ctDNA Can Flag Pseudoprogression in Melanoma Treated With Immunotherapy

Source: Cancer Network, March 2018

Circulating tumor DNA (ctDNA) can help differentiate what is known as pseudoprogression from true progression of disease in patients with melanoma who are treated with programmed death 1 (PD-1) inhibitors, according to a new study. It also showed that ctDNA could be used as a powerful biomarker to predict long-term outcomes.
“Pseudoprogression, a response that occurs after the initial development of new lesions or an increase in the size of target lesions, occurs in up to 10% of patients treated with PD-1 antibodies,” wrote study authors led by Jenny H. Lee, MBBS, of Macquarie University in Sydney, Australia. “Confirmation of pseudoprogression requires subsequent imaging, imposing an ongoing challenge.”
Previous research has shown that ctDNA levels at baseline could be used to predict response to PD-1 therapy, so investigators examined whether ctDNA could be used to aid in differentiating pseudoprogression from true progression. The study included 125 patients with stage IV melanoma and established BRAF or NRAS mutations receiving PD-1 antibodies alone or in combination with ipilimumab. The results were published in JAMA Oncology.