Physicochemical and functional characterization of MYL-1501D, a proposed biosimilar to insulin glargine

Modeling sex-specific whole-body metabolic responses to feeding and fasting

Men generally favor carbohydrate metabolism, while women lean towards lipid metabolism, resulting in significant sex-based differences in energy oxidation across various metabolic states such as fasting and feeding. These differences are influenced by body composition and inherent metabolic fluxes, including increased lipolysis rates in women. However, understanding how sex influences organ-specific metabolism and systemic manifestations remains incomplete. To address these gaps, we developed a sex-specific, whole-body metabolic model for feeding and fasting scenarios in healthy young adults. Our model integrates organ metabolism with whole-body responses to mixed meals, particularly high-carbohydrate and high-fat meals. Our predictions suggest that differences in liver and adipose tissue nutrient storage and oxidation patterns drive systemic metabolic disparities. We propose that sex differences in fasting hepatic glucose output may result from the different handling of free fatty acids, glycerol, and glycogen. We identified a metabolic pathway, possibly more prevalent in female livers, redirecting lipids towards carbohydrate metabolism to support hepatic glucose production. This mechanism is facilitated by the TG-FFA cycle between adipose tissue and the liver. Incorporating sex-specific data into multi-scale frameworks offers insights into how sex modulates human metabolism.

Basic regulatory science behind drug substance and drug product specifications of monoclonal antibodies and other protein therapeutics

In this review, we focus on providing basics and examples for each component of the protein therapeutic specifications to interested pharmacists and biopharmaceutical scientists with a goal to strengthen understanding in regulatory science and compliance. Pharmaceutical specifications comprise a list of important quality attributes for testing, references to use for test procedures, and appropriate acceptance criteria for the tests, and they are set up to ensure that when a drug product is administered to a patient, its intended therapeutic benefits and safety can be rendered appropriately. Conformance of drug substance or drug product to the specifications is achieved by testing an article according to the listed tests and analytical methods and obtaining test results that meet the acceptance criteria. Quality attributes are chosen to be tested based on their quality risk, and consideration should be given to the merit of the analytical methods which are associated with the acceptance criteria of the specifications. Acceptance criteria are set forth primarily based on efficacy and safety profiles, with an increasing attention noted for patient-centric specifications. Discussed in this work are related guidelines that support the biopharmaceutical specification setting, how to set the acceptance criteria, and examples of the quality attributes and the analytical methods from 60 articles and 23 pharmacopeial monographs. Outlooks are also explored on process analytical technologies and other orthogonal tools which are on-trend in biopharmaceutical characterization and quality control.

Comparative physicochemical and structural characterisation studies establish high biosimilarity between BGL-ASP and reference insulin aspart

Biosimilar insulin analogues are increasing market access for diabetic patients globally. Scientific establishment of biosimilarity is cornerstone of this key change in the medical landscape. BGL-ASP is a biosimilar insulin aspart developed by BioGenomics Limited, India. BioGenomics has considered a stepwise approach in generating the totality of evidence required to establish similarity with reference product. Insulin aspart is a recombinant rapid-acting human insulin analogue utilised in the treatment of type-1 and type-2 diabetes mellitus. The single amino acid substitution at position B28 where proline is replaced with aspartic acid results in a decreased propensity to form hexamers, thus increasing the absorption rate on subcutaneous administration compared to native insulin. In order to establish the safety and efficacy of BGL-ASP, the critical quality attributes (CQAs) of BGL-ASP are identified based on the impact created on biological activity, pharmacokinetic/pharmacodynamic (PK/PD), immunogenicity and safety. The CQAs of insulin aspart are related to product structure, purity and functionality and are characterised using a series of state-of-the-art orthogonal analytical tools. The primary protein sequence, the secondary, tertiary and quaternary structure are found to be highly similar for BGL-ASP and reference product. The product related impurities of insulin aspart and the assay content are determined using high performance liquid chromatography (HPLC) based analysis and is similar for BGL-ASP and reference insulin aspart sourced from United States of America (US), Europe Union (EU) and India. The safety, efficacy and immunogenicity of BGL-ASP is also found to be comparable with reference product and is confirmed through the clinical trials conducted as recommended by International Council for Harmonisation of Technical Requirements of Pharmaceuticals for Human Use (ICH) and European Medicines Agency (EMA) guidelines. The data encompassed in this study demonstrates that reference insulin aspart and BGL-ASP are highly similar in terms of structural, physicochemical, and biological properties, thus confirming its safety and efficacy for usage as potential alternative economical medicinal treatment for diabetes mellitus.

Protocol to Assess the Biological Activity of Insulin Glargine, Insulin Lispro, and Insulin Aspart In Vitro

Insulin is a hormone produced by β-cells of the pancreas and controls the amount of sugar in the blood. Since its discovery over 100 years ago, insulin has been used as a life-saving treatment for people with diabetes. Historically, the biological activity or bioidentity of insulin products has been assessed using an in vivo model. However, reduction in animal experiments is a goal for many worldwide, and there is a need to develop in vitro bioassays to reliably test the biological activity of insulin products. This article describes an in vitro cell-based method to assess the biological activity of insulin glargine, insulin aspart, and insulin lispro in a step-by-step manner.

Assessing the Structural and Functional Similarity of Insulin Glargine Biosimilars

BACKGROUND

A biosimilar product is expected to exhibit similar safety, efficacy, and quality as that of the approved reference product. Only a few reports of thorough evaluation of the quality of insulin glargine biosimilars are available in literature. Here, we examine the structural and functional similarity of biosimilars of insulin glargine, the first basal long-acting insulin analogue with respect to its innovator product (Lantus^® from Sanofi Aventis).

METHODS

Structural similarity was established using mass spectrometry, chromatographic, and spectroscopic techniques. Stability was compared by performing accelerated thermal stress studies. Functional similarity was established via in vitro assay.

RESULTS

Biosimilar 4 exhibited greater content of high molecular weight species (HMWs) (0.80%) and related substances (RS) (0.45±0.06%) vs others (HMWs of 0.04% and RS of 0.17%). Biosimilars 1 and 3 exhibited higher rate of impurity generation (0.78% and 0.73% per week, respectively), as compared with other drug products (0.02% to 0.43% per week). Furthermore, %aggregation at 14 days was found to statistically correlate (R²= 0.99, root mean square error (RMSE) = 0.095) with %aggregation at 0 day (linearly) and the number of months from expiry (nonlinearly), highlighting the overpowering impact of the latter.

CONCLUSIONS

While an overall structural and functional similarity was observed across insulin glargine biosimilars with respect to the innovator product, low amounts of product-related variants were seen in some biosimilars and these impact product stability. The %aggregation at 14 days exhibits statistical correlation with %aggregation at 0 day and the number of months from expiry. The order of biosimilarity was denoted as Lantus^®>Biosimilar 2>Biosimilar 4>Biosimilar 1>Biosimilar 3.

Single-chain insulin analogs threaded by the insulin receptor αCT domain

Insulin is a mainstay of therapy for diabetes mellitus, yet its thermal stability complicates global transportation and storage. Cold-chain transport, coupled with optimized formulation and materials, prevents to some degree nucleation of amyloid and hence inactivation of hormonal activity. These issues hence motivate the design of analogs with increased stability, with a promising approach being single-chain insulins (SCIs), whose C domains (foreshortened relative to proinsulin) resemble those of the single-chain growth factors (IGFs). We have previously demonstrated that optimized SCIs can exhibit native-like hormonal activity with enhanced thermal stability and marked resistance to fibrillation. Here, we describe the crystal structure of an ultrastable SCI (C-domain length 6; sequence EEGPRR) bound to modules of the insulin receptor (IR) ectodomain (N-terminal α-subunit domains L1-CR and C-terminal αCT peptide; "microreceptor" [μIR]). The structure of the SCI-μIR complex, stabilized by an Fv module, was determined using diffraction data to a resolution of 2.6 Å. Remarkably, the αCT peptide (IR-A isoform) "threads" through a gap between the flexible C domain and the insulin core. To explore such threading, we undertook molecular dynamics simulations to 1) compare threaded with unthreaded binding modes and 2) evaluate effects of C-domain length on these alternate modes. The simulations (employing both conventional and enhanced sampling simulations) provide evidence that very short linkers (C-domain length of -1) would limit gap opening in the SCI and so impair threading. We envisage that analogous threading occurs in the intact SCI-IR complex-rationalizing why minimal C-domain lengths block complete activity-and might be exploited to design novel receptor-isoform-specific analogs.

The Coming of Age of Biosimilars: A Personal Perspective

Biosimilars have come of age over the past 17 years, with 84 approvals in the EU and 35 in the US, representing almost 90% of the world market. While the acceptance of biosimilars in the US is catching up with that in the EU, the cost benefits remain elusive due to the high development barrier and complex distribution system involved, mainly in the US. In the EU, the cost of biosimilars has already dropped 70% or more, and interchangeability is a routine in some European jurisdictions, unlike in the US, where a separate regulatory approval is required. This paper projects significant changes coming in the US and EU’s biosimilars approval requirements that will impact the approval procedures in the rest of the world, leading to dramatic changes in the cost of biosimilars to patients. This perspective is based on the author’s first-hand experience to secure FDA approvals of biosimilars and an extensive analysis of the rationality of testing to demonstrate biosimilarity. Multiple citizen petitions by the author and meetings with the FDA may have prompted the recent announcement by the FDA to award a $5 million research grant to scientists to develop novel testing models to establish biosimilarity, including modifying the interchangeability protocols. Soon, demonstration of biosimilarity will not require animal testing and, in most cases, clinical efficacy testing; over time, the clinical pharmacology testing will be reduced as the regulatory agencies develop more confidence in the safety and efficacy of biosimilars. Biosimilars have come of age; now it is the turn of the developers to grow up, and one way to show this is to challenge the current regulatory guidelines but only on scientific grounds to seek more concessions, for which both FDA and EMA are ready.