MedicalResearch.com Interview with: Dr. Alexey Aleshin, M.D., MBA Senior Medical Director Natera MedicalResearch.com: What is the background for this study? Response: Checkpoint inhibitor-based immunotherapies (ICI)  have changed the management of a range of cancers of diverse histologies. While these therapies are well tolerated and efficacious, only a minority (<20%) of patients respond to treatment or derive durable clinical benefit from them, highlighting the need for a pan-cancer biomarker that can predict response prior to, or shortly after, treatment initiation. With immune checkpoint inhibitors (ICIs) rapidly becoming a cornerstone of cancer therapy, early determination of response to ICI treatment can optimize patient benefit and minimize the risk of toxicities, while potentially reducing unnecessary treatment and costs to patients and payers. Additionally, due to the nature of immune checkpoint inhibition, atypical patterns of response have emerged. For instance, tumor pseudoprogression — a transient increase in tumor size due to the infiltration of immune cells, followed by delayed shrinkage — has been reported in as much as 10% of patients receiving ICI therapy. Distinguishing pseudoprogression from true progression is clinically important to avoid premature discontinuation of a treatment that may have future benefit, or delay the initiation of an alternative line of therapy. However, they are hard to differentiate using current imaging techniques. Our study published in Nature Cancer earlier this month, demonstrates that bespoke circulating tumor DNA (ctDNA) testing may be a valuable tool that sheds light on both of these issues. (more…)