Can laboratories’ experience of PD-L1 companion diagnostic testing be improved? 

November 1st, 2017

During the last few years there has been intense debate about the biomarker PD-L1. It has become a significant feature of precision medicine but its uptake in diagnostic testing has been affected by a number of factors such as availability in labs, confusion over testing options, the platforms required and the interpretation and reporting of results. It’s a situation Diaceutics has been following closely by tracking PD-L1 developments and providing analyses of the global laboratory landscape. The subject arose again recently as we attended the 2017 Institute of Biomedical Science Congress in the UK where there was discussion around how laboratories rise to the challenges of PD-L1 diagnostic testing for pharma companies.  

When a drug with different companion (and complementary) diagnostics is released, labs are faced with a number of issues that can lead to confusion and uncertainty around testing. It is certainly a factor in the relatively slow adoption of PD-L1 testing across Europe.  

  • There are issues around platforms – a pharma company might expect a lab to invest in a new platform for its particular companion diagnostic test. If, however, the laboratory already has a different platform, it will not necessarily have the resources to invest in not only a new platform but the training for staff to use it. So this may not be a viable option. 
  • There are issues around the testing protocol – some labs face questions from diagnostic companies about their testing methods for PD-L1 and validation within the lab which may not be fully aligned with the test label and be a cause for confusion.  
  • There are further issues around samples – a lot of clinical trials for PD-L1 have used core biopsies but now there is increasing evidence to show good concordance between FFPE cell block testing and core biopsies in PD-L1 testing. The main UK reference centres are saying there isn’t a problem with FFPE cell block testing as long as laboratories validate them in-house on their own samples. There is still confusion among smaller laboratories, however, which are being told by the diagnostic companies that those samples are not validated with their kit.   

PD-L1 is not an easy test to interpret and this has impacted the rate of test availability in labs. More labs are making the test available but confusion still exists about which test to adopt for each therapy and indication. It’s important, therefore, for stakeholders to deliver broad and up-to-date information and education to support laboratories. Diagnostic companies have contributed to training for some pathologists and laboratories but in reality this is needed across the board in relation to PD-L1.  

Laboratories play such a vital role in precision medicine and ensuring patients do not miss out on testing, yet we know they often feel forgotten. At Diaceutics we understand their concerns about the rapidly changing world of diagnostic testing for pharma companies. With our experts coming from the laboratory and quality assessment spaces, we recognise and appreciate the service they provide. We have built the global network and the regional teams of experts to advise and support labs with continuing education, workshops and direct communication with pathologists to address issues such as those outlined above.  

Precision medicine is about getting the right test to the patient at the right time, but without the laboratory this would not happen. It is imperative, therefore, that labs are educated, supported and appreciated in their work, especially when new biomarkers or therapy indications drive such rapid change in the companion diagnostic landscape. 

On November 15, 2017, Diaceutics is hosting a webinar discussing Why 50% of patients could be missing out on the right targeted therapy, which will go into more detail about some of these issues. To register for the webinar please click here. 


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