F. John Mills

In the life sciences, there has always been a need to store biological materials such as blood samples and active pharmaceutical ingredients generated during research and drug development. Stored biomaterials can be used for a range of purposes, from medical education to examination of disease processes over time. In the biopharmaceutical industry specifically, there are many compelling reasons to store samples derived from clinical research, all of which have potential commercial, scientific, and medico-legal importance in drug development.  

However, despite sophisticated protocols that delineate all aspects of drug development, companies often overlook the critical step of developing a strategy for the specialized, long-term storage of biological samples. This represents a significant missed opportunity for many businesses because of the intrinsic value these samples can represent. Biotech and pharmaceutical companies, large and small, must take seriously the need to develop such strategies, which can help them: 					

react quickly to unexpected adverse reactions

identify new assay techniques or biomarkers.

A carefully planned sample management strategy will include considerations such as cold chain logistics and storage, a centralized sample inventory, and information management systems to track and manage data. These elements should be backed by a comprehensive audit trail showing exactly how samples were managed from collection to destruction, and they should be compliant with all applicable regulations. 

				This article outlines the commercial, scientific, and legal implications for storing biological samples from clinical research and suggests steps companies can take to develop "good storage practice."			

Stored samples can have a critical impact on the commercial viability of a drug in several ways. 

 Time is of the essence in drug development. A day lost in development is a day lost in the marketplace. Because one day during the product's peak sales may be worth millions of dollars, biopharm companies must investigate all options for working more efficiently and effectively. It may be necessary to start clinical work on a drug before the assay has been developed to an ideal level of precision or before metabolite assays have been fully developed. Stored clinical trial samples may then be used later for retrospective analyses once the assay has been fully developed and its accuracy and precision validated. 

Additionally, it is not uncommon for existing assay techniques to be improved upon further and made more sensitive during the course of a drug's development. For example, there may be a need for an assay with enhanced sensitivity if the drug has a long half-life or is widely distributed through the body so that it is only present in very low concentrations in plasma. Furthermore, active metabolites of the drug may be discovered after it has already been administered to many subjects, which would allow the metabolite to be developed instead of the original parent molecule. Again, in these situations, retrospective analyses of stored samples may eliminate the need to repeat a large number of studies and can reduce the resulting delays in development. 

All clinical studies must be conducted with the informed consent of the subjects, and the consent form associated with the protocol needs to make clear that samples may be stored and analyzed at some point in the future. The subject should also be able to withdraw their samples from future testing at any time. The use of stored samples to uncover genetic markers of predisposition to a disease has engendered much debate on how to handle patient consent under these circumstances. Clearly the ethical implications of discovering that a seemingly healthy person (and their healthy descendants) may develop a serious condition are very significant.

 One trend in the pharmaceutical industry has been that larger companies are in-licensing more and more compounds that are developed by much smaller biopharmaceutical companies or research centers. To ensure quality and perform due diligence, these larger companies may use the samples to re-examine analytical methods and re-assay specimens collected during early development of the drug. Confirmation of the findings from stored samples adds important financial value to the acquisition of the product. Hence, even small companies should have a clearly defined sample storage policy and process. 

 Because drug development is a long and protracted process, new biomarkers that further delineate disease processes may be discovered during the development phase. The impact of the drug on those biomarkers may be very important to understanding its efficacy and safety. However, these biomarkers may not have been discovered when the original development plans were written and the trials started. In this case, stored samples can be reanalyzed to look retrospectively at these effects and, at the very least, can help developers save time by designing better prospective trials of the drug. 

It is important that samples are maintained in the best possible condition and a history of the samples' storage kept in the greatest possible detail. For example, plasma samples should be stored at –70°C to –80°C without any freeze–thaw cycles, which could damage the integrity of the samples. Research has shown there is a minimal effect on protein in plasma stored at –70°C for four years, compared to samples that were thawed and refrozen.

In order to validate such results fully, it is also necessary to prove long-term stability of the biomarker under consideration. These tests can be run in parallel with the further clinical development of the drug. 

Proper sample storage can also have a significant impact on scientific research in several areas. 

 Over the years, stored samples have proved invaluable in establishing the natural history of diseases and their transmission. For example, analysis of stored samples from a variety of sources (including a plasma sample from an immune system study in the Congo in 1959,

  tissue samples from an American teenager who died in 1969,

  and samples from the NIH archives) have helped researchers learn more about the progression of HIV/AIDS. Scientists have been able to discover when the disease first appeared in humans, when it might have been introduced to various populations, and how it evolved. 

 There is a continuing discussion of the need for long-term storage of samples from blood transfusions to test for diseases that were not tested for, or were unknown or undetectable when the blood was collected. For example, infectious diseases like Bovine Spongiform Encephalopathy ("mad cow disease") can take years or even decades to incubate in humans. If an infected person donated blood several times, their blood could potentially infect many people. However, if transfusion samples were kept longer than the usual several weeks, it might be possible to test them in the future to determine if an individual contracted the disease through the blood transfusion and to determine who else might have been infected. 

Addressing the needs of unique populations.

 Different patients respond differently to drugs, may not respond at all, or may develop adverse effects. Because these groups will not be discovered until trials have been completed and unblinded, stored samples can be used for later analysis to see if there are biological reasons for the differences in patient response. For instance, a lack of response may be caused by genetic differences in the way the drug is metabolized. As the "genomic revolution" progresses, allowing scientists to use their understanding of the human genome to develop drugs targeted at populations with a specific genetic makeup, there has never been a more pressing reason to store samples. 

 Stored genomic material from patients with particular diseases may yield genetic clues as to how the disease may be treated and allow biopharmaceuticals to be designed and "targeted" specifically for the disease. For example, it is now possible to quantify the likelihood of breast cancer recurrence in women with newly diagnosed, early-stage breast cancer. In addition to predicting distant disease recurrence, the test on the disease tissue can assess the benefit from certain types of chemotherapy.

 DNA analysis is becoming increasingly important as a source of medical information. In the future, DNA banking will be a critical element in the design of therapies for many diseases. It is often said that "your genetic profile loads the gun but environmental factors fire it." DNA banking will allow the identification of these genetic factors and potentially provide targets for therapeutic products that could "disarm the gun" or protect from environmental triggers. 

Such ventures may well take up national resources. In fact, the UK Government has largely funded the UK Biobank, which is a long-term national project to build the world's largest information resource for medical researchers. It will follow the health of 500,000 volunteers aged 40–69 in the United Kingdom for up to 30 years.

The project will help approved researchers develop new and better ways of preventing, diagnosing, and treating common illnesses such as cancer, heart disease, diabetes, and Alzheimer's disease, with much of these advances being based on DNA analysis. In line with the discussion earlier on informed consent, the project has an established governance procedure to ensure that appropriate consents are obtained for future analysis of samples.

Recently, certain high-profile drugs have been withdrawn from the market due to unpredicted life-threatening adverse effects. These events have highlighted the need to retain samples from patients who received the drug during clinical trials. 

Clinical trial samples can be used to identify particular groups at high risk, especially if the medication was continued in responding patients at the end of the trial. The identification of such subgroups increases the safety of the drug and may prevent it from being removed from the market, which could cause billions of dollars in losses for the pharmaceutical company and deprive patients of its life-saving effects.

Recent damages awarded by courts to plaintiffs and potential litigation due to adverse effects are strong motivators for the industry to store samples, if only to help prove that adverse effects were truly unpredictable. 

There are several key components to an organization's good storage practice. 

 Because it may be years before samples are needed for future research, testing, or audits, specimens must be maintained in highly specialized and consistent conditions, often for decades. For example, scientists recently deciphered the genetic sequence of the devastating 1918 influenza virus using samples that had been preserved since that epidemic. To maintain sample integrity for such long periods of time, standardized, secure, and compliant storage is critical. Some factors that must be considered in defining sound storage practices include: 					

a facility capable of storing specimens at a wide range of temperatures, from ambient to vapor phase liquid nitrogen (–190°C)

reliable, state-of-the-art storage equipment

business continuity plans and redundant systems to protect sample integrity during emergencies.

 Biopharmaceutical manufacturers often store samples at multiple investigator centers and laboratories. In this situation, it can often take up to several weeks to locate specific samples when there is a regulatory request for more information or when further testing is required due to an unexpected effect of the drug. Because rapid response in this situation is in the best interest of all concerned, centralized specimen storage is an important consideration. 

 Cold chain logistics refers to the supply and distribution chain for products that must be kept within a specific low-temperature range. Maintaining the integrity of the cold chain requires logistics and management expertise to ensure that temperature-sensitive samples are constantly monitored and properly packaged so they do not degrade during packing, shipping, processing, and storage. Effective cold chain practices incorporate continuous monitoring and tracking systems to ensure that sample integrity is not compromised at any stage. 

Additionally, well-documented, centralized systems and processes as well as comprehensive inventory management and knowledge management strategies are critical to ensuring sample integrity. Without them, staff turnover can jeopardize sample integrity because of the loss of "knowledge" that occurs when employees leave an organization. Processes and procedures ensure uniform application of best practices and successful knowledge transfer. 

 Implicit in good storage practice is the associated documentation that verifies that samples have been stored in optimal conditions from collection to final retrieval. Complete electronic audit trails help prove the samples have not been compromised. For a comprehensive audit trail, continuous freezer temperature recording is required. 

As the volume of sample collections increases, there is a need for a well-designed sample or inventory management system capable of recording each specimen's: 									

exact location, from specific freezer to shelf and package position

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