Monitoring monoclonal antibody delivery in oncology: the example of bevacizumab. PLoS One. 2013;8:e72021. [PMID: 23951280 PMCID: PMC3741214 DOI: 10.1371/journal.pone.0072021]

Adaptive resistance of tumor cells to anti-vascular endothelial growth factor therapy: A reversible phenomenon

Vascular endothelial growth factor (VEGF) inhibition is an essential targeted strategy for malignant tumors, but its efficacy is severely constrained by drug resistance. The traditional view holds that the target of VEGF inhibition is endothelial cells, and thus compensatory angiogenesis is considered the main mechanism of drug resistance. In this study, we found that tumor cells themselves could develop acquired resistance to VEGF therapy, indicating an independent resistance mechanism apart from angiogenesis. Notably, this acquired resistance was temporary, disappearing completely four days after discontinuing exposure to the drug in vitro. Our findings suggest that tumor cells may also be targets of VEGF inhibition, and their response to treatment should not be overlooked in contributing to drug resistance.

Basic Fibroblast Growth Factor Accumulation in Culture Medium Masks the Direct Antitumor Effect of Anti-VEGF Agent Bevacizumab

The direct antitumor effect of bevacizumab (BEV) has long been debated. Evidence of the direct antitumor activities of drugs are mainly obtained from in vitro experiments, which are greatly affected by experimental conditions. In this study, we evaluated the effect of BEV-containing medium renewal on the results of in vitro cytotoxicity experiments in A549 and U251 cancer cells. We observed starkly different results between the experiments with and without BEV-containing medium renewal. Specifically, BEV inhibited the tumor cell growth in the timely replacement with a BEV-containing medium but promoted tumor cell growth without medium renewal. Meanwhile, compared with the control, a significant basic fibroblast growth factor (bFGF) accumulation in the supernatant was observed in the group without medium renewal but none in that with replaced medium. Furthermore, bFGF neutralization partially reversed the pro-proliferative effect of BEV in the medium non-renewed group, while exogenous bFGF attenuated the tumor cell growth inhibition of BEV in the medium-renewed group. Our data explain the controversy over the direct antitumor effect of BEV in different studies from the perspective of the compensatory autocrine cytokines in tumor cells.

Comparative characterization of two monoclonal antibodies targeting canine PD-1

Monoclonal antibodies targeting immune checkpoints have revolutionized oncology. Yet, the effectiveness of these treatments varies significantly among patients, and they are associated with unexpected adverse events, including hyperprogression. The murine research model used in drug development fails to recapitulate both the functional human immune system and the population heterogeneity. Hence, a novel model is urgently needed to study the consequences of immune checkpoint blockade. Dogs appear to be uniquely suited for this role. Approximately 1 in 4 companion dogs dies from cancer, yet no antibodies are commercially available for use in veterinary oncology. Here we characterize two novel antibodies that bind canine PD-1 with sub-nanomolar affinity as measured by SPR. Both antibodies block the clinically crucial PD-1/PD-L1 interaction in a competitive ELISA assay. Additionally, the antibodies were tested with a broad range of assays including Western Blot, ELISA, flow cytometry, immunofluorescence and immunohistochemistry. The antibodies appear to bind two distinct epitopes as predicted by molecular modeling and peptide phage display. Our study provides new tools for canine oncology research and a potential veterinary therapeutic.

Exposure-response analysis using time-to-event data for bevacizumab biosimilar SB8 and the reference bevacizumab

Purpose: This analysis aimed to characterize the exposure-response relationship of bevacizumab in non-small-cell lung cancer (NSCLC) and evaluate the efficacy of SB8, a bevacizumab biosimilar, and Avastin®, the reference bevacizumab sourced from the European Union (EU), based on the exposure reported in a comparative phase III efficacy and safety study (EudraCT, 2015-004026-34; NCT02754882). Materials and methods: The overall survival (OS) and progression-free survival (PFS) data from 224 patients with steady-state trough concentrations (Css,trough) were analyzed. A parametric time-to-event (TTE) model was developed using NONMEM®, and the effects of treatments (SB8 and bevacizumab-EU) and patient demographic and clinical covariates on OS and PFS were evaluated. Simulations of median OS and PFS by bevacizumab Css,trough were conducted, and concentrations required to achieve 50% and 90% of the maximum median TTE were computed. Results: A log-logistics model with Css,trough best described the OS and PFS data. Treatment was not a predictor of the hazard for OS or PFS. Simulations revealed steep exposure-response curves with a phase of rapid rise before saturating to a plateau. The median Css,trough values of SB8 and bevacizumab-EU reported from the clinical study were on the plateaus of the exposure-response curves. The concentrations required to achieve 50% and 90% of the maximum effect were 82.4 and 92.2 μg/mL, respectively, for OS and 79.7 and 89.1 μg/mL, respectively, for PFS. Conclusion: Simulations based on the constructed TTE models for OS and PFS have well described the exposure-response relationship of bevacizumab in advanced NSCLC. The analysis demonstrated comparable efficacy between SB8 and bevacizumab-EU in terms of OS and PFS based on their exposure levels.

Antiangiogenic exclusion rules in glioma trials: Historical perspectives and guidance for future trial design

Background

Despite the lack of proven therapies for recurrent high-grade glioma (HGG), only 8%-11% of patients with glioblastoma participate in clinical trials, partly due to stringent eligibility criteria. Prior bevacizumab treatment is a frequent exclusion criterion, due to difficulty with response assessment and concerns for rebound edema following antiangiogenic discontinuation. There are no standardized trial eligibility rules related to prior antiangiogenic use.

Methods

We reviewed ClinicalTrials.gov listings for glioma studies starting between May 2009 and July 2022 for eligibility rules related to antiangiogenics. We also reviewed the literature pertaining to bevacizumab withdrawal.

Results

Two hundred and ninety-seven studies for patients with recurrent glioma were reviewed. Most were phase 1 (n = 145, 49%), non-randomized (n = 257, 87%), evaluated a drug-only intervention (n = 223, 75%), and had a safety and tolerability primary objective (n = 181, 61%). Fifty-one (17%) excluded participants who received any antiangiogenic, one (0.3%) excluded participants who received any non-temozolomide systemic therapy. Fifty-nine (20%) outlined washout rules for bevacizumab (range 2-24 weeks, 4-week washout n = 35, 12% most common). Seventy-eight required a systemic therapy washout (range 1-6 weeks, 4-week washout n = 34, 11% most common). Nine permitted prior bevacizumab use with limitations, 18 (6%) permitted any prior bevacizumab, 5 (2%) were for bevacizumab-refractory disease, and 76 (26%) had no rules regarding antiangiogenic use. A literature review is then presented to define standardized eligibility criteria with a 6-week washout period proposed for future trial design.

Conclusions

Interventional clinical trials for patients with HGG have substantial heterogeneity regarding eligibility criteria pertaining to bevacizumab use, demonstrating a need for standardizing clinical trial design.

A chimeric hairpin DNA aptamer-based biosensor for monitoring the therapeutic drug bevacizumab

The accurate and rapid detection of specific antibodies in blood is very important for efficient diagnosis and precise treatment. Conventional methods often suffer from time-consuming operations and/or a narrow detection range. In this work, for the rapid determination of bevacizumab in plasma, a series of chimeric hairpin DNA aptamer-based probes were designed by the modification, labeling and theoretical computation of an original aptamer. Then, the dissociation constant of the modified hairpin DNA to bevacizumab was measured and screened using microscale thermophoresis. The best chimeric hairpin DNA aptamer-based probe was then selected, and a one-step platform for the rapid determination of bevacizumab was constructed. This strategy has the advantages of being simple, fast and label-free. Because of the design and screening of the hairpin DNA, as well as the optimization of the concentration and electrochemical parameters, a low detection limit of 0.37 pM (0.054 ng mL-1) with a wide linear range (1 pM-1 μM) was obtained. Finally, the rationally constructed biosensor was successfully applied to the determination of bevacizumab in spiked samples, and it showed good accuracy and precision. This method is expected to truly realize accurate and rapid detection of bevacizumab and provides a new idea for the precise treatment of diseases.

Tetrazolium-based colorimetric assays underestimat the direct antitumor effects of anti-VEGF agent bevacizumab

The direct antitumor effect of bevacizumab (BEV) has long been debated. Assessment of the direct cytotoxic activities of drugs is usually conducted via in vitro experiments, of which tetrazolium-based colorimetric assays are widely employed to measure the direct antitumor activity of BEV. This study aimed to investigate whether tetrazolium-based colorimetric assays are applicable when evaluating the cytotoxicity of BEV against tumor cells. Our results showed that BEV significantly augmented tumor-cell mitochondrial metabolism. Enhanced mitochondrial metabolism caused changes in cellular oxidation-and-reduction environment and upregulated succinate dehydrogenase, which in turn promoted the reduction of tetrazolium to produce formazan. Increased formazan formation resulted in underestimation of the in vitro direct antitumor effect of BEV. Furthermore, inhibition of mitochondrial hypermetabolism partially corrected the underestimation of colorimetric assays in evaluating the direct antitumor activity of BEV. Our findings suggest that tetrazolium-based colorimetric assays are unsuitable for accurately assessing the in vitro cytotoxicity of anti-VEGF drugs and may be the methodological reason for the controversial direct antitumor effect of BEV.

Development of an Anti-Idiotype Aptamer-Based Electrochemical Sensor for a Humanized Therapeutic Antibody Monitoring

Therapeutic monoclonal antibodies (mAbs) are currently the most effective medicines for a wide range of diseases. Therefore, it is expected that easy and rapid measurement of mAbs will be required to improve their efficacy. Here, we report an anti-idiotype aptamer-based electrochemical sensor for a humanized therapeutic antibody, bevacizumab, based on square wave voltammetry (SWV). With this measurement procedure, we were able to monitor the target mAb within 30 min by employing the anti-idiotype bivalent aptamer modified with a redox probe. A fabricated bevacizumab sensor achieved detection of bevacizumab from 1–100 nM while eliminating the need for free redox probes in the solution. The feasibility of monitoring biological samples was also demonstrated by detecting bevacizumab in the diluted artificial serum, and the fabricated sensor succeeded in detecting the target covering the physiologically relevant concentration range of bevacizumab. Our sensor contributes to ongoing efforts towards therapeutic mAbs monitoring by investigating their pharmacokinetics and improving their treatment efficacy.

Quantitation of Trastuzumab and an Antibody to SARS-CoV-2 in Minutes Using Affinity Membranes in 96-Well Plates

Quantitation of therapeutic monoclonal antibodies (mAbs) in human serum could ensure that patients have adequate levels of mAbs for effective treatment. This research describes the use of affinity, glass-fiber membranes in a 96-well-plate format for rapid (<5 min) quantitation of the therapeutic mAb trastuzumab and a mAb against the SARS-CoV-2 spike protein. Adsorption of a poly(acrylic acid)-containing film in membrane pores and activation of the -COOH groups in the film enable covalent-linking of affinity peptides or proteins to the membrane. Passage of mAb-containing serum through the affinity membrane results in mAb capture within 1 min. Subsequent rinsing, binding of a secondary antibody conjugated to a fluorophore, and a second rinse yield mAb-concentration-dependent fluorescence intensities in the wells. Calibration curves established from analyses on different days have low variability and allow determination of mAb levels in separately prepared samples with an average error <10%, although errors in single-replicate measurements may reach 40%. The assays can occur in diluted serum with physiologically relevant mAb concentrations, as well as in undiluted serum. Thus, the combination of 96-well plates containing affinity membranes, a microplate reader, and a simple vacuum manifold affords convenient mAb quantitation in <5 min.

Assessment of exposure-response relationship for bevacizumab in patients with metastatic colorectal cancer

Limited literature is available for bevacizumab exposure-response relationship and there is not a concentration threshold associated with an optimal disease control. This prospective observational study in patients with metastatic colorectal cancer (mCRC) aims to evaluate, in a real-life setting, the relationship between bevacizumab through concentrations at steady state (C_{trough, SS}) and disease control. C_{trough, SS} were drawn, coinciding with the radiological evaluation of the response (progression or clinical benefit). Generalized estimating equations (GEE) analysis was performed. To test the association between C_{trough, SS} in each patient with overall survival (OS) or progression-free survival (PFS), Cox proportional hazard models were developed. Data included 50 bevacizumab C_{trough, SS} from 27 patients. The GEE model did not suggest any positive association between bevacizumab C_{trough, SS} and clinical benefit (OR 0.99, 95% CI: 0.98-1.02, p = 0.863). The Cox regression showed association between higher median C_{trough, SS} with better OS (HR 0.86, 95% CI: 0.73-1.01, p = 0.060), but not with PFS. We cannot confirm a relationship between bevacizumab C_{trough, SS} and clinical benefit but this is the first real-world study trying to show a relationship between bevacizumab C_{trough, SS} and disease control in mCRC. It was conducted in a small sample size which reduces the level of evidence. Further controlled randomized studies with a sufficient number of patients are required.

Determination of the Serum Concentrations of the Monoclonal Antibodies Bevacizumab, Rituximab, and Panitumumab Using Porous Membranes Containing Immobilized Peptide Mimotopes

Effective monoclonal antibody (mAb) therapies require a threshold mAb concentration in patient serum. Moreover, the serum concentration of the mAb Bevacizumab should reside in a specific range to avoid side effects. Methods for conveniently determining the levels of mAbs in patient sera could allow for personalized dosage schedules that lead to more successful treatments. This work utilizes microporous nylon membranes functionalized with antibody-binding peptides to capture Bevacizumab, Rituximab, or Panitumumab from diluted (25%) serum. Modification of the capture-peptide terminus is often crucial to creating the affinity necessary for effective binding. The high purity of eluted mAbs allows for their quantitation using native fluorescence, and membranes are effective in spin devices that can be used in any laboratory. The technique is effective over the therapeutic range of Bevacizumab concentrations. Future work aims at further modifications to develop rapid point-of-care devices and decrease detection limits.

Circulating Tumor Cells and Bevacizumab Pharmacokinetics during Neoadjuvant Treatment Combining Chemotherapy and Bevacizumab for Early Breast Cancer: Ancillary Analysis of the AVASTEM Trial

The phase II AVASTEM trial explored the impact of chemotherapy-bevacizumab combination on breast cancer stem cells in the neoadjuvant setting. We aimed to identify biological features associated with preoperative chemotherapy efficacy and prognosis by analyses of circulating tumor cells (CTCs) and bevacizumab pharmacokinetics (PK). The main objective was to assess the prognostic (relapse-free survival and overall survival) and predictive (pathological complete response, pCR) values of CTCs (CellSearch technology) and bevacizumab PK (ELISA). Seventy-five patients were included. Out of them 50 received bevacizumab-chemotherapy and 25 received chemotherapy alone. CTC results were available for 60 patients and PK data for 29 patients in the experimental arm. The absence of CTC at inclusion was correlated to better outcome. Five-years overall survival (OS) was 91% for CTC-negative patients vs. 54% for CTC-positive cases (HR = 6.21; 95%CI (1.75-22.06), p = 0.001, log-rank test). Similar results were observed for RFS with 5 y-RFS of 78% vs. 44% (HR = 3.51; 95%CI (1.17-10.52), p = 0.017, log-rank test). However, CTC status at baseline was not predictive of pCR (p = 0.74). CTC status after one cycle was not a significant prognostic factor (HR = 1.56; 95%CI (0.19-12.67); p = 0.68 for OS and HR = 2.76; 95%CI (0.60-12.61); p = 0.17 for RFS, log-rank test). Bevacizumab serum levels could not predict pCR and survival. PK values were not associated with treatment-related toxicities. In conclusion, CTCs detection at baseline is a prognostic marker for breast cancer receiving a neoadjuvant chemotherapy-bevacizumab combination independently of tumor response.

Pharmacogenomics, Pharmacokinetics and Circulating Proteins as Biomarkers for Bevacizumab Treatment Optimization in Patients with Cancer: A Review

Bevacizumab is a monoclonal antibody that targets VEGF-A and inhibits tumor angiogenesis. Bevacizumab is approved for the treatment of various cancer, including metastatic colorectal cancer (mCRC), ovarian cancer, lung cancer, and others. Thus, it is widely used in oncology, but contrary to other therapeutic classes, there is still a lack of validating predictive factors for treatment outcomes with these agents. In recent years, the research for factors predictive of anti-VEGF treatments and especially bevacizumab response has been one of the most competitive translational research fields. Herein, we review and present the available literature of the clinical use of biomarkers, pharmacogenomics (PG), and therapeutic drug monitoring (TDM) approaches that can be used for the optimization of bevacizumab use in the era of precision medicine.

Correlation Between Bevacizumab Exposure and Survival in Patients with Metastatic Colorectal Cancer

BACKGROUND

Bevacizumab treatment is subject to large interpatient variability in efficacy, which may partly be explained by differences in complex bevacizumab pharmacokinetic characteristics that influence bevacizumab exposure. Exposure-response relationships have been identified for other monoclonal antibodies. We aimed to identify possible exposure-survival relationships in bevacizumab-treated patients with metastatic colorectal cancer (mCRC).

MATERIALS AND METHODS

Patients with mCRC who started first-line bevacizumab-based chemotherapy between July 2012 and July 2014, and from whom serial blood samples and survival were prospectively collected, were included. Follow-up was carried out until July 2018. Total bevacizumab trough concentrations were measured from cycle 2 to cycle 30 of treatment. The receiver operating characteristic (ROC) curve analysis and Cox analysis were used to identify the relationship between concentrations and overall survival (OS). In addition, OS was compared between different trough concentration groups.

RESULTS

One hundred fifty-seven blood samples from 46 patients were evaluable for analyses. ROC analysis showed a clear separation in survival based on trough levels (area under the curve = 0.739, p = .009). Cox regression also showed a strong positive correlation between trough levels and survival (p = .0004). Three distinct groups of exposure were identified: low (median trough concentration [C_tm ] ≤41.9 mg/L); medium (C_tm 43-87.2 mg/L) with median OS of 12.8 and 36 months, respectively (p = .0003); and high (C_tm ≥7.9 mg/L), where the majority of patients were still alive 60 months after the initiation of treatment.

CONCLUSION

This study shows that survival was proportional to the magnitude of exposure in patients with mCRC. Further clinical research should focus on clarifying these exposure-outcome relationships in order to optimize dosing.

IMPLICATIONS FOR PRACTICE

Bevacizumab-based chemotherapy is standard first-line treatment in metastatic colorectal cancer. Moreover, bevacizumab presents complicated pharmacokinetics, and in many cases, clinical outcomes can be highly variable, with some patients responding remarkably well and others not. This study's results show that patients who experienced longer overall survival also had significantly higher exposure to bevacizumab. Therefore, bevacizumab trough concentrations could be used both as a predictive biomarker and as a tool for treatment monitoring and optimization. Finally, the development of validated, rapid, and sensitive assays for bevacizumab concentration measurements in combination with these results may lead to a therapeutic drug monitoring-guided approach in bevacizumab treatment with better clinical outcomes.

High-Throughput Bioanalysis of Bevacizumab in Human Plasma Based on Enzyme-Linked Aptamer Assay Using Anti-Idiotype DNA Aptamer

We propose a highly selective, sensitive, accurate, and high-throughput bioanalysis method for bevacizumab utilizing an anti-idiotype DNA aptamer. With this method, bevacizumab in a plasma sample was reacted in a 96-well plate immobilized with the aptamer and further reacted with a protein A-HRP conjugate. The resulting HRP activity was colorimetrically detected using a microplate reader. The calibration curve of bevacizumab ranged from 0.05 to 5.0 μg/mL, and showed a good correlation coefficient ( r² = 1.000). The limit of detection was 2.09 ng/mL. We also demonstrated both the possibility of highly sensitive detection using luminol chemiluminescence and the repeated use of affinity plates. The proposed method is applicable for planning optimal therapeutic programs and for an evaluation of the biological equivalencies in the development of biosimilars.

What sample preparation should be chosen for targeted MS monoclonal antibody quantification in human serum?

Aim: Monoclonal antibody-based treatment of cancer has been established as one of the most successful therapeutic strategies. Materials & methods: In this work, we developed a workflow based on an automated protein-A capture and LC–MS/MS analysis to quantify bevacizumab on patient serum during treatment. This analytical approach was fully validated and compared with a commercially available Monoclonal antibody-based treatment preparation (nanosurface and molecular-orientation limited kit). Results: The analytical comparison of the two preparative workflows based on protein-A capture gave similar results with a better lower limit of quantification for the nanosurface and molecular-orientation limited kit (0.26986 vs 1.9565 μg/ml). Conclusion: LC–MS/MS has clear advantages compared with ELISA when considering method development time, multiplexing capacities and absolute quantification with internal standardization.

Protein based therapeutic delivery agents: Contemporary developments and challenges

As unique biopolymers, proteins can be employed for therapeutic delivery. They bear important features such as bioavailability, biocompatibility, and biodegradability with low toxicity serving as a platform for delivery of various small molecule therapeutics, gene therapies, protein biologics and cells. Depending on size and characteristic of the therapeutic, a variety of natural and engineered proteins or peptides have been developed. This, coupled to recent advances in synthetic and chemical biology, has led to the creation of tailor-made protein materials for delivery. This review highlights strategies employing proteins to facilitate the delivery of therapeutic matter, addressing the challenges for small molecule, gene, protein and cell transport.

Total and not bevacizumab-bound vascular endothelial growth factor as potential predictive factors to bevacizumab-based chemotherapy in colorectal cancer

AIM: To identify suitable biomarkers of response to bevacizumab (BV) - it remains an open question. The measurement of serum vascular endothelial growth factor (VEGF) has been proposed as a predictive factor for this drug, even if literature data are contradictory.

METHODS: We prospectively evaluated the role of BV, total and not BV-bound VEGF and angiopoietin-2 (Ang-2) serum levels as potential predictive factors of response for BV in combination with an oxaliplatin-based chemotherapy. BV, Ang-2, total and not BV-bound VEGF levels were measured at baseline, before 2^nd and 5^th cycle of oxaliplatin-based chemotherapy in 20 consecutive metastatic colorectal cancer patients.

RESULTS: Results were correlated to response to treatment. Variability in BV levels have been found, with decreased level in less responding patients. In particular, the concentration of BV increased of 3.96 ± 0.69 folds in serum of responsive patients after 3 more cycles of therapy compared to those with stable or progressive disease with a 0.72 ± 0.25 and 2.10 ± 0.13 fold increase, respectively. The determination of free and total VEGF demonstrated that the ratio between the two values, evaluated immediately before the 2^nd and the 5^th cycle of therapy, decreased from 26.65% ± 1.33% to 15.50% ± 3.47% in responsive patients and from 53.41% ± 4.75 to 34.95% ± 2.88% in those with stable disease. Conversely, in those with progression of disease, the ratio showed the opposite behavior coming up from 25.99% ± 5.23% to 51.71% ± 5.28%. The Ang-2 levels did not show any relationship.

CONCLUSION: Our data show that the ratio of not BV-bound VEGF to total VEGF serum and BV plasma concentrations for predicting the response to BV plus oxaliplatin-based chemotherapy could be a promising biomarker of response to BV.

Pharmacotherapies for the treatment of glioblastoma - current evidence and perspectives

INTRODUCTION

Glioblastoma, the most common malignant brain tumor, exhibits a poor prognosis with little therapeutic progress in the last decade. Novel treatment strategies beyond the established standard of care with temozolomide-based radiotherapy are urgently needed.

AREAS COVERED

We reviewed the literature on glioblastoma with a focus on phase III trials for pharmacotherapies and/or innovative concepts until December 2015.

EXPERT OPINION

In the last decade, phase III trials on novel compounds largely failed to introduce efficacious pharmacotherapies beyond temozolomide in glioblastoma. So far, inhibition of angiogenesis by compounds such as bevacizumab, cediranib, enzastaurin or cilengitide as well as alternative dosing schedules of temozolomide did not prolong survival, neither at primary diagnosis nor at recurrent disease. Promising strategies of pharmacotherapy currently under evaluation represent targeting epidermal growth factor receptor (EGFR) with biomarker-stratified patient populations and immunotherapeutic concepts including checkpoint inhibition and vaccination. The clinical role of the medical device delivering 'tumor-treating fields' in newly diagnosed glioblastoma which prolonged overall survival in a phase III study has remained controversial. After failure of several phase III trials with previously promising agents, improvement of concepts and novel compounds are urgently needed to expand the still limited therapeutic options for the treatment of glioblastoma.

Fully validated LCMS bioanalysis of Bevacizumab in human plasma using nano-surface and molecular-orientation limited (nSMOL) proteolysis

The chemistry of nano-surface and molecular-orientation limited (nSMOL) proteolysis is the Fab-selective limited proteolysis by making use the difference of protease nanoparticle diameter (200 nm) and antibody resin pore diameter (100 nm). In this report, we have demonstrated that the full validation for Bevacizumab bioanalysis in human plasma using nSMOL. The immunoglobulin fraction was collected by Protein A resin from plasma, then nSMOL reaction was performed using the FG nanoparticle-immobilized trypsin under the nondenaturing physiological condition at 50 °C for 6 h. After removal of resin and nanoparticles, the signature peptide of Bevacizumab complementarity-determining region (CDR) and internal standard P14R were simultaneously quantified by LCMS multiple reaction monitoring (MRM). This nSMOL method quantification of Bevacizumab showed sensitivity of 0.146 μg/ml and linearity of 0.146-300 μg/ml. The intra- and inter-assay precision of lower limit of quantification (LLOQ), low quality control (LQC), middle quality control (MQC), and high quality control (HQC) was 7.94-15.2% and 14.6%, 7.15-13.5% and 11.7%, 2.63-6.47% and 5.83%, and 3.09-4.35% and 4.45%, respectively. These results indicate that nSMOL is also significant method for Bevacizumab bioanalysis in human plasma.

Identification of the Key Fields and Their Key Technical Points of Oncology by Patent Analysis

Background

This paper aims to identify the key fields and their key technical points of oncology by patent analysis.

Methodology/Principal Findings

Patents of oncology applied from 2006 to 2012 were searched in the Thomson Innovation database. The key fields and their key technical points were determined by analyzing the Derwent Classification (DC) and the International Patent Classification (IPC), respectively. Patent applications in the top ten DC occupied 80% of all the patent applications of oncology, which were the ten fields of oncology to be analyzed. The number of patent applications in these ten fields of oncology was standardized based on patent applications of oncology from 2006 to 2012. For each field, standardization was conducted separately for each of the seven years (2006–2012) and the mean of the seven standardized values was calculated to reflect the relative amount of patent applications in that field; meanwhile, regression analysis using time (year) and the standardized values of patent applications in seven years (2006–2012) was conducted so as to evaluate the trend of patent applications in each field. Two-dimensional quadrant analysis, together with the professional knowledge of oncology, was taken into consideration in determining the key fields of oncology. The fields located in the quadrant with high relative amount or increasing trend of patent applications are identified as key ones. By using the same method, the key technical points in each key field were identified. Altogether 116,820 patents of oncology applied from 2006 to 2012 were retrieved, and four key fields with twenty-nine key technical points were identified, including “natural products and polymers” with nine key technical points, “fermentation industry” with twelve ones, “electrical medical equipment” with four ones, and “diagnosis, surgery” with four ones.

Conclusions/Significance

The results of this study could provide guidance on the development direction of oncology, and also help researchers broaden innovative ideas and discover new technological opportunities.

Bevacizumab: A dose review

Angiogenesis is a key process in cancer development and has been described has a hallmark of cancer. Two dose-intensities were approved for cancer treatment by the Food and Drug Administration and European Medicines Agency: 2.5mg/kg/week dose equivalent and 5mg/kg/week dose equivalent. While bevacizumab has shown its effectiveness in clinical trials, pharmacodynamics is not fully understood and a dose-effect relationship has not been proven in vivo. Direct trials comparing high or low doses are rare with potential dose-effect toxicity. Discordant data have been reported on the efficacy of doses. This review discusses the dose of bevacizumab via the analysis of studies that led to the approval of bevacizumab in clinical practice. Optimization of doses schemes could reduce potential dose-effect toxicities, potentiate synergetic effects with chemotherapy and permit the prescription to a larger population with a better cost-effectiveness ratio.