Monitoring Pseudoprogression Using Circulating Small Extracellular Vesicles Expressing PD-L1 in a Melanoma Patient...

Area of Science:

• Oncology
• Immunology
• Biomarker Discovery

Background:

• Immune checkpoint inhibitors (ICI) have transformed metastatic cancer treatment.
• Pseudoprogression, a temporary tumor growth or new lesion appearance, can be misidentified as disease progression, leading to premature treatment cessation.
• Current lack of reliable biomarkers hinders accurate differentiation between pseudoprogression and true progression.

Purpose of the Study:

• To report a case of pseudoprogression in metastatic melanoma during ICI therapy.
• To investigate the role of circulating small extracellular vesicles expressing PD-L1 (sEV-PD-L1) as a potential biomarker for treatment response and pseudoprogression.
• To highlight the clinical utility of monitoring sEV-PD-L1 levels in patients receiving ICI therapy.

Main Methods:

• A case study of a metastatic melanoma patient treated with nivolumab and ipilimumab.
• Monitoring of circulating sEV-PD-L1 levels during the course of ICI treatment.
• Clinical and radiological assessment to evaluate treatment response and identify pseudoprogression.

Main Results:

• The patient experienced pseudoprogression, characterized by initial lesion changes followed by regression.
• A decrease in circulating sEV-PD-L1 levels was observed concurrently with the pseudoprogression.
• This decrease preceded or coincided with the eventual tumor regression, indicating a response to ICI.

Conclusions:

• Reduced circulating sEV-PD-L1 may serve as an early indicator of response to ICI therapy.
• Monitoring sEV-PD-L1 could aid in distinguishing pseudoprogression from true disease progression.
• sEV-PD-L1 warrants further investigation as a predictive biomarker for ICI responders, particularly in cases of pseudoprogression.