No significant cytokine release from human PBMCs or WBCs in vitro
“In contrast, no significant release of cytokines was observed after isatuximab incubation under any of the various assays and conditions used and for any of the donors tested.”
✓ VerifiedFDA multi-discipline review, p. 49Source ↗
Biodistribution & persistence
Human TCR: lymphoid tissues and bone marrow, plus pituitary endothelium and prostate epithelium
“The TCR test indicated that isatuximab-specific binding was mainly in the lymphoid tissues (spleen, thymus, lymph node and tonsil) and in the bone marrow; binding was also detected in the pituitary gland (endothelial cells) and prostate gland (glandular epithelial cells).”
✓ VerifiedFDA multi-discipline review, p. 36Source ↗
Modality-specific risk
No relevant tox species; safety assessment relies on mechanism of action and clinical findings
“The safety assessment of isatuximab for general toxicity is mainly based on the mechanism of action (MOA) and findings in patients.”
✓ VerifiedFDA multi-discipline review, p. 37Source ↗
Anti-drug antibodies: animals
No ADA with the clinical batch; 4 of 6 monkeys given an expired batch ADA positive (titers 160-320)
“All samples collected from animals treated with batch C1053598 (20, 50 and 100 mg/kg/week) were found to be ADA negative, while the majority of the samples from animals (4 out of 6) that received the batch VAB-LCX1-000004, which was beyond its current shelf-life, were ADA positive, with titers ranging from 160 to 320.”
Treatment-emergent ADA 2.3% (N=564); persistent ADA 0.35%; neutralizing status not determined
“In antidrug-antibody (ADA) evaluable patients from all completed studies (N=564), the incidence of treatment emergent ADAs was low (2.3%), with 2 patients having a persistent treatment induced ADA (0.35%). However, since no confirmed positive ADA samples were detected in the pivotal Phase 3 study, the neutralizing ADA status was not determined.”
✓ VerifiedFDA multi-discipline review, p. 76Source ↗
In vitro whole-blood cytokine release far below alemtuzumab/TGN1412 controls; no effects on monkey TDAR, lymphocyte subsets or serum cytokines; ADA in some monkeys