Identification of Extracellular Vesicle Signatures of Daratumumab Treated Multiple Myeloma

Area of Science:

• Hematology
• Oncology
• Biochemistry

Background:

• Daratumumab (DARA) is a key therapy for multiple myeloma (MM), a plasma cell malignancy.
• Extracellular vesicles (EVs) in MM patients receiving DARA have shown altered protein profiles, including PDL1, linked to treatment response.
• Identifying additional EV protein markers could enhance monitoring of MM patients.

Purpose of the Study:

• To identify novel protein alterations in peripheral blood (PB) EVs from MM patients treated with DARA.
• To develop predictive protein signatures in EVs for MM diagnosis and DARA treatment response.
• To explore the potential of EV signatures as a non-invasive liquid biopsy alternative to bone marrow sampling.

Main Methods:

• Flow cytometry was used to analyze protein expression on PB EVs from MM patients and healthy controls.
• Proteins such as CD31, CD36, CD44, CD8, LAT1, CD38, and PDL1 were quantified.
• Multivariate Receiver Operating Characteristic (ROC) curve analysis was employed to establish diagnostic and predictive signatures.

Main Results:

• MM PB EVs showed significantly elevated CD31, CD36, and CD44, and decreased CD8 and LAT1 compared to healthy controls.
• Higher levels of CD38, LAT1, and PDL1 in PB EVs correlated with a long-term response to DARA.
• A diagnostic signature (MM panel) achieved 86.4% sensitivity and 91.6% specificity; a predictive signature (Response panel) achieved 80% sensitivity and 91.2% specificity.

Conclusions:

• Two distinct EV protein signatures were identified in MM patients undergoing DARA treatment.
• These signatures demonstrate potential as non-invasive biomarkers for MM diagnosis and monitoring of DARA therapy response.
• EV-based liquid biopsy could complement or replace invasive bone marrow sampling for MM patient management.