Predicting Chemotherapy-Induced Neutropenia and Granulocyte Colony-Stimulating Factor Response Using Model-Based In Vitro to Clinical Translation

Quantitative systems toxicology modeling in pharmaceutical research and development: An industry-wide survey and selected case study examples

Quantitative systems toxicology (QST) models are increasingly being applied for predicting and understanding toxicity liabilities in pharmaceutical research and development. A European Federation of Pharmaceutical Industries and Associations (EFPIA)-wide survey was completed by 15 companies. The results provide insights into the current use of QST models across the industry. 73% of responding companies with more than 10,000 employees utilize QST models. The most applied QST models are for liver, cardiac electrophysiology, and bone marrow/hematology. Responders indicated particular interest in QST models for the central nervous system (CNS), kidney, lung, and skin. QST models are used to support decisions in both preclinical and clinical stages of pharmaceutical development. The survey suggests high demand for QST models and resource limitations were indicated as a common obstacle to broader use and impact. Increased investment in QST resources and training may accelerate application and impact. Case studies of QST model use in decision-making within EFPIA companies are also discussed. This article aims to (i) share industry experience and learnings from applying QST models to inform decision-making in drug discovery and development programs, and (ii) share approaches taken during QST model development and validation and compare these with recommendations for modeling best practices and frameworks proposed in the literature. Discussion of QST-specific applications in relation to these modeling frameworks is relevant in the context of the recently proposed International Council for Harmonization (ICH) M15 guideline on general principles for Model-Informed Drug Development (MIDD).

How Can Oncology Nurses and Advanced Practice Providers Reduce the Burden of Chemotherapy-Induced Febrile Neutropenia in the US?

Background

Neutropenia and febrile neutropenia (FN) are serious complications of myelosuppressive chemotherapy and present a considerable burden to patients with cancer. Febrile neutropenia is associated with increased risks of infection and hospitalization, a particular concern during the coronavirus disease 2019 (COVID-19) pandemic. Oncology nurses and advanced practice providers (APPs; including nurse practitioners, physician assistants, advanced practice nurses, and pharmacists) play a vital role in the management of patients with cancer and the prevention of infections.

Objectives

The objectives of this article are to summarize the burden of chemotherapy-related neutropenia and FN in patients with cancer in the US and to evaluate the role of oncology nurses and APPs in preventing and managing FN.

Methods

This article provides a narrative review of US studies reporting on the burden of FN, FN during COVID-19, adherence to guidelines for the use of prophylactic granulocyte colony-stimulating factors (G-CSFs), the involvement of oncology nurses in FN prevention, management, and patient quality of life, and inappropriate and/or incomplete G-CSF treatment.

Findings

Despite advances in supportive care for patients with cancer receiving myelosuppressive chemotherapy, neutropenia and FN present a considerable burden to patients, particularly during the COVID-19 pandemic. Oncology nurses and APPs play a vital role in the appropriate and timely delivery of supportive care, which can improve patient outcomes and minimize treatment costs.

Topical application of gemcitabine generates microvesicle particles in human and murine skin

Chemotherapy has remained the mainstay for the treatment of multiple types of cancers. In particular, topical use of chemotherapy has been used for skin cancers. Though effective, topical chemotherapy has been limited due to adverse effects such as local and even systemic toxicities. Our recent studies demonstrated that exposure to pro-oxidative stressors, including therapeutic agents induces the generation of extracellular vesicles known as microvesicle particles (MVP) which are dependent on activation of the Platelet-activating factor-receptor (PAFR), a G-protein coupled receptor present on various cell types, and acid sphingomyelinase (aSMase), an enzyme required for MVP biogenesis. Based upon this premise, we tested the hypothesis that topical application of gemcitabine will induce MVP generation in human and murine skin. Our ex vivo studies using human skin explants demonstrate that gemcitabine treatment results in MVP generation in a dose-dependent manner in a process blocked by PAFR antagonist and aSMase inhibitor. Importantly, gemcitabine-induced MVPs carry PAFR agonists. To confirm the mechanisms, we employed PAFR-expressing and deficient (Ptafr^-/- ) mouse models as well as mice deficient in aSMase enzyme (Spmd1^-/- ). Similar to the findings using pharmacologic tools, genetic-based approaches demonstrate that gemcitabine-induced MVP release in WT mice was blunted in Ptafr^-/- and Spmd1^-/- mice. These findings demonstrate a novel mechanism by which local chemotherapy can generate bioactive components as a bystander effect in a process that is dependent upon the PAFR-aSMase pathway.

Improving categorical endpoint longitudinal exposure-response modeling through the joint modeling with a related endpoint

Exposure-response modeling is important to optimize dose and dosing regimens in clinical drug development. While primary clinical trial endpoints often have few categories and thus provide only limited information, sometimes there may be additional, more informative endpoints. Benefits of fully incorporating relevant information in longitudinal exposure-response modeling through joint modeling have recently been shown. This manuscript aims to further investigate the benefit of joint modeling of an ordered categorical primary endpoint with a related near-continuous endpoint, through the sharing of model parameters in the latent variable indirect response (IDR) modeling framework. This is illustrated by analyzing the data collected through up to 116 weeks from a phase 3b response-adaptive trial of ustekinumab in patients with psoriasis. The primary endpoint was based on the 6-point physician's global assessment (PGA) score. The Psoriasis area and severity Index (PASI) data, ranging from 0 to 72 with 0.1 increments, were also available. Separate and joint latent variable Type I IDR models of PGA and PASI scores were developed and compared. The results showed that the separate PGA model had a substantial structural bias, which was corrected by the joint modeling of PGA and PASI scores.

Supportive therapies in the prevention of chemotherapy-induced febrile neutropenia and appropriate use of granulocyte colony-stimulating factors: a Delphi consensus statement

PURPOSE

Data indicate that the use of prophylactic granulocyte colony-stimulating factors (G-CSFs) for chemotherapy-induced febrile neutropenia (FN) in routine practice is not consistent with guideline recommendations. The initiative "supportive care for febrile neutropenia prevention and appropriateness of G-CFS use" was undertaken to address the issue of inappropriate prescription of G-CSFs and to improve guideline adherence in the treatment of FN.

METHODS

In a two-round Delphi procedure, 36 medical oncologists reviewed clinically relevant recommendations on risk assessment, the appropriate use of G-CSFs, and the prevention of FN based on available literature and individual clinical expertise.

RESULTS

The consensus was reached on 16 out of 38 recommendations, which are backed by evidence from randomised clinical trials and routine clinical practice. The medical oncologists agreed that the severity of neutropenia depends on patients' characteristics and chemotherapy intensity, and therefore, the risk of severe neutropenia or FN should be assessed at each chemotherapy cycle so as to initiate prophylaxis with G-CSFs if required. The use of biosimilar G-CSFs, with similar efficacy and safety profiles to the originator biologic, has improved the availability and sustainability of cancer care. The timing of supportive therapy is crucial; for example, long-acting G-CSF should be administered 24-72 h after chemotherapy administration. Each biological agent has a recommended administration dose and duration, and it is important to follow these recommendations to avoid complications associated with under-prophylaxis.

CONCLUSION

It is hoped that these statements will help to increase adherence to guideline recommendations for appropriate G-CSF use and improve patient care.

G-CSF and G-CSF-related vasculitis: a systematic review of the literature and intriguing future research perspectives

Background: There are several case reports suggesting that G-CSFs may, in rare conditions, produce serious side effects, such as vasculitis. Materials & methods: A systematic search was conducted in Medline via PubMed, Embase and Cochrane Library to describe this unusual side effect to raise awareness among clinicians for early recognition and treatment. Results: Fifty-seven patients were analyzed. The most prevalent cancer type was breast cancer (47%). Long-acting G-CSF was used in 38 patients (67%). Only 47% of patients were treated with steroids. Conclusion: Although the benefit of G-CSF treatment outweighs the potential damage, oncologists should consider the possibility of triggering a vascular toxicity and try to identify patients at increased risk for this side effect.

A whole-body circulatory neutrophil model with application to predicting clinical neutropenia from in vitro studies

A circulatory model of granulopoiesis and its regulation is presented that includes neutrophil trafficking in the lungs, liver, spleen, bone marrow, lymph nodes, and blood. In each organ, neutrophils undergo transendothelial migration from vascular to interstitial space, clearance due to apoptosis, and recycling via the lymphatic flow. The model includes cell cycling of progenitor cells in the bone marrow, granulocyte colony-stimulating factor (G-CSF) kinetics and its neutrophil regulatory action, as well as neutrophil margination in the blood. From previously reported studies, 111 In-labeled neutrophil kinetic data in the blood and sampled organs were used to estimate the organ trafficking parameters in the model. The model was further developed and evaluated using absolute neutrophil count (ANC), band cell, and segmented neutrophil time course data from healthy volunteers following four dose levels of pegfilgrastim (r2  = 0.77-0.99), along with ANC time course responses following filgrastim (r2  = 0.96). The baseline values of various cell types in bone marrow and blood, as well as G-CSF concentration in the blood, predicted by the model are consistent with available literature reports. After incorporating the mechanism of action of both paclitaxel and carboplatin, as determined from an in vitro bone marrow studies, the model reliably predicted the observed ANC time course following paclitaxel plus carboplatin observed in a phase I trial of 46 patients (r2  = 0.70). The circulatory neutrophil model may provide a mechanistic framework for predicting multi-organ neutrophil homeostasis and dynamics in response to therapeutic agents that target neutrophil dynamics and trafficking in different organs.