Pegfilgrastim Enhances the Antitumor Effect of Therapeutic Monoclonal Antibodies

Prophylactic pegfilgrastim reduces febrile neutropenia in ramucirumab plus docetaxel after chemoimmunotherapy in advanced NSCLC: post hoc analysis from NEJ051

Ramucirumab plus docetaxel (RD) can cause febrile neutropenia (FN), which frequently requires the prophylactic administration of pegfilgrastim. However, the effects of prophylactic pegfilgrastim on FN prevention, therapeutic efficacy, and prognosis after RD have not been fully evaluated in patients with advanced non-small-cell lung cancer (NSCLC). Two hundred and eighty-eight patients with advanced NSCLC who received RD as second-line therapy after platinum-based chemotherapy plus PD-1 blockade were included. Patients were divided into groups with and without prophylactic pegfilgrastim, and adverse events, efficacy, and prognosis were compared between both groups. Of the 288 patients, 247 received prophylactic pegfilgrastim and 41 did not. The frequency of grade 3/4 neutropenia was 62 patients (25.1%) in the pegfilgrastim group and 28 (68.3%) in the control group (p < 0.001). The frequency of FN was 25 patients (10.1%) in the pegfilgrastim group and 10 (24.4%) in the control group (p = 0.018). The objective response rate was 31.2% and 14.6% in the pegfilgrastim and control groups (p = 0.039), respectively. The disease control rate was 72.9% in the pegfilgrastim group and 51.2% in the control group (p = 0.009). Median progression free survival was 4.3 months in the pegfilgrastim group and 2.5 months in the control group (p = 0.002). The median overall survival was 12.8 and 8.1 months in the pegfilgrastim and control groups (p = 0.004), respectively. Prophylactic pegfilgrastim for RD reduced the frequency of grade 3/4 neutropenia and febrile neutropenia and did not appear to be detrimental to patient outcome RD.Clinical Trial Registration Number: UMIN000042333.

PEG-rhG-CSF for prophylaxis of neutropenia after chemotherapy in patients with non-small cell lung cancer: A multicenter, prospective, randomized study

BACKGROUND

To evaluate the efficacy and safety of pegylated recombinant human granulocyte colony-stimulating factor (PEG-rhG-CSF) in preventing neutropenia during multiple cycles of chemotherapy in patients with non-small cell lung cancer (NSCLC).

METHOD

In a multicenter, prospective, randomized trial, patients with NSCLC were randomly assigned in a 2:1 ratio to treatment group (PEG-rhG-CSF as primary prophylactic therapy) or control group. Patients in the control group were administered rhG-CSF when white blood cell count was <2.0 × 10⁹ /L or absolute neutrophil count <1.0 × 10⁹ /L. The primary endpoint was the incidence of grade 3/4 neutropenia. Secondary endpoints included the incidence and duration of grade 3/4 neutropenia in each cycle, the incidence of febrile neutropenia (FN), delay rate of chemotherapy, prolonged time of chemotherapy, and safety.

RESULTS

Between January 2019 and July 2021, 130 patients were enrolled (treatment group: n = 87, control group: n = 43). The incidence of grade 3/4 neutropenia in the treatment group was significantly lower than that in the control group (1.15% vs. 11.63%, p < 0.05). The mean duration of grade 3/4 neutropenia for the treatment and control group was 2.00 and 3.75 days, respectively. There were no statistical differences in the incidence of FN, delay rate of chemotherapy, prolonged time of chemotherapy, and antibiotic use between the two groups (all p > 0.05). Adverse events were reported in 47.13% of patients in the treatment group and 48.84% patients in the control group.

CONCLUSIONS

Primary prophylactic treatment with PEG-rhG-CSF could reduce the incidence of neutropenia in patients with NSCLC during multiple cycles of chemotherapy, with acceptable safety and tolerability.

Therapeutic exploitation of neutrophils to fight cancer

Antibody-based immunotherapy is a promising strategy in cancer treatment. Antibodies can directly inhibit tumor growth, induce complement-dependent cytotoxicity and induce Fc receptor-mediated elimination of tumor cells by macrophages and natural killer cells. Until now, however, neutrophils have been largely overlooked as potential effector cells, even though they are the most abundant type of immune cells in the circulation. Neutrophils display heterogeneity, especially in the context of cancer. Therefore, their role in cancer is debated. Nevertheless, neutrophils possess natural anti-tumor properties and appropriate stimulation, i.e. specific targeting via antibody therapy, induces potent tumor cell killing, especially via targeting of the immunoglobulin A Fc receptor (FcαRI, CD89). In this review we address the mechanisms of tumor cell killing by neutrophils and the role of neutrophils in induction of anti-tumor immunity. Moreover, possibilities for therapeutic targeting are discussed.

The Neutrophil: The Underdog That Packs a Punch in the Fight against Cancer

The advent of immunotherapy has had a major impact on the outcome and overall survival in many types of cancer. Current immunotherapeutic strategies typically aim to (re)activate anticancer T cell immunity, although the targeting of macrophage-mediated anticancer innate immunity has also emerged in recent years. Neutrophils, although comprising ≈ 60% of all white blood cells in the circulation, are still largely overlooked in this respect. Nevertheless, neutrophils have evident anticancer activity and can induce phagocytosis, trogocytosis, as well as the direct cytotoxic elimination of cancer cells. Furthermore, therapeutic tumor-targeting monoclonal antibodies trigger anticancer immune responses through all innate Fc-receptor expressing cells, including neutrophils. Indeed, the depletion of neutrophils strongly reduced the efficacy of monoclonal antibody treatment and increased tumor progression in various preclinical studies. In addition, the infusion of neutrophils in murine cancer models reduced tumor progression. However, evidence on the anticancer effects of neutrophils is fragmentary and mostly obtained in in vitro assays or murine models with reports on anticancer neutrophil activity in humans lagging behind. In this review, we aim to give an overview of the available knowledge of anticancer activity by neutrophils. Furthermore, we will describe strategies being explored for the therapeutic activation of anticancer neutrophil activity.

Plasticity in Pro- and Anti-tumor Activity of Neutrophils: Shifting the Balance

Over the last decades, cancer immunotherapies such as checkpoint blockade and adoptive T cell transfer have been a game changer in many aspects and have improved the treatment for various malignancies considerably. Despite the clinical success of harnessing the adaptive immunity to combat the tumor, the benefits of immunotherapy are still limited to a subset of patients and cancer types. In recent years, neutrophils, the most abundant circulating leukocytes, have emerged as promising targets for anti-cancer therapies. Traditionally regarded as the first line of defense against infections, neutrophils are increasingly recognized as critical players during cancer progression. Evidence shows the functional plasticity of neutrophils in the tumor microenvironment, allowing neutrophils to exert either pro-tumor or anti-tumor effects. This review describes the tumor-promoting roles of neutrophils, focusing on their myeloid-derived suppressor cell activity, as well as their role in tumor elimination, exerted mainly via antibody-dependent cellular cytotoxicity. We will discuss potential approaches to therapeutically target neutrophils in cancer. These include strategies in humans to either silence the pro-tumor activity of neutrophils, or to activate or enhance their anti-tumor functions. Redirecting neutrophils seems a promising approach to harness innate immunity to improve treatment for cancer patients.

Pegylated recombinant human granulocyte colony-stimulating factor regulates the immune status of patients with small cell lung cancer

BACKGROUND

Small cell lung cancer (SCLC) is an aggressive disease involving immunodeficiency for which chemotherapy is the standard treatment. Pegylated recombinant human granulocyte colony-stimulating factor (PEG-rhG-CSF) is widely used for primary or secondary prophylaxis of febrile neutropenia (FN) in chemotherapy. However, whether PEG-rhG-CSF influences immune cells, such as lymphocytes, remains unclear.

METHODS

A total of 17 treatment-naïve SCLC patients were prospectively enrolled and divided into the PEG-rhG-CSF and control groups according to their FN risk. Longitudinal sampling of peripheral blood was performed before, after and 4-6 days after the first cycle of chemotherapy. Flow cytometry was used to assess lymphocyte subsets, including CD3⁺ T, CD4⁺ T, CD8⁺ T, NK, and B cells. The diversity and clonality of the T-cell receptor (TCR) repertoire was analyzed by next-generation sequencing.

RESULTS

In the PEG-rhG-CSF group, the proportions of CD3⁺ T and CD4⁺ T cells had increased significantly (P = 0.002, P = 0.020, respectively), whereas there was no increase in CD8⁺ T cells. Further, TCR diversity increased (P = 0.009) and clonality decreased (P = 0.004) significantly after PEG-rhG-CSF treatment. However, these factors showed opposite trends before and after chemotherapy. Vβ and Jβ gene fragment types, which determine TCR diversity, were significantly amplified in the PEG-rhG-CSF group. The change in TCR diversity was significantly correlated with changes in the CD3⁺ T or CD4⁺ T cell proportions, but not the CD8⁺ T cell proportion.

CONCLUSIONS

PEG-rhG-CSF regulates the immune status of SCLC patients; CD4⁺ T cells may be the main effector cells involved in this process. These findings may optimize the treatment of SCLC.

KEY POINTS

PEG-rhG-CSF regulates SCLC immunity. PEG-rhG-CSF increased CD3⁺ T and CD4⁺ T cell proportions. PEG-rhG-CSF increased TCR diversity and decreased clonality in peripheral blood. Change in TCR diversity were correlated with CD3⁺ T or CD4⁺ T changes.

Flow cytometry-based assessment of direct-targeting anti-cancer antibody immune effector functions

Monoclonal antibody-based therapies are increasingly being used to treat cancer. Some mediate their therapeutic effects through modifying the function of immune cells globally, while others bind directly to tumor cells and can recruit immune effector cells through their Fc regions. As new direct-binding agents are developed, having the ability to test their Fc-mediated functions in a high-throughput manner is important for selecting antibodies with immune effector properties. Here, using monoclonal anti-CD20 antibody (rituximab) as an example and the CD20⁺ Raji cell line as tumor target, we describe flow cytometry-based assays for determining an antibody's capacity for mediating antibody-dependent cellular cytotoxicity (ADCC), antibody-dependent cellular phagocytosis (ADCP) and complement-dependent cytotoxicity (CDC). These assays are sensitive, reliable, affordable and avoid the use of radioactivity.

Filgrastim enhances T-cell clearance by antithymocyte globulin exposure after unrelated cord blood transplantation

Residual antithymocyte globulin (ATG; Thymoglobulin) exposure after allogeneic hematopoietic (stem) cell transplantation (HCT) delays CD4⁺ T-cell immune reconstitution (CD4⁺ IR), subsequently increasing morbidity and mortality. This effect seems particularly present after cord blood transplantation (CBT) compared to bone marrow transplantation (BMT). The reason for this is currently unknown. We investigated the effect of active-ATG exposure on CD4⁺ IR after BMT and CBT in 275 patients (CBT n = 155, BMT n = 120; median age, 7.8 years; range, 0.16-19.2 years) receiving their first allogeneic HCT between January 2008 and September 2016. Multivariate log-rank tests (with correction for covariates) revealed that CD4⁺ IR was faster after CBT than after BMT with <10 active-ATG × day/mL (P = .018) residual exposure. In contrast, >10 active-ATG × day/mL exposure severely impaired CD4⁺ IR after CBT (P < .001), but not after BMT (P = .74). To decipher these differences, we performed ATG-binding and ATG-cytotoxicity experiments using cord blood- and bone marrow graft-derived T-cell subsets, B cells, natural killer cells, and monocytes. No differences were observed. Nevertheless, a major covariate in our cohort was Filgrastim treatment (only given after CBT). We found that Filgrastim (granulocyte colony-stimulating factor [G-CSF]) exposure highly increased neutrophil-mediated ATG cytotoxicity (by 40-fold [0.5 vs 20%; P = .002]), which explained the enhanced T-cell clearance after CBT. These findings imply revision of the use (and/or timing) of G-CSF in patients with residual ATG exposure.

Granulocyte-Colony Stimulating Factor Nanocarriers for Stimulation of the Immune System (Part II): Dose-Dependent Biodistribution and In Vivo Antitumor Efficacy in Combination with Rituximab

The purpose of immuno-modulation is to increase or restore the action of immunocompetent cells against tumors with or without the use of monoclonal antibodies. The innate immune system is a key player in various pathological situations, but cells of this system appear to be inhibited or insufficiently active in malignancy or severe infectious diseases. The present study was designed to investigate therapeutic value of nanoparticles (NPs) coupled with bioactive hematopoietic growth factors acting on the innate immune system. The use of nanoparticles (NPs) allowing multimodal detection and multifunctional grafting are currently of great interest for theranostic purposes. In the present work, we have evaluated the impact of the number of granulocyte-colony stimulating factor (G-CSF) grafted on the surface on the NPs on the biodistribution in mice thanks to indium 111 radiolabeling. Furthermore, we have investigated whether grafted G-CSF NPs could stimulate the immune innate system and enhance the therapeutic efficacy of the monoclonal antibody rituximab in mice bearing human lymphoma xenografts. Following intravenous (i.v.) administration of NP-DTPA and NP-DTPA/G-CSF-X high levels of radioactivity were observed in the liver. Furthermore, spleen uptake was correlated with the number of G-CSF molecules grafted on the surface of the NPs. Combining NP-DTPA/G-CSF-34 with rituximab strongly reduced RL tumor growth compared to rituximab alone or in combination with conventional G-CSF + rituximab. The use of highly loaded G-CSF NPs as immune adjuvants could enhance the antitumor activity of therapeutic monoclonal antibodies by amplifying tumor cell destruction by innate immune cells.

Neutrophils in cancer

Neutrophils play an important role in cancer. This does not only relate to the well-established prognostic value of the presence of neutrophils, either in the blood or in tumor tissue, in the context of cancer progression or for the monitoring of therapy, but also to their active role in the progression of cancer. In the current review, we describe what is known in general about the role of neutrophils in cancer. What is emerging is a complex, rather heterogeneous picture with both pro- and anti-tumorigenic roles, which apparently differs with cancer type and disease stage. Furthermore, we will discuss the well-known role of neutrophils as myeloid-derived suppressor cells (MDSC), and also on the role of neutrophils as important effector cells during antibody therapy in cancer. It is clear that neutrophils contribute substantially to cancer progression in multiple ways, and this includes both direct effects on the cancer cells and indirect effect on the tumor microenvironment. While in many cases neutrophils have been shown to promote tumor progression, for instance by acting as MDSC, there are also protective effects, particularly when antibody immunotherapy is performed. A better understanding of the role of neutrophils is likely to provide opportunities for immunomodulation and for improving the treatment of cancer patients.