Imagine the human body as a complex machine, with countless processes and reactions happening every moment. Biomarkers are the measurable signs that reveal the state of this machine - whether it’s operating perfectly, under stress, or in the process of healing. They are found in our blood, tissues, and even the air we exhale, serving as clues to understanding normal biological pathways, disease mechanisms, and how we respond to medication.
Some biomarkers help diagnose diseases, while others monitor the progress of a condition or predict how a patient may respond to a treatment. The Biomarkers, Endpoints, and Other Tools (BEST) Resource - classifies them into several categories. Each biomarker type serves a specific purpose in the context of disease diagnosis, management, and treatment, highlighting biomarkers’ versatile role in advancing medical knowledge and improving patient care. Biomarker categories include:
- Diagnostic: Used to identify the presence of a particular disease or condition.
- Surveillance: Used to monitor the status of a disease or condition over time.
- Pharmacodynamic/Response: Indicates the body’s biological response to a therapy.
- Predictive: Helps predict a patient’s likely response to a particular treatment.
- Prognostic: Indicates the overall outcome of a disease, regardless of treatment.
- Safety: Indicates the potential for toxic effects of drug candidates and other therapies.
- Sensitivity/Risk: Indicates an individual’s susceptibility to a disease or condition.
As scientists continue to explore and validate these indicators, they open new avenues for diagnosis, treatment, and the personalized care that is becoming the hallmark of modern medicine. We’ll dig into the specifics of biomarker validation and showcase how the bioanalytical team at WuXi AppTec validated four indicators and contributed to better medical research and patient care.
The Regulatory Landscape
Once regulatory authorities recognized biomarkers’ immense potential, they highlighted their role in revolutionizing drug development in a landmark 2004 white paper, “Innovation/Stagnation: Challenges and Opportunities in the Critical Path of New Medical Products.” In its analysis, they concluded that biomarkers could significantly enhance the research and development of new medications and urged for their continued use as drug development tools. This marked a pivotal moment, acknowledging that biomarkers could streamline the path to bringing new, effective treatments to patients.
Despite widespread use and importance, the regulatory framework for biomarkers is not one-size-fits-all. Regulatory agencies worldwide have noted the complexity of biomarkers and their challenges in method validation - a crucial step in ensuring that biomarker measurements are accurate and reliable.
New guidance on bioanalytical method validation in 2018, introduced a flexible approach called “fit-for-purpose” (FFP), which is tailored to the specific needs and stages of each drug’s development path. This flexibility is fundamental in drug development, ensuring that the level of method validation aligns with the study’s objectives.
Regulatory authorities mandate comprehensive method validation for critical studies affecting regulatory decisions, like those supporting new drug applications (NDAs) or biologics license applications (BLAs). Conversely, for exploratory phases, such as early drug development or candidate selection, the extent of validation can be adjusted to meet specific needs. This tailored approach acknowledges biomarkers’ diverse roles and allows scientists to optimize resources and focus validation efforts where they are most impactful.
Develop an Approach to FFP and Practical Applications
Scientists hoping to develop an in-house biomarker method validation strategy could start with a structured approach. Divided into three levels, this structured approach categorizes each method based on the biomarker’s intended use. Levels may include:
- Establishing a non-GLP method: This initial level (1) may involve methods to gather evidence for exploratory concepts or hypotheses. These results would not be used for regulatory submission, simply for internal decision-making.
- Method confirmation: At this intermediate level (2), the method may be used for exploratory purposes, requiring the evaluation of several performance parameters. While the results are submitted to regulatory authorities, they are not used for critical decision-making.
- Method validation: This final level (3) would require full validation of all parameters per bioanalytical regulatory requirements. Results from these tests are submitted to regulatory bodies as secondary endpoints to assess drug efficacy.
Using advanced biological immunoassay platforms such as ELISA, MSD, Gyros, and Luminex, scientists could detect biomarkers across small molecules, proteins, cells, and genetic markers. As is apparent in later examples, cytokines, and disease biomarkers would be analyzed differently. These case studies demonstrate the practical application of the FFP validation approach and highlight how biomarkers have become vital tools in the fight against disease.
Biomarker 1 : IL-23, IL-22 & IL-17A (Level 3)
Psoriasis is a chronic skin condition that significantly affects quality of life. While mild to moderate cases may rely on topical treatments, more severe instances require systemic therapies, often including glucocorticoids. The disease is characterized by rapid skin cell growth and immune cell infiltration, with IL-23, IL-17, and IL-22 cytokines driving the inflammation. IL-23, in particular, plays a pivotal role in initiating this process by promoting the expansion of Th17 cells, which then produce inflammatory factors leading to the symptoms of psoriasis.
This methodological validation ensures accurate and precise measurement of these cytokines, crucial for understanding their role in psoriasis and evaluating treatment efficacy. The validated method demonstrates consistent performance, with accuracy and precision within acceptable ranges, and confirms the stability of these biomarkers in samples stored at ultra-low temperatures for up to 12 months.
Recent therapeutic advancements have focused on targeting IL-23, with the development of monoclonal antibodies that bind specifically to a component of IL-23, showing promise in treating plaque psoriasis.
Biomarker 2: Total GLP-1 & Active GLP-1 (Level 3)
Changes in diet and lifestyle around the world have amplified the social and health challenges associated with overweight conditions. This situation has spurred the growth of the weight loss industry, including the development of pharmaceutical solutions like GLP-1 (glucagon-like peptide-1) based drugs, which have become a hot topic in drug research and development.
GLP-1, naturally secreted by intestinal cells in response to food intake, regulates blood sugar levels and creates that “full” feeling, thereby aiding in weight loss. However, the effect of natural GLP-1 is fleeting due to rapid breakdown in the body. This limitation paved the way for developing synthetic GLP-1 drugs that are resistant to degradation and have extended activity, offering new strategies for treating Type II diabetes and aiding in weight management.
WuXi AppTec’s bioanalytical services division recently completed the full validation of Total GLP-1 and Active GLP-1 detection in P800 plasma using the Meso Scale Discovery (MSD) platform. This Level 3 validation ensures the method’s reliability for clinical sample analysis. The process demonstrated that both Total and Active GLP-1 could be accurately and precisely measured, with stability confirmed over 12 months at storage temperatures of -20 °C and -70°C.
Biomarker 3: TGF-β1 (Level 3)
Cancer is the leading cause of death around the world, with lung, colorectal, gastric, liver, and breast cancer among the most prevalent types. Within the tumor microenvironment (TME), a complex interplay of cancer cells and immune cells secrete growth factors like transforming growth factor-β (TGF-β), which are implicated in tumor growth, invasion, and resistance to therapy. Specifically, TGF-β, activated by Glycoprotein-A repetition predominant (GARP) found on cancer cells and regulatory T cells (Tregs) in the TME, is known for promoting cancer cell proliferation and evading anticancer treatments.
Understanding the mechanisms of TGF-β activation and its impact on cancer cells and the immune system is critical for developing effective cancer therapies. Advances in this area have led to the development of therapies targeting TGF-β, such as Bintrafusp alfa, Galunisertib, and Vactosertib, which are currently under clinical trials.
WuXi AppTec’s bioanalytical services division has fully validated the detection of TGF-β1 in K2EDTA plasma using the ELISA platform. This validation ensures the method’s reliability for analyzing clinical samples, which is crucial for assessing the efficacy of TGF-β targeted treatments. The validation process confirmed the method’s accuracy, precision, and stability of TGF-β1 in samples stored at -20°C and -70°C for up to 12 months.
Biomarker 4 : Cytokines IFN-γ, IL-1β, IL-2, IL 4,IL-6, IL-8, IL-10, IL-12p70, IL-13 & TNF-α (Level 2)
Cytokines, small proteins secreted by both immune and some non-immune cells, play crucial roles in the body’s immune response. However, their dysregulation can lead to severe conditions, such as a “cytokine storm,” an excessive immune reaction contributing to the progression of various diseases. It was notably a factor in the withdrawal of the drug Removab in 2017.
Recognizing the importance of cytokines as biomarkers for disease diagnosis, progression, and treatment efficacy, WuXi AppTec’s bioanalytical services division developed a comprehensive method for validating a panel of 10 cytokines, including IFN-γ, IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12p70, IL-13, and TNF-α, using the MSD platform (V-Plex kits). This method is inspiring, given its potential to advance precision medicine and personalized treatment strategies.
The WuXi AppTec team supported various cytokine combinations using different technology platforms, including Luminex, Simoa, and ELISA. This flexibility allows for developing and validating customized detection methods to meet specific client needs, further enhancing cytokines as sensitive indicators of inflammation and immune response.
The linearity range for the ten cytokines of completed validation is as follows:
A Final Word
Exploring biomarkers and implementing the FFP validation strategy reveal significant advancements in precision medicine. This article has highlighted the crucial role of biomarkers in drug development, the importance of regulatory guidance, and the innovative validation work carried out by one bioanalytical services team. These developments mark a critical step towards more personalized, effective treatments. As research progresses and collaborations expand, the potential for tailored patient care moves closer to becoming an everyday reality in healthcare.
About WuXi AppTec
As a global company with operations across Asia, Europe, and North America, WuXi AppTec provides a broad portfolio of R&D and manufacturing services that enable the pharmaceutical and healthcare industry around the world to advance discoveries and deliver groundbreaking treatments to patients. Through its unique business models, WuXi AppTec’s integrated, end-to-end services include chemistry drug CRDMO (Contract Research, Development, and Manufacturing Organization), biology discovery, preclinical testing, and clinical research services, and cell and gene therapies CTDMO (Contract Testing, Developme,nt and Manufacturing Organization), helping customers improve the productivity of advancing healthcare products through cost-effective and efficient solutions. WuXi AppTec received an AA ESG rating from MSCI in 2023 and its open-access platform is enabling more than 6,000 customers from over 30 countries to improve the health of those in need – and to realize the vision that “every drug can be made and every disease can be treated.”
Author Details
Peipei Liang, MS and Wenbi Chen, MS- WuXi AppTec
Wenbi Chen, MS is the Immunology Study Director/Principal Investigator/ Contribution Scientist at WuXi AppTec. She has a robust background in biology. In Wenbi’s current role as a group leader, she is in charge of new 18 | | July/August 2024 immunology assays, including method development, validation, and sample analysis in large molecular biology. Wenbi joined WuXi AppTec in July 2018 after graduating with her master’s in biochemistry and molecular biology from Ningbo University, where she published multiple articles in biological research and received one patent.
Peipei Liang, MS is the Group leader, Immunochemistry Principal Investigator/Study Director, overseeing the Biomarker Team within the Bioanalytical Services Department at WuXi AppTec. She has been with the company since 2016. Peipei is an experienced bioengineer with a master’s degree in biological engineering from the Huazhong University of Science and Technology.”
Publication Details
This article appeared in American Pharmaceutical Review: Vol. 27, No. 5 July/Aug 2024Pages: 14-18
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