Filgrastim biosimilar (EP2006): A review of 15 years' post-approval evidence.

Filgrastim is approved for several indications, including reduction of the incidence and duration of chemotherapy-induced neutropenia and for stem cell mobilization. The filgrastim biosimilar, EP2006, has been available in Europe since 2009, and in the United States since 2015. In this time, preclinical and clinical data used to support the approval of EP2006 have been published. These data established the biosimilarity of EP2006 to reference filgrastim in terms of structure, pharmacokinetics, pharmacodynamics, efficacy, safety, and immunogenicity. Additional real-world evidence studies have also demonstrated equivalent efficacy and safety of EP2006 compared with reference filgrastim, both in the reduction of neutropenia and in stem cell mobilization in clinical practice. This review summarizes these preclinical, clinical, and real-world data, as well as the available cost-effectiveness data, for EP2006 since its approval 15 years ago.

Cost-effectiveness of granulocyte colony-stimulating factors (G-CSFs) for the prevention of febrile neutropenia (FN) in patients with cancer.

PURPOSE: Clinical practice guidelines recommend the use of all approved granulocyte colony-stimulating factors (G-CSFs), including filgrastim and pegfilgrastim, as primary febrile neutropenia (FN) prophylaxis in patients receiving high- or intermediate-risk regimens (in those with additional patient risk factors). Previous studies have examined G-CSF cost-effectiveness by cancer type in patients with a high baseline risk of FN. This study evaluated patients with breast cancer (BC), non-small cell lung cancer (NSCLC), or non-Hodgkin's lymphoma (NHL) receiving therapy who were at intermediate risk for FN and compared primary prophylaxis (PP) and secondary prophylaxis (SP) using biosimilar filgrastim or biosimilar pegfilgrastim in Austria, France, and Germany. METHODS: A Markov cycle tree-based model was constructed to evaluate PP versus SP in patients with BC, NSCLC, or NHL receiving therapy over a lifetime horizon. Cost-effectiveness was evaluated over a range of willingness-to-pay (WTP) thresholds for incremental cost per quality-adjusted life year (QALY) gained. Sensitivity analyses evaluated uncertainty. RESULTS: Results demonstrated that using biosimilar filgrastim as PP compared to SP resulted in incremental cost-effectiveness ratios (ICERs) well below the most commonly accepted WTP threshold of €30,000. Across all three countries, PP in NSCLC had the lowest cost per QALY, and in France, PP was both cheaper and more effective than SP. Similar results were found using biosimilar pegfilgrastim, with ICERs generally higher than those for filgrastim. CONCLUSIONS: Biosimilar filgrastim and pegfilgrastim as primary prophylaxis are cost-effective approaches to avoid FN events in patients with BC, NSCLC, or NHL at intermediate risk for FN in Austria, France, and Germany.

Targeting the innate immunoreceptor RIG-I overcomes melanoma-intrinsic resistance to T cell immunotherapy.

Understanding tumor resistance to T cell immunotherapies is critical to improve patient outcomes. Our study revealed a role for transcriptional suppression of the tumor-intrinsic HLA class I (HLA-I) antigen processing and presentation machinery (APM) in therapy resistance. Low HLA-I APM mRNA levels in melanoma metastases before immune checkpoint blockade (ICB) correlated with nonresponsiveness to therapy and poor clinical outcome. Patient-derived melanoma cells with silenced HLA-I APM escaped recognition by autologous CD8+ T cells. However, targeted activation of the innate immunoreceptor RIG-I initiated de novo HLA-I APM transcription, thereby overcoming T cell resistance. Antigen presentation was restored in interferon-sensitive (IFN-sensitive) but also immunoedited IFN-resistant melanoma models through RIG-I-dependent stimulation of an IFN-independent salvage pathway involving IRF1 and IRF3. Likewise, enhanced HLA-I APM expression was detected in RIG-Ihi (DDX58hi) melanoma biopsies, correlating with improved patient survival. Induction of HLA-I APM by RIG-I synergized with antibodies blocking PD-1 and TIGIT inhibitory checkpoints in boosting the antitumor T cell activity of ICB nonresponders. Overall, the herein-identified IFN-independent effect of RIG-I on tumor antigen presentation and T cell recognition proposes innate immunoreceptor targeting as a strategy to overcome intrinsic T cell resistance of IFN-sensitive and IFN-resistant melanomas and improve clinical outcomes in immunotherapy.

A Mass Spectrometry-Based Profiling of Interactomes of Viral DDB1- and Cullin Ubiquitin Ligase-Binding Proteins Reveals NF-κB Inhibitory Activity of the HIV-2-Encoded Vpx.

Viruses and hosts are situated in a molecular arms race. To avoid morbidity and mortality, hosts evolved antiviral restriction factors. These restriction factors exert selection pressure on the viruses and drive viral evolution toward increasingly efficient immune antagonists. Numerous viruses exploit cellular DNA damage-binding protein 1 (DDB1)-containing Cullin RocA ubiquitin ligases (CRLs) to induce the ubiquitination and subsequent proteasomal degradation of antiviral factors expressed by their hosts. To establish a comprehensive understanding of the underlying protein interaction networks, we performed immuno-affinity precipitations for a panel of DDB1-interacting proteins derived from viruses such as mouse cytomegalovirus (MCMV, Murid herpesvirus [MuHV] 1), rat cytomegalovirus Maastricht MuHV2, rat cytomegalovirus English MuHV8, human cytomegalovirus (HCMV), hepatitis B virus (HBV), and human immunodeficiency virus (HIV). Cellular interaction partners were identified and quantified by mass spectrometry (MS) and validated by classical biochemistry. The comparative approach enabled us to separate unspecific interactions from specific binding partners and revealed remarkable differences in the strength of interaction with DDB1. Our analysis confirmed several previously described interactions like the interaction of the MCMV-encoded interferon antagonist pM27 with STAT2. We extended known interactions to paralogous proteins like the interaction of the HBV-encoded HBx with different Spindlin proteins and documented interactions for the first time, which explain functional data like the interaction of the HIV-2-encoded Vpr with Bax. Additionally, several novel interactions were identified, such as the association of the HIV-2-encoded Vpx with the transcription factor RelA (also called p65). For the latter interaction, we documented a functional relevance in antagonizing NF-κB-driven gene expression. The mutation of the DDB1 binding interface of Vpx significantly impaired NF-κB inhibition, indicating that Vpx counteracts NF-κB signaling by a DDB1- and CRL-dependent mechanism. In summary, our findings improve the understanding of how viral pathogens hijack cellular DDB1 and CRLs to ensure efficient replication despite the expression of host restriction factors.

Acquired IFNγ resistance impairs anti-tumor immunity and gives rise to T-cell-resistant melanoma lesions.

Melanoma treatment has been revolutionized by antibody-based immunotherapies. IFNγ secretion by CD8+ T cells is critical for therapy efficacy having anti-proliferative and pro-apoptotic effects on tumour cells. Our study demonstrates a genetic evolution of IFNγ resistance in different melanoma patient models. Chromosomal alterations and subsequent inactivating mutations in genes of the IFNγ signalling cascade, most often JAK1 or JAK2, protect melanoma cells from anti-tumour IFNγ activity. JAK1/2 mutants further evolve into T-cell-resistant HLA class I-negative lesions with genes involved in antigen presentation silenced and no longer inducible by IFNγ. Allelic JAK1/2 losses predisposing to IFNγ resistance development are frequent in melanoma. Subclones harbouring inactivating mutations emerge under various immunotherapies but are also detectable in pre-treatment biopsies. Our data demonstrate that JAK1/2 deficiency protects melanoma from anti-tumour IFNγ activity and results in T-cell-resistant HLA class I-negative lesions. Screening for mechanisms of IFNγ resistance should be considered in therapeutic decision-making.

Biophysical Characterization of Nucleophosmin Interactions with Human Immunodeficiency Virus Rev and Herpes Simplex Virus US11.

Nucleophosmin (NPM1, also known as B23, numatrin or NO38) is a pentameric RNA-binding protein with RNA and protein chaperon functions. NPM1 has increasingly emerged as a potential cellular factor that directly associates with viral proteins; however, the significance of these interactions in each case is still not clear. In this study, we have investigated the physical interaction of NPM1 with both human immunodeficiency virus type 1 (HIV-1) Rev and Herpes Simplex virus type 1 (HSV-1) US11, two functionally homologous proteins. Both viral proteins show, in mechanistically different modes, high affinity for a binding site on the N-terminal oligomerization domain of NPM1. Rev, additionally, exhibits low-affinity for the central histone-binding domain of NPM1. We also showed that the proapoptotic cyclic peptide CIGB-300 specifically binds to NPM1 oligomerization domain and blocks its association with Rev and US11. Moreover, HIV-1 virus production was significantly reduced in the cells treated with CIGB-300. Results of this study suggest that targeting NPM1 may represent a useful approach for antiviral intervention.