BAY 1862864

BAY 1862864 is a first-in-class targeted thorium-227 conjugate consisting of the humanized anti-CD22 monoclonal antibody epratuzumab chemically linked via a chelator to the alpha-emitting radionuclide thorium-227, developed by Bayer for the treatment of CD22‑positive B‑cell non‑Hodgkin lymphoma.[1][8][10] By binding CD22 on malignant B cells, the conjugate delivers potent, short‑range alpha radiation that induces clustered DNA double‑strand breaks, apoptosis, and immunogenic cell death while limiting exposure to surrounding normal tissues.[1][4][5] In a first‑in‑human, dose‑escalation phase 1 trial in relapsed/refractory CD22‑positive non‑Hodgkin lymphoma, intravenous BAY 1862864 demonstrated dose‑proportional pharmacokinetics, a manageable hematologic toxicity profile without reaching a maximum tolerated dose, and preliminary antitumor activity with objective responses in a subset of heavily pretreated patients.[1][2][4] The construct originated from Algeta’s targeted thorium conjugate platform (later integrated into Bayer) using Immunomedics’ epratuzumab antibody, but further clinical development beyond early‑phase evaluation has not been actively pursued.[6][10]

Other names

227Th-labeled anti-CD22 antibody227Th-epratuzumab conjugate