Tailoring in vitro selection for a picomolar affinity human antibody directed against vascular endothelial growth factor receptor 2 for enhanced neutralizing activity

Isolation and Characterization of the Vascular Endothelial Growth Factor Receptor Targeting ScFv Antibody Fragments Derived from Phage Display Technology

Angiogenesis, as a tumor hallmark, plays an important role in the growth and development of the tumor vasculature system. There is a huge amount of evidence suggesting that the vascular endothelial growth factor receptor (VEGFR-2)/VEGF-A axis is one of the main contributors to tumor angiogenesis and metastasis. Thus, inhibition of the VEGFR-2 signaling pathway by anti-VEGFR-2 mAb can retard tumor growth. In this study, we employ phage display technology and solution-phase biopanning (SPB) to isolate specific single-chain variable fragments (scFvs) against VEGFR-2 and report on the receptor binding characteristics of the candidate scFvs A semisynthetic phage antibody library to isolate anti-VEGFR-2 scFvs through an SPB performed with decreasing concentrations of the VEGFR-2-His tag and VEGFR-2-biotin. After successful expression and purification, the specificity of the selected scFv clones was further analyzed by enzyme-linked immunosorbent assay (ELISA), flow cytometry, and immunoblotting. The competition assay was undertaken to identify the VEGFR-2 receptor-blocking properties of the scFvs. Furthermore, the molecular binding characteristics of candidate scFvs were extensively studied by peptide-protein docking. Polyclonal ELISA analysis subsequent to four rounds of biopanning showed a significant enrichment of VEGFR-2-specific phage clones by increasing positive signals from the first round toward the fourth round of selection. The individual VEGFR-2-reactive scFv phage clones were identified by monoclonal phage ELISA. The sequence analysis and complementarity-determining region alignment identified the four unique anti-VEGFR-2-scFv clones. The soluble and purified scFvs displayed binding activity against soluble and cell-associated forms of VEGFR-2 protein in the ELISA and flow cytometry assays. Based on the inference from the molecular docking results, scFvs D3, E1, H1, and E9 recognized domains 2 and 3 on the VEGFR-2 protein and displayed competition with VEGF-A for binding to VEGFR-2. The competition assay confirmed that scFvs H1 and D3 can block the VEGFR-2/VEGF-A interaction. In conclusion, we identified novel VEGFR-2-blocking scFvs that perhaps exhibit the potential for angiogenesis inhibition in VEGFR-2-overexpressed tumor cells.

A phase 1 trial utilizing a pharmacokinetic endpoint to determine the optimal dose of ramucirumab in children and adolescents with relapsed or refractory solid tumors, including central nervous system tumors

BACKGROUND

Ramucirumab is a monoclonal antibody that binds the extracellular domain of vascular endothelial growth factor receptor (VEGFR-2) and prevents binding of VEGF ligands. Based on population pharmacokinetic (PK) analysis and correlation with efficacy in adults, a target steady state trough concentration (Css,min ) ≥ 50 µg/mL was established.

PROCEDURES

This phase 1 trial (ADVL1416) used a rolling six design and a PK primary endpoint to define the recommended phase 2 dose (RP2D) of ramucirumab in children with recurrent/refractory solid tumors. Two dose levels (DL) were planned (DL1: 8 mg/kg, DL2: 12 mg/kg administered intravenously [IV] every 2 weeks). Toxicity during the initial 6 weeks was used to assess maximum tolerated dose (MTD). Cycle 1 Day 42 trough (Cmin ) ≥ 50 µg/mL was the target concentration for the PK endpoint. At the RP2D, cohorts for PK expansion and children with central nervous tumors were planned.

RESULTS

Twenty-nine patients were enrolled; 28 were eligible; median age [range] = 13.5 [1-21] years; 22 were evaluable for the PK endpoint. Dose-limiting proteinuria occurred at both DLs; however, the MTD was not exceeded. At DL2 (12 mg/kg), the median Day 42 Cmin (n = 16) was 87.8 µg/mL; 15 of 16 patients achieved a Cmin  ≥ 50 µg/mL.

CONCLUSION

Ramucirumab was well tolerated in children and adolescents with solid tumors. The RP2D for ramucirumab was 12 mg/kg IV every 2 weeks. This trial demonstrates the feasibility of incorporating a primary PK endpoint to determine dose escalation and the RP2D in children. Studies of ramucirumab in children with selected solid tumors are ongoing.

Hepatocellular carcinoma: signaling pathways, targeted therapy, and immunotherapy

Hepatocellular carcinoma (HCC) is the most common primary liver cancer with a high mortality rate. It is regarded as a significant public health issue because of its complicated pathophysiology, high metastasis, and recurrence rates. There are no obvious symptoms in the early stage of HCC, which often leads to delays in diagnosis. Traditional treatment methods such as surgical resection, radiotherapy, chemotherapy, and interventional therapies have limited therapeutic effects for HCC patients with recurrence or metastasis. With the development of molecular biology and immunology, molecular signaling pathways and immune checkpoint were identified as the main mechanism of HCC progression. Targeting these molecules has become a new direction for the treatment of HCC. At present, the combination of targeted drugs and immune checkpoint inhibitors is the first choice for advanced HCC patients. In this review, we mainly focus on the cutting-edge research of signaling pathways and corresponding targeted therapy and immunotherapy in HCC. It is of great significance to comprehensively understand the pathogenesis of HCC, search for potential therapeutic targets, and optimize the treatment strategies of HCC.

Biology and therapeutic targeting of vascular endothelial growth factor A

The formation of new blood vessels, called angiogenesis, is an essential pathophysiological process in which several families of regulators have been implicated. Among these, vascular endothelial growth factor A (VEGFA; also known as VEGF) and its two tyrosine kinase receptors, VEGFR1 and VEGFR2, represent a key signalling pathway mediating physiological angiogenesis and are also major therapeutic targets. VEGFA is a member of the gene family that includes VEGFB, VEGFC, VEGFD and placental growth factor (PLGF). Three decades after its initial isolation and cloning, VEGFA is arguably the most extensively investigated signalling system in angiogenesis. Although many mediators of angiogenesis have been identified, including members of the FGF family, angiopoietins, TGFβ and sphingosine 1-phosphate, all current FDA-approved anti-angiogenic drugs target the VEGF pathway. Anti-VEGF agents are widely used in oncology and, in combination with chemotherapy or immunotherapy, are now the standard of care in multiple malignancies. Anti-VEGF drugs have also revolutionized the treatment of neovascular eye disorders such as age-related macular degeneration and ischaemic retinal disorders. In this Review, we emphasize the molecular, structural and cellular basis of VEGFA action as well as recent findings illustrating unexpected interactions with other pathways and provocative reports on the role of VEGFA in regenerative medicine. We also discuss clinical and translational aspects of VEGFA. Given the crucial role that VEGFA plays in regulating angiogenesis in health and disease, this molecule is largely the focus of this Review.

Global parameter optimisation and sensitivity analysis of antivenom pharmacokinetics and pharmacodynamics

In recent years it has become possible to design snakebite antivenoms with diverse pharmacokinetic properties. Owing to the pharmacokinetic variability of venoms, the choice of antivenom scaffold may influence a treatment's neutralisation coverage. Computation offers a useful medium through which to assess the pharmacokinetics and pharmacodynamics of envenomation-treatment systems, as antivenoms with identical neutralising capacities can be simulated. In this study, we simulate envenomation and treatment with a variety of antivenoms, to define the properties of effective antivenoms. Systemic envenomation and treatment were described using a two-compartment pharmacokinetic model. Treatment of Naja sumatrana and Cryptelytrops purpureomaculatus envenomation was simulated with a set of 200,000 theoretical antivenoms across 10 treatment time delays. These two venoms are well-characterised and have differing pharmacokinetic properties. The theoretical antivenom set varied across molecular weight, dose, kon, koff, and valency. The best and worst treatments were identified using an area under the curve metric, and a global sensitivity analysis was performed to quantify the influence of the input parameters on treatment outcome. The simulations show that scaffolds of diverse molecular formats can be effective. Molecular weight and valency have a negligible direct impact on treatment outcome, however low molecular weight scaffolds offer more flexibility across the other design parameters, particularly when treatment is delayed. The simulations show kon to primarily mediate treatment efficacy, with rates above 105 M-1s-1 required for the most effective treatments. koff has the greatest impact on the performance of less effective scaffolds. While the same scaffold preferences for improved treatment are seen for both model snakes, the parameter bounds for C. purpureomaculatus envenomation are more constrained. This paper establishes a computational framework for the optimisation of antivenom design.

Pharmacokinetic considerations for angiogenesis inhibitors used to treat hepatocellular carcinoma: an overview

INTRODUCTION

Hepatocellular carcinoma (HCC) is the fifth malignancy in terms of frequency and the fourth malignancy in terms of cancer-related death worldwide. Systemic therapy of advanced HCC has probably gone through the greatest wave of change in the last decade, with the introduction of several anti-angiogenic drugs and immune checkpoint inhibitors, able to significantly improve patients' prognosis.

AREAS COVERED

In this review, we summarize the pharmacokinetic characteristic of the antiangiogenic drugs currently approved for the treatment of HCC, from oral tyrosine kinase inhibitors (sorafenib, lenvatinib, regorafenib and cabozantinib) to monoclonal antibodies (bevacizumab and ramucirumab), focusing on the main aspects that differ among compounds from the same class, on factors that can exert an influence on pharmacokinetic parameters and the main issues that could limit their clinical use.

EXPERT OPINION

Anti-angiogenic drugs have different profiles in terms of bioavailability, metabolism, elimination and interindividual variability in their pharmacokinetics and effectiveness. More studies should be developed to address the intrinsic and extrinsic factors influencing pharmacokinetics parameters to improve the individual therapeutic response and, furthermore, to evaluate the benefit and the harm of systemic therapy for advanced HCC in selected patients with liver impairment.

Ramucirumab as second-line treatment in Chinese patients with advanced hepatocellular carcinoma and elevated alpha-fetoprotein after sorafenib (REACH-2 China): A randomised, multicentre, double-blind study

BACKGROUND

In the global REACH-2 study, ramucirumab significantly improved overall survival (OS) compared with placebo in patients with advanced hepatocellular carcinoma (HCC) and elevated alpha-fetoprotein (AFP). REACH-2 China study aimed to evaluate the efficacy and safety of ramucirumab in Chinese patients with advanced HCC (NCT02435433).

METHODS

REACH-2 China was a randomised, double-blind, placebo-controlled, phase 3 study done at 31 centres in China between Sep 16, 2015, and March 15, 2021. Patients with advanced HCC and AFP ≥400 ng/mL after first-line sorafenib were randomly assigned (2:1) to receive ramucirumab 8 mg/kg intravenously or placebo Q2W, until disease progression or unacceptable toxicity. The primary endpoint was OS. Efficacy was assessed per intention-to-treat, and safety in patients who received any treatment.

FINDINGS

Of 104 Chinese patients enrolled (44 in the global study and 60 in the China extension study), 70 received ramucirumab and 34 received placebo. Median OS was 9·1 months in the ramucirumab group and 6·2 months in the placebo group (HR = 0·854 [95% CI: 0·536, 1·359]). The most common grade 3 or worse treatment-emergent adverse event were hypertension (5 [7·1%] of 70 patients in the ramucirumab group vs 1 [2.9%] of 34 in the placebo group), pneumonia (5 [7·1%] vs 1 [2·9%]), and hyponatraemia (4 [5·7%] vs 0 [0%]).

INTERPRETATION

Ramucirumab demonstrated clinically meaningful improvement in OS compared to placebo for Chinese patients with advanced HCC and elevated AFP, although lacking statistical superiority. Ramucirumab was well tolerated, with a manageable safety profile. The results are consistent with those of the global REACH-2 study, supporting a favourable risk-benefit profile for ramucirumab in this population.

FUNDING

Eli Lilly and Company, USA.

Small-molecule inhibitors, immune checkpoint inhibitors, and more: FDA-approved novel therapeutic drugs for solid tumors from 1991 to 2021

The United States Food and Drug Administration (US FDA) has always been a forerunner in drug evaluation and supervision. Over the past 31 years, 1050 drugs (excluding vaccines, cell-based therapies, and gene therapy products) have been approved as new molecular entities (NMEs) or biologics license applications (BLAs). A total of 228 of these 1050 drugs were identified as cancer therapeutics or cancer-related drugs, and 120 of them were classified as therapeutic drugs for solid tumors according to their initial indications. These drugs have evolved from small molecules with broad-spectrum antitumor properties in the early stage to monoclonal antibodies (mAbs) and antibody‒drug conjugates (ADCs) with a more precise targeting effect during the most recent decade. These drugs have extended indications for other malignancies, constituting a cancer treatment system for monotherapy or combined therapy. However, the available targets are still mainly limited to receptor tyrosine kinases (RTKs), restricting the development of antitumor drugs. In this review, these 120 drugs are summarized and classified according to the initial indications, characteristics, or functions. Additionally, RTK-targeted therapies and immune checkpoint-based immunotherapies are also discussed. Our analysis of existing challenges and potential opportunities in drug development may advance solid tumor treatment in the future.

Renin‑angiotensin system inhibitors may have an advantage over calcium channel blockers in reducing proteinuria in gastric cancer patients receiving ramucirumab

This study aimed to investigate whether renin-angiotensin system inhibitors (RAS-I) have an advantage over calcium channel blockers (CCB) for suppression of proteinuria in hypertensive patients with gastric cancer receiving ramucirumab (RAM) treatment. Adult Japanese patients with gastric cancer who were outpatients at Asahikawa Medical University Hospital, National Hospital Organization Hokkaido Cancer Center, and Iwate Medical University Hospital between July 1, 2015, and March 31, 2021, were included in this study. Of these patients, those who had received first-time RAM treatment, and those treated with antihypertensive agents including RAS-I or a CCB at initial RAM administration were included. A total of 36 patients were analyzed in this study. Of these patients, 17 patients were classified into the RAS-I group and the remaining 19 into the CCB group. After 12 weeks of RAM administration, the prevalence of proteinuria in the RAS-I group was significantly lower than that in the CCB group. Additionally, Kaplan-Meier analysis showed that the cumulative occurrence of proteinuria in the RAS-I group over 12 weeks following RAM administration was significantly lower than that in the CCB group. Furthermore, simulation of the time course of RAM blood concentrations based on the O'Brien model showed that there may not be differences in the RAM blood concentration profiles over 12 weeks between the two groups. RAS-I may have an advantage over CCB for suppressing proteinuria in hypertensive patients with gastric cancer treated with blood pressure antihypertensive agents. Our results provide useful information to healthcare professionals involved in the administration of RAM treatment.

An overview on display systems (phage, bacterial, and yeast display) for production of anticancer antibodies; advantages and disadvantages

Antibodies as ideal therapeutic and diagnostic molecules are among the top-selling drugs providing considerable efficacy in disease treatment, especially in cancer therapy. Limitations of the hybridoma technology as routine antibody generation method in conjunction with numerous developments in molecular biology led to the development of alternative approaches for the streamlined identification of most effective antibodies. In this regard, display selection technologies such as phage display, bacterial display, and yeast display have been widely promoted over the past three decades as ideal alternatives to traditional methods. The display of antibodies on phages is probably the most widespread of these methods, although surface display on bacteria or yeast have been employed successfully, as well. These methods using various sizes of combinatorial antibody libraries and different selection strategies possessing benefits in screening potency, generating, and isolation of high affinity antibodies with low risk of immunogenicity. Knowing the basics of each method assists in the design and retrieval process of antibodies suitable for different diseases, including cancer. In this review, we aim to outline the basics of each library construction and its display method, screening and selection steps. The advantages and disadvantages in comparison to alternative methods, and their applications in antibody engineering will be explained. Finally, we will review approved or non-approved therapeutic antibodies developed by employing these methods, which may serve as therapeutic antibodies in cancer therapy.

The Use of Bacteriophages in Biotechnology and Recent Insights into Proteomics

Phages have certain features, such as their ability to form protein-protein interactions, that make them good candidates for use in a variety of beneficial applications, such as in human or animal health, industry, food science, food safety, and agriculture. It is essential to identify and characterize the proteins produced by particular phages in order to use these viruses in a variety of functional processes, such as bacterial detection, as vehicles for drug delivery, in vaccine development, and to combat multidrug resistant bacterial infections. Furthermore, phages can also play a major role in the design of a variety of cheap and stable sensors as well as in diagnostic assays that can either specifically identify specific compounds or detect bacteria. This article reviews recently developed phage-based techniques, such as the use of recombinant tempered phages, phage display and phage amplification-based detection. It also encompasses the application of phages as capture elements, biosensors and bioreceptors, with a special emphasis on novel bacteriophage-based mass spectrometry (MS) applications.

Safety of ramucirumab treatment in patients with advanced hepatocellular carcinoma and elevated alpha-fetoprotein

INTRODUCTION

Hepatocellular carcinoma (HCC) is the second most common cause of cancer-induced deaths worldwide, and limited therapeutic options are available for patients with advanced disease. Ramucirumab, a monoclonal antibody that blocks the vascular endothelial growth factor (VEGF) receptor-2, is the first biomarker-selected systemic agent with therapeutic efficacy, tolerability, and favorable patient-reported outcomes in patients with advanced HCC and elevated serum α-fetoprotein levels ≥400 ng/mL, who are resistant or intolerant to sorafenib therapy. However, treatment-induced adverse events (AEs), such as hypertension, proteinuria, bleeding, thromboembolism, and gastrointestinal perforation remain challenging and potentially fatal concerns.

AREAS COVERED

This review discusses the published or ongoing studies and subgroup analyses on ramucirumab therapy in patients with advanced HCC. We present information on the risks of ramucirumab-induced common or rare AEs and their management.

EXPERT OPINION

Ramucirumab toxicity secondary to VEGF inhibition is similar to the AEs that are known to be associated with other VEGF-blocking antibodies. Common AEs can be safely treated using conventional measures; however, rare and potentially fatal AEs necessitate close monitoring. With regard to the safety profile, more promising ramucirumab-containing combination therapies are likely to pave the future path for effective HCC treatment.

Simultaneous affinity maturation and developability enhancement using natural liability-free CDRs

Affinity maturation is often a necessary step for the development of potent therapeutic molecules. Many different diversification strategies have been used for antibody affinity maturation, including error-prone PCR, chain shuffling, and targeted complementary-determining region (CDR) mutation. Although effective, they can negatively impact antibody stability or alter epitope recognition. Moreover, they do not address the presence of sequence liabilities, such as glycosylation, asparagine deamidation, aspartate isomerization, aggregation motifs, and others. Such liabilities, if present or inadvertently introduced, can potentially create the need for new rounds of engineering, or even abolish the value of the antibody as a therapeutic molecule. Here, we demonstrate a sequence agnostic method to improve antibody affinities, while simultaneously eliminating sequence liabilities and retaining the same epitope binding as the parental antibody. This was carried out using a defined collection of natural CDRs as the diversity source, purged of sequence liabilities, and matched to the antibody germline gene family. These CDRs were inserted into the lead molecule in one or two sites at a time (LCDR1-2, LCDR3, HCDR1-2) while retaining the HCDR3 and framework regions unchanged. The final analysis of 92 clones revealed 81 unique variants, with each of 24 tested variants having the same epitope specificity as the parental molecule. Of these, the average affinity improved by over 100 times (to 96 pM), and the best affinity improvement was 231-fold (to 32 pM).

Efficacy and safety of weekly paclitaxel with or without ramucirumab as second-line therapy for the treatment of advanced gastric or gastroesophageal junction adenocarcinoma (RAINBOW-Asia): a randomised, multicentre, double-blind, phase 3 trial

BACKGROUND

In the global phase 3 RAINBOW study, ramucirumab plus paclitaxel significantly improved overall survival compared with placebo plus paclitaxel in patients with advanced gastric or gastro-oesophageal junction (GEJ) adenocarcinoma. RAINBOW-Asia, a bridging study with similar design to RAINBOW, aimed to evaluate the efficacy and safety of ramucirumab plus paclitaxel for advanced gastric or GEJ adenocarcinoma in Asian, predominantly Chinese, patients.

METHODS

RAINBOW-Asia was a randomised, double-blind, placebo-controlled, phase 3 trial done at 32 centres in China, Malaysia, the Philippines, and Thailand. Adult patients (≥18 years) with metastatic or locally advanced, unresectable gastric or GEJ adenocarcinoma who previously received fluoropyrimidine-platinum-based chemotherapy were randomly assigned with a centralised interactive web response system in a 2:1 ratio to receive ramucirumab 8 mg/kg or placebo intravenously on days 1 and 15 plus paclitaxel 80 mg/m2 intravenously on days 1, 8, and 15 of every 28-day cycle. Randomisation was stratified by Eastern Cooperative Oncology Group performance status and presence of peritoneal metastases. The co-primary endpoints were progression-free survival and overall survival. Efficacy analyses were done in the intention-to-treat population, and safety analysis included patients who received at least one dose of study treatment. This trial is registered with ClinicalTrials.gov, NCT02898077, and has been completed.

FINDINGS

Between March 2, 2017, and June 30, 2020, 440 patients were randomly assigned to receive ramucirumab plus paclitaxel (n=294) or placebo plus paclitaxel (n=146). Median progression-free survival was 4·14 months (95% CI 3·71-4·30) in the ramucirumab plus paclitaxel group compared with 3·15 months (2·83-4·14) in the placebo plus paclitaxel group (hazard ratio [HR] 0·765, 95% CI 0·613-0·955, p=0·0184). Median overall survival was 8·71 months (95% CI 7·98-9·49) in the ramucirumab plus paclitaxel group and 7·92 months (6·31-9·10) in the placebo plus paclitaxel group (HR 0·963, 95% CI 0·771-1·203, p=0·7426). The most common grade 3 or worse treatment-emergent adverse events were decreased neutrophil count (159 [54%] of 293 patients in the ramucirumab plus paclitaxel group vs 56 [39%] of 145 in the placebo plus paclitaxel group), decreased white blood cell count (127 [43%] vs 42 [29%]), anaemia (46 [16%] vs 24 [17%]), hypertension (21 [7%] vs nine [6%]), and febrile neutropenia (18 [6%] vs one [<1%]).

INTERPRETATION

These findings, along with the results from RAINBOW, support the use of ramucirumab plus paclitaxel as second-line therapy in a predominantly Chinese population with advanced gastric or GEJ adenocarcinoma.

FUNDING

Eli Lilly and Company, USA.

TRANSLATION

For the Chinese translation of the abstract see Supplementary Materials section.

Functional antibody characterization via direct structural analysis and information-driven protein-protein docking

Detailed description of the mechanism of action of the therapeutic antibodies is essential for the functional characterization and future optimization of potential clinical agents. We recently developed KD035, a fully human antibody targeting vascular endothelial growth factor receptor 2 (VEGFR2). KD035 blocked VEGF‐A, and VEGF‐C‐mediated VEGFR2 activation, as demonstrated by the in vitro binding and competition assays and functional cellular assays. Here, we report a computational model of the complex between the variable fragment of KD035 (KD035(Fv)) and the domains 2 and 3 of the extracellular portion of VEGFR2 (VEGFR2(D2‐3)). Our modeling was guided by a priori experimental information including the X‐ray structures of KD035 and related antibodies, binding assays, target domain mapping and comparison of KD035 affinity for VEGFR2 from different species. The accuracy of the model was assessed by molecular dynamics simulations, and subsequently validated by mutagenesis and binding analysis. Importantly, the steps followed during the generation of this model can set a precedent for future in silico efforts aimed at the accurate description of the antibody–antigen and more broadly protein–protein complexes.

Concentration-Independent Multivalent Targeting of Cancer Cells by Genetically Encoded Core-Crosslinked Elastin/Resilin-like Polypeptide Micelles

Valency is a fundamental principle to control macromolecular interactions and is used to target specific cell types by multivalent ligand-receptor interactions using self-assembled nanoparticle carriers. At the concentrations encountered in solid tumors upon systemic administration, these nanoparticles are, however, likely to show critical micelle concentration (CMC)-dependent disassembly and thus loss of function. To overcome this limitation, core-crosslinkable micelles of genetically encoded resilin-/elastin-like diblock polypeptides were recombinantly synthesized. The amphiphilic constructs were covalently photo-crosslinked through the genetically encoded unnatural amino acid para-azidophenylalanine in their hydrophobic block and they carried different anticancer ligands on their hydrophilic block: the wild-type tenth human fibronectin type III domain, a GRGDSPAS peptide-both targeting α_vβ₃ integrin-and an engineered variant of the third fibronectin type III domain of tenascin C that is a death receptor 5 agonist. Although uncrosslinked micelles lost most of their targeting ability below their CMC, the crosslinked analogues remained active at concentrations up to 1000-fold lower than the CMC, with binding affinities that are comparable to antibodies.

Phage Display Technology as a Powerful Platform for Antibody Drug Discovery

Antibody drugs with a high affinity and specificity are effective and safe for intractable diseases, such as cancers and autoimmune diseases. Furthermore, they have played a central role in drug discovery, currently accounting for eight of the top 20 pharmaceutical products worldwide by sales. Forty years ago, clinical trials on antibody drugs that were thought to be a magic bullet failed, partly due to the immunogenicity of monoclonal antibodies produced in mice. The recent breakthrough in antibody drugs is largely because of the contribution of phage display technology. Here, we reviewed the importance of phage display technology as a powerful platform for antibody drug discovery from various perspectives, such as the development of human monoclonal antibodies, affinity enhancement of monoclonal antibodies, and the identification of therapeutic targets for antibody drugs.

Health-related quality of life in the randomized phase 3 study of ramucirumab plus docetaxel versus placebo plus docetaxel in platinum-refractory advanced urothelial carcinoma (RANGE)

BACKGROUND

To evaluate patient-reported outcomes with ramucirumab plus docetaxel, a regimen which improved progression-free survival in platinum-refractory advanced urothelial carcinoma (aUC).

METHODS

RANGE-a randomized, double-blinded, phase 3 trial in patients with platinum-refractory aUC. Ramucirumab (10 mg/kg) plus docetaxel (75 mg/m2) or placebo plus docetaxel were administered every 21 days until disease progression or unacceptable toxicity. Patients received maximum 10 cycles of docetaxel. European Organization for Research and Treatment of Cancer Quality of Life Questionnaire C30 (EORTC QLQ-C30) and EuroQoL five-dimensions (EQ-5D-5L) were administered at baseline, start of each cycle, and 30-day follow-up visit. A ≥ 10-point change in QLQ-C30 scores was considered meaningful. Rates of improved/stable scores were compared between treatment arms using Fisher's exact test. Time to deterioration (TtD) was estimated and compared using Kaplan-Meier estimation and log-rank test.

RESULTS

Of the 530 patients, ~ 97% patients in each arm provided baseline QLQ-C30 data. On-treatment compliance was ≥ 88% for first 8 cycles. Mean baseline QLQ-C30 scores were similar between arms, with global quality of life (QoL), fatigue, pain, and insomnia having greatest impairment. Postbaseline rates of improved/stable QLQ-C30 scores were similar between treatment arms except for greater improvement in pain score with ramucirumab. TtD of QLQ-C30 scales favored ramucirumab arm. Baseline EQ-5D-5L index and visual analogue scale scores were similar between arms, followed by relatively stable on-treatment scores. EQ-5D-5L scores worsened at post-discontinuation follow-up visit.

CONCLUSIONS

Ramucirumab plus docetaxel did not negatively impact QoL compared with docetaxel alone in platinum-refractory aUC. Improved TtD and tumor associated rates of pain favored ramucirumab treatment.

CLINICAL TRAIL REGISTRATION

NCT02426125. https://clinicaltrials.gov/ct2/show/NCT02426125 . Date of registration: April 24th 2015.

VEGFR2 as a target for CAR T cell therapy of Ewing sarcoma

BACKGROUND

T cells engineered to express chimeric antigen receptors (CARs) are a novel modality to treat refractory cancers. The development of CAR T cells against Ewing sarcoma (EwS) is limited by a lack of targetable surface antigens. We investigated vascular endothelial growth factor receptor 2 (VEGFR2) expressed on tumor-associated blood vessels as potential CAR target in this cancer.

METHODS

Expression of VEGFR2 was studied by immunohistochemistry in human EwS biopsies and in murine xenografts and by flow cytometry in EwS cell lines. CARs with short, medium, and long hinge domains against either human or murine VEGFR2 were generated and expressed in human T cells by retroviral gene transfer. The capacity of the individual CARs to activate T cells in response to VEGFR2-expressing cells was compared in vitro.

RESULTS

Tumor-associated endothelial cells in human EwS biopsies and in xenografts expressed VEGFR2. Tumor cells in the majority of EwS biopsies were also VEGFR2-positive. Following modification with anti-mouse or anti-human VEGFR2-specific CAR genes, T cells specifically lysed VEGFR2-expressing target cells of the respective species. CAR T cells with short-length or medium-length hinge domains were functionally superior over those with the long hinge region by in vitro parameters, including antigen-specific degranulation responses, lysis of tumor spheroids, tumor necrosis factor α secretion, sequential killing, and proliferation.

CONCLUSIONS

VEGFR2 is consistently expressed on endothelial cells of the tumor stroma in EwS and thus is a candidate target for CAR T cells in this cancer. Among various VEGFR2-specific CARs, a construct with a short hinge domain was chosen to be further developed toward clinical translation.

Preclinical assessment of intravitreal ramucirumab: in vitro and in vivo safety profile

Background

Anti-angiogenic drugs remain the mainstay therapy for several vascular retinal pathologies. The repurposing of approved anti-angiogenic drugs for use in ophthalmology can increase therapeutic options and reduce costs. The purpose of this study was to investigate the ocular safety profile of intravitreal (IVT) ramucirumab, an approved anti-vascular endothelial growth factor molecule for systemic treatment, using cell culture and animal models.

Methods

The cytotoxicity of ramucirumab at different concentrations was evaluated in human retinal pigment epithelial cells (ARPE-19) using the MTT assay. In addition, 250 or 500 µg of ramucirumab or vehicle was injected in the eye of 16 chinchilla rabbits. The eyes were evaluated by ophthalmoscopy, electroretinography, spectral-domain optical coherence tomography (SD-OCT) and by light and transmission electron microscopy.

Results

Electroretinography or SD-OCT did not detect functional or morphological alterations at 24 h or one week after injection. Light and transmission electron microscopy confirmed the absence of major signs of toxicity, although we found a statistically significant reduction in ganglion cell number between the controls and the eyes that received 500 µg of ramucirumab after 7 days. Compared to lower concentrations, 500 µg of ramucirumab caused reduction in cell viability and changes in morphology in ARPE-19 cells. Compared to the baseline, ocular and serum osmolarity showed no difference after IVT injection at all timepoints.

Conclusion

In conclusion, IVT injection of ramucirumab in rabbits is safe and does not cause functional damage to the retina. At the lower dose tested in vivo (250 µg), the morphology and ultrastructural anatomy were normal at 24 h and 1 week after the injection. However, the 500 µg dose can cause a decrease in ganglion cell number seven days after the injection.

Phage Display Derived Monoclonal Antibodies: From Bench to Bedside

Monoclonal antibodies (mAbs) have become one of the most important classes of biopharmaceutical products, and they continue to dominate the universe of biopharmaceutical markets in terms of approval and sales. They are the most profitable single product class, where they represent six of the top ten selling drugs. At the beginning of the 1990s, an in vitro antibody selection technology known as antibody phage display was developed by John McCafferty and Sir. Gregory Winter that enabled the discovery of human antibodies for diverse applications, particularly antibody-based drugs. They created combinatorial antibody libraries on filamentous phage to be utilized for generating antigen specific antibodies in a matter of weeks. Since then, more than 70 phage–derived antibodies entered clinical studies and 14 of them have been approved. These antibodies are indicated for cancer, and non-cancer medical conditions, such as inflammatory, optical, infectious, or immunological diseases. This review will illustrate the utility of phage display as a powerful platform for therapeutic antibodies discovery and describe in detail all the approved mAbs derived from phage display.

Aortic dissection after ramucirumab infusion

A female patient in her seventies affected by a signet-ring cell carcinoma G3pT4N3 (24/29), with lymphovascular invasion, HER2-negative. After completing three cycles of first-line systemic treatment in combination with cisplatin (CDDP) + 5-fluorouracil (5FU), a new systemic therapy line with paclitaxel + Cyramza (ramucirumab) was planned. On the day after the first administration the patient manifested a Standford type A aortic dissection (AD), with a diameter of around 6.5 cm and dissection flap originating in the ascending aorta below the brachiocephalic trunk, extended to the whole descending aorta until the carrefour. The causal relationship between adverse drug reactions and Cyramza, calculated using the Naranjo algorithm, led to a result of 'probable' correlation between ramucirumab and AD. The endothelial dysfunction associated with vascular endothelial growth factor pathway inhibitors (VPIs) would seem to be the most plausible explanation for such events: it causes thromboembolic events and cardiovascular complications.

Ramucirumab: A Review in Hepatocellular Carcinoma

Ramucirumab (Cyramza®), a fully human anti-VEGFR-2 monoclonal antibody, has been approved as monotherapy for the treatment of patients with hepatocellular carcinoma (HCC) and α-fetoprotein levels ≥ 400 ng/mL who have been treated with sorafenib. Ramucirumab significantly prolonged overall survival (OS) and progression-free survival (PFS) relative to placebo in this population in the randomized, double-blind phase 3 REACH 2 trial. These benefits were seen in key prespecified subgroups based on demographic and disease characteristics. Ramucirumab had an acceptable tolerability profile and manageable safety profile in these patients, with the majority of treatment-related adverse events being mild or moderate in severity. The safety profile of ramucirumab was consistent with that expected for agents targeting the VEGF/VEGFR axis. Currently, ramucirumab is the only therapy specifically tested in patients with α-fetoprotein levels ≥ 400 ng/mL, which is associated with an aggressive disease and poor prognosis. Therefore, ramucirumab is an important treatment option for patients with HCC and α-fetoprotein levels ≥ 400 ng/mL who have been treated with sorafenib.

Development of therapeutic antibodies for the treatment of diseases

It has been more than three decades since the first monoclonal antibody was approved by the United States Food and Drug Administration (US FDA) in 1986, and during this time, antibody engineering has dramatically evolved. Current antibody drugs have increasingly fewer adverse effects due to their high specificity. As a result, therapeutic antibodies have become the predominant class of new drugs developed in recent years. Over the past five years, antibodies have become the best-selling drugs in the pharmaceutical market, and in 2018, eight of the top ten bestselling drugs worldwide were biologics. The global therapeutic monoclonal antibody market was valued at approximately US$115.2 billion in 2018 and is expected to generate revenue of $150 billion by the end of 2019 and $300 billion by 2025. Thus, the market for therapeutic antibody drugs has experienced explosive growth as new drugs have been approved for treating various human diseases, including many cancers, autoimmune, metabolic and infectious diseases. As of December 2019, 79 therapeutic mAbs have been approved by the US FDA, but there is still significant growth potential. This review summarizes the latest market trends and outlines the preeminent antibody engineering technologies used in the development of therapeutic antibody drugs, such as humanization of monoclonal antibodies, phage display, the human antibody mouse, single B cell antibody technology, and affinity maturation. Finally, future applications and perspectives are also discussed.

Multigram scale synthesis of polycyclic lactones and evaluation of antitumor and other biological properties

An efficient four-step synthesis of tetracyclic lactones from 1,4-benzodioxine-2-carboxylic acid was developed. Ellipticine derivatives exhibit antitumor activity however only a few derivatives without carbazole subunit have been studied to date. Herein, several tetracyclic lactones were synthesized and biologically evaluated. Several compounds (2a, 3a, 4a and 5a) were found to be inhibitors of the Kras-Wnt pathway. The lactone 2a also exerted a potent inhibition of Tau protein translation and was shown to have capacity for CYP1A1-bioactivation. The results obtained are further evidence of the therapeutic potential of tetracyclic lactones related to ellipticine. Molecular modeling studies showed that compound 2a is inserted between helix α3 and α4 of the KRas protein making interactions with the hydrophobic residues Phe90, Glu91, Ile9364, Hie94, Leu133 and Tyr137and a hydrogen bond with residue Arg97.

Phage Display Derived Monoclonal Antibodies: From Bench to Bedside

Monoclonal antibodies (mAbs) have become one of the most important classes of biopharmaceutical products, and they continue to dominate the universe of biopharmaceutical markets in terms of approval and sales. They are the most profitable single product class, where they represent six of the top ten selling drugs. At the beginning of the 1990s, an in vitro antibody selection technology known as antibody phage display was developed by John McCafferty and Sir. Gregory Winter that enabled the discovery of human antibodies for diverse applications, particularly antibody-based drugs. They created combinatorial antibody libraries on filamentous phage to be utilized for generating antigen specific antibodies in a matter of weeks. Since then, more than 70 phage-derived antibodies entered clinical studies and 14 of them have been approved. These antibodies are indicated for cancer, and non-cancer medical conditions, such as inflammatory, optical, infectious, or immunological diseases. This review will illustrate the utility of phage display as a powerful platform for therapeutic antibodies discovery and describe in detail all the approved mAbs derived from phage display.

Anti-VEGF/VEGFR2 Monoclonal Antibodies and their Combinations with PD-1/PD-L1 Inhibitors in Clinic

The vascular endothelial growth factor (VEGF)/VEGF receptor 2 (VEGFR2) signaling pathway is one of the most important pathways responsible for tumor angiogenesis. Currently, two monoclonal antibodies, anti-VEGF-A antibody Bevacizumab and anti-VEGFR2 antibody Ramucizumab, have been approved for the treatment of solid tumors. At the same time, VEGF/VEGFR2 signaling is involved in the regulation of immune responses. It is reported that the inhibition of this pathway has the capability to promote vascular normalization, increase the intra-tumor infiltration of lymphocytes, and decrease the number and function of inhibitory immune cell phenotypes, including Myeloid-derived suppressor cells (MDSCs), regulatory T cells (Tregs) and M2 macrophages. On this basis, a number of clinical studies have been performed to investigate the therapeutic potential of VEGF/VEGFR2-targeting antibodies plus programmed cell death protein 1 (PD-1)/ programmed cell death ligand 1 (PD-L1) inhibitors in various solid tumor types. In this context, VEGF/VEGFR2- targeting antibodies, Bevacizumab and Ramucizumab are briefly introduced, with a description of the differences between them, and the clinical studies involved in the combination of Bevacizumab/ Ramucizumab and PD-1/PD-L1 inhibitors are summarized. We hope this review article will provide some valuable clues for further clinical studies and usages.

Ramucirumab as a second line therapy for advanced HCC: a significant achievement or a wasted opportunity for personalised therapy?

The second line treatment of hepatocellular carcinoma (HCC) has recently become an exciting area of interest since new emerging options have demonstrated survival benefits versus placebo. Unfortunately, predictive biomarkers are unavailable for these treatments. Ramucirumab, a monoclonal antibody against VEGFR-2, has demonstrated overall survival superiority against placebo as a second line therapy for patients with AFP > 400 ng/ml in the recent REACH-2 trial. This review will provide the current updated knowledge regarding the HCC cancerogenesis and angiogenic VEGF/VEGFR-2 pathways and the clinical development of ramucirumab in advanced HCC. This study will also critically assess the gaps in a previous negative phase III trial that tested other potentially useful treatments and suggest ways to modernise clinical trials and personalise therapy for advanced HCC.

Ramucirumab for the treatment of gastric or gastro-esophageal junction cancer

Introduction: Gastric cancer remains one of the most lethal malignancy, accounting for an estimated 783,000 deaths worldwide in 2018. Although there are several approved drugs for the treatment of gastric cancer, the survival of patients with advanced disease remains dismal. Ramucirumab, a vascular endothelial growth factor receptor-2 inhibitor, is an important new targeted drug approved for gastric and gastroesophageal adenocarcinoma (GEJ) in second-line setting. Areas covered: In this article, we have reviewed the role of ramucirumab in the management of gastric and GEJ adenocarcinoma. A comprehensive review of various clinical trials is presented that support the use of ramucirumab in gastric cancer. Expert opinion: In our opinion, ramucirumab should be considered as a standard of care option, either alone or with paclitaxel, after progression on first-line therapy for advanced or metastatic disease. The results of large, randomized phase III clinical trials show benefit of ramucirumab on median overall survival (OS). However, the benefit is limited, with only about two months OS benefit of using ramucirumab with paclitaxel compared to paclitaxel alone. Novel combination therapies, such as ramucirumab with other targeted agents and immune checkpoint inhibitors in ongoing clinical trials, may provide important information to further improve the patient outcomes.

Novel human Ab against vascular endothelial growth factor receptor 2 shows therapeutic potential for leukemia and prostate cancer

Vascular endothelial growth factor receptor 2 (VEGFR2) is highly expressed in tumor‐associated endothelial cells, where it modulates tumor‐promoting angiogenesis, and it is also found on the surface of tumor cells. Currently, there are no Ab therapeutics targeting VEGFR2 approved for the treatment of prostate cancer or leukemia. Therefore, development of novel efficacious anti‐VEGFR2 Abs will benefit cancer patients. We used the Institute of Cellular and Organismic Biology human Ab library and affinity maturation to develop a fully human Ab, anti‐VEGFR2‐AF, which shows excellent VEGFR2 binding activity. Anti‐VEGFR2‐AF bound Ig‐like domain 3 of VEGFR2 extracellular region to disrupt the interaction between VEGF‐A and VEGFR2, neutralizing downstream signaling of the receptor. Moreover, anti‐VEGFR2‐AF inhibited capillary structure formation and exerted Ab‐dependent cell‐mediated cytotoxicity and complement‐dependent cytotoxicity in vitro. We found that VEGFR2 is expressed in PC‐3 human prostate cancer cell line and associated with malignancy and metastasis of human prostate cancer. In a PC‐3 xenograft mouse model, treatment with anti‐VEGFR2‐AF repressed tumor growth and angiogenesis as effectively and safely as US FDA‐approved anti‐VEGFR2 therapeutic, ramucirumab. We also report for the first time that addition of anti‐VEGFR2 Ab can enhance the efficacy of docetaxel in the treatment of a prostate cancer mouse model. In HL‐60 human leukemia‐xenografted mice, anti‐VEGFR2‐AF showed better efficacy than ramucirumab with prolonged survival and reduced metastasis of leukemia cells to ovaries and lymph nodes. Our findings suggest that anti‐VEGFR2‐AF has strong potential as a cancer therapy that could directly target VEGFR2‐expressing tumor cells in addition to its anti‐angiogenic action.

New Insight into Therapies Targeting Angiogenesis in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a malignancy characterized by neoangiogenesis that is determined by an augmented production of proangiogenesis factors by tumor and adjacent cells. This unbalanced angiogenesis process is a key feature of HCC carcinogenesis and progression. Proangiogenic factors also have a relevant role in the generation and maintenance of an immunosuppressive tumor microenvironment. Several therapeutic options for HCC treatment are based on the inhibition of angiogenesis, both in the early/intermediate stages of the disease and in the late stages of the disease. Conventional treatment options employing antiangiogenic approaches provide for the starving of tumors of their blood supply to avoid the refueling of oxygen and nutrients. An emerging alternative point of view is the normalization of vasculature leading to enhance tumor perfusion and oxygenation, potentially capable, when proposed in combination with other treatments, to improve delivery and efficacy of other therapies, including immunotherapy with checkpoint inhibitors. The introduction of novel biomarkers can be useful for the definition of the most appropriate dose and scheduling for these combination treatment approaches. The present review provides a wide description of the pharmaceutical compounds with an antiangiogenic effect proposed for HCC treatment and investigated in clinical trials, including antibodies and small-molecule kinase inhibitors.

Cognizance of Molecular Methods for the Generation of Mutagenic Phage Display Antibody Libraries for Affinity Maturation

Antibodies leverage on their unique architecture to bind with an array of antigens. The strength of interaction has a direct relation to the affinity of the antibodies towards the antigen. In vivo affinity maturation is performed through multiple rounds of somatic hypermutation and selection in the germinal centre. This unique process involves intricate sequence rearrangements at the gene level via molecular mechanisms. The emergence of in vitro display technologies, mainly phage display and recombinant DNA technology, has helped revolutionize the way antibody improvements are being carried out in the laboratory. The adaptation of molecular approaches in vitro to replicate the in vivo processes has allowed for improvements in the way recombinant antibodies are designed and tuned. Combinatorial libraries, consisting of a myriad of possible antibodies, are capable of replicating the diversity of the natural human antibody repertoire. The isolation of target-specific antibodies with specific affinity characteristics can also be accomplished through modification of stringent protocols. Despite the ability to screen and select for high-affinity binders, some 'fine tuning' may be required to enhance antibody binding in terms of its affinity. This review will provide a brief account of phage display technology used for antibody generation followed by a summary of different combinatorial library characteristics. The review will focus on available strategies, which include molecular approaches, next generation sequencing, and in silico approaches used for antibody affinity maturation in both therapeutic and diagnostic applications.

Purification of a Novel Anti-VEGFR2 Single Chain Antibody Fragment and Evaluation of Binding Affinity by Surface Plasmon Resonance

Purpose: The single-chain variable fragment (scFv) domain of antibodies is now considered as one of the therapeutic tools that can be produced by phage display technology (PDT). Antibody purification is one of the most important steps in antibodies production. The aim of study was purification and characterization of anti-VEGFR2 scFv antibody fragments.

Methods: After the coating of vascular endothelial growth factor receptor 2 (VEGFR2) peptide in ELISA microplates, the phage display library of Tomlinson was used for antibody isolation. The targeted scFv was purified by chromatography using a zeolite-based column. The purity and functional assessment of purified scFv were evaluated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and western blotting techniques, respectively. Affinity binding was evaluated by surface plasmon resonance (SPR).

Results: The desired scFv was selected after four stages of biopanning. SDS-PAGE analysis showed a 28 kDa scFv with high purity (>90%). The western bloting analysis confirmed the binding of produced scFv antibody to the desired peptide. The affinity binding of scFv antibody analyzed by SPR was about 60 μM.

Conclusion: In this study, the novel scFv antibody against VEGFR2 peptide was purified by chromatography column containing zeolite. Based on our findings the produced antibody may be applied for diagnosis or targeting of VEGFR2 in antibody-based therapy strategies.

Role of FcγRs in Antibody-Based Cancer Therapy

Monoclonal antibodies can mediate antitumor activity by multiple mechanisms. They can bind directly to tumor receptors resulting in tumor cell death, or can bind to soluble growth factors, angiogenic factors, or their cognate receptors blocking signals required for tumor cell growth or survival. Monoclonal antibodies, upon binding to tumor cell, can also engage the host's immune system to mediate immune-mediated destruction of the tumor. The Fc portion of the antibody is essential in engaging the host immune system by fixing complement resulting in complement-mediated cytotoxicity (CDC) of the tumor, or by engaging Fc receptors for IgG (FcγR) expressed by leukocytes leading to antibody-dependent cellular cytotoxicity (ADCC) or antibody-dependent cellular phagocytosis (ADCP) of tumor cells. Antibodies whose Fc portion preferentially engage activating FcγRs have shown greater inhibition of tumor growth and metastasis. Monoclonal antibodies can also stimulate the immune system by binding to targets expressed on immune cells. These antibodies may stimulate antitumor immunity by antagonizing a negative regulatory signal, agonizing a costimulatory signal, or depleting immune cells that are inhibitory. The importance of Fc:FcγR interactions in antitumor therapy for each of these mechanisms have been demonstrated in both mouse models and clinical trials and will be the focus of this chapter.

VEGFA and VEGFR2 RNAscope determination in gastric cancer

Gastric cancer is the fifth most common cancer and third leading cause of cancer-related death worldwide. Several studies on angiogenic blocking agents in gastric cancer revealing promising results by the use of monoclonal antibodies against VEGFA or its receptor VEGFR2 or against VEGFA activating pathway. The validation of biomarkers useful to better organize the clinical trials involving anti-angiogenic therapies is crucial. Molecular markers such as RNA are increasingly used for cancer diagnosis, prognosis, and therapy guidance as in the case of the targeted therapies concerning the inhibition of angiogenesis. The aim of this study is to set the conditions for evaluating the expression of VEGFA and VEGFR2 in gastric cancer specimens and in healthy gastric mucosa by the use of RNAscope, a novel RNA in situ hybridization (ISH) method that allows the visualization of a specific gene expression in individual cells. We found the increased expression of VEGFA in the tubular glands and VEGFR2 in the endothelium of gastric cancer samples mainly in the T2, T3 and T4 stages of tumor progression as compared to the healthy controls. These results obtained by the application of this highly sensitive method for oligonucleotide detection the role of angiogenesis in gastric cancer progression already highlighted by conventional immunohistochemical methods, and offer significant promise as a new platform for developing and implementing RNA-based molecular diagnostics also in the conditions in which immunohistochemistry is not applicable.

ScFvs as Allosteric Inhibitors of VEGFR-2: Novel Tools to Harness VEGF Signaling

Vascular Endothelial Growth Factor Receptor 2 (VEGFR-2) is the main mediator of angiogenic signaling in endothelial cells and a primary responder to VEGF. VEGF dependent VEGFR-2 activation regulates endothelial cell migration and proliferation, as well as vessel permeability. VEGF is presented as an antiparallel homodimer, and its binding to VEGFR-2 brings two receptors in close proximity. Downstream signaling is triggered by receptor dimerization, kinase activation, and receptor internalization. Our aim was to further investigate allosteric inhibition using binders targeting extracellular subdomains 4⁻7 of VEGFR-2 as an alternative to existing anti-angiogenic therapies, which rely on neutralizing VEGF or blocking of the ligand-binding site on the receptor. We applied phage display technology to produce single chain antibody fragments (scFvs) targeting VEGFR-2. Selected antibody fragments were characterized using biophysical and biological assays. We characterized several antibody fragments, which exert their inhibitory effect of VEGFR-2 independent of ligand binding. These reagents led to rapid clearance of VEGFR-2 from the cell surface without kinase activation, followed by an increase in intracellular receptor-positive vesicles, suggesting receptor internalization. Our highly specific VEGFR-2 binders thus represent novel tools for anti-angiogenic therapy and diagnostic applications.

Efficacy and safety of targeting VEGFR drugs in treatment for advanced or metastatic gastric cancer: a systemic review and meta-analysis

The value of targeting VEGFR (vascular endothelial growth factor receptor) drugs has demonstrated encouraging anti-cancer activity in advanced solid tumors within current clinical trials. This study aimed to serve as the first systemic review to assess their safety and efficacy according to biochemical characteristics of targeting VEGFR drugs in gastric cancer. We analyzed eight clinical trials on targeting VEGFR drugs in gastric cancer. Results showed that targeting VEGFR drugs significantly improved overall survival (OS) [Hazard Ratio (HR) 0.69, 95% confidence interval (CI) (0.55, 0.83), P < 0.001], progression free survival (PFS) [HR 0.50, 95% CI (0.34, 0.66), P < 0.001], disease control rate (DCR) [Odds Ratio (OR) 3.83, 95% CI (2.39, 6.15), P < 0.001] and significantly decreased the progressive disease rate(PDR)[OR 0.45, 95% CI (0.34, 0.59), P < 0.001], but not objective response rate (ORR) [OR 1.46, 95% CI (0.93, 2.29), P = 0.098]. Further subgroup revealed that VEGFR antibody (VEGFR-Ab) drugs were superior to VEGFR tyrosine kinase inhibitor (VEGFR-TKI) drugs in terms of the OS, PFS and PDR. To determine the toxic effect of targeting VEGFR drugs, the relative risk of adverse events (grade ≥ 3) of special interest(AESIs) were estimated. Most of these were predictable and manageable. Furthermore, less AESIs were observed in the VEGFR-Ab than the VEGFR-TKI drugs. In conclusion, VEGFR drugs were effective targeted therapy in advanced or metastatic gastric cancer, and its toxicity is within a controllable range. VEGFR-Ab drugs were more effective than VEGFR-TKI drugs in terms of the OS, PFS and PDR of gastric cancer patients with little toxicity.

Progress and Challenges in the Design and Clinical Development of Antibodies for Cancer Therapy

The remarkable progress in engineering and clinical development of therapeutic antibodies in the last 40 years, after the seminal work by Köhler and Milstein, has led to the approval by the United States Food and Drug Administration (FDA) of 21 antibodies for cancer immunotherapy. We review here these approved antibodies, with emphasis on the methods used for their discovery, engineering, and optimization for therapeutic settings. These methods include antibody engineering via chimerization and humanization of non-human antibodies, as well as selection and further optimization of fully human antibodies isolated from human antibody phage-displayed libraries and immunization of transgenic mice capable of generating human antibodies. These technology platforms have progressively led to the development of therapeutic antibodies with higher human content and, thus, less immunogenicity. We also discuss the genetic engineering approaches that have allowed isotype switching and Fc modifications to modulate effector functions and bioavailability (half-life), which together with the technologies for engineering the Fv fragment, have been pivotal in generating more efficacious and better tolerated therapeutic antibodies to treat cancer.

Population pharmacokinetic meta-analysis of ramucirumab in cancer patients

AIMS

Ramucirumab is a human IgG1 monoclonal antibody that specifically binds vascular endothelial growth factor receptor-2 (VEGFR-2) and blocks binding of VEGF-A, VEGF-C and VEGF-D. The objective of the analysis was to characterize the clinical pharmacology profile of ramucirumab using a population pharmacokinetic approach.

METHODS

A total of 1639 patients with 6427 serum concentrations from 11 Phase 1b, 2 and 3 clinical trials in patients with various cancer indications were included in the analysis. Ramucirumab was administered as an intravenous infusion over 1 h at 8 mg kg-1 every 2 weeks or 10 mg kg-1 every 3 weeks. A series of pharmacostatistical models were developed to describe the concentration data. The best model was used to evaluate patient factors for their effect on ramucirumab pharmacokinetics.

RESULTS

The pharmacokinetics of ramucirumab were well characterized by a two-compartment model. Mean population estimates of clearance, volume of distribution and half-life for a typical 68-kg patient were 0.0148 l h-1 , 5.30 l and 13.4 days, respectively. A modest relationship was observed between body weight and ramucirumab disposition; clearance and central compartment volume increased with body weight. No other patient characteristics were shown to influence the disposition of ramucirumab in this patient population.

CONCLUSIONS

The final model adequately described the concentration-time profile of ramucirumab in patients with a range of cancer indications. The model confirmed that a weight-normalized dosing regimen is appropriate for ramucirumab therapy. Dose adjustment was not required for patients with mild to moderate renal impairment or mild hepatic impairment.

Evolution of ramucirumab in the treatment of cancer - A review of literature

Ramucirumab is a recombinant human monoclonal antibody and is used in the treatment of advanced malignancies. Its mechanism of action is by inhibiting angiogenesis in tumor cells by targeting the vascular endothelial growth factor receptor 2. United States Food and Drug Administration (FDA) approved it initially in 2014 for the treatment of advanced gastric or gastro-esophageal junction adenocarcinoma and metastatic non-small cell lung carcinoma. It was approved by FDA in 2015 for the treatment of advanced colorectal cancer. This manuscript consolidates pre-clinical trials to phase I, II, and III trial data indicating the effects of ramucirumab on different cancer types, which led to its approval. By comparing these clinical trials alongside each other, we can more easily examine the studies that have already been completed, along with currently ongoing studies and potential further areas of interest for this newly approved treatment. This approach makes it convenient to compare dosages, overall survival, adverse events, as well as possible routes for combination therapy with ramucirumab. By compiling results for various oncological malignancies, we can differentiate between treatments that are effective and have the highest incidence of stable disease, and those that do not seem promising. Ramucirumab has been effective in the treatment of various carcinomas and this article outlines other tumors in which this treatment option may be successful.

Strategies for Selecting Membrane Protein-Specific Antibodies using Phage Display with Cell-Based Panning

Membrane proteins are attractive targets for monoclonal antibody (mAb) discovery and development. Although several approved mAbs against membrane proteins have been isolated from phage antibody libraries, the process is challenging, as it requires the presentation of a correctly folded protein to screen the antibody library. Cell-based panning could represent the optimal method for antibody discovery against membrane proteins, since it allows for presentation in their natural conformation along with the appropriate post-translational modifications. Nevertheless, screening antibodies against a desired antigen, within a selected cell line, may be difficult due to the abundance of irrelevant organic molecules, which can potentially obscure the antigen of interest. This review will provide a comprehensive overview of the different cell-based phage panning strategies, with an emphasis placed on the optimisation of four critical panning conditions: cell surface antigen presentation, non-specific binding events, incubation time, and temperature and recovery of phage binders.

Phase I Dose-Escalation Study of Ramucirumab in Chinese Patients with Advanced Solid Tumors

LESSONS LEARNED

Ramucirumab was well tolerated in Chinese patients with advanced solid tumors, and adverse events were manageable in this study.Pharmacokinetics characteristics in Chinese patients were similar to those in other populations. Immunogenicity was not detected.No efficacy conclusion could be drawn, and further randomized studies are warranted.

BACKGROUND

This single-arm, nonrandomized, open-label, dose-escalation, phase I study was designed to evaluate the safety, tolerability, and pharmacokinetics (PK) of ramucirumab in Chinese patients with advanced solid tumors that were resistant to standard therapy or no standard therapy was available.

METHODS

Dose escalation was a 3 + 3 design, with expansion in Cohorts 2 and 3 for PK. Ramucirumab was given intravenously at three different dosages: 6 mg/kg every 2 weeks, 10 mg/kg every 3 weeks, and 8 mg/kg every 2 weeks. Safety analyses included all patients. PK, immunogenicity, and antitumor activity were also assessed.

RESULTS

Among 28 patients treated, 2 experienced dose-limiting toxicity, possibly related to ramucirumab. No maximum tolerated dose was determined. All patients experienced at least one treatment-emergent adverse event. Grade ≥3 adverse event was reported for 53.6% (n = 15) of patients. PK analyses indicated that ramucirumab had low clearance, small volume of distribution, and long half-life in Chinese patients, as in other populations. Immunogenicity was not detected. No patient had complete/partial response, and 64.3% (n = 18) had stable disease with a median duration of 5.55 months (95% confidence interval: 3.38-7.13 months).

CONCLUSION

Ramucirumab appeared to be well tolerated in Chinese patients with advanced solid tumors. PK characteristics in Chinese patients were similar to those in other populations.

A phase 1 study of ramucirumab in Japanese patients with advanced solid tumors

OBJECTIVE

Ramucirumab is a recombinant human immunoglobulin G1 monoclonal antibody targeting the vascular endothelial growth factor receptor-2. The aim of this phase 1 study was to evaluate the safety and tolerability of ramucirumab monotherapy in Japanese patients with advanced solid tumors.

METHODS

Patients with solid tumors who had not responded to standard therapy or for whom no standard therapy was available received escalating doses of ramucirumab, administered once every 2 (Q2W) or 3 (Q3W) weeks. The primary objective was to establish the safety and pharmacokinetic profiles of ramucirumab. Secondary and exploratory objectives included assessment of immunogenicity and antitumor activity. ClinicalTrials.gov: NCT01005355.

RESULTS

Fifteen patients were treated with ramucirumab at a dose of 6 mg/kg Q2W (N = 3), 8 mg/kg Q2W (N = 6) or 10 mg/kg Q3W (N = 6). There were no dose-limiting toxicities and the maximum tolerated dose was not reached. The most common ramucirumab-related adverse events were headache, pyrexia, hypertension and increased aspartate aminotransferase. Following single-dose administration of ramucirumab, there appeared to be a dose-proportional increase in maximum observed drug concentration but not in area under the curve. Treatment-emergent anti-ramucirumab antibodies were not detected in any patient.

CONCLUSIONS

Ramucirumab monotherapy was well tolerated and feasible at the doses and schedules used in this study population of Japanese patients with advanced solid tumors.

Ramucirumab for the treatment of advanced or metastatic non-small cell lung cancer

INTRODUCTION

On 12 December 2014, the U.S. Food and Drug Administration (FDA) approved ramucirumab for use in combination with docetaxel for the treatment of patients with metastatic non-small cell lung cancer (NSCLC) with disease progression on or after platinum-based chemotherapy. Areas covered: This review discusses the best treatment strategy for ramucirumab, a vascular endothelial growth factor receptor-2 inhibitor for patients with advanced NSCLC. Expert opinion: The addition of ramucirumab to docetaxel in the treatment of patients with metastatic NSCLC who have progressed on or after platinum-based chemotherapy confers a 1.4-month improvement in overall survival, with an acceptable toxicity profile. The potential impact of the approval of the programmed death receptor-1 (PD-1)-blocking antibody nivolumab or pembrolizumab on the use of ramucirumab plus docetaxel in advanced NSCLC patient population is uncertain in clinical practice. In order to improve overall outcomes for patients with advanced NSCLC, both ramucirumab plus docetaxel and the PD-1-blocking antibody should be used in any treatment line.

The safety and efficacy of ramucirumab in combination with docetaxel in the treatment of lung cancer

INTRODUCTION

Angiogenesis is critical for tumor growth, proliferation and metastasis with the crucial role of Vascular Endothelial Growth factor (VEGF) pathway. Ramucirumab is a monoclonal antibody that specifically targets the extracellular domain of Vascular Endothelial Growth Factor Receptor 2. Areas covered: We performed a search on Medline to browse the current literature on Ramucirumab and anti-angiogenic agents, for the treatment of NSCLC. The REVEL study demonstrated a significant improvement of response rate, progression-free survival and overall survival by adding ramucirumab to docetaxel compared to docetaxel plus a placebo in second-line treatment of advanced non-small cell lung cancer, irrespective of histology, with an acceptable safety profile. This article has for objective to summarize efficacy and safety data of the use of ramucirumab in combination with docetaxel in second line in NSCLC. Expert commentary: REVEL constitutes the first significant advance in second-line setting for patients eligible to anti-angiogenic therapy. The landscape of post-platinum therapy in NSCLC is considerably evolving and the role of ramucirumab or other anti-angiogenic agents as nintedanib in this setting has to be discussed for each patient with other available treatment options, among which immune checkpoints inhibitors, as well as the best treatment sequence.

The safety and efficacy of ramucirumab in combination with paclitaxel for the treatment of advanced gastric or gastro-esophageal junction adenocarcinoma

INTRODUCTION

Gastric cancer (GC) is a health problem. Platinum and fluoropyrimidine-based combinations have been established as first-line drugs used worldwide. However, there are no other options for treatment if first-line therapy fails. Therefore, second-line treatment options are needed. Targeted therapies have optimized the results of chemotherapy, specifically trastuzumab as a first-line and ramucirumab in second-line.

AREAS COVERED

Vascular endothelial growth factor (VEGF) and VEGF receptor-2 (VEGFR-2) are involved in the pathogenesis of GC. Clinical studies have evaluated VEGFR-2 blocked in second line. Two phase III trials using ramucirumab alone or associated to paclitaxel have demonstrated that second-line therapy could improve the survival of patients with GC. Expert commentary: VEGF-2 receptor blockade is effective at treating GC. The combination of paclitaxel with ramucirumab can be used to establish an angiogenic blockade in second-line therapy. The magnitude of the treatment effect suggests that this combination should be used as the current standard.