Notes
DM4 maytansinoid ADC (huC242-DM4 / IMGN242); DISTINCT from DM1 cantuzumab mertansine (SB-408075). Target CanAg = CA242, a sialylated carbohydrate epitope on MUC1 (ADCdb and ADC Review map the target gene to MUC1). MTD = RP2D = 168 mg/m² (BSA dosing in mg/m², NOT mg/kg); single IV infusion Q3W. OCULAR TOXICITY was the primary dose-limiting toxicity: Ph1 (n=30, doses 18-297 mg/m²) — 2/30 (6.7%) ocular DLTs (decreased visual acuity, corneal deposits, keratitis) at 223 mg/m² i.e. 2/6 within that above-MTD cohort, cycle 2, reversible (resolved in 1, markedly improved in the other) with lubricating drops; Ph2 gastric/GEJ Study 102 — 3/6 (50%) drug-related ocular toxicities in the first 6 pts at 168 mg/m². Ocular tox correlated with LOW plasma CanAg (<1000 U/mL, driving higher ADC exposure); protocol amended to CanAg-based dosing (126 vs 168 mg/m²), after which 0/3 pts had ocular tox. 'No clinically significant myelosuppression' and no HAHA/HADA -> hematologic columns left blank (not a documented 0). Ph1 had 12 grade 3/4 drug-related AEs (full breakdown not public) incl. 1 grade 3 diarrhea+dehydration at 168 mg/m². Program discontinued (Phase 2 terminated) for insufficient efficacy + ocular toxicity. CTCAE version not stated in sources (study era ~2006-2009 = CTCAE v3.0 era). DM4 payload physchem (MW 780.4, xLogP3 3.2, logD 3.0, TPSA 157, pKa 10.3, neutral, bystander Yes) and SPDB linker physchem (LIN0VZYER; same SPDB as coltuximab ravtansine) reused from class-standard values; SPDB is the non-sulfonated disulfide (no sulfonate masking; mirvetuximab uses sulfo-SPDB). dar_mean 3.5 = midpoint of ADCdb/ADC Review 'DAR 3-4'. Trials per screen: NCT00352131, NCT00620607. Note interim AACR abstract reported n=36 treated; the final Ph1 publication and Eaton 2015 review report n=30 (used here). Confidence: composition/chemistry/payload from ADCdb + secondary sources (C); dosing/MTD and Ph1 ocular DLT pattern peer-reviewed (B); RP2D 50% ocular rate from Ph2 ASCO 2009 abstract corroborated by Eaton 2015 review (D-to-C).