Partnering for Bioanalytical Studies

Bioanalytical studies are an important aspect in biologic drug development because data from these studies are needed to define the characteristics of potential new biologics. Bioanalyses data are also an important inclusion in regulatory filings, driving the need for outsourcing partners with in-depth bioanalytical experience and experience interacting with regulatory authorities. 

Pharmaceutical Technology spoke with Robert Kernstock, PhD, director, Immunoassay Laboratory Services at ICON, and Neelanjan Bose, PhD, Director of Bioanalytical Chemistry at Emery Pharma, both contract research organizations (CROs), about the need for bioanalytical testing programs and regulatory strategies for potential new biologics.

Importance of bioanalytical studies

PharmTech: Why is it so important to conduct bioanalytical studies during the development process of a new biological therapeutic?

Bose (Emery Pharma): Bioanalytical studies, which are designed to provide estimates for concentration of drugs and biologics in pre-clinical and clinic studies of the therapeutic molecule or their metabolites, are critical for various aspects of human clinical pharmacology, studies related to bioavailability (BA)/bioequivalence (BE) evaluation, and some nonclinical studies requiring concentration information for pharmacokinetics, toxicokinetics, or biomarkers. Bioanalytical work serves to supplement pivotal studies and aid in the decision-making process for approval, safety, and/or labeling of a drug or biologic; in short, without proper bioanalytical data, the therapeutic product would not be approved. 

Kernstock (ICON): Beyond the regulatory requirements for conducting bioanalytical studies, the scientific importance of the data that these assays generate is invaluable. Bioanalytical assays provide information on certain safety aspects of the therapeutic in determining the maximum tolerated dose. Pharmacokinetic (PK) scientists use the data to determine exposure, half-life, and other pharmacological parameters, which are used to guide decisions on how often and how much of a therapeutic should be given for efficacy without undue toxicity. 

Bioanalytical assays extend beyond simply measuring drug concentrations over time but are also used to assess drug efficacy by way of pharmacodynamic (PD) endpoints (i.e., biomarkers). Biomarker assay results may provide early indicators of efficacy, or even safety issues. They can also be used to stratify patients to predict responders or non-responders.  Another key bioanalytical assay for biotherapeutics is the assessment of immunogenicity (both wanted and unwanted). For vaccine development, a positive immunogenicity result may be considered to be potential evidence that the vaccine is working as intended. Unwanted immunogenicity is much more complicated as the impact of anti-drug antibodies may influence the pharmacokinetics, efficacy, and safety, and has to be looked at down to the individual patient level.

Regulatory particulars

PharmTech: What type of data/information in particular do global regulatory authorities require from bioanalytical studies?

Kernstock (ICON): For any regulated bioanalytical study to occur, a validated method is required. FDA has issued guidance documents detailing the scope of bioanalytical method validation required for PK/PD endpoints, but it is also important to consider other regional guidance documents (e.g., European Medicines Agency, Pharmaceuticals and Medical Devices Agency [Japan], Agência Nacional de Vigilância Sanitária [Anvisa] [Brazil], etc.) when conducting method validations. The general assessments for method validation consist of accuracy, precision, selectivity/specificity, linearity, robustness, and stability.  

Depending on the type of assay, certain parameters may be added or removed to meet the assays’ context-of-use, and the analytical acceptance criteria may also vary. For immunogenicity assays, a statistical report or summary is required to justify your cut point(s). A well-described validation plan detailing the experiments and a priori acceptance criteria should be written and approved resulting in a bioanalytical report summarizing the experiments in tables, descriptions of deviations, and any pertinent conclusions. A quality statement from a quality assurance unit is typically included in the report for any regulated work. 

Once the methods are validated, the sample analysis commences that follows bioanalytical plans and/or standard operating procedures (SOPS). The reported data typically contain information on subject (or animal) number, dose/treatment group, time point, and analytical result. A listing of assay performance characteristics, which include tables of assay control results, run summaries, and calibration curve results, are typically provided. Additional information, such as incurred sample reanalysis results and sample condition (e.g., hemolyzed) may also be included.

Bose (Emery Pharma): On a broader perspective, FDA requires PK, toxicokinetic, or biomarker concentration evaluation through bioanalytical studies. It is critical that the data [are] generated via phase-appropriately validated methods (i.e., the methods are ‘fit-for-purpose’) and in many cases adhere to Code of Federal Regulations (CFR), 21, Part 58 (21 CFR 58), Good Laboratory Practice for Nonclinical Laboratory Studies (1). These involve much experimentation, data curation and storage, quality review, personnel training, and generation of SOPs-all related documentation should be available for review by FDA, along with the bioanalytical report. 

On a global scale, requirements and expectations around regulated bioanalysis generally follow the same thread as FDA, but with specific regional differences. Most jurisdictions have independent bioanalytical method validation guidance. 

Early development considerations

PharmTech: What types of approaches or strategies are best to plan out early on in the drug development process? 

Bose (Emery Pharma): Bioanalytical studies are challenging to design and plan properly at the onset of the drug/biologic development process, as they involve samples from multiple pre-clinical species, tissue types, and human-derived samples with a diverse (and in most cases unknown) genetic and metabolic makeup. The bioanalytical methods need to be robust enough to work with the variability that comes with such a diverse set of samples. 

It is thus important to anticipate these challenges early on while in the R&D phase, and develop sample preparation protocol(s) and method(s) that can work with such diverse types of samples, varying sample amounts, and be able to account for less-than-ideal sample handling during shipment and storage. It is also preferable to start the method validation process early that ensures that the data are reliable. While FDA guidance suggest that the level of validation should be appropriate for the intended purpose of the study, it is often helpful and cost-effective in the longer term to expand validation a bit beyond that so as to get better prepared for the later development process.  

Kernstock (ICON): Early in clinical development, it is important to understand the context-of-use for your bioanalytical assays, what type of therapeutic you have, and how your clinical studies are going to evolve. For instance, if you think your lowest effective concentration of your therapeutic is 500 µg/mL (trough levels), then developing an immunogenicity assay that is tolerant to high levels of therapeutic would be a critical consideration early in development. Whether or not your Phase I study is going to be in patients or healthy volunteers is another important consideration. 

Similarly, the disease-state biomarker assays may require different sensitivities than if it was in a normal population. Understanding the sensitivity requirements for your PK assay is also important. Intravenous administration of the therapeutic may require a less sensitive assay in your serum samples, whereas an ocular injection of the therapeutic will require a very sensitive serum PK assay to measure circulating drug levels. When conducting a preclinical toxicology study, the PK assay may not need a very low limit of quantitation since the therapeutic will be dosed at high(er) levels, and the immunogenicity assay may not have a confirmatory tier as an immune response is expected from a foreign protein. Perhaps you have a novel cell therapy, and a flow cytometer is used to collect ‘cellular kinetics’. This means special handling instructions to analyze the samples within the demonstrated stability window, or the use of additives in the collection tube to stabilize study samples.   

Best practices

PharmTech: Are there any ‘best practices’ procedures or steps you can recommend for beginning a bioanalytical study program for a new therapeutic?

Kernstock (ICON): There are a few best practices to consider, including identifying an appropriate blank matrix pool, testing disease-state selectivity as early as possible, and having a good supply of excellent critical reagents identified and appropriately characterized. Addressing these considerations will go a long way to avoiding future analytical headaches. Understanding the mechanism of action of your drug and how it relates to the sample is a critical assessment. For instance, if the drug target is a soluble cytokine that is abundant in serum and plasma, don’t be surprised if your selectivity experiment fails. More importantly in that case, what matrix pool are you using for your standard curve? Is the pool stripped of the cytokine, or did you use a surrogate matrix that doesn’t contain the interfering molecule?  

Bose (Emery Pharma): FDA’s 2018 guidance on bioanalytical method validation (2) is a great place to start. Additionally, while still in draft form, the International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use (ICH) M10 Bioanalytical Method Validation guidance (3) has been a decade-long collaborative initiative of analytical sciences and regulatory agencies around the globe; it is among the best resource currently available to plan for, and design bioanalytical studies.

Expert partnership benefits

PharmTech: Why is it important, or even necessary, for some biopharma companies to partner with an outsourcing partner for the purpose of bioanalytic studies?

Bose (Emery Pharma): Method development in bioanalytical studies is a black box to many, requiring intense training and somewhat intuitive understanding of how analytes behave in diverse biological matrices. It is important to note that, unlike standard analytical studies, bioanalyses involve highly complex and largely undefined biological matrices, with likely millions of compounds that can interfere with specific and accurate concentration evaluation. 

The required knowledge and expertise to successfully navigate bioanalytical studies may not be acquired quickly in-house, particularly when the regulatory landscape around bioanalyses changes regularly. Additionally, most bioanalytical studies are moving towards mass spectrometry (MS)-based analyses, which involve instrumentation that is too expensive to acquire for many companies and require specialized training for use and data analyses. 

Furthermore, most bioanalytical studies involve conducting the work under good laboratory practice (GLP), thus, the analytical laboratory must adhere to 21 CFR 58. This requires companies having a quality system in place, regular audit of the facility, maintaining documentation, training records, instrument qualification, and so on, all of which often becomes too cumbersome for many biopharma companies with limited operational budget. It is thus much simpler to partner with a CRO with expertise in bioanalyses, which already have an established quality system and the required experience in interaction and data presentation to FDA and other regulatory bodies.  

Kernstock (ICON): Partnering with contract laboratories can be extremely beneficial, and there are a number of reasons for doing so. The capacity in your own lab may have been exceeded and the need to outsource work to a partner lab would be necessary. Your own lab may be lacking in certain analytical equipment or experience, and a contract lab would be able to provide that service and expertise. CROs are particularly useful to smaller biotechs as the CROs can provide valuable consulting services and an expanded scope of service offerings such that they can be a ‘one-stop-shop’ for all of your bioanalytical needs. CROs have a very deep understanding of bioanalysis based on the number and diversity of assays they have developed. This is reflected in their scientific expertise as well as their understanding of global regulatory practices, since they are more frequently audited by multiple regulatory agencies; these factors end up benefiting all of their clients.

References

1. CFR Title 21, Part 58 (Government Printing Office, Washington, DC). 
2. FDA, Bioanalytical Method Validation Guidance for Industry (CDER, May 2018).
3. ICH, M10 

 (Feb. 26, 2019). 

Article Details

Pharmaceutical Technology
Vol. 44, No. 6
June 2020
Pages: 54–58

Citation

When referring to this article, please cite it as F. Mirasol, “The Importance of Partnering for Bioanalytical Studies,” Pharmaceutical Technology 44 (6) 2020.