No TNF-α, IL-6 or IL-1β release from unstimulated human PBMC or whole blood in vitro
“In an in vitro cytokine release assay, treatment of unstimulated human PBMCs or whole blood cultures with soluble tremelimumab for up to 48 hours did not result in release of TNF‐α, IL‐6, or IL‐1β compared to untreated controls”
✓ VerifiedFDA multi-discipline review, p. 37Source ↗
Biodistribution & persistence
Tissue cross-reactivity in monkey and human tissues: binding only to CTLA-4-expressing cells, similar between species
“In vitro tissue cross‐reactivity studies were conducted in both monkey (IM645; Module 4.2.3.7.7 ) and human (IM676; Module 4.2.3.7.7). Tremelimumab bound only to cells in tissues expected to contain CTLA‐4 expressing cells and were considered similar between species.”
✓ VerifiedFDA multi-discipline review, p. 54Source ↗
“Consistent with nonclinical findings, diarrhea, decreased appetite, rash, hypothyroidism, and anemia have been seen clinically and the IMJUDO (tremelimumab) label includes warnings for immune‐mediated adverse events and infusion reactions.”
✓ VerifiedFDA multi-discipline review, p. 33Source ↗
Anti-drug antibodies: animals
ADAs in monkeys with limited impact on exposure; few animals showed declining exposure from neutralising ADAs
“Tremelimumab did give rise to antidrug antibodies in the monkeys, however with limited impact on exposure. Only few animals showed decreasing exposure over time due to neutralising antidrug antibodies.”
HIMALAYA: ADA 11% (20/182); 40% of these neutralizing
“11% (20/182) of patients tested positive for anti-tremelimumab-actl antibodies. Among the 20 patients who tested positive for ADAs 40% (8/20) tested positive for neutralizing antibodies against tremelimumab-actl.”
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