Notes
MOLECULE (AACR 2025 abstract 5447): JK-06 is a humanized, quadrivalent/tetravalent biparatopic anti-5T4 (TPBG) ADC built from two mAbs binding distinct 5T4 epitopes — the first clone converted to an scFv and fused to the C-terminal Fc of the second mAb, yielding 4 binding sites across 2 epitopes; DAR2 with stable, site-specific MMAE conjugation; picomolar 5T4 affinity with enhanced internalization. 5T4 = oncofetal Type I transmembrane glycoprotein (limited normal-tissue expression).
LINKER UNDISCLOSED: ADCdb (DRG0CNJHC) lists the linker as "Undisclosed" with NO LIN cross-reference id, so all adcdb{} linker physchem fields (SMILES/formula/MW/TPSA/xLogP) and linker_name/class/cleavage/attachment are left blank. MMAE payload implies a cleavable (likely protease/Val-Cit) linker by class analogy, but this is not confirmed in any source, so not asserted. ADCdb also lists antibody name, isotype, and DAR as "Undisclosed"; DAR2, "humanized," and "site-specific" come from the AACR 2025 abstract.
THREE DATA CUTS reconciled: (1) ESMO 2025 abstract 961P — dose escalation n=34, 1.5-8.0 mg/kg Q3W IV; only G3+ TRAEs: G3 peripheral neuropathy (1, at 1.5-3.0 mg/kg), G3 keratitis (1, at 4.5 mg/kg), G3 fatigue (1), G3 ALT increase (1), and G5 pneumonitis (1) (last three at 6.0-8.0 mg/kg). (2) AACR 2026 (cutoff 2026-03-29; 153 total / 112 expansion, doses up to 5.2 mg/kg): asthenia 11% was the ONLY AE >10%, all other TRAEs <10%; only 3 G3 events (fatigue, gait disturbance, keratitis); keratitis G3 1/112 (<1%); no G4/5; dose reductions 7/153 (4.6%). (3) ASCO 2026 (cutoff 2026-05-12; 173 total = 42 escalation + 131 expansion at RP2D 4.5 mg/kg) — used for the RP2D ocular/toxicity rows.
RP2D = 4.5 mg/kg IV Q3W. RP2D expansion cohort (n=131) TRAEs >=5%: alopecia 15%, asthenia 15%, dry eye 10%, fatigue 10%, nausea 10%. G3 TRAEs: keratitis 2% (n=2), fatigue 1% (n=1), gait disturbance 1% (n=1), neuralgia 1% (n=1); NO G4/G5 TRAEs at RP2D. 3 discontinuations (2%): fatigue, gait disturbance, pneumonitis. PN-driven dose reductions in 2 pts (2%).
OCULAR (qualifying signal): dry eye 10% (any grade, most frequent ocular AE, all low-grade) and keratitis G3 2% (n=2). Any-grade keratitis <5% (below the >=5% reporting threshold) yet G3 keratitis = 2% — uncommon but can be severe. dominant_ae_tissue/subtype set to Corneal/Corneal off-target because keratitis is the defining, severe, off-target (MMAE class) corneal event and 5T4 has no notable corneal/conjunctival expression; dry eye (surface) is numerically the most frequent. No ocular AE-related discontinuations; reversibility not explicitly characterized (Unknown). Grading scale = CTCAE, version not stated. dose_oae_available=FALSE (ocular rates essentially reported only at the 4.5 mg/kg RP2D, not across >=2 dose levels).
NOT REPORTED (left blank, NOT 0): Hematologic (neutropenia/thrombocytopenia/anemia) and infusion reactions were not among reported TRAEs (i.e., <5%, below threshold) — a notable differentiated, low-myelosuppression MMAE profile, but no documented 0, so cells are blank. Blurred vision and conjunctivitis ocular PTs not reported. Constitutional AEs not mapped to the 7 organ-system buckets (and therefore not made into rows): alopecia 15%, asthenia 11-15%, fatigue 10% (G3 1%), decreased appetite.
PCT DERIVATION: dose-escalation single-patient rows (G5 pneumonitis 14.3%, G3 ALT 14.3%, G3 PN 8.3%) report the source's count divided by the source's own dose-binned cohort denominator (1/7, 1/7, 1/12); flagged tier D with raw n in notes. RP2D rows use the percentages stated directly by the source.
Annals of Oncology 961P fulltext returned HTTP 403; dose-escalation AE details corroborated via the ADC Review ESMO 2025 coverage and the Salubris ESMO 2025 press release (consistent). Efficacy (context, not required): ESMO NSCLC ORR 38% (5/13); ASCO 2026 squamous NSCLC ORR 50% (5/10) at 4.5 mg/kg, overall squamous NSCLC 35% (6/17)/DCR 94%, EGFRm NSCLC 43%, HR+ breast 30%, TNBC 25%.