Patient-Specific Nanoparticle Targeting in Human Leukemia Blood

Area of Science:

• Nanomedicine
• Immunology
• Oncology

Background:

• Antibody-targeted nanoparticles offer potential for cancer therapy by enhancing efficacy and reducing toxicity.
• Clinical outcomes with targeted nanomedicines show significant patient-to-patient variability.

Purpose of the Study:

• To investigate patient-specific targeting of nanoparticles in chronic lymphocytic leukemia (CLL) using an ex vivo whole blood model.
• To identify factors contributing to the variability in nanomedicine response.

Main Methods:

• Prepared and tested nine different nanoparticle formulations with varying surface chemistries and antibody functionalization.
• Developed an ex vivo assay using whole blood from 15 CLL patients to assess nanoparticle targeting and phagocytosis.
• Quantified patient-specific targeting efficiency and off-target effects of nanoparticles.

Main Results:

• Anti-CD20 functionalized nanoparticles showed efficient targeting of CLL cells with low phagocytosis by immune cells.
• Significant patient-to-patient variability (up to 164-fold) was observed in nanoparticle targeting of CLL cells.
• Interpersonal differences in targeting and off-target phagocytosis were also noted for clinically relevant PEGylated liposomes.
• Anti-PEG immunoglobulin G levels correlated with off-target nanoparticle association with granulocytes and monocytes.
• Anti-PEG immunoglobulin M levels showed a negative correlation with nanoparticle targeting of CLL cells.

Conclusions:

• Anti-PEG antibodies are key modulators of patient-specific nanoparticle targeting in human leukemia blood.
• Nanoparticle fouling and target cell antigen expression also influence patient-specific delivery.
• The developed ex vivo assay is valuable for evaluating interpersonal variances in targeted nanomedicine response.