Antibody–Drug Conjugate Made of Zoledronic Acid and the Anti-CD30 Brentuximab–Vedotin Exert Anti-Lymphoma and Immunostimulating Effects

Relevant advances have been made in the management of relapsed/refractory (r/r) Hodgkin Lymphomas (HL) with the use of the anti-CD30 antibody–drug conjugate (ADC) brentuximab–vedotin (Bre–Ved). Unfortunately, most patients eventually progress despite the excellent response rates and tolerability. In this report, we describe an ADC composed of the aminobisphosphonate zoledronic acid (ZA) conjugated to Bre–Ved by binding the free amino groups of this antibody with the phosphoric group of ZA. Liquid chromatography–mass spectrometry, inductively coupled plasma–mass spectrometry, and matrix-assisted laser desorption ionization–mass spectrometry analyses confirmed the covalent linkage between the antibody and ZA. The novel ADC has been tested for its reactivity with the HL/CD30+ lymphoblastoid cell lines (KMH2, L428, L540, HS445, and RPMI6666), showing a better titration than native Bre–Ved. Once the HL-cells are entered, the ADC co-localizes with the lysosomal LAMP1 in the intracellular vesicles. Also, this ADC exerted a stronger anti-proliferative and pro-apoptotic (about one log fold) effect on HL-cell proliferation compared to the native antibody Bre–Ved. Eventually, Bre–Ved–ZA ADC, in contrast with the native antibody, can trigger the proliferation and activation of cytolytic activity of effector-memory Vδ2 T-lymphocytes against HL-cell lines. These findings may support the potential use of this ADC in the management of r/r HL.