ADC TOXICITY ATLAS
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PF-06647263

Investigational
PF-6647263; anti-EFNA4 calicheamicin ADC; huE22-AcButDMH-N-Ac-calicheamicin conjugate; Anti-EFNA4-ADC
Sponsor
Pfizer
Indication
Advanced solid tumors (dose-expansion in metastatic triple-negative breast cancer)
Target family
Receptor tyrosine kinase
RP2D dose
0.015 mg/kg
QW (weekly)RP2D
01
Multi-organ toxicity

Fingerprint & organ drill-down

Also reported
0%severity100%
0
Assessed · clear
true 0%
No data
never assessed
9 adverse-event terms

Ocular

Any-grade
8%
G3+
0%
RP2D
sagittal schematic · Unknown

Tissues shaded by reported adverse-event rate.

Cornea
AE
-
Express.
-
Limbus
AE
-
Express.
-
Conjunctiva
AE
-
Express.
-
Lens
AE
-
Express.
-
Retina / RPE
AE
-
Express.
-
Dominant tissue
Mixed
Surface subtype
Unknown
Reversibility
Unknown
Reported ocular events
Dry eye10%
n=60
Lacrimation increased10%
n=60
Vision blurred6.7%
n=60
Eye irritation3.3%
n=60
Ocular hyperaemia3.3%
n=60
Iritis1.7%
n=60
Cataract1.7%
n=60
Diplopia1.7%
n=60
Conjunctival haemorrhage1.7%
n=60
02
Construct

Molecular anatomy

Antibody
IgG1
Humanized
Linker
Cleavable
4.6
DAR
Payload
DNA strand break
Linker structureC12H15NO3
CC(=O)c1ccc(OCCCC(N)=O)cc1
Payload structureC57H76IN3O22S4
CCN([C@H]1CO[C@H](C[C@@H]1OC)O[C@@H]2[C@H]([C@@H]([C@H](O[C@H]2O[C@H]3C#C/C=C\C#C[C@@]4(CC(=O)C(=C3C4=CCSSSC)NC(=O)OC)O)C)NO[C@H]5C[C@@H]([C@@H]([C@H](O5)C)SC(=O)C6=C(C(=C(C(=C6OC)OC)O[C@H]7[C@@H]([C@@H]([C@H]([C@@H](O7)C)O)OC)O)I)C)O)O)C(=O)C
03
Antibody

Antibody & Fc engineering

Antibody
huE22 (anti-EFNA4)
Isotype
IgG1
Origin
Humanized
Fc modifications
None
Glycoengineering
Standard
Effector silencing
None
FcγR binding
Retained
C1q binding
Retained
04
Linker & conjugation

Linker chemistry

Linker profile
Linker
AcButDMH (AcBut acid-labile hydrazone + disulfide)
Class
Cleavable
Cleavage
Cleavable
Attachment
Lysine
Conjugation
Conventional Lys (NHS); random lysine
Symmetry
Symmetric
DAR (mean)
4.6
DAR homogeneity
Heterogeneous
Plasma t½
-
Cleavage trigger
pH/acid (hydrazone) + GSH/reductive (disulfide)
Release control
Conditional
Hydrophilicity mask
None
Formula
C12H15NO3
Linker MW
221.256 Da
Linker TPSA
69.39 Ų
Linker xLogP
1.5335
ADCdb linker
LIN0KWKDL
In-vitro stability
Unknown
05
Payload

Payload & physicochemistry

Payload profile
Payload
N-acetyl-gamma-calicheamicin
Class
Calicheamicin
Mechanism
DNA strand break
Released catabolite
N-acetyl-gamma-calicheamicin (active enediyne), released from conjugated N-acetyl-gamma-calicheamicin dimethylhydrazide (N-Ac-gamma-cal-DMH) via acid-labile hydrazone hydrolysis + reductive disulfide cleavage; Garrido-Laguna 2019 states payload is hydrolytically released in the lysosome and generates double-strand DNA breaks
Mechanistic subtype
DNA-strand-break
Stereochem / salt
Unknown
Bystander
Partial
PAMPA rank
-
MW
1368.4 Da
XLogP3
2
logD₇.₄
2
TPSA
410 Ų
pKa
-
Charge pH 7.4
0
H-bond donors
7
H-bond acceptors
27
IC50 (HCEC)
-
Formula
C57H76IN3O22S4
PubChem CID
134819845
ADCdb payload
PAY0RZSDY
Hydrophobicity · logD₇.₄
hydrophilic −2+2+4 lipophilic
Bioactivity note
ADCdb reports clinical objective response rate (ORR) 10.4% across all dose groups (9.1% at 0.015 mg/kg weekly) in the terminated Phase 1; no payload IC50 or ADC binding-affinity values reported. Payload is N-acetyl-gamma-calicheamicin, a DNA-cleaving enediyne (same warhead class
06
Dosing & regimen

Dosing

RP2D dose
0.015 mg/kg
Schedule
QW (weekly)
Route
Other
Fractionated
-
n at RP2D
25
Dose basis
TBW
Trial phase
Phase 1
Dose-OAE available
Yes
Tox summary basis
RP2D
07
Ocular & expression

Ocular profile & eye-tissue target expression

Target profile
OAE any-grade
8 %
OAE grade 3+
0 %
OAE data status
reported
Severity (weighted)
2.4
Keratopathy
-
Conjunctival
-
Dry eye
8 %
Blurred vision
8 %
Dominant tissue
Mixed
Surface subtype
Unknown
Grading scale
CTCAE v4
Reversibility
Unknown
Target expression in eye tissues (HCA detection · HPA bulk)
Cornea (central)
-
Cornea (limbal)
-
Conjunctiva
-
RPE
-
Retina (HPA)
-
Cross-trial comparability · source-verified
Ascertainment: Symptom-driven reportingScale: CTCAE v4Denominator: RP2D⚠ OAE rate not directly comparable across trials
08
Identity & registry

Identifiers, registry & notes

ADC id
pf-06647263
Approval status
Investigational
Approval year
-
UniProt
P52798
ADCdb ADC
DRG0SHGPV
ADCdb antibody
ANI0ONCDU
ADCdb target
TAR0IMOZN
Primary source
ClinicalTrials.gov NCT02078752 (all-causality AE table); Garrido-Laguna et al., Int J Cancer 2019;145(7):1798-1808 (PMID 30680712)
Aliases & development codes
PF-6647263; anti-EFNA4 calicheamicin ADC; huE22-AcButDMH-N-Ac-calicheamicin conjugate; Anti-EFNA4-ADC
Notes
EFNA4 (Ephrin-A4)-targeted ADC; antibody huE22 (humanized IgG1); linker AcButDMH (acid-labile hydrazone + disulfide; ADCdb LIN0KWKDL, the SAME shared calicheamicin linker as gemtuzumab-ozogamicin, inotuzumab-ozogamicin, and CMD-193); payload N-acetyl-gamma-calicheamicin (enediyne, DNA double-strand breaks); DAR 4.6 (ADCdb); random-lysine conjugation; Pfizer. Phase 1 FIH NCT02078752 (Garrido-Laguna et al., Int J Cancer 2019;145(7):1798-1808, PMID 30680712), advanced solid tumors with a metastatic-TNBC dose-expansion; development discontinued (Phase 1 terminated). RP2D 0.015 mg/kg QW; MTD not reached for either Q3W or QW; 1 DLT (thrombocytopenia) on QW. OCULAR — CRITICAL ATTRIBUTION CAVEAT: the ocular AEs are ALL-CAUSALITY events from the ClinicalTrials.gov posted results, NOT treatment-related. The peer-reviewed publication's treatment-related AE tables (Tables 3-4) contain ZERO ocular events. Calicheamicin is not a classically ocular-toxic payload (gemtuzumab/inotuzumab report 0% ocular AEs in their FDA labels). These eye AEs are almost certainly background/incidental in an advanced-cancer population; causal attribution to PF-06647263 is weak. No ocular AE was serious or Grade >=3 (CT.gov serious-AE table has zero eye disorders; the paper lists no ocular event among Grade 3/4 AEs) -> oae_g3plus_pct=0 is a documented zero. CORRECTION to the screening hint: the hint's 'conjunctivitis 5.0%' is NOT an Eye-disorders SOC ocular-surface event -- it is 'Conjunctivitis' under the Infections & infestations SOC (infective conjunctivitis, 3/60: groups EG001/EG007/EG008), not a drug-induced ocular toxicity. The only Eye-disorders conjunctival PT is conjunctival haemorrhage (1/60, 1.7%, a hemorrhagic event likely related to thrombocytopenia). Hence ae_conjunctival_pct is left blank (no on-target conjunctivitis). DENOMINATOR NOTE: the CT.gov AE table is split into 10 dose-level groups (no pooled column). RP2D = 0.015 mg/kg QW = EG001 (Part 1, n=13) + EG009 (Part 2 TNBC expansion, n=12) = n=25. ocular{} summary and all line_context=RP2D rows use this n=25 all-causality slice (tier D, no grade resolution at this cohort). Treatment-related grade data (tier B) live in line_context=dose-escalation rows (Q3W arm n=25; QW arm n=35). Per-group RP2D ocular detail: 0.015 QW Part 1 (n=13) vision blurred 15.4%, dry eye/eye irritation/iritis/mydriasis 7.7% each; 0.015 QW Part 2 (n=12) dry eye/cataract/diplopia 8.3% each. Whole-study pooled all-cause (N=60) ocular: dry eye 10.0%, lacrimation increased 10.0%, vision blurred 6.7%, eye irritation 3.3%, ocular hyperaemia 3.3%; iritis/cataract/diplopia/conjunctival haemorrhage/mydriasis/vitreous floaters/eye discharge/eye haemorrhage/eye pruritus/eye symptom 1.7% each. NON-OCULAR (Garrido-Laguna 2019, treatment-related): dominant toxicities are thrombocytopenia (QW 31.4% any/5.7% G3+; Q3W 44% any/20% G3+ [G3 8% + G4 12%]), GI (nausea/vomiting/diarrhea/mucositis 20-64%; G3+ rare: Q3W vomiting 4%, QW nausea 2.9%, QW gastritis G4 2.9%), and the calicheamicin-class hepatobiliary signal (Q3W Grade-3 hyperbilirubinemia 8%; 1 grade-1 hepatic VOD + 1 nodular regenerative hyperplasia/portal hypertension in the Q3W arm; pooled all-cause VOD 1.7%, blood bilirubin increased 11.7%, AST increased 10%). Neutropenia infrequent (~1.7-5% pooled), consistent with attenuated marrow toxicity in a solid-tumor (non-hematologic-target) setting vs gemtuzumab/inotuzumab. Peripheral neuropathy 10% pooled all-cause/low-grade (not a calicheamicin toxicity). No drug-related ILD/pneumonitis (1 'radiation pneumonitis' = radiotherapy-related) and no infusion-related reactions reported -> pulm_ild and infusion left BLANK (not zero). Linker physchem (SMILES/formula/MW 221.256/TPSA 69.39/xLogP 1.5335) carried from the shared LIN0KWKDL platform (verified on the ADCdb linker page, shared with gemtuzumab/inotuzumab/CMD-193). payload_physchem uses the standard calicheamicin-gamma1 reference values (shared payload) per DB convention. Derived columns (dna_damage subtype, FcgammaR/C1q status, stability conditional/unconditional, severity, HCA/HPA) intentionally left blank for downstream computation.