Publications by authors named "P B Bondarenko"

97 Publications

Identification of critical chemical modifications by size exclusion chromatography of stressed antibody-target complexes with competitive binding.

MAbs 2021 Jan-Dec;13(1):1887612

Attribute Sciences, Process Development, Amgen Inc , Thousand Oaks, CA, USA.

Chemical modifications (attributes) in the binding regions of stressed therapeutic proteins may affect binding to target and efficacy of therapeutic proteins. The method presented here describes the criticality assessment of therapeutic antibody modifications by size-exclusion chromatography (SEC) of competitive binding between a stressed antibody and its target, human epidermal growth factor receptor-2 (HER2), followed by SEC fractionation and peptide mapping characterization of bound and unbound antibodies. When stressed antibody and its target were mixed at a stoichiometric molar ratio of 1:2, only antibody-receptor complex eluted from SEC, indicating that binding was not decreased to break the complex. When a smaller amount of the receptor was provided (1:1), the antibody species with modifications reducing binding eluted as unbound from SEC, while the antibody-receptor complex eluted as the bound fraction. Peptide mapping revealed ratios of modifications between unbound and bound fractions. Statistical analysis after triplicate measurements (n = 3) indicated that heavy chain (HC) D102 isomerization and light chain (LC) N30 deamidation were four-fold higher in unbound fraction with high statistical significance. Although HC N55 deamidation and M107 oxidation were also abundant, they were not statistically different between unbound and bound. Our findings agree with previously published potency measurements of collected CEX fractions and the crystal structure of antibody and HER2. Overall, competitive SEC of stressed antibody-receptor mixture followed by peptide mapping is a useful tool in revealing critical residues and modifications involved in the antibody-target binding, even if they elute as a complex from SEC when mixed at 1:2 stoichiometric ratio.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1080/19420862.2021.1887612DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7899689PMC
February 2021

Identification of critical chemical modifications and paratope mapping by size exclusion chromatography of stressed antibody-target complexes.

MAbs 2021 Jan-Dec;13(1):1887629

Attribute Sciences, Process Development, Amgen Inc , Thousand Oaks, CA, USA.

Therapeutic proteins including antibodies and Fc-fusion proteins undergo a large number of chemical modifications during cell culture, purification, storage and in human circulation. They are also exposed to harsh conditions during stress studies, including elevated temperature, extremes of pH, forced oxidation, physiological pH, UV light to assess the possible degradation pathways and suitability of methods for detecting them. Some of these modifications are located on residues in binding regions, leading to loss of binding and potency and classified as critical quality attributes. Currently, criticality of modifications is assessed by a laborious process of collecting antibody fractions from the soft chromatography techniques ion exchange and hydrophobic interaction chromatography and characterizing the fractions one-by-one for potency and chemical modifications. Here, we describe a method for large-scale, parallel identification of all critical chemical modifications in one experiment. In the first step, the antibody is stressed by one or several stress methods. It is then mixed with target protein and separated by size-exclusion chromatography (SEC) on bound antibody-target complex and unbound antibody. Peptide mapping of fractions and statistical analysis are performed to identify modifications on amino acid residues that affect binding. To identify the modifications leading to slight decreases in binding, competitive SEC of antibody and antigen mixtures was developed and described in a companion study by Shi et al, where target protein is provided at lower level, below the stoichiometry. The newly described method was successfully correlated to crystallography for assessing criticality of chemical modifications and paratope mapping. It is more sensitive to low-level modifications, better streamlined and platform ready.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1080/19420862.2021.1887629DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7899697PMC
February 2021

[Surgical treatment of a huge paraganglioma of the right common carotid artery bifurcation].

Angiol Sosud Khir 2020 ;26(4):155-159

Department of Training Physicians for the Navy, Military Medical Academy named after S.M. Kirov, Saint Petersburg, Russia.

Described herein is a clinical case report regarding successful surgical treatment of a female patient presenting with a large paraganglioma of the right common carotid artery. On admission, the woman had complained of a mass in her neck, having significantly enlarged within the previous 6 months, with the appearance of dysphagia and moderate pain syndrome. The findings of multislice computed angiography and ultrasonographic duplex angioscanning of the brachiocephalic arteries helped to verify the location, size, and topography of the tumour. Taking into account the diagnosed secondary foci in the lungs, it was decided to first perform embolization of the artery supplying the tumour, which was followed by biopsy of tissue of the neoplasm. After histological verification and ruling out malignancy, successful radical resection of the paraganglioma was performed.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.33529/ANGIO2020417DOI Listing
December 2020

[Hybrid treatment of a patient with dissecting thoracoabdominal aortic aneurysm and single kidney].

Angiol Sosud Khir 2020 ;26(3):173-178

Department of Surgical Diseases, National Medical Research Centre named after V.A. Almazov under the RF Ministry of Public Health, Saint Petersburg, Russia.

Presented herein is a clinical case report regarding a repeat intervention for a type II dissecting thoracoabdominal aortic aneurysm treated by means of a hybrid technique in a 76-year-old male patient with a single kidney, having 9 years previously endured resection of an aneurysm of the infrarenal aortic portion. The first stage consisted in prosthetic repair of the thoracoabdominal aortic aneurysm by an oblique anastomosis, with the second stage (7 days thereafter) being endoprosthetic repair of the descending thoracic aorta. The findings of check-up computed tomography at 16 months postoperatively demonstrated no negative dynamics.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.33529/ANGIO2020318DOI Listing
October 2020

[Are hybrid technologies appropriate for revascularization of aortoiliac-femoral segment?]

Khirurgiia (Mosk) 2020 (8):49-54

Mechnikov North-West State Medical University, St. Petersburg, Russia.

Objective: To compare various approaches to revascularization of aortoiliac-femoral segment.

Material And Methods: Data were collected prospectively for retrospective analysis. There were 192 patients with atherosclerotic lesion of the aortoiliac-femoral segment who underwent reconstructive surgeries. All patients were divided into 3 groups depending on the type of reconstruction: 85 patients underwent open surgical interventions, 63 patients - endovascular interventions, 44 patients - hybrid techniques. Between-group differences were considered significant at -value <0.05.

Results: Hybrid revascularization is characterized by less duration of surgery, blood loss and morbidity. Hybrid interventions ensured favorable primary patency compared to open surgery within the follow-up period.

Conclusion: Hybrid revascularization of aortoiliac-femoral segment is characterized by less duration of surgery, blood loss and morbidity.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.17116/hirurgia202008149DOI Listing
September 2020