High-throughput screening (HTS) is widely used in drug discovery. Its benefits, including simplicity, low cost, high efficiency, and speed, are well known. Almost as widely known is that biopharmaceutical companies are outsourcing significant portions of their discovery activities. According to a 2016 Kalorama Information report entitled “Outsourcing in Drug Discovery”, within the next five years, half of all drug discovery activities could be outsourced.

Outsourcing is not just a boon to the bottom line though. Contract research organizations (CROs) have wide-ranging expertise, extensive experience, and access to innovative technologies that can shorten the drug discovery process.

We asked four well-established and highly regarded CROs, AMRI, Charles River Laboratories, Evotec, and Icagen, to talk about their HTS services, what clients should look for in an outsourcing partner, what their specific expertise is, and what innovative technologies they are incorporating into their offerings now or see on the horizon.

Whether your HTS projects are handled in-house or outsourced, the insights shared in this article can help increase your HTS efficiency and save time and money.

What should clients look for when outsourcing HTS services? What are some of the qualities an ideal partner offers?

AMRI: The ideal partner will have access to more sophisticated and cutting-edge systems than those that are available internally to customers. These will be backed up by a scientific team skilled in the arts of assay development, screening, and drug discovery. For example, CROs using liquid handling and detection systems identical to those employed by biopharmaceutical companies for assay development provide a lower risk option for assay transfer and screening.

CROs extending these capabilities into high-throughput detection methods beyond those currently available to biopharma provide their clients with opportunities to explore new target classes and screen older ones under more physiologically relevant conditions. Some of these detection methods include HTS by MALDI-TOF/TOF mass spec, using systems like PharmaPulse, a technology platform that AMRI acquired from Bruker Daltonics and HighRes Biosolutions earlier this year.

The extreme sensitivity of Bruker's MALDI-TOF technology enables AMRI to execute thousands of assays an hour while providing a level of information that often exceeds traditional screening assays. The ultimate goal is to use these technologies to identify solid molecules that can be progressed into therapeutic development. CROs that are combining these technologies with medicinal chemistry and DMPK, an intellectual property protection culture, and extensive skills and capabilities for downstream hit-to-lead and lead optimization, provide a powerful option for virtual biotechs, non-profit organizations, academia, biopharma, and larger pharma organizations.

Charles River: The focus for any high-throughput screening (HTS) campaign has to be quality and attention to detail with a sound understanding of the underlying biology. As a customer, you should ask your provider to demonstrate an ability to develop or transfer an assay and generate reproducible, high-quality data under pharmacologically relevant conditions.

The ability to prosecute a wide range of targets with a broad range of assay platforms may be less important if you have a one-off project, where a niche provider may be the best choice. But if you are looking to build a long-term collaboration, the ability to cover as many bases as possible is preferable as it makes the hidden aspects of HTS less of a hurdle.

Generating HTS data is the easy part; the hidden parts are building a rapport with the project team members and making sure the data are analyzed, interpreted, and transferred in an appropriate form. If you have specific requirements and guidelines, you should only have to implement these once.

Additionally, with breadth of coverage comes depth of expertise, and with expertise comes the ability to troubleshoot a wide range of issues quickly and to add insight into the data. This should include providing assistance with hit calling. This insight adds value to your dataset above and beyond provision of a simple list of hits. That said, from any screen you can only identify hits if the compound is there to be screened. The composition of the screening library cannot be underestimated.

As we all know, communication is a huge influence in driving the success of a project. While the ability to communicate and interact with the scientific team and project manager is not something that can be quantified, it should be an important consideration when selecting your screening partner. Questions you should ask yourself include:

  • Is the partner willing to introduce you to members of a typical project team?
  • If yes, do you get the sense that the scientific and technical strength runs throughout the team?
  • Are you able to talk openly with the technical team and feel they understand your project and the specific requirements?
  • How do you think the provider will respond if things go wrong? Will they pick up the phone or email, rather than wait for the next project team meeting?

Evotec: As HTS is a first entry point into drug discovery it needs to be made sure that the technology platform applied provides an optimal source for hit tractability, e.g., low attrition, minimum of falses (positives and negatives). Comprehensiveness on screening technologies and flexibility on assay systems, lab automation, and compound handling are important elements for a smooth project start or project transition together with an attractive chemical library to screen against (partner and client). In addition, speed and cost of execution are of pivotal relevance for a successful partnership together with trustful project management at the partner’s end.

Icagen: Porting an assay from one lab to another lab is always a challenging exercise. It is even more critical when establishing a screen because of the costs associated with large volumes of reagents. It is important that the HTS vendor is able to take an assay and optimize it in high-density formats and then demonstrate the performance of the assay to meet strict performance criteria. It is important that they have historical experience performing this assay adaptation and validation activity.

The expertise of an ideal partner is critically important. When engaging with partners on HTS, partners should expect that the provider has more than 10 years of experience preferably within a pharmaceutical industry setting. The vendor should be able to provide the ability to miniaturize assays to 1536 wells and demonstrate that the assay is robust and as reproducible as performed in other density configurations. High density not only enables high throughput, but it also enables reduced assay volume, which will drive HTS costs. The cost of a 200,000 compound screen performed in 384 well plates using reagents that cost $75,000 dollars could be miniaturized to 1536 wells, which would reduce the reagent costs to less the $25,000 for the screen.

Vendors should be able to perform hit confirmation follow up and dose response of all active molecules identified in the screen. In addition they should be able to perform QC by mass spectroscopy to ensure that the molecules identified actually correspond to the identity of the compound in the well.

It is very important that an HTS provider is flexible in order to meet the needs of the partner. Whether it is adapting to different assay formats or different conditions, flexibility is essential toward ensuring high-quality results that are generated as quickly as possible.

What makes your services/screening programs unique?

AMRI: Our screening services are based on industry-standard liquid handling and automation capabilities combined with common and unique high-throughput detection instrumentation and analysis software. For example, AMRI is unique in offering high-throughput screening by high content imaging with multiparametric, statistical analysis (HCI-MPSA) and HTS by MALDI-TOF mass spectrometry (MS) and MALDI-TOF/TOF MS (PharmaPulse).

Data is analyzed using IDBS ActivityBase, Bruker MPP, or Revvity Signals for Screening software with results visualized and inspected using Tibco SpotFire to keep pace with data production, provide rapid assessments of assay plate data quality and identify compounds worthy of further evaluation. We believe we are one of the only CROs applying multiparametric statistical analysis combined with machine learning to define therapeutic effect phenotypes and are the only CRO able to apply this technology to image and MS data analysis at the scales required to support active compound (hit) identification during high-throughput screening.

HTS is a major cornerstone of drug discovery; however, the availability of an innovative, relevant, and high-quality compound collection for screening often dictates the fate of a drug discovery campaign. Given that the chemical space to be sampled in research programs is vast and sparsely populated, significant resources need to be invested to generate and maintain a competitive compound collection. By leveraging diverse experience and industrial expertise in synthetic and medicinal chemistry, AMRI addresses this challenge in a novel way through the Compound Library Consortium (CLC), a cross-industry compound library consortium developed around the synthesis of new and unique compounds for drug discovery.

Biocompare’s Drug Screening Search Tool
Find, compare and review drug screening
tools from different suppliers Search

Charles River: We work hard to engage with our potential screening customers to understand their specific project requirements and to identify the approach that offers the best chance of success. Our scientific team works with the customer to determine the most appropriate assay platform and screening conditions, and provides insight into downstream assays that should be considered. This scientific experience is then used to directly translate these discussions into work plans, including provision of estimated timelines and prices.

As scientists, we know that things do not always go as planned and, as such, we approach each project with flexibility, with decisions being driven by the data and not constrained by the project plan.

Within the department we have a depth of expertise gained from across the pharmaceutical industry, underpinned with a strong biology background. These skills have been used to execute over 70 screens in the past three years, across a diverse range of target classes and assay platforms. The assay platforms in use cover most, if not all, screening technologies in the industry and screens are typically conducted in 384- or 1536-well formats with data analysis performed using industry-standard software. The HTS team works closely with our chemistry colleagues to add additional insight into the data provided.

Above all, we believe in completely open communication with the customer to allow us to act as an extension of the customer’s laboratory. Data is presented by the scientists responsible for generating the data, and the complete data package, not just the hits, are made available to the customer.

Evotec: We try to be unbiased on the screening technology, which means our position is to jointly discuss the objective of the hit discovery project together with the client as early as possible. Sometimes the client has a very clear idea what he/she wants to achieve, in other cases the project plan is being put into place by mutual experiences and ideas. We have access to almost all biochemical, cellular, and biophysical screening approaches available in the market, and we are committed to apply them for the best purpose of the discovery project. Our scientists have experiences derived from more than 600 assay development and HTS projects over a period of more than 15 years, which means the likelihood for the client to find experience in a particular target/disease area space is very high, which significantly speeds up project execution in a very cost-efficient manner.

Icagen: At Icagen we are unique in that our platform is the only high-throughput screening center that was historically part of a global pharmaceutical company (Sanofi) for over 25 years. We have standard pharmaceutical industry practices and equipment in place to execute on every imaginable screen required. We have two high-throughput robotic platforms that can be operated simultaneously to increase our throughput and enhance our ability to perform follow-up assays at a large scale in parallel.

Our North Carolina facility is extremely well outfitted to perform HTS on ion channels and perform electrophysiology. At our Tucson we perform cellular or biochemical screens on almost any target. At that site we also have the ability to run radioactive screens, high-content screens that are based on microscopic image analysis or transcriptional expression. At Icagen we also have a very unique HTS platform called XRPRO, which is a screening platform that utilizes x-ray fluorescence. This technology allows us to monitor ion transport in an unlabeled manner. This platform can detect metal transport as well.

Are there any novel technologies/techniques currently being implemented or on the horizon you think will improve HTS in the near future?

AMRI: Our scientists are always forward-thinking and in touch with what new technologies are on the horizon to ensure that we are providing our customers with the highest-grade support, which is why we have invested in the partnerships we have. We will continue to explore opportunities to add new technologies and screening strategies to our portfolio through development and strategic alliances.

Charles River: We are seeing increased interest in the use of flow cytometry as a screening tool. To make screens more biologically relevant, the use of primary cells and stem cells are of great interest of course. Alongside this I think we will see a greater implementation of 3D cell culture/tissue spheroids in screening, which provide a better model of the disease in the hitidentification process. However, the challenge is one of scale and data interpretation.

Evotec: There is a clear interplay between classical biochemical or cellular assays, structure-based drug design projects derived from fragment screens and phenotypic approaches. They are not mutually exclusive, there are technological advancements in all of these areas. A clear understanding of the disease background and molecular pathways together with access to human(ized) assay systems in primary cells, tissues and most importantly stem cell approaches will increase the success of HTS projects in the future. We are very much building our advanced assay and screening technologies on induced pluripotent stem cells (iPSCs) in a number of disease areas but in particular in neurosciences. By running phenotypic screening approaches we are applying a full panel of downstream target deconvolution strategies by transcriptomics and high-end proteomics.

Icagen: We are seeing high-content capabilities become faster and faster, which enables them to be used in real-time within the screening process. The speed of these instruments and the data analysis pipeline is enabling single-cell assessment.

We are also seeing a broad interest in the use of stem cells in HTS. Tissues differentiated from iPSCs are being employed for screening. At our laboratory we have been using stem cells to generate human skeletal muscle myotubes that can be screened in HTS.

Image: Shutterstock Images