Is weight-based IV dosing of trastuzumab preferable to SC fixed-dose in some patients? A systematic scoping review

Fixed Versus Body-Sized-Based Dosing of Monoclonal Antibodies

Monoclonal antibody products are an increasing portion of novel drug approvals. The labeling of initial drug approvals frequently involves body-size-based rather than fixed-dose administration regimens for adults without clear rationale for doing so. This presents challenges when prescribing these products for patients with extremes of body habitus who constitute a small portion of enrollment in pre-approval investigations. Fixed-dose regimens allow for standardized preparation with the potential to reduce the risk of calculation errors, drug waste, and make home administration more practical. Fixed-dose rather than body-size-based monoclonal antibody regimens should serve as the initial approach in early phase 1 clinical trials.

Effect of Obesity on the Pharmacokinetics and Pharmacodynamics of Anticancer Agents

An objective of the Precision Medicine Initiative, launched in 2015 by the US Food and Drug Administration and National Institutes of Health, is to optimize and individualize dosing of drugs, especially anticancer agents, with high pharmacokinetic and pharmacodynamic variability. The American Society of Clinical Oncology recently reported that 40% of obese patients receive insufficient chemotherapy doses and exposures, which may lead to reduced efficacy, and recommended pharmacokinetic studies to guide appropriate dosing in these patients. These issues will only increase in importance as the incidence of obesity in the population increases. This publication reviews the effects of obesity on (1) tumor biology, development of cancer, and antitumor response; (2) pharmacokinetics and pharmacodynamics of small-molecule anticancer drugs; and (3) pharmacokinetics and pharmacodynamics of complex anticancer drugs, such as carrier-mediated agents and biologics. These topics are not only important from a scientific research perspective but also from a drug development and regulator perspective. Thus, it is important to evaluate the effects of obesity on the pharmacokinetics and pharmacodynamics of anticancer agents in all categories of body habitus and especially in patients who are obese and morbidly obese. As the effects of obesity on the pharmacokinetics and pharmacodynamics of anticancer agents may be highly variable across drug types, the optimal dosing metric and algorithm for difference classes of drugs may be widely different. Thus, studies are needed to evaluate current and novel metrics and methods for measuring body habitus as related to optimizing the dose and reducing pharmacokinetic and pharmacodynamic variability of anticancer agents in patients who are obese and morbidly obese.

Impact of body mass index in therapeutic response for HER2 positive breast cancer treated with neoadjuvant targeted therapy: a multi-center study and meta-analysis

While overweight/obesity has become a major public health issue worldwide, any association between body mass index (BMI) and therapeutic response in neoadjuvant targeted therapy treated HER2 positive breast cancer patients remain unclear. The information from a total of four-hundred and ninety-one neoadjuvant targeted therapy treated HER2 positive breast cancer patients from four institutions were retrospectively collected. Univariate and multivariate logistic analysis was developed to determine the association between BMI and therapeutic response. A meta-analysis of published literature was then conducted to confirm the effect of overweight/obesity on pCR for patients treated with neoadjuvant targeted therapy. Restricted cubic spline (RCS) adjusted for confounding factors demonstrated a decrease pCR with increasing BMI (OR = 0.937, P = 0.045). Patients were then categorized into under/normal weight (n = 299) and overweight/obesity (n = 192). Overweight/obese patients were independently associated with a poor therapeutic response. In the subgroup analysis, a significant negative impact of overweight/obesity on pCR can be observed both in single-targeted (OR = 0.556; P = 0.02) and dual-targeted (OR = 0.392; P = 0.021) populations. Six eligible studies involving 984 neoadjuvant targeted therapy treated HER2 positive breast cancer patients were included in the meta-analysis. The meta-analysis also demonstrated that overweight/obesity was significantly associated with a poor response to neoadjuvant anti-HER2 therapy (OR = 0.68; P = 0.007). Our result show that overweight and obese HER2 positive breast cancer patients are less likely to achieve pCR after neoadjuvant targeted therapy.

The Challenges of Treating Patients with Breast Cancer and Obesity

Obesity is defined as a body mass index (BMI) of 30 kg/m² or more and is associated with worse outcomes in patients with breast cancer, resulting in an increased incidence of breast cancer, recurrence, and death. The incidence of obesity is increasing, with almost half of all individuals in the United States classified as obese. Patients with obesity present with unique pharmacokinetics and physiology and are at increased risk of developing diabetes mellitus and cardiovascular disease, which leads to specific challenges when treating these patients. The aim of this review is to summarize the impact of obesity on the efficacy and toxicity of systemic therapies used for breast cancer patients, describe the molecular mechanisms through which obesity can affect systemic therapies, outline the existing American Society of Clinical Oncology (ASCO) guidelines for treating patients with cancer and obesity, and highlight additional clinical considerations for treating patients with obesity and breast cancer. We conclude that further research on the biological mechanisms underlying the obesity-breast cancer link may offer new treatment strategies, and clinicals trials that focus on the treatment and outcomes of patients with obesity and all stages of breast cancer are needed to inform future treatment guidelines.

A Systematic Review of Time and Resource Use Costs of Subcutaneous Versus Intravenous Administration of Oncology Biologics in a Hospital Setting

BACKGROUND

The introduction of human epidermal growth factor receptor 2 (HER2)-targeted treatment options, including dual HER2 blockade, has improved the prognosis for patients with HER2-positive breast cancer (BC) substantially. However, most of these treatments are administered via the intravenous (IV) route, which can present many challenges, such as long infusion and observation times, issues associated with repeated IV access, and increased strain on time and resources of medical centers and healthcare professionals. A fixed-dose combination of pertuzumab and trastuzumab for subcutaneous (SC) injection (pertuzumab, trastuzumab, and hyaluronidase-zzxf (PHESGO^®, F. Hoffmann-La Roche Ltd, Basel, Switzerland; PH FDC SC)) has been approved for use alongside chemotherapy for early-stage and metastatic HER2-positive BC.

OBJECTIVES

This systematic literature review was performed to identify evidence relating to time/resource use and resulting cost differences between SC and IV administration of oncology biologics in a hospital setting, and, ultimately, to inform economic modeling and associated health technology assessment of PH FDC SC.

METHODS

Electronic databases (Embase, MEDLINE, and EconLit) were searched on 9 April 2020. Additional hand searches were performed to identify publications not captured in the electronic database search. Publication screening and data extraction (study characteristics, participants, interventions, costs, and time/resource use) were carried out per the standard Cochrane review methodology. The quality of economic evidence of cost analyses was assessed using the 36-item checklist of the National Institute for Health and Care Excellence Single Technology Appraisal Specification for submission of evidence (January 2015).

RESULTS

The database search identified 2,740 records, of which 237 underwent full text screening. Full text screening, prioritization of publications about patients with a cancer diagnosis, and the addition of four citations identified during the hand search resulted in 72 final included publications, relating to 71 unique studies. This included 40 publications that described the time/resource use and/or costs associated with SC versus IV trastuzumab administration for the treatment of HER2-positive BC, and 28 publications that described time/resource use and/or costs associated with rituximab SC versus IV administration for the treatment of non-Hodgkin's lymphoma/follicular lymphoma and diffuse large B-cell lymphoma. The majority of publications showed substantial time savings for preparation and administration of SC versus IV therapy, and cost savings associated with reductions in healthcare professional time and resource use for SC administration.

LIMITATIONS

There was a lack of consensus between publications regarding time and cost measurements. In addition, the search was limited to publications related to anticancer drugs; the majority of the studies included were performed in European countries.

CONCLUSIONS AND IMPLICATIONS

This review indicated a substantial body of evidence showing time/resource and cost savings of SC versus IV administration of oncology biologics in a hospital setting, which can be used to inform economic evaluations of PH FDC SC.