New USP Research Shows MAM As Alternative To Conventional Methods

By Diane McCarthy, Ph.D., United States Pharmacopeia

Recent United States Pharmacopeia (USP) research evaluating the performance of an emerging analytical approach called the multi-attribute method (MAM) could help pave the way for increased regulatory acceptance and industry adoption of MAM to identify and characterize critical quality attributes of biologics and biosimilars more efficiently and effectively.

USP’s research comparing MAM with conventional methods for quality control testing of biotherapeutics showed that it yielded comparable quantitation of product variants, provided superior specificity, and detected molecular modifications that were not detected or could not be readily resolved using conventional methods. At the same time, a single MAM analysis was able to replace multiple conventional methods, providing greater efficiency and the potential to reduce biotherapeutics development times and related costs.

Biotherapeutics Quality In Focus

The MAM research was conducted by USP under a two-year, $1.5 million grant through the FDA Biosimilars User Fee Act (BsUFA) III Regulatory Research Pilot Program.

The USP study addressed the BsUFA III program’s goal of exploring how advanced analytical technologies and increased reliance on analytical data could facilitate better and/or more efficient quality assessments of biosimilars. Biosimilars are biologic medications that are analytically highly similar to previously available reference biologics with no clinically meaningful differences – roughly analogous to generic versions of small molecule drugs. Since biotherapeutic products are large molecules with complex structures, they have the inherent potential to contain variations or modified molecular structures that can affect product purity, stability, biological activity, and overall quality. Detecting such variants can help ensure biotherapeutic products are safe and work as intended.

USP presented a poster on the research during an FDA BsUFA III public meeting on September 18.

What Is The Multi-Attribute Method?

Conventional quality control strategies can require over a dozen different analytical tests – including chromatographic and electrophoretic assays – to identify and monitor critical quality attributes of complex biotherapeutics. However, a common form of MAM introduced in the last decade and used by manufacturers combines liquid chromatographic separation with mass spectrometry (MS) detection to simultaneously measure multiple protein modifications in a single assay or test, offering the potential to replace multiple conventional analytical tests and to improve efficiency. The process is aided by software for examining this rich source of data and monitoring both expected and unexpected attributes throughout a product's life cycle.

Since MS is better able to discriminate between molecular entities than traditional techniques, this approach can provide manufacturers with more detailed insights into the impact of molecular modifications on product quality.

Data Could Facilitate Method’s Adoption

In recent years, MAM’s advantages have helped it gain traction in biotherapeutic development and quality control labs to streamline lab work and decrease development times. However, previously, there was a lack of publicly available data directly comparing conventional methods to MAM that could facilitate broader adoption and regulatory decision-making.

USP’s study comparing MAM to conventional methods will provide a publicly available, confidence-building data set that could facilitate adoption of MAM by more stakeholders and help support regulatory decision-making. FDA’s BsUFA III Regulatory Research Pilot Program Research Roadmap notes that “more confidence” from analytical assessments of biosimilarity “may decrease the need and, thus the time and resources required for, additional preclinical and/or clinical similarity data.”

Reduced time and effort needed for data collection, made possible in part by MAM’s innate potential to increase the efficiency of biosimilars quality assessments, ultimately could help accelerate biosimilars development, reduce industry costs, and benefit more patients. Biosimilars bolster marketplace competition and are typically less costly than their reference biologics – not unlike generic versions of small molecule drugs – which can help improve patient access.

Multi-Attribute Versus Conventional Testing

USP’s analysis focused on the performance of MAM versus conventional analytical methods for evaluation of the quality attributes of two common types of biologics – monoclonal antibodies (mAbs) and “Fc fusion” proteins. Fc fusion proteins combine the fragment crystallizable (Fc) region of an antibody with another protein or peptide to enhance its therapeutic properties.

USP’s evaluation utilized the anti-inflammatory biologics adalimumab and etanercept as representative examples of mAb and Fc fusion protein therapeutics, respectively. The assessment included adalimumab and etanercept originator products (with the brand names Humira and Enbrel, respectively), as well as corresponding biosimilars and research-grade products. Each of the samples were subjected to forced degradation – including thermal and chemical stress – to induce the kinds of molecular changes that could be used to compare quality assessment methods.

MAM compared favorably to conventional methods, providing more detailed, site-specific information on modifications and enabling detection and quantitation of some modifications that could not be detected using conventional methods. During USP’s study, some limitations were observed in the analyses of etanercept using both MAM and conventional methods, specifically for detection of carbohydrate chains called glycans. Conventional methods were unable to distinguish glycans from multiple locations within the molecule. MAM was able to resolve this issue but was unable to reliably detect a subset of glycans that contained sialic acid. Therefore, a conventional assay may also be needed for quality assessments of biotherapeutics that contain sialic acid.

USP is preparing the full research results for publication in multiple peer-reviewed journals within the coming months and anticipates portions of the final report will also be released by FDA in the near future. 

Other Tools Supporting MAM Adoption

As innovations in biotherapeutic medicine continue to advance, new analytical tools and methods for understanding quality like MAM will also be central to fully realizing their promise. Beyond the new MAM research, USP solutions to help address potential barriers to MAM adoption include a recently published standard that describes considerations and best practices for the use of MAM to help ensure the quality of therapeutic proteins, titled USP General Chapter <1060> Mass Spectrometry-Based Multi-Attribute Method for Therapeutic Proteins. USP is also developing physical reference standards to further support industry stakeholders that may wish to pursue MAM adoption.

Combined with other USP standards and tools for biologics and biosimilars quality testing, this work helps support regulatory predictability and the ability of manufacturers to operate with a high level of confidence and certainty throughout the drug development and approval process. USP will continue to engage stakeholders and explore opportunities for developing quality-focused tools and solutions to support biologics and biosimilars development.

To learn more about USP’s work to support the quality of biologics and biosimilars, click here.

About The Author:

Diane McCarthy, Ph.D., is vice president of Global Biologics at USP where she leads development and maintenance of standards and tools to support the quality of medicines and oversees the USP biologics laboratories in the U.S. and India. Her team supports standards and tools across a diverse range of therapies, including vaccines, peptides, cell and gene therapies, monoclonal antibodies, and other protein therapeutics.