New developments in the treatment of chemotherapy-induced neutropenia: focus on balugrastim

Implications of glycosylation for the development of selected cytokines and their derivatives for medical use

Cytokines are important regulators of immune responses, making them attractive targets for autoimmune diseases and cancer therapeutics. Yet, the significance of cytokine glycosylation remains underestimated. Many cytokines carry N- and O-glycans and some even undergo C-mannosylation. Recombinant cytokines produced in heterologous host cells may lack glycans or exhibit a different glycosylation pattern such as varying levels of galactosylation, sialylation, fucosylation or xylose addition compared to their human counterparts, potentially impacting critical immune interactions. We focused on cytokines that are currently utilized or designed in advanced therapeutic formats, including immunocytokines, fusokines, engager cytokines, and genetically engineered 'supercytokines.' Despite the innovative designs of these cytokine derivatives, their glycosylation patterns have not been extensively studied. By examining the glycosylation of the human native cytokines, G-CSF and GM-CSF, interferons β and γ, TNF-α and interleukins-2, -3 -4, -6, -7, -9, -12, -13, -15, -17A, -21, and - 22, we aim to assess its potential impact on their therapeutic derivatives. Understanding the glycosylation of the native cytokines could provide critical insights into the safety, efficacy, and functionality of these next-generation cytokine therapies, affecting factors such as stability, bioactivity, antigenicity, and half-life. This knowledge can guide the choice of optimal expression hosts for production and advance the development of effective cytokine-based therapeutics and synthetic immunology drugs.

Inflammation-Targeted Drug Delivery Strategies via Albumin-Based Systems

Albumin, being the most abundant serum protein, has the potential to significantly enhance the physicochemical properties of therapeutic payloads, thereby improving their pharmacological effects. Apart from its passive transport via the enhanced permeability and retention effect, albumin can actively accumulate in tumor microenvironments or inflammatory tissues via receptor-mediated processes. This unique property makes albumin a promising scaffold for targeted drug delivery. This review focuses on exploring different delivery strategies that combine albumin with drug payloads to achieve targeted therapy for inflammatory diseases. Also, albumin-derived therapeutic products on the market or undergoing clinical trials in the past decade have been summarized to gain insight into the future development of albumin-based drug delivery systems. Given the involvement of inflammation in numerous diseases, drug delivery systems utilizing albumin demonstrate remarkable advantages, including enhanced properties, improved in vivo behavior and efficacy. Albumin-based drug delivery systems have been demonstrated in clinical trials, while more advanced strategies for improving the capacity of drug delivery systems with the help of albumin remain to be discovered. This could pave the way for biomedical applications in more effective and precise treatments.

New insight into strategies used to develop long-acting G-CSF biologics for neutropenia therapy

Over the last 20 years, granulocyte colony-stimulating factors (G-CSFs) have become the major therapeutic option for the treatment of patients with neutropenia. Most of the current G-CSFs require daily injections, which are inconvenient and expensive for patients. Increased understanding of G-CSFs' structure, expression, and mechanism of clearance has been very instrumental in the development of new generations of long-acting G-CSFs with improved efficacy. Several approaches to reducing G-CSF clearance via conjugation techniques have been investigated. PEGylation, glycosylation, polysialylation, or conjugation with immunoglobulins or albumins have successfully increased G-CSFs' half-lives. Pegfilgrastim (Neulasta) has been successfully approved and marketed for the treatment of patients with neutropenia. The rapidly expanding market for G-CSFs has increased demand for G-CSF biosimilars. Therefore, the importance of this review is to highlight the principle, elimination's route, half-life, clearance, safety, benefits, and limitations of different strategies and techniques used to increase the half-life of biotherapeutic G-CSFs. Understanding these strategies will allow for a new treatment with more competitive manufacturing and lower unit costs compared with that of Neulasta.

The Uniqueness of Albumin as a Carrier in Nanodrug Delivery

Albumin is an appealing carrier in nanomedicine because of its unique features. First, it is the most abundant protein in plasma, endowing high biocompatibility, biodegradability, nonimmunogenicity, and safety for its clinical application. Second, albumin chemical structure and conformation allows interaction with many different drugs, potentially protecting them from elimination and metabolism in vivo, thus improving their pharmacokinetic properties. Finally, albumin can interact with receptors overexpressed in many diseased tissues and cells, providing a unique feature for active targeting of the disease site without the addition of specific ligands to the nanocarrier. For this reason, albumin, characterized by an extended serum half-life of around 19 days, has the potential of promoting half-life extension and targeted delivery of drugs. Therefore, this article focuses on the importance of albumin as a nanodrug delivery carrier for hydrophobic drugs, taking advantage of the passive as well as active targeting potential of this nanocarrier. Particular attention is paid to the breakthrough NAB-Technology, with emphasis on the advantages of Nab-Paclitaxel (Abraxane), compared to the solvent-based formulations of Paclitaxel, i.e., CrEL-paclitaxel (Taxol) in a clinical setting. Finally, the role of albumin in carrying anticancer compounds is depicted, with a particular focus on the albumin-based formulations that are currently undergoing clinical trials. The article sheds light on the power of an endogenous substance, such as albumin, as a drug delivery system, signifies the importance of the drug vehicle in drug performance in the biological systems, and highlights the possible future trends in the use of this drug delivery system.

Advances in the pharmacological management of neutropenia in solid tumors: the advent of biosimilars

Introduction: Severe neutropenia and infections are potentially life-threatening complications of cytotoxic antineoplastic therapies and often require hospitalization with a severe economic impact. Furthermore, hematological toxicity frequently results in chemotherapy dose reductions and delays that could interfere with disease control.Areas covered: This review provides an overview of granulocyte colony-stimulating factors (G-CSFs) including pegylated molecules, as well as more recent biosimilar G-CSFs, focusing on the toxicity, pharmacokinetics, and efficacy of these compounds.Expert opinion: The administration of hematopoietic growth factors in primary and secondary prophylaxis of neutropenia is a standard supportive care measure. Recently, several biosimilars have been developed. The market for biosimilar agents seems to be increasing over time thanks to their similar effectiveness and safety, compared with their originators, but lower costs.

Opportunistic Oral Infections

An opportunistic infection (OI) is a disease of microbial cause or pathogenesis generally thought to occur in hosts with weakened immunity. Oral OIs are associated with many risk factors and pathogens. Causative organisms for oral OIs have unique modes of transmission. The clinical presentation of oral OIs is heterogeneous and diagnosis can be challenging. Therefore, laboratory identification of causative pathogens is useful for definitive diagnosis and targeted therapeutics, and can be achieved by biological, serologic, histologic, and/or molecular methods. Clinical risk assessment and history with review of systems, and accurate diagnosis, treatment, and follow-up, are essential.

Preventing chemotherapy-induced myelosuppression by repurposing the FLT3 inhibitor quizartinib

We describe an approach to inhibit chemotherapy-induced myelosuppression. We found that short-term exposure of mice to the FLT3 inhibitor quizartinib induced the transient quiescence of multipotent progenitors (MPPs). This property of quizartinib conferred marked protection to MPPs in mice receiving fluorouracil or gemcitabine. The protection resulted in the rapid recovery of bone marrow and blood cellularity, thus preventing otherwise lethal myelosuppression. A treatment strategy involving quizartinib priming that protected wild-type bone marrow progenitors, but not leukemic cells, from fluorouracil provided a more effective treatment than conventional induction therapy in mouse models of acute myeloid leukemia. This strategy has the potential to be extended for use in other cancers where FLT3 inhibition does not adversely affect the effectiveness of chemotherapy. Thus, the addition of quizartinib to cancer treatment regimens could markedly improve cancer patient survival and quality of life.

An open-label, dose-ranging study of Rolontis, a novel long-acting myeloid growth factor, in breast cancer

This randomized, open‐label, active‐controlled study investigated the safety and efficacy of three doses of Rolontis (eflapegrastim), a novel, long‐acting myeloid growth factor, versus pegfilgrastim in breast cancer patients being treated with docetaxel and cyclophosphamide (TC). The primary efficacy endpoint was duration of severe neutropenia (DSN) during the first cycle of treatment. Patients who were candidates for adjuvant/neoadjuvant TC chemotherapy were eligible for participation. TC was administered on Day 1, followed by 45, 135, or 270 μg/kg Rolontis or 6 mg pegfilgrastim on Day 2. Complete blood counts were monitored daily when the absolute neutrophil count (ANC) fell to <1.5 × 10⁹/L. Up to four cycles of TC were investigated. The difference in DSN (time from ANC <0.5 × 10⁹/L to ANC recovery ≥2.0 × 10⁹/L) between the Rolontis and pegfilgrastim groups was −0.28 days (confidence interval [CI]: −0.56, −0.06) at 270 μg/kg, 0.14 days (CI: −0.28, 0.64) at 135 μg/kg, and 0.72 days (CI: 0.19, 1.27) at 45 μg/kg. Noninferiority to pegfilgrastim was demonstrated at 135 μg/kg (P = 0.002) and 270 μg/kg (P < .001), with superiority demonstrated at 270 μg/kg (0.03 days; P = 0.023). The most common treatment‐related adverse events (AEs) were bone pain, myalgia, arthralgia, back pain, and elevated white blood cell counts, with similar incidences across groups. All doses of Rolontis were well tolerated, and no new or significant treatment‐related toxicities were observed. In Cycle 1, Rolontis demonstrated noninferiority at the 135 μg/kg dose and statistical superiority in DSN at the 270 μg/kg dose when compared to pegfilgrastim.