme-linked immunosorbent assay method, and the occurrence of immune grade III or IV toxicity or any toxicity leading to treatment discontinuation (immune-related acute limiting toxicity [irALT]).

RESULTS

In our population (n = 92) with a majority of lung cancer (72%), forty-five (51.7%) patients were sarcopenic. The median plasma nivolumab C_min at day 14 was 15.4 μg/mL (interquartile range = 11.8-21.0). In multivariate analysis, hypoalbuminaemia (<35 g/L) was independently associated with low nivolumab C_min on day 14 (odds ratio [OR] = 0.09; 95% confidence interval [CI] = 0.01-0.59, p = 0.01) and overweight/obesity with high nivolumab C_min on day 14 (OR = 5.94; 95% CI = 1.25-28.29, p = 0.03). We observed 22 irALTs in 19 patients (21%). The most frequent irALT was respiratory (6.5%) disorders and gastrointestinal (4.3%) disorders. Patients with sarcopenia were at significantly increased risk of experiencing an irALT (OR = 3.84; 95% CI = 1.02-14.46, p = 0.047). No association was found between toxicity and nivolumab plasma C_min at day 14.

CONCLUSIONS

Our results highlight the importance of assessing body composition and suggest that sarcopenia could predict severe immune-related toxicity of nivolumab in real life.

Pertuzumab in HER2-positive early breast cancer: current use and perspectives

Although the prognosis of HER2-positive breast cancer patients has dramatically improved with modern chemotherapy and the monoclonal antibody trastuzumab, up to 31% of them will experience a recurrence in the long term. After the unprecedented benefit in overall survival with the addition of the second monoclonal antibody pertuzumab for patients with metastatic disease, the drug was tested with various degrees of success in the preoperative and postoperative settings. In this review, we will focus on the pharmacologic aspects of the drug, including mechanism of action and toxicities, and discuss clinical data regarding its use in advanced and early stage HER2-positive breast cancer, placing in perspective the pros and cons regarding other available drugs and biomarkers.

Pertuzumab for the treatment of breast cancer

Introduction: Pertuzumab, a humanized monoclonal antibody that binds the human epidermal growth factor receptor 2 (HER2), inhibits the heterodimerization of HER2 with other HER receptors. It has been approved both by the Food and Drug Administration and the European Medicine Agency in the metastatic, neoadjuvant and adjuvant setting.Areas covered: This review analyses and discusses preclinical and clinical studies of pertuzumab in breast cancer. In this article, we review the status of pertuzumab, the completed and ongoing trials, and its safety.Expert opinion: Pertuzumab is a key drug for the treatment of HER2-positive metastatic or early breast cancer. However, it is imperative to identify patients that will need dual-targeting and mechanisms of resistance. Moreover, the value of pertuzumab beyond progression needs to be evaluated.

Population pharmacokinetics of exendin-(9-39) and clinical dose selection in patients with congenital hyperinsulinism

AIMS

Congenital hyperinsulinism (HI) is the most common cause of persistent hypoglycaemia in infants and children. Exendin-(9-39), an inverse glucagon-like peptide 1 (GLP-1) agonist, is a novel therapeutic agent for HI that has demonstrated glucose-raising effect. We report the first population pharmacokinetic (PopPK) model of the exendin-(9-39) in patients with HI and propose the optimal dosing regimen for future clinical trials in neonates with HI.

METHODS

A total of 182 pharmacokinetic (PK) observations from 26 subjects in three clinical studies were included for constructing the PopPK model using first order conditional estimation (FOCE) with interaction method in nonlinear mixed-effects modelling (NONMEM). Exposure metrics (area under the curve [AUC] and maximum plasma concentration [C_max ]) at no observed adverse effect levels (NOAELs) in rats and dogs were determined in toxicology studies.

RESULTS

Observed concentration-time profiles of exendin-(9-39) were described by a linear two-compartmental PK model. Following allometric scaling of PK parameters, age and creatinine clearance did not significantly affect clearance. The calculated clearance and elimination half-life for adult subjects with median weight of 69 kg were 11.8 l h^-1 and 1.81 h, respectively. The maximum recommended starting dose determined from modelling and simulation based on the AUC_0-last at the NOAEL and predicted AUC_0-inf using the PopPK model was 27 mg kg^-1  day^-1 intravenously.

CONCLUSIONS

This is the first study to investigate the PopPK of exendin-(9-39) in humans. The final PopPK model was successfully used with preclinical toxicology findings to propose the optimal dosing regimen of exendin-(9-39) for clinical studies in neonates with HI, allowing for a more targeted dosing approach to achieve desired glycaemic response.

Potential Sources of Inter-Subject Variability in Monoclonal Antibody Pharmacokinetics

Understanding inter-subject variability in drug pharmacokinetics and pharmacodynamics is important to ensure that all patients attain suitable drug exposure to achieve efficacy and avoid toxicity. Inter-subject variability in the pharmacokinetics of therapeutic monoclonal antibodies (mAbs) is generally moderate to high; however, the factors responsible for the high inter-subject variability have not been comprehensively reviewed. In this review, the extent of inter-subject variability for mAb pharmacokinetics is presented and potential factors contributing to this variability are explored and summarised. Disease status, age, sex, ethnicity, body size, genetic polymorphisms, concomitant medication, co-morbidities, immune status and multiple other patient-specific details have been considered. The inter-subject variability for mAb pharmacokinetics most likely depends on the complex interplay of multiple factors. However, studies aimed at investigating the reasons for the inter-subject variability are sparse. Population pharmacokinetic models and physiologically based pharmacokinetic models are useful tools to identify important covariates, aiding in the understanding of factors contributing to inter-subject variability. Further understanding of inter-subject variability in pharmacokinetics should aid in development of dosing regimens that are more appropriate.

Fixed Dosing of Monoclonal Antibodies in Oncology

Most monoclonal antibodies in oncology are administered in body-size-based dosing schedules. This is believed to correct for variability in both drug distribution and elimination between patients. However, monoclonal antibodies typically distribute to the blood plasma and extracellular fluids only, which increase less than proportionally with the increase in body weight. Elimination takes place via proteolytic catabolism, a nonspecific immunoglobulin G elimination pathway, and intracellular degradation after binding to the target. The latter is the primary route of elimination and is related to target expression levels rather than body size. Taken together, the minor effects of body size on distribution and elimination of monoclonal antibodies and their usually wide therapeutic window do not support body-size-based dosing. We evaluated effects of body weight on volume of distribution and clearance of monoclonal antibodies in oncology and show that a fixed dose for most of these drugs is justified based on pharmacokinetics. A survey of the savings after fixed dosing of monoclonal antibodies at our hospital showed that fixed dosing can reduce costs of health care, especially when pooling of preparations is not possible (which is often the case in smaller hospitals). In conclusion, based on pharmacokinetic parameters of monoclonal antibodies, there is a rationale for fixed dosing of these drugs in oncology. Therefore, we believe that fixed dosing is justified and can improve efficiency of the compounding. Moreover, drug spillage can be reduced and medication errors may become less likely.

IMPLICATIONS FOR PRACTICE

The currently available knowledge of elimination of monoclonal antibodies combined with the publicly available data from clinical trials and extensive population pharmacokinetic (PopPK) modeling justifies fixed dosing. Interpatient variation in exposure is comparable after body weight and fixed dosing and most monoclonal antibodies show relatively flat dose-response relationships. For monoclonal antibodies, this results in wide therapeutic windows and no reduced clinical efficacy after fixed dosing. Therefore, we believe that fixed dosing at a well-selected dose can increase medication safety and help in reduction of costs of health care without the loss of efficacy or safety margins.

Incidence and management of diarrhea in patients with HER2-positive breast cancer treated with pertuzumab

Background

Pertuzumab disrupts heterodimerization between human epidermal growth factor receptor 2 (HER2) and epidermal growth factor receptor (EGFR), HER3, and HER4. Thus, pertuzumab could result in adverse events similar to those observed with EGFR antagonists, such as diarrhea. We report the incidence and severity of diarrhea observed with pertuzumab in the CLEOPATRA, NeoSphere, and TRYPHAENA studies.

Patients and methods

Patients (n = 1443) had metastatic [CLEOPATRA (n = 804)] or early-stage breast cancer [NeoSphere (n = 416) and TRYPHAENA (n = 223)]. The incidence and severity of diarrhea were analyzed by treatment received. The incidence of febrile neutropenia concurrent with diarrhea and the effect of pre-existing gastrointestinal comorbidities were also evaluated. Subgroup analyses were carried out using CLEOPATRA data.

Results

The incidence of all-grade diarrhea across studies was generally greater for pertuzumab-based treatment, ranging from 28% to 72% (grade 1, 21%-54%; grade 2, 8%-37%; grade 3, 0%-12%; grade 4, 0%). Incidence was highest during the first pertuzumab-containing cycle, decreasing with subsequent cycles. Dose delays or discontinuations due to diarrhea were infrequent, ranging from 0% to 8%. Among pertuzumab-treated patients with diarrhea, 47%-67% received pharmacological intervention, most commonly with loperamide. Overlap between diarrhea and febrile neutropenia was uncommon, ranging from 0% to 11%. No relationship was observed between pre-existing gastrointestinal comorbidities and diarrhea. In CLEOPATRA, patients ≥65 years treated with pertuzumab had a higher incidence of grade 3 diarrhea than patients <65 years (19% versus 8%). All-grade diarrhea occurred at greater frequency among pertuzumab-treated Asian versus white patients with metastatic breast cancer (74% versus 63%); the corresponding rates in the control arm were 53% and 45%, respectively.

Conclusions

In both the metastatic and early-stage breast cancer settings, diarrhea was common but manageable for all pertuzumab-containing regimens. Diarrheal episodes were mainly low grade and occurred most often during the first treatment cycle. Diarrheal-related drug delays or discontinuations were uncommon.

ClinicalTrials.gov identifiers

NCT00567190 (CLEOPATRA), NCT00545688 (NeoSphere), NCT00976989 (TRYPHAENA).

Pharmacokinetic and exposure-response analyses of pertuzumab in combination with trastuzumab and docetaxel during neoadjuvant treatment of HER2+ early breast cancer

Purpose

The NeoSphere trial evaluated pertuzumab in the neoadjuvant setting [early breast cancer (EBC)] with pathological complete response (pCR) as the primary efficacy end point. This analysis of pertuzumab aimed to (1) compare its pharmacokinetics (PK) in patients with EBC versus advanced cancers, (2) to further evaluate PK drug–drug interactions (DDIs) when given in combination with trastuzumab, and (3) to assess the relationship between exposure and efficacy to assess the clinical dosing regimen in the EBC patients.

Methods

Pertuzumab serum concentration data from 180 patients in NeoSphere were compared to historical observations and potential DDI was assessed, by applying simulation techniques using a population PK model. The impact of pertuzumab exposure on pCR rate was evaluated using a logit response model (n = 88).

Results

The observed PK matched the population PK model simulations, confirming that the PK in neoadjuvant EBC appear to be in agreement with the historical observations. No evidence of a DDI effect of trastuzumab or docetaxel on pertuzumab was observed supporting the doses when given in combination. In NeoSphere >90% of EBC patients achieved the non-clinical target serum concentration. There was no association between the pertuzumab serum concentration and pCR within the range observed in this study (20–100 μg/mL) supporting no dose adjustments needed for patients with lower exposure.

Conclusions

This analysis further supports the lack of DDI between the two therapeutic proteins and the appropriateness of the approved fixed non-body-weight-adjusted pertuzumab dose in the treatment of neoadjuvant EBC with pertuzumab in combination with trastuzumab and docetaxel.

Electronic supplementary material

The online version of this article (doi:10.1007/s00280-016-3218-0) contains supplementary material, which is available to authorized users.

Evaluation of the dosing strategies of biologic agents and the theoretical impact of dose rounding

Introduction

Monoclonal antibodies possess unique pharmacokinetic properties that permit flexible dosing. Increased use and high costs of these medications have led to the development of cost-containing strategies. This study aims to quantify the cost savings and clinical impact associated with dose rounding monoclonal antibodies to the nearest vial size.

Methods

This study was a single-arm, retrospective chart review assessing all monoclonal antibody doses dispensed at an outpatient community infusion center associated with an academic medical center between August 2014 and August 2015. All monoclonal antibody doses were reviewed to determine the cost of drug wasted using two methods. The waste-cost analysis described the amount of drug disposed of due to the use of partial vials. The theoretical dose savings described potential cost avoidance based on rounding the ordered dose to the nearest vial size. The theoretical rounded dose was compared to the actual ordered dose to explore clinical implications.

Results

A total of 436 doses were included. Of these, 237 were not rounded to the nearest vial size and included in the analysis. The cost of waste associated with these doses was $108,013.64 using actual wholesale price. The potential cost avoidance associated with the theoretical dose calculation was $83,595.53. Rounding these doses to the nearest vial size resulted in a median 6.7% (range, 1.4–20%) deviation from ordered dose.

Conclusions

Rounding monoclonal antibodies to the nearest vial size could lead to significant cost and waste savings with minimal deviation from the actual ordered dose.

Management of patients treated with pertuzumab in the Australian clinical practice setting

AIM

Treatment with pertuzumab-trastuzumab-taxane combinations has become the international standard of care for patients with HER2-positive metastatic breast cancer. In this paper we discuss the practicalities of treating patients with this combination with a particular focus on treatment in the Australian setting.

METHOD

An expert panel was convened to discuss practical aspects for use of pertuzumab in the Australian clinical setting. The findings of this panel are reported in this article.

RESULTS

The combination of pertuzumab-trastuzumab-docetaxel has established efficacy in patients with HER2-positive metastatic breast cancer, prolonging progression-free and overall survival compared to trastuzumab-taxane combinations. In Australia, combinations of pertuzumab and trastuzumab with docetaxel or paclitaxel are reimbursed. Management of treatment related side-effects such as diarrhea, febrile neutropenia and neuropathy typically include dose reduction or switching taxane. Specific patients with poorer tolerance of chemotherapy such as the elderly or those from Asian backgrounds may require particular management strategies.

CONCLUSIONS

The advent of targeted therapies for women with metastatic HER2-positive breast cancer has markedly improved survival. Combinations of pertuzumab-trastuzumab and a taxane are the standard of care in patients with good performance status. Given prolongation of survival and the importance of quality of life endpoints, the treatment paradigm for patients with metastatic HER2-positive breast cancer is changing rapidly. Careful management of toxicities is required, and dose reduction or switching taxane may be necessary. Further research is required on the efficacy of pertuzumab combinations in patients with brain metastases, and on those who relapse quickly following adjuvant therapy.

Modeling the pharmacokinetic-pharmacodynamic relationship of the monoclonal anti-macaque-IL-15 antibody Hu714MuXHu in cynomolgus monkeys

Hu714MuXHu is a recombinant chimeric murine‐human monoclonal antibody directed against interleukin‐15 (IL‐15), a proinflammatory cytokine associated with memory CD8+ and natural killer (NK) T‐cell activation and implicated in the pathogenesis of inflammatory diseases. A pharmacokinetic‐pharmacodynamic (PK/PD) model was developed to describe the NK cell count reduction in cynomolgus monkeys after treatment with Hu714MuXHu. Cynomolgus monkeys were dosed with Hu714MuXHu in three studies: as a single dose at 0.1 or 1 mg·kg⁻¹ i.v.; weekly for 5 weeks at 0, 30, 60, or 150 mg·kg⁻¹ i.v. or 150 mg·kg⁻¹ s.c.; weekly for 13 weeks at 0, 5, 30, or 150 mg·kg⁻¹ s.c. Serum Hu714MuXHu concentration‐time data were analyzed using noncompartmental analysis and the PK/NK cell count relationship was assessed via simultaneous PK/PD modeling. Hu714MuXHu PK was approximately dose‐proportional between 0.1–150 mg·kg⁻¹ for i.v. and 5–150 mg·kg⁻¹ for s.c. administration with an elimination half‐life of 12.7–18 days. Hu714MuXHu administration resulted in rapid and marked reductions in NK cell counts after the first dose which recovered fully after the serum Hu714MuXHu concentrations approached 0.1 μg·mL⁻¹ (assay limit of quantification). PK/PD modeled Hu714MuXHu effects on NK cells had an EC₅₀ of 0.09 μg·mL⁻¹. In summary, weekly i.v. or s.c. doses with Hu714MuXHu for up to 3 months in cynomolgus monkeys demonstrated linear PK and significant NK cell count reduction, which was described using PK/PD modeling. This approach may be used to guide investigative product dose selections for inflammatory diseases where NK cell count alterations are quantifiable.

Pertuzumab in gastrointestinal cancer

INTRODUCTION

Human epidermal growth factor receptor 2 (HER2) and HER3 are altered in multiple tumor types, including gastrointestinal cancer. The HER2/HER3 dimer is crucial for HER2-mediated signaling in HER2-positive tumors. HER2-targeting agents, including trastuzumab, lapatinib, trastuzumab emtansine, and pertuzumab, have been approved for the treatment of HER2-positive breast cancer, with trastuzumab also approved for the treatment of HER2-positive gastric cancer. Pertuzumab, a recombinant humanized immunoglobulin (Ig) G1 monoclonal antibody targeting HER-2, binds to the dimerization domain (extracellular domain II) of HER2, which leads to blocking of ligand-induced HER2 heterodimerization. It is under investigation in gastrointestinal cancers, including HER2-positive gastric cancer.

AREA COVERED

In this review, the authors summarize the biology of HER2/HER3 and its alterations in gastrointestinal cancers. The authors focus specifically on the current status of development of pertuzumab in gastrointestinal cancers.

EXPERT OPINION

The HER2/HER3 alteration in gastrointestinal cancers is quite interesting. In HER2-positive gastric cancer, the dual blockade of HER2 and HER3 using trastuzumab and pertuzumab is being tested in an international phase III trial, the JACOB study. This strategy may benefit HER2-positive gastric cancer patients more as in the case of HER2-positive breast cancer. In other gastrointestinal cancers, including biliary tract cancer, esophageal cancer, pancreatic cancer, and colorectal cancer, there is huge room for the development of pertuzumab.

Incorporation of FcRn-mediated disposition model to describe the population pharmacokinetics of therapeutic monoclonal IgG antibody in clinical patients

PURPOSE

The two-compartment linear model used to describe the population pharmacokinetics (PK) of many therapeutic monoclonal antibodies (TMAbs) offered little biological insight to antibody disposition in humans. The purpose of this study is to develop a semi-mechanistic FcRn-mediated IgG disposition model to describe the population PK of TMAbs in clinical patients.

METHODS

A standard two-compartment linear PK model from a previously published population PK model of pertuzumab was used to simulate intensive PK data of 100 subjects for model development. Two different semi-mechanistic FcRn-mediated IgG disposition models were developed and First Order Conditional Estimation (FOCE) with the interaction method in NONMEM was used to obtain the final model estimates. The performances of these models were then compared with the two-compartment linear PK model used to simulate the data for model development.

RESULTS

A semi-mechanistic FcRn-mediated IgG disposition model consisting of a peripheral tissue compartment and FcRn-containing endosomes in the central compartment best describes the simulated pertuzumab population PK data. This developed semi-mechanistic population PK model had the same number of model parameters, produced very similar concentration-time profiles but provided additional biological insight to the FcRn-mediated IgG disposition in human subjects compared with the standard linear two-compartment linear PK model.

CONCLUSION

This first reported semi-mechanistic model may serve as an important model framework for developing future population PK models of TMAbs in clinical patients.

Therapeutic drug monitoring of monoclonal antibodies in inflammatory and malignant disease: Translating TNF-α experience to oncology

Lack of response to monoclonal antibodies (mAbs) has been associated with inadequate mAb serum concentrations. Therapeutic drug monitoring (TDM) of mAbs has the potential to guide to more effective dosing in individual patients. This review discusses the mechanisms responsible for interpatient variability of mAb pharmacokinetics, summarizes exposure-response data of mAbs used in inflammatory and malignant disease, presents current evidence of mAb-TDM in inflammatory disease, and provides hurdles and required future steps for further implementing mAb-TDM.

Population Pharmacokinetic Model of Sublingual Buprenorphine in Neonatal Abstinence Syndrome

OBJECTIVE

Neonatal abstinence syndrome (NAS)--a clinical entity of infants from in utero exposure to psychoactive xenobiotic and buprenorphine--has been successfully used to treat NAS. However, nothing is known about the pharmacokinetics (PK) of buprenorphine in neonates with NAS. To our knowledge, this is the first study to investigate the population pharmacokinetic of sublingual buprenorphine in neonates with NAS.

DESIGN

A retrospective population PK analysis of: (1) neonates with NAS treated with sublingual buprenorphine in randomized, double blinded clinical study and (2) data from healthy adults from a previously published pharmacokinetic study.

SETTING

Neonatal intensive care unit and general clinical research unit.

PATIENTS

Twenty-four neonates with NAS and five healthy adults.

INTERVENTIONS

All participants received sublingual buprenorphine per study protocol.

MEASUREMENTS AND MAIN RESULTS

A total of 303 PK data from 29 neonates and adults were used for model development. A population pharmacokinetic analysis was conducted using a first order conditional estimation with interaction in the NONMEM software program. A two-compartment linear PK model with first-order absorption process best described the pharmacokinetics of sublingual buprenorphine in neonates. The apparent clearance (CL) of buprenorphine was linearly related to body weight and matured with increasing age via two distinct saturated pathways. A typical neonate with NAS (body weight, 2.9 kg; postnatal age; 5.4 days) had a CL of 3.5 L/kg/hour and elimination half-life of 11 hours. Phenobarbital did not affect the clearance of buprenorphine compared to neonates of similar age and weight.

CONCLUSIONS

This is the first study to investigate the population PK of sublingual buprenorphine in neonatal NAS. To our knowledge, this is also the first report to describe the age-dependent changes of buprenorphine PK in this patient population. No buprenorphine dose adjustment is needed for neonates with NAS treated with buprenorphine and concurrent phenobarbital.

Pertuzumab in combination with trastuzumab and docetaxel for HER2-positive metastatic breast cancer

Overexpression of HER2 - found in approximately 15-20% of all breast cancers - is a negative prognostic factor. Although trastuzumab significantly improves the prognosis of HER2-positive breast cancer, half of the patients with metastatic breast cancer experience disease progression within 1 year. Pertuzumab is a novel HER2-targeted humanized monoclonal antibody that binds to the dimerization domain of HER2 and acts synergically with trastuzumab in inhibiting tumor progression. The CLEOPATRA trial demonstrated that adding pertuzumab to trastuzumab plus docetaxel significantly prolonged progression-free survival and overall survival without increasing severe adverse events. Conclusively, pertuzumab was approved by the US FDA in June 2012 for use in combination with trastuzumab and docetaxel for the treatment of patients with HER2-positive metastatic breast cancer. Furthermore, various clinical trials to evaluate the efficacy and safety of pertuzumab combined with other cytotoxic agents are ongoing at present. Thus, pertuzumab has been becoming important for the treatment of patients with HER2-positive metastatic breast cancer.

The European Medicines Agency Review of Pertuzumab for the treatment of adult patients with HER2-positive metastatic or locally recurrent unresectable breast cancer: summary of the scientific assessment of the committee for medicinal products for human use

Pertuzumab is a recombinant humanized monoclonal antibody that specifically targets the extracellular dimerization domain (subdomain II) of HER2. Based on the positive opinion from the European Medicines Agency (EMA) on March 4, 2013, a marketing authorization valid throughout the European Union (EU) was issued for pertuzumab (Perjeta) for use in combination with trastuzumab and docetaxel for the treatment of adult patients with HER2-positive metastatic or locally recurrent unresectable breast cancer who have not received previous anti-HER2 therapy or chemotherapy for their metastatic disease. The demonstration of clinical benefit for pertuzumab was based on a single, phase III, randomized, double-blind, placebo-controlled trial comparing the efficacy and safety of pertuzumab plus trastuzumab plus docetaxel versus placebo plus trastuzumab plus docetaxel in previously untreated patients with locally advanced or metastatic HER2-positive breast cancer. In the primary analysis, median progression-free survival was 18.5 months in the pertuzumab group compared with 12.4 months in the placebo group (hazard ratio [HR]: 0.62; 95% confidence interval [CI]: 0.51-0.75; p < .0001). For the secondary endpoints, overall survival (HR: 0.66; 95% CI: 0.52-0.84; p = .0008) and objective response rate (80.2% vs. 69.3%) were also favored in the pertuzumab group. Toxicity was similar between groups except for higher incidence of diarrhea, rash, mucosal inflammation, dry skin, and neutropenia for pertuzumab compared with placebo. This paper summarizes the scientific review of the application leading to approval in the EU. The detailed scientific assessment report and product information, including the summary of product characteristics, are available on the EMA website (http://www.ema.europa.eu).

Mechanistic considerations for the use of monoclonal antibodies for cancer therapy

Since the approval of rituximab in 1997, monoclonal antibodies (mAbs) have become an increasingly important component of therapeutic regimens in oncology. The success of mAbs as a therapeutic class is a result of great strides that have been made in molecular biology and in biotechnology over the past several decades. Currently, there are 14 approved mAb products for oncology indications, and there are ten additional mAbs in late stages of clinical trials. Compared to traditional chemotherapeutic agents, mAbs have several advantages, including a long circulating half-life and high target specificity. Antibodies can serve as cytotoxic agents when administered alone, exerting a pharmacologic effect through several mechanisms involving the antigen binding (Fab) and/or Fc domains of the molecule, and mAbs may also be utilized as drug carriers, targeting a toxic payload to cancer cells. The extremely high affinity of mAbs for their targets, which is desirable with respect to pharmacodynamics (i.e., contributing to the high therapeutic selectivity of mAb), often leads to complex, non-linear, target-mediated pharmacokinetics. In this report, we summarize the pharmacokinetic and pharmacodynamics of mAbs that have been approved and of mAbs that are near approval for oncology indications, with particular focus on the molecular and cellular mechanisms responsible for their disposition and efficacy.

Pertuzumab for the treatment of breast cancer

HER2-targeted therapies have revolutionized the outcome of patients with HER2-positive breast cancer. Pertuzumab is the first in a new class of monoclonal antibodies that target the extracellular dimerization domain of HER2 receptors, also known as HER dimerization inhibitors. The development of pertuzumab and preclinical and clinical data in breast cancer are reviewed. Regulatory affairs related to pertuzumab and the recent accelerated approval granted by the FDA for the treatment of breast cancer in the neoadjuvant setting are also covered. This process opens doors for further approvals which could considerably shorten the time between initial drug development and availability.

Pertuzumab in human epidermal growth-factor receptor 2-positive breast cancer: clinical and economic considerations

In the absence of specific therapy, the 15%–20% of breast cancers demonstrating human epidermal growth-factor receptor 2 (HER2) protein overexpression and/or gene amplification are characterized by a more aggressive phenotype and poorer prognosis compared to their HER2-negative counterparts. Trastuzumab (Herceptin), the first anti-HER2-targeted therapy, has been associated with improved survival outcomes in HER2-positive breast cancer. However, many patients with early stage disease continue to relapse, and metastatic disease remains incurable. In order to further improve these outcomes, several novel HER2-targeted agents have recently been developed. Pertuzumab (Perjeta), a monoclonal antibody against the HER2 dimerization domain, has also been associated with improved patient outcomes in clinical trials, and has recently been approved in combination with chemotherapy and trastuzumab for neoadjuvant therapy of early stage, HER2-positive breast cancer and first-line treatment of metastatic disease. This review briefly summarizes pertuzumab’s clinical development as well as the published evidence supporting its use, and highlights some of the currently unanswered questions that will influence pertuzumab’s incorporation into clinical practice.

Pertuzumab in Combination with Trastuzumab and Chemotherapy in the Treatment of HER2-Positive Metastatic Breast Cancer: Safety, Efficacy, and Progression Free Survival

Tyrosine kinase inhibitors have revolutionized the oncology community and were pioneered by the use in HER2-targeted therapies. Improved outcomes were seen with the advent of trastuzumab, leading investigators to develop newer agents to target the HER2 pathway such as the novel monoclonal antibody pertuzumab. In this paper, we describe the attributes of pertuzumab including: mechanism of action, pharmacokinetics and metabolism, safety/cardiotoxicity, drug interactions, efficacy, and role in HER2-positive breast cancer management. Newly reviewed here versus previously published reviews on pertuzumab oriented therapy are data of pertuzumab monotherapy as it is used in combination with other anti-HER2 agents derived from preclinical research and ongoing clinical trials.

Pertuzumab: a review of its use for first-line combination treatment of HER2-positive metastatic breast cancer

Pertuzumab (Perjeta®) is a humanized anti-HER2 monoclonal antibody that binds to the extracellular dimerization subdomain of the HER2 receptor and reduces HER2 intracellular signalling by preventing HER2 from forming heterodimers with other HER receptors. Inhibition of HER2 signalling results in a reduction of tumour cell proliferation, invasiveness and survival. Pertuzumab and trastuzumab bind to different sites on the HER2 receptor and have complementary antitumour activities; they act synergistically in inhibiting the growth of HER2-overexpressing breast cancer cell lines in vitro. The efficacy of intravenous pertuzumab (840 mg loading dose, then 420 mg every 3 weeks) in combination with trastuzumab plus docetaxel in the first-line treatment of HER2-positive metastatic breast cancer was demonstrated in the randomized, double-blind, placebo-controlled, multinational, phase III CLEOPATRA trial. Pertuzumab in combination with trastuzumab and docetaxel significantly increased independently assessed median progression-free survival (primary endpoint), objective response rate and overall survival compared with placebo in combination with trastuzumab and docetaxel. Pertuzumab had an acceptable tolerability profile when added to trastuzumab and docetaxel in the pivotal CLEOPATRA trial. Thus, pertuzumab is a valuable addition to the growing list of anti-HER2 targeted therapies for breast cancer.

Precision medicine and personalized breast cancer: combination pertuzumab therapy

Trastuzumab (Herceptin), a monoclonal antibody directed against the human epidermal growth-factor receptor 2 (HER2), is the poster child for antibody-based targeted therapy in breast cancer. Pertuzumab, another humanized monoclonal antibody, binds to a different domain of HER2 and prevents the formation of HER2:HER3 dimers, which is the most potent heterodimer in the HER family. The combination of trastuzumab and pertuzumab has synergistic activity, and is associated with improved clinical outcomes. The US Food and Drug Administration (FDA) approved pertuzumab in combination with trastuzumab-based chemotherapy originally as first-line therapy for metastatic HER2-positive breast cancer in 2012, and more recently as neoadjuvant therapy for localized disease in 2013. Pertuzumab is the first neoadjuvant drug to receive accelerated approval by the FDA based on pathological complete response as the primary end point. In this article, we review the mechanism of action, pharmacokinetics, clinical efficacy, safety, and current role of pertuzumab in the management of breast cancer, as well as ongoing clinical trials and future directions regarding the utility of pertuzumab as a personalized therapeutic option for HER2-positive breast cancer. In the coming years, we anticipate increased utilization of neoadjuvant trials for drug development, biomarker discovery, and validation, and envision conduct of personalized breast cancer clinics in which therapies will be routinely selected based on genetic alterations in the tumor. Regardless of the targeted therapy combinations employed based on tumor genomic profile, trastuzumab and pertuzumab will likely continue to form the backbone of the personalized regimen for HER2-positive breast cancer.

Population pharmacokinetics of sifalimumab, an investigational anti-interferon-α monoclonal antibody, in systemic lupus erythematosus

BACKGROUND AND OBJECTIVES

Sifalimumab is a fully human immunoglobulin G1κ monoclonal antibody that binds to and neutralizes a majority of the subtypes of human interferon-α. Sifalimumab is being evaluated as a treatment for systemic lupus erythematosus (SLE). The primary objectives of this analysis were (a) to develop a population pharmacokinetic model for sifalimumab in SLE; (b) to identify and quantitate the impact of patient/disease characteristics on pharmacokinetic variability; and (c) to evaluate fixed versus body weight (WT)-based dosing regimens.

METHODS

Sifalimumab serum concentration-time data were collected from a phase Ib study (MI-CP152) designed to evaluate the safety and tolerability of sifalimumab in adult patients with SLE. Sifalimumab was administered every 14 days as a 30- to 60-minute intravenous infusion with escalating doses of 0.3, 1.0, 3.0, and 10 mg/kg and serum concentrations were collected over 350 days. A total of 120 patients provided evaluable pharmacokinetic data with a total of 2,370 serum concentrations. Sifalimumab serum concentrations were determined using a validated colorimetric enzyme-linked immunosorbent assay (ELISA) with a lower limit of quantitation of 1.25 μg/mL. Population pharmacokinetic modeling of sifalimumab was performed using a non-linear mixed effects modeling approach with NONMEM VII software. Impact of patient demographics, clinical indices, and biomarkers on pharmacokinetic parameters were explored using a stepwise forward selection and backward elimination approach. The appropriateness of the final model was tested using visual predictive check (VPC). The impact of body WT-based and fixed dosing of sifalimumab was evaluated using a simulation approach. The final population model was utilized for phase IIb dosing projections.

RESULTS

Sifalimumab pharmacokinetics were best described using a two-compartment linear model with first order elimination. Following intravenous dosing, the typical clearance (CL) and central volume of distribution (V 1) were estimated to be 176 mL/day and 2.9 L, respectively. The estimates (coefficient of variation) of between-subject variability for CL and V 1 were 28 and 31 %, respectively. Patient baseline body WT, interferon gene signature from 21 genes, steroid use, and sifalimumab dose were identified as significant covariates for CL, whereas only baseline body WT was a significant covariate for V 1 and peripheral volume of distribution (V 2). Although the above-mentioned covariates were statistically significant, they did not explain variability in pharmacokinetic parameters to any relevant extent (<7 %). Thus, no dosing adjustments are necessary. VPC confirmed good predictability of the final population pharmacokinetic model. Simulation results demonstrate that both fixed and body WT-based dosing regimens yield similar median steady state concentrations and overall variability. Fixed sifalimumab doses of 200, 600, and 1,200 mg monthly (with a loading dose at Day 14) were selected for a phase IIb clinical trial.

CONCLUSION

A two-compartment population pharmacokinetic model adequately described sifalimumab pharmacokinetics. The estimated typical pharmacokinetic parameters were similar to other monoclonal antibodies without target mediated elimination. Although the population pharmacokinetic analysis identified some statistically significant covariates, they explained <7 % between-subject variability in pharmacokinetic parameters indicating that these covariates are not clinically relevant. The population pharmacokinetic analysis also demonstrated the feasibility of switching to fixed doses in phase IIb clinical trials of sifalimumab.

Pertuzumab for the treatment of human epidermal growth factor receptor type 2-positive metastatic breast cancer

Purpose

The pharmacology, pharmacokinetics, clinical efficacy, safety, and administration of pertuzumab in patients with metastatic human epidermal growth factor receptor type 2 (HER2)-positive breast cancer are reviewed.

Summary

Disease progression in HER2-positive breast cancer is often due to resistance to or a lack of efficacy of trastuzumab-based anti-HER2 therapy. Pertuzumab is the first humanized monoclonal antibody in a new class of drugs, the HER dimerization inhibitors, approved by the Food and Drug Administration for the first-line treatment of patients with metastatic HER2-positive breast cancer who have not received prior anti-HER2 therapy or chemotherapy for metastatic disease. Since pertuzumab binds to a different epitope than trastuzumab, combination therapy with pertuzumab and trastuzumab results in a more complete blockade of HER2 signaling than trastuzumab monotherapy. The efficacy of adding pertuzumab to trastuzumab–docetaxel dual therapy was demonstrated in a pivotal randomized multicenter Phase III trial, which showed a significant benefit in terms of progression-free survival, with improved overall survival, in favor of the triple therapy as an initial regimen in treatment-naive patients with metastatic HER2-positive breast cancer. The combination of pertuzumab and trastuzumab has been found to have a tolerable toxicity profile. As clinical trials of pertuzumab for adjuvant, neoadjuvant, and metastatic-disease treatment continue, its role in the treatment of HER2-positive breast cancer will continue to evolve.

Conclusion

Pertuzumab, a novel HER2 dimerization inhibitor, has been shown to be effective in the treatment of metastatic HER2-positive breast cancer when used in combination with trastuzumab and docetaxel and is recommended for first-line therapy.

Exposure-response analysis of pertuzumab in HER2-positive metastatic breast cancer: absence of effect on QTc prolongation and other ECG parameters

Purpose

The phase III trial of pertuzumab plus trastuzumab plus docetaxel versus placebo plus trastuzumab plus docetaxel for first-line treatment of HER2-positive metastatic breast cancer included a substudy to determine whether pertuzumab affected the corrected QT (QTc) interval or other electrocardiogram parameters.

Methods

Triplicate 12-lead electrocardiogram measurements and serum samples were collected before (–30 and –15 min) and after (0–15 and 60–75 min) pertuzumab/placebo infusions (Cycles 1 and 3), and at 72 h post-infusion (Cycle 1). Fridericia’s correction was applied to QT measurements (QTcF) and change from baseline (ΔQTcF) calculated. Statistical analyses were performed on baseline-adjusted, placebo-corrected QTcF values (ΔΔQTcF). Linear mixed-effects modeling evaluated potential exposure–response relationships between ΔQTcF and observed pertuzumab concentrations.

Results

Thirty-seven female patients participated in the substudy. QTcF values in both groups were within the normal range and below critical thresholds of clinical concern. No pertuzumab-treated patient showed abnormal electrocardiogram morphology. In Cycle 1, mean ΔΔQTcF (90 % CI) values at 0–15 min, 60–75 min, and 72 h post-infusion were −6.96 (−13.69, −0.23), −6.35 (−13.57, 0.88), and −4.08 (−12.64, 4.48), all of which were <5 ms, with upper CI limits <10 ms. One Cycle 3 post-infusion mean ΔΔQTcF value exceeded 5 ms. Other electrocardiogram parameters were within normal ranges. Concentration–QTc modeling showed no apparent relationship between ΔQTcF and pertuzumab concentrations.

Conclusions

Cardiac monitoring and concentration–QTc modeling demonstrated that pertuzumab, combined with trastuzumab and docetaxel, had no clinically relevant effects on QTcF and other electrocardiogram parameters.

Electronic supplementary material

The online version of this article (doi:10.1007/s00280-013-2279-6) contains supplementary material, which is available to authorized users.

Pertuzumab: a new targeted therapy for HER2-positive metastatic breast cancer

Trastuzumab, a humanized monoclonal antibody, has become an important targeted therapy for patients with all stages of human epidermal growth factor receptor-2 (HER2)-positive breast cancer. However, primary and acquired resistance to trastuzumab remains a significant problem. Pertuzumab, a humanized monoclonal antibody that binds to a domain of the HER2 receptor separate from trastuzumab, may have the potential to overcome trastuzumab resistance. Clinical trials have shown that pertuzumab can be effectively combined with other biologic therapy or chemotherapy in patients with metastatic HER2-positive breast cancer. Pertuzumab is relatively well tolerated with minimal increases in hematologic and cardiac toxicity observed when added to trastuzumab and/or docetaxel. In addition to becoming the standard of care in combination with docetaxel and trastuzumab in patients with newly diagnosed HER2-positive metastatic breast cancer, clinical trials continue to evaluate pertuzumab in combination with other targeted therapy, chemotherapy, and in patients with early stage breast cancer. These trials will help to further determine the role of pertuzumab in the treatment of HER2-positive breast cancer.

Are hepatic impairment studies necessary for therapeutic proteins?

OBJECTIVE

This study assessed whether trials to investigate the effect of hepatic impairment on the pharmacokinetics of therapeutic proteins (TPs), which are conducted for small molecule drugs, are necessary.

METHODS

The product labeling for 91 TPs that have been approved by the US Food and Drug Administration were reviewed. A PubMed search was also conducted to identify completed studies that assessed the effect of hepatic impairment on the pharmacokinetics of TPs. Biologic License Applications were subsequently reviewed to gather further descriptions of the trials conducted in patients with hepatic impairment and data analyses.

RESULTS

No dedicated pharmacokinetics trials were conducted in patients with hepatic impairment for these approved TPs, but subgroup (n = 2 [2.2%]) or population (n = 5 [5.5%]) pharmacokinetic analyses were performed for 7 TPs. The pharmacokinetics of these proteins were not affected by the hepatic dysfunction, with the exception that the clearance of drotrecogin alfa seemed 25% higher in patients with hepatic impairment than in patients without hepatic impairment; however, no dose reduction was recommended. Thus, the effect of hepatic impairment on the pharmacokinetics of TPs is unclear based on the limited analyses completed to date.

CONCLUSIONS

A dedicated pharmacokinetics trial for TPs in patients with hepatic impairment is not necessary. Recognizing that the data are very limited, it would be important to continue collecting pharmacokinetic data of TP in patients with hepatic impairment and using population pharmacokinetic analyses to evaluate the effect of hepatic impairment on the pharmacokinetics of TP.

Use of pertuzumab for the treatment of HER2-positive metastatic breast cancer

INTRODUCTION

Targeting the human epidermal growth factor receptor (HER) family of tyrosine kinase receptors has proven to be effective as a therapeutic strategy for HER type 2 (HER2)-positive breast cancer. Since resistance to trastuzumab occurs relatively frequently, particularly in the metastatic setting, novel anti-HER2 targeted therapies with complementary and/or synergistic mechanisms of action have been under development. Pertuzumab, a HER2-targeted monoclonal antibody that prevents HER2 dimerisation, is the first of a class of promising targeted agents for the treatment of HER2-positive breast cancer.

METHODS

A review of the biomedical literature published prior to February 2013 was conducted in English using PubMed. ClinicalTrials.gov was searched for appropriate clinical trials. The search terms used included breast neoplasm, pertuzumab, dimerisation, and HER2-positive. Abstracts of studies presented at the ASCO and ESMO Annual Meetings, and San Antonio Breast Cancer Symposium were also included.

RESULTS

Pertuzumab represents a novel anti-HER2 targeted therapy for HER2-positive breast cancers. In this article, we describe the mechanism of action of pertuzumab, as well as its drug development process and preclinical testing results. Based on the results of ancillary studies, dual inhibition using pertuzumab and trastuzumab was shown to be effective for the management of HER2-positive metastatic breast cancers pre-treated with trastuzumab-based therapy. For the first-line setting, the combination of both pertuzumab and trastuzumab with docetaxel (CLEOPATRA trial; clinical evaluation of pertuzumab and trastuzumab) has changed the paradigm of patient management.

CONCLUSION

Pertuzumab provided a more comprehensive inhibition of HER2-driven signalling pathways. When administered together with trastuzumab, pertuzumab represent a significant advancement for the treatment of HER2-positive metastatic breast cancer patients.

Pertuzumab for the treatment of patients with previously untreated HER2-positive metastatic breast cancer

Pertuzumab is a humanized monoclonal antibody directed at the dimerization domain of the receptor tyrosine-protein kinase erbB-2 (HER2) receptor. It possesses a unique and complimentary mechanism of action compared to trastuzumab, which has historically been the cornerstone of therapy for HER2-amplified breast cancer. Clinical trials demonstrate improved outcomes, with minimal increases in toxicity with the addition of pertuzumab to trastuzumab in patients with HER2-positive metastatic breast cancer, indicating the advantage of dual HER2 receptor blockade. Pertuzumab is approved as first-line therapy in combination with trastuzumab and docetaxel for HER2-positive metastatic breast cancer, with future opportunities to investigate its efficacy in other stages of breast cancer, as well as in the treatment of other malignancies.

HER2 Dimerization Inhibitor Pertuzumab - Mode of Action and Clinical Data in Breast Cancer

The humanized monoclonal antibody pertuzumab prevents the dimerization of HER2 with other HER receptors, in particular the pairing of the most potent signaling heterodimer HER2/HER3, thus providing a potent strategy for dual HER2 inhibition. It binds to the extracellular domain of HER2 at a different epitope than trastuzumab. Pertuzumab and trastuzumab act in a complementary fashion and provide a more complete blockade of HER2-mediated signal transduction than either agent alone. Phase II studies demonstrated that pertuzumab was generally well tolerated as a single agent or in combination with trastuzumab and/or cytotoxic agents, and implied an improved clinical efficacy of the combination of pertuzumab and trastuzumab in early and advanced HER2-positive breast cancer. Results of the pivotal phase III study CLEOPATRA in patients with HER2-positive metastatic breast cancer demonstrated that the addition of pertuzumab to first-line combination therapy with docetaxel and trastuzumab significantly prolonged progression-free and overall survival without increasing cardiac toxicity. Currently, the combination of both antibodies is being explored in the palliative setting as well as in the treatment of early HER2-positive breast cancer. Dual HER2 inhibition with the HER2 dimerization inhibitor pertuzumab and trastuzumab may change clinical practice in HER2-positive first-line metastatic breast cancer treatment.