Analytical characterization of recombinant hCG and comparative studies with reference product

Characterization of Concanavalin A-based lectin sorbents for the extraction of the human chorionic gonadotropin glycoforms prior to analysis by nano liquid chromatography-high resolution mass spectrometry

Human chorionic gonadotropin (hCG) is constituted of the hCGα and hCGβ subunits and is a highly glycosylated protein. Affinity supports based on immobilized Concanavalin A (Con A) lectin were used in solid phase extraction (SPE) to fractionate the hCG glycoforms according to their glycosylation state. For the first time, the lectin SPE fractions were off-line analysed by a nano liquid chromatography - high-resolution mass spectrometry (nanoLC-HRMS) method keeping the glycoforms intact. For this, home-made Con A sorbents were prepared by immobilizing lectin on Sepharose with a mean grafting yield of 98.2% (relative standard deviation (RSD) of 3.5%, n = 15). A capacity of about 100 μg of purified urinary hCG (uhCG) per ml of sorbent, grafted with a density of 10 mg of Con A per ml, was estimated. Average extraction yields of around 60% for both hCGα and hCGβ glycoforms were obtained after optimization of the extraction protocol. Intra- and inter-assay evaluation led to average RSD values of around 10%, indicating a repeatable extraction procedure. Similar results were obtained with commercial Con A-based sorbents but only after their 3rd use or after an extensive pre-conditioning step. Finally, the Con A SPE led to the fractionation of some glycoforms of uhCG, allowing the detection of an hCGα glycoform with two tetra-antennary N-glycans that couldn't be detected by direct analysis in nanoLC-HRMS without Con A SPE. Regarding a recombinant hCG, a fractionation was also observed leading to the detection of unretained hCGα glycoforms with tri-antennary N-glycans. Therefore, the combination of lectin SPE with intact protein analysis by nanoLC-HRMS can contribute to a more detailed glycosylation characterization of the hCG protein.

Physicochemical Characterization of a Recombinant eCG and Comparative Studies with PMSG Commercial Preparations

Equine chorionic gonadotropin (eCG) is a glycoprotein hormone widely used in timed artificial ovulation (TAI) and superovulation protocols to improve the reproductive performance in livestock. Until recently, the only eCG products available in the market for veterinary use consisted in partially purified preparations of pregnant mare serum gonadotropin (PMSG). Here, a bioactive recombinant eCG (reCG) produced in suspension CHO-K1 cells was purified employing different chromatographic methods (hydrophobic interaction chromatography and reverse-phase (RP)-HPLC) and compared with a RP-HPLC-purified PMSG. To gain insight into the structural and functional characteristics of reCG, a bioinformatics analysis was performed. An exhaustive characterization comprising the determination of the purity degree, aggregates and nicked forms through SDS-PAGE, RP-HPLC and SEC-HPLC was performed. Higher order structures were studied by fluorescence spectroscopy and SEC-HPLC. Isoforms profile were analyzed by isoelectric focusing. Glycosylation analysis was performed through pulsed amperometric detection and PNGase F treatment following SDS-PAGE and weak anion exchange-HPLC. Slight differences between the purified recombinant hormones were found. However, recombinant molecules and PMSG exhibited variations in the glycosylation pattern. In fact, differences in sialic acid content between two commercial preparations of PMSG were also obtained, which could lead to differences in their biological potency. These results show the importance of having a standardized production process, as occurs in a recombinant protein bioprocess. Besides, our results reflect the importance of the glycan moieties on eCG conformation and hence in its biological activity, preventing denaturing processes such as aggregation.

Benchmarking Cleavable Biotin Tags for Peptide-Centric Chemoproteomics

Click chemistry─specifically the copper-catalyzed azide-alkyne cycloaddition─has enabled the development of a wide range of chemical probes to analyze subsets of the functional proteome. The "clickable" proteome can be selectively enriched by using diverse cleavable biotin tags, but the direct identification of probe/tag-modified peptides (or peptide-centric analysis) remains challenging. Here, we evaluated the performance of five commercially available cleavable biotin tags in three most common chemoproteomic workflows, resulting in a comparative analysis of 15 methods. An acid-cleavable biotin tag with a dialkoxydiphenylsilane moiety, in combination with the protein "click", peptide "capture" workflow, outperforms all other methods in terms of enrichment efficiency, identification yield, and reproducibility, although its performance may be slightly compromised by the formation of an unwanted formate product revealed by blind search. Despite being inferior, photocleavable, and reduction-cleavable, biotin tags can also find their applicable sceneries, especially when dealing with acid-sensitive probes or probe-derived modifications. Furthermore, the systematic comparison of LC-MS/MS characteristics of tag-modified peptides provides valuable information for the future development of cleavable biotin reagents. Taken together, our data provides a much-needed practical guidance for researchers interested in developing and/or applying an ideal cleavable biotin tag to peptide-centric chemoproteomics.

Analytical Similarity Assessment of Biosimilars: Global Regulatory Landscape, Recent Studies and Major Advancements in Orthogonal Platforms

Biopharmaceuticals are one of the fastest-growing sectors in the biotechnology industry. Within the umbrella of biopharmaceuticals, the biosimilar segment is expanding with currently over 200 approved biosimilars, globally. The key step towards achieving a successful biosimilar approval is to establish analytical and clinical biosimilarity with the innovator. The objective of an analytical biosimilarity study is to demonstrate a highly similar profile with respect to variations in critical quality attributes (CQAs) of the biosimilar product, and these variations must lie within the range set by the innovator. This comprises a detailed comparative structural and functional characterization using appropriate, validated analytical methods to fingerprint the molecule and helps reduce the economic burden towards regulatory requirement of extensive preclinical/clinical similarity data, thus making biotechnological drugs more affordable. In the last decade, biosimilar manufacturing and associated regulations have become more established, leading to numerous approvals. Biosimilarity assessment exercises conducted towards approval are also published more frequently in the public domain. Consequently, some technical advancements in analytical sciences have also percolated to applications in analytical biosimilarity assessment. Keeping this in mind, this review aims at providing a holistic view of progresses in biosimilar analysis and approval. In this review, we have summarized the major developments in the global regulatory landscape with respect to biosimilar approvals and also catalogued biosimilarity assessment studies for recombinant DNA products available in the public domain. We have also covered recent advancements in analytical methods, orthogonal techniques, and platforms for biosimilar characterization, since 2015. The review specifically aims to serve as a comprehensive catalog for published biosimilarity assessment studies with details on analytical platform used and critical quality attributes (CQAs) covered for multiple biotherapeutic products. Through this compilation, the emergent evolution of techniques with respect to each CQA has also been charted and discussed. Lastly, the information resource of published biosimilarity assessment studies, created during literature search is anticipated to serve as a helpful reference for biopharmaceutical scientists and biosimilar developers.

The best execution of the DuoStim strategy (double stimulation in the follicular and luteal phase of the same ovarian cycle) in patients who are poor ovarian responders

BACKGROUND

Patients found to be poor ovarian responders (POR) are a challenging patient population for any assisted reproduction technology. Despite attempts at various controlled ovarian stimulation schemes, reproductive outcomes in this patient population have not improved. In recent years, the DuoStim protocol (both follicular and luteal phase stimulation during the same menstrual cycle) has shown a potential for use in patients with POR.

METHODS

This retrospective study reviewed the medical records of 304 women who were diagnosed as POR and underwent the DuoStim protocol. We compared follicular phase stimulation (FPS) data and luteal phase stimulation (LPS) data of the same patients. We also compared the effects of different trigger drugs including urine human chorionic gonadotropin (uHCG; 10,000 IU), recombinant human chorionic gonadotropin (rHCG; 250 μg), and gonadotropin-releasing hormone agonist (GnRH-a; 0.2 mg) at the FPS and LPS stages.

RESULTS

POR undergoing the DuoStim protocol resulted in a significantly higher number of oocytes retrieved, normal fertilised oocytes, cleaved embryos, cryopreserved embryos, and good quality embryos at the LPS stage than at the FPS stage. Trigger drugs at the FPS stage did not affect the FPS stage data. Regardless of the stage, rHCG and GnRH-a yielded significantly more cryopreserved embryos and good quality embryos than uHCG.

CONCLUSION

The use of GnRH-a or rHCG as the trigger drug may be better than uHCG in both the FPS and LPS stages for POR undergoing the DuoStim protocol. This will increase the number of good quality embryos at the LPS stage. We found that the LPS stage results in more oocytes (and therefore more embryos) than the FPS stage.

Comparative Pharmacokinetics, Bioequivalence and Safety Study of Two Recombinant Human Chorionic Gonadotropin Injections in Healthy Chinese Subjects

Objective

To evaluate the pharmacokinetics (PK), bioequivalence and safety profile of the recombinant human chorionic gonadotropin (r-hCG) injection formulation LZM003 (test drug) comparing with that of Ovidrel^® (reference drug) in healthy Chinese subjects.

Methods

This is a randomized, single-blind, single-dose, two-arm and two-period crossover Phase I study. Subjects were randomized evenly to a single dose of LZM003 or reference drug injected subcutaneously, with a 10-day or longer between-treatment washout period. PK parameters, anti-drug antibodies (ADAs), and adverse events (AEs) were assessed. The primary PK endpoints were area under the curve (AUC) of the concentration-time curve from zero to last quantifiable concentration (AUC_0-t), AUC from zero to infinity (AUC_0-∞), and peak concentration (C_max). Bioequivalence was determined by assessing whether the 90% confidence intervals (CIs) for the geometric mean ratio (GMR) of LZM003 to reference drug fell within predefined margins of 80% -125%.

Results

Forty-eight subjects (24 males and 24 females) were enrolled and one subject withdrew for personal reasons. Mean values of primary PK parameters were similar (p > 0.05) between LZM003 and the reference drug. The 90% CIs for primary PK endpoints' GMR of LZM003 to reference drug ranged between 0.9144 and 1.1845, which were within bioequivalence margins of 80-125%. Incidence of AEs was similar (p > 0.05) between the two groups. Neither LZM003 nor reference drug produced anti-drug antibody (ADA) in healthy subjects.

Conclusion

LZM003 and reference drug were bioequivalent. The PK and safety assessments were similar (p > 0.05) between the two formulations in healthy Chinese subjects.

Trial Registration Number

ChiCTR-IIR-16010158 (http://www.chictr.org.cn).

Trial Registration Date

December 15, 2016.

Mass spectrometry-based qualitative and quantitative N-glycomics: An update of 2017-2018

N-glycosylation is one of the most frequently occurring protein post-translational modifications (PTMs) with broad cellular, physiological and pathological relevance. Mass spectrometry-based N-glycomics has become the state-of-the-art instrumental analytical pipeline for sensitive, high-throughput and comprehensive characterization of N-glycans and N-glycomes. Improvement and new development of methods in N-glycan release, enrichment, derivatization, isotopic labeling, separation, ionization, MS, tandem MS and informatics accompany side-by-side wider and deeper application. This review provides a comprehensive update of mass spectrometry-based qualitative and quantitative N-glycomics in the years of 2017-2018.

Proteomics for cancer drug design

Introduction: Signal transduction cascades drive cellular proliferation, apoptosis, immune, and survival pathways. Proteins have emerged as actionable drug targets because they are often dysregulated in cancer, due to underlying genetic mutations, or dysregulated signaling pathways. Cancer drug development relies on proteomic technologies to identify potential biomarkers, mechanisms-of-action, and to identify protein binding hot spots. Areas covered: Brief summaries of proteomic technologies for drug discovery include mass spectrometry, reverse phase protein arrays, chemoproteomics, and fragment based screening. Protein-protein interface mapping is presented as a promising method for peptide therapeutic development. The topic of biosimilar therapeutics is presented as an opportunity to apply proteomic technologies to this new class of cancer drug. Expert opinion: Proteomic technologies are indispensable for drug discovery. A suite of technologies including mass spectrometry, reverse phase protein arrays, and protein-protein interaction mapping provide complimentary information for drug development. These assays have matured into well controlled, robust technologies. Recent regulatory approval of biosimilar therapeutics provides another opportunity to decipher the molecular nuances of their unique mechanisms of action. The ability to identify previously hidden protein hot spots is expanding the gamut of potential drug targets. Proteomic profiling permits lead compound evaluation beyond the one drug, one target paradigm.

Human chorionic gonadotrophin pharmaceutical formulations of urinary origin display high levels of contaminant proteins-A label-free quantitation proteomics study

To determine whether there is a measurable protein background in different formulations of urinary and recombinant human chorionic gonadotropin (hCG). Primary outcome measures: identification of contaminant proteins in urinary‐derived formulations of hCG; secondary outcome measures: quantitative values of contaminant proteins in different batches of urinary –derived hCG formulations. It was found that urinary‐derived batches have high presence of contaminant proteins beside the active substance. The relative amount of contaminant proteins and hCG differs strongly between different batches.