NeoGenomics has a menu of >600 assays across many different technologies and approaches. Clients often approach us after searching our menu online and ask if we can “Provide Test X for Clinical Trial Y.” Typically, our answer is yes. Then the client asks if the assay is validated.
Yes. Maybe. It’s complicated.
NeoGenomics is a CAP/CLIA laboratory and all of our assays are validated as per CLIA requirements, NYS requirements, and CLSI guidelines. Or, for FDA assays, they are used as per the instructions for use. These assays are all sufficiently validated for use in routine diagnostic use, typically only within tumor types where that biomarker is commonly used for diagnostic or prognostic use. Is the assay validated for your drug, your patient population, and intended use? That requires further discussion.
More often than not, when a client is requesting an assay on our menu to be used in a clinical trial, that intended use is outside of its original diagnostic use. For example, HER2 by IHC. NeoGenomics offers this assay for breast cancer and gastric cancer. NeoGenomics’ validation used those two tissue types. Can we use the same assay to screen NSCLC patients for HER2 expression? Yes, but first the assay must be validated or verified for use in NSCLC and an appropriate scoring algorithm developed. IHC assays must be validated in the intended tissue, since histology and scoring will vary by tumor type.
With NGS gene panels, it’s even more complicated. It is not feasible to validate every possible variant for a 500+ gene panel, especially rare variants such as ALK, ROS, or other gene fusions. Typically, validation is performed using well-characterized and routinely available specimens. For that reason, you can expect EGFR, KRAS, or MSI variants to be well-validated for lung cancer or CRC within a panel. But to expect the same level of validation for rare gene deletions or gene fusions (or any variants present at <5% in that tumor type), is not feasible. To validate all variants across multiple tumor types is simply not achievable.
In conclusion, does every assay need to be validated for a new tissue, or target? It depends on the intended use.
If the assay is to be used for patient management, selection, or enrollment; or used for a primary or secondary endpoint, a full analytical validation for the target should be performed. For exploratory, biomarkers, a verification or qualification may be sufficient. And if a client is willing to accept results that are considered wholly exploratory, the assay can be utilized as-is.
So, to summarize. Is it validated?
Yes, for a narrow window of diagnostic applications and indications. Further development and validation will most likely be needed for your intended use. And if the assay is to be used for selection and enrollment, unless a client plans on re-using an existing IVD as per the instructions for use, additional validation of an assay will most likely be required.
A few key points to keep in mind for any validation project. We’re here to help with any of your assay validation projects
The biggest rate limiting step is tissue acquisition. If you are looking for a marker that has a prevalence of 1%, we need to screen a lot of samples to find a validation set. A typical CLIA validation utilizes 20 positive and 20 negative samples. I think we’ll cover this in a future blog post.
IHC or ISH must be validated for each new tissue type. Morphology differs between tumor types, and this must be accounted for in the scoring algorithm.
Molecular methods, generally, do not need to be validated by tumor type (only the nucleic acid extraction type). Validation for each variant, however, is required.
Plan at least 4-6 months ahead for analytical validation activities.