Immunotherapy and Targeted Therapy in Patients With Advanced Melanoma and the V600 BRAF Mutation: Which One First? / Inmunoterapia vs. terapia diana en el paciente con melanoma avanzado y mutación BRAF V600, ¿por cuál comenzar?

Systemic treatment with immunotherapy or targeted therapy can significantly improve survival in patients with advanced (metastatic or high-risk) melanoma. Fifty percent of patients with melanoma have a BRAF mutation. Decisions on optimal sequencing of systemic treatments should take into account drug- and tumor-related factors and patient characteristics. Although the combination of ipilimumab and nivolumab is associated with the best survival outcomes, it is associated with significant toxicity. Targeted therapy may be a more favorable option in certain clinical situations. We review the literature on immunotherapy and targeted therapy in melanoma and present an algorithm for guiding decision-making on their use as first-line systemic treatments for advanced BRAF-mutated melanoma.

[Translated article] Immunotherapy and Targeted Therapy in Patients With Advanced Melanoma and the V600 BRAF Mutation: Which One First?

Systemic treatment with immunotherapy or targeted therapy can significantly improve survival in patients with advanced (metastatic or high-risk) melanoma. Fifty percent of patients with melanoma have a BRAF mutation. Decisions on optimal sequencing of systemic treatments should take into account drug- and tumor-related factors and patient characteristics. Although the combination of ipilimumab and nivolumab is associated with the best survival outcomes, it is associated with significant toxicity. Targeted therapy may be a more favorable option in certain clinical situations. We review the literature on immunotherapy and targeted therapy in melanoma and present an algorithm for guiding decision-making on their use as first-line systemic treatments for advanced BRAF-mutated melanoma.

Construction of a full-length antibody phage display vector.

Antibody phage display technology plays an important role in the development of monoclonal antibodies, humanization, and affinity evolution of antibodies. Thus far, antibody phage display mainly focuses on the display of antibody variable region or antigen-binding fragments. In this study, we constructed a new phage display system that can display full-length IgG antibodies on M13 phage. The phage display vector contains open reading frames (ORFs) encoding full-length the heavy and light chains of the antibody. NcoI/XhoI restriction enzyme sites were used to clone the variable region of the heavy chain into the heavy chain ORF, and SalI/NotI sites were used to clone the light chain variable region. SnaBI and SbfI restriction enzyme sites were designed between the cloning sites of heavy and light chains, respectively, to increase the cloning efficiency. The full-length antibodies of nivolumab against programmed death factor 1, trastuzumab against human epidermal growth factor 2, diL2K against the cluster of differentiation 3 epsilon, and adalimumab against tumor necrosis factor- alpha were displayed on phage with the vector. Phage-displayed antibodies showed their original antigen-binding activity. An amber codon shifted the vector to express IgG in non-suppressed Escherichia coli. The heavy and light chains of the E. coli-expressed antibodies could be detected through western blotting, and the antigen-binding activity was confirmed using an enzyme-linked immunosorbent assay. Biopanning was carried out with a model phage display antibody library, and the results showed that the novel phage system could be used for antibody library construction and highly efficient antibody screening. The reported system is the first full-length antibody phage display system.

Characterization of a single chain variable fragment of nivolumab that targets PD-1 and blocks PD-L1 binding.

Activated T-cells express Programmed cell Death protein 1 (PD-1), a key immune checkpoint receptor. PD-1 functions primarily in peripheral tissues, where T cells may encounter tumor-derived immunosuppressive ligands. Monoclonal antibodies that disrupt the interaction between T-cell derived PD-1 and immunosuppressive ligands, such as PD-L1, have revolutionized approaches to cancer therapy. For instance, Nivolumab is a monoclonal Ab that targets human PD-1 and has played an important role in immune checkpoint therapy. Herein we report the purification and initial characterization of a ~27 kDa single chain variable fragment (scFv) of Nivolumab that targets human PD-1 and blocks binding by PD-L1. The possibility that the anti-PD-1 scFv can serve as both an anti-tumor agent and as an anti-viral agent is discussed. IMPORTANCE: The clinical significance of anti-PD-1 antibodies for treatment of a range of solid tumors is well documented (reviewed in [1-4]). In this report, we describe the results of studies that establish that an anti-PD-1 scFv purified from E. coli binds tightly to human PD-1. Furthermore, we demonstrate that upon binding, the anti-PD-1 scFv disrupts the interaction between PD-1 and PD-L1. Thus, the properties of this scFv, including its small size, stability and affinity for human PD-1, suggest that it has the potential to be a useful reagent in subsequent immunotherapeutic, diagnostic and anti-viral applications.

A Multivariable Regression Model-based Nomogram for Estimating the Overall Survival of Patients Previously Treated With Nivolumab for Advanced Non-small-cell Lung Cancer.

AIM: Although nivolumab improves progression-free (PFS) and overall (OS) survival of patients previously treated for metastatic non-small-cell lung cancer (NSCLC), approximately 50% of treated patients experience disease progression within 3 months. As predictive biomarkers of response are not yet established, development of biomarkers to predict longer PFS and OS of patients treated with nivolumab is crucial. Therefore, we analyzed the impact of predictive markers of response to nivolumab and quantified the impact of each factor using nomograms. PATIENTS AND METHODS: Clinical data at nivolumab commencement were retrospectively collected from 201 patients treated with nivolumab between December 2015 and July 2016. Immunohistochemistry for programmed cell death ligand 1 (PD-L1) was performed using two assay systems (22C3 and 28-8). OS was calculated from nivolumab treatment initiation. Multivariate Cox regression analysis was conducted to identify independent predictors of OS. A nomogram was constructed to estimate OS. RESULTS: The median patient age was 68 years (135 males). Thirty-nine patients had driver mutations (epidermal growth factor receptor mutations and anaplastic lymphoma kinase rearrangement). In 22C3 and 28-8 immunostaining assays, 36.3% and 36.8% patients had PD-L1-negative cells, 17.4% and 14.4% had 1-49% PD-L1-positive cells, 11.9% and 14.9% had ≥50% PD-L1-positive cells, and 34.3% and 33.8% had unknown PD-L1 status, respectively. Kendall's rank correlation coefficient between the staining assays was 0.8414. The median OS of the whole patient cohort was 12.27 months [95% confidence interval (CI)=10.87-15.6]. Performance status ≥2 [hazard ratio (HR)=2.15, 95% CI=1.35-3.42, p=0.001) and high baseline lactate dehydrogenase (HR=1.15, 95% CI=1.05-1.26, p=0.004] were independent predictors of shorter OS. There was no significant correlation between PD-L1 status and OS. We constructed a nomogram to estimate the OS of patients previously treated with nivolumab. CONCLUSION: The multivariate analysis-based nomogram might be useful to estimate the OS of patients previously treated with nivolumab for advanced NSCLC.

Structural and In Vitro Functional Analyses of Novel Plant-Produced Anti-Human PD1 Antibody.

Immunotherapy has emerged as a promising and effective treatment for cancer. The frequently used immunotherapy agents are immune checkpoint inhibitors, such as antibodies specific to PD1, PD-L1, or CTLA-4. However, these drugs are highly expensive, and most people in the world cannot access the treatment. The development of recombinant protein production platforms that are cost-effective, scalable, and safe is needed. Plant platforms are attractive because of their low production cost, speed, scalability, lack of human and animal pathogens, and post-translational modifications that enable them to produce effective monoclonal antibodies. In this study, an anti-PD1 IgG4 monoclonal antibody (mAb) was transiently produced in Nicotiana benthamiana leaves. The plant-produced anti-PD1 mAb was compared to the commercial nivolumab produced in CHO cells. Our results showed that both antibodies have similar protein structures, and the N-glycans on the plant-produced antibody lacks plant-specific structures. The PD1 binding affinity of the plant-produced and commercial nivolumab, determined by two different techniques, that is, enzyme-linked immunosorbent assay (ELISA) and surface plasmon resonance (SPR), are also comparable. Plant-produced nivolumab binds to human PD1 protein with high affinity and specificity, blocks the PD-1/PD-L1 interaction, and enhances T cell function, comparable to commercial nivolumab. These results confirmed that plant-produced anti-PD1 antibody has the potential to be effective agent for cancer immunotherapy.

Native Mass Spectrometry, Ion Mobility, and Collision-Induced Unfolding for Conformational Characterization of IgG4 Monoclonal Antibodies.

Although the majority of FDA and EMA approved therapeutic monoclonal antibodies (mAbs) are IgG1, the number of IgG4-based formats reaching the market is increasing. IgG4 differs from other mAb isotypes by its specificity to form half mAbs that recombine into bispecific (bsAbs) molecules, through a process termed fab-arm exchange (FAE). We report here the complementarity of native mass spectrometry (MS), ion mobility (IM), and collision-induced unfolding (CIU) experiments for the structural characterization of members of the IgG4 subfamily (wild-type (wt), hinge-stabilized (hs, S228P mutation), and the resulting bsAb IgG4s). Native MS allows confirming/invalidating the occurrence of FAE as a function of these different types of IgG4. While IM-MS was unable to distinguish iso-cross-section IgG4 species, CIU experiments provide unique specific structural signatures of each individual IgG4 based on their specific unfolding pathways. Common CIU features of IgG4 formats include the observation of three conformational states and two transitions. In addition, CIU experiments demonstrated that S228P mutation stabilizes gas phase conformations of hsIgG4, in agreement with increased stability related to more rigid hinge regions. CIU patterns also appear to be more informative than IM-MS for bsAb structural characterization, unfolding signature of the bsAb being intermediate to the ones of the former parent wt-IgG4s, highlighting that bsAb CIU profiles keep the memory of their origins. Altogether, our results demonstrate that CIU patterns can serve as mAb specific structural signatures and are mature to be included in MS-based analytical workflows for conformational/structural characterization of mAb formats in early development phases and for multiple attribute monitoring.