Whole-blood assays: no cytokine increase <1 nM; IL-6, TNFa, IFNg at 10-100 nM; no alloreactivity or platelet activation
“Tebentafusp did not show evidence for increased release of 5 key cytokines in the presence of whole blood at < 1 nM.”
✓ VerifiedFDA multi-discipline review, p. 41Source ↗
Biodistribution & persistence
Mouse non-GLP PK/biodistribution: tumor retention longer than other tissues (tumor t1/2 ~20-24 h vs blood 1.5 h); renal excretion
“Preclinical biodistribution studies demonstrate that tebentafusp is being retained in the melanoma tumor for a significantly longer timeframe compared to other non-target tissues, with a half-life of tumour retention of approximately 24 hours.”
✓ VerifiedFDA multi-discipline review, p. 43Source ↗
Modality-specific risk
On-target/off-tumor melanocyte killing (rash, vitiligo) and CRS; HLA/peptide off-target cross-reactivity and alloreactivity
“Based on these [astrocyte and melanocyte] data, skin rash and potentially vitiligo were expected as the primary TCR mediated on‐target, off‐tumor toxicities.”
✓ VerifiedFDA multi-discipline review, p. 42Source ↗