ATG-022

Investigational

ATG-022; ATG022; ATN-022

Target

Claudin-18.2 (CLDN18.2) · CLDN18

Sponsor

Antengene Corporation

Indication

Advanced/metastatic gastric and gastroesophageal junction cancer (GC/GEJC)

Target family

Claudin / tight-junction

RP2D dose

1.8 and 2.4 mg/kg

Q3WPooled

Multi-organ toxicity

Fingerprint & organ drill-down

Also reported

0%severity100%

Assessed · clear

true 0%

No data

never assessed

1 adverse-event term

Ocular

Any-grade

G3+

Pooled

sagittal schematic · -

↳

Tissues shaded by reported adverse-event rate.

Cornea

Express.

Limbus

Express.

Conjunctiva

Express.

Lens

Express.

Retina / RPE

Express.

Dominant tissue

Surface subtype

None

Reversibility

Reported ocular events

Any ocular / ophthalmological toxicity (none observed)0%

n=63

Construct

Molecular anatomy

Antibody

Humanized

Linker

Peptide

Cleavable

DAR

Payload

Monomethyl auristatin E (MMAE)

Microtubule polymerization inhibitor

Linker structureC28H40N6O7

[H]OC([H])([H])c1c([H])c([H])c(N([H])C(=O)[C@@]([H])(N([H])C(=O)[C@@]([H])(N([H])C(=O)C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])N2C(=O)C([H])=C([H])C2=O)C([H])(C([H])([H])[H])C([H])([H])[H])C([H])([H])C([H])([H])C([H])([H])N([H])C(=O)N([H])[H])c([H])c1[H]

Payload structureC39H67N5O7

CC[C@H](C)[C@@H]([C@@H](CC(=O)N1CCC[C@H]1[C@@H]([C@@H](C)C(=O)N[C@H](C)[C@H](C2=CC=CC=C2)O)OC)OC)N(C)C(=O)[C@H](C(C)C)NC(=O)[C@H](C(C)C)NC

Antibody

Antibody & Fc engineering

Antibody

Undisclosed humanized anti-CLDN18.2 monoclonal antibody

Isotype

Origin

Humanized

Fc modifications

Glycoengineering

Effector silencing

FcγR binding

Retained

C1q binding

Retained

Linker & conjugation

Linker chemistry

Linker profile

Linker

Mc-Val-Cit-PABC (maleimidocaproyl-valine-citrulline-PABC)

Class

Peptide

Cleavage

Cleavable

Attachment

Cysteine (interchain)

Conjugation

Cysteine-maleimide (stochastic interchain)

Symmetry

Symmetric

DAR (mean)

DAR homogeneity

Plasma t½

Cleavage trigger

Cathepsin B (Val-Cit dipeptide)

Release control

Conditional

Hydrophilicity mask

None

Formula

C28H40N6O7

Linker MW

572.663 Da

Linker TPSA

200.03 Å²

Linker xLogP

0.6769

ADCdb linker

LIN0SQEDQ

In-vitro stability

Payload

Payload & physicochemistry

Payload profile

Payload

Monomethyl auristatin E (MMAE)

Class

Auristatin

Mechanism

Microtubule polymerization inhibitor

Released catabolite

MMAE (monomethyl auristatin E)

Mechanistic subtype

Tubulin-auristatin

Stereochem / salt

Bystander

Yes

PAMPA rank

717.98 Da

XLogP3

2.9

logD₇.₄

2.9

TPSA

159 Å²

pKa

8.2 pKa

Charge pH 7.4

H-bond donors

H-bond acceptors

IC50 (HCEC)

Formula

C39H67N5O7

PubChem CID

11542188

ADCdb payload

PAY0FSXOW

Hydrophobicity · logD₇.₄

hydrophilic −2+2.9+4 lipophilic

Dosing & regimen

Dosing

RP2D dose

1.8 and 2.4 mg/kg

Schedule

Q3W

Route

Fractionated

n at RP2D

Dose basis

TBW

Trial phase

Phase 1/2

Dose-OAE available

Yes

Tox summary basis

all-doses pooled

Ocular & expression

Ocular profile & eye-tissue target expression

Target profile

OAE any-grade

0 %

OAE grade 3+

0 %

OAE data status

documented-absent

Severity (weighted)

Keratopathy

Conjunctival

Dry eye

Blurred vision

Dominant tissue

Surface subtype

None

Grading scale

CTCAE (unversioned)

Reversibility

Target expression in eye tissues (HCA detection · HPA bulk)

Cornea (central)

Cornea (limbal)

Conjunctiva

RPE

Retina (HPA)

Cross-trial comparability

Ascertainment: Symptom-driven reportingScale: CTCAE (unversioned)Denominator: RP2D⚠ OAE rate not directly comparable across trials

Identity & registry

Identifiers, registry & notes

ADC id

atg-022

Approval status

Investigational

Approval year

UniProt

P56856

ADCdb ADC

DRG0FGLFW

ADCdb antibody

ADCdb target

TAR0IBZAS

Primary source

ATG-022 CLINCH Phase 1/2, ESMO 2025 abstract 2113P (Ann Oncol 2025, S0923-7534(25)03653-1) + Antengene PR Newswire 2025-10-20

Aliases & development codes

ATG-022; ATG022; ATN-022

Notes

ATG-022 (Antengene) is a humanized anti-CLDN18.2 vc-MMAE ADC, DAR 4, Mc-Val-Cit-PABC cathepsin-cleavable linker (ADCdb DRG0FGLFW / linker LIN0SQEDQ; NCT05718895). CLINCH Phase 1/2 in advanced GC/GEJC: dose escalation 0.3-3.0 mg/kg Q3W; RP2D 1.8 and 2.4 mg/kg Q3W; n=63 GC/GEJC patients. Ocular anchor confirmed: explicit statement 'No ophthalmological toxicities or interstitial lung disease have been observed' -> oae_any_pct=0 (explicit-zero), subtype=None. Toxicity is hematologic + GI dominated. All-grade TRAEs (all 63 pts): nausea 49.2%, neutrophil decrease 46.0%, WBC decrease 38.1%. Grade >=3 TRAEs (>=5%) reported specifically for the 2.4 mg/kg dose-expansion cohort: neutrophil decrease 16.7%, decreased appetite 14.6%, anaemia 8.3%; n for that cohort imputed/approximate. The 1.8 mg/kg cohort showed grade >=3 TEAEs 18.2% (highlighted as cleaner for first-line combination). Payload physchem are standard MMAE values (tier C). Linker plasma half-life, DAR homogeneity, exact thrombocytopenia/vomiting/fatigue/transaminase percentages, and CTCAE version were not retrievable from the accessible (non-paywalled) sources; the Annals of Oncology full text and ASCO/JCO abstract were 403-blocked. Antibody isotype/origin undisclosed in ADCdb (humanized per ESMO press coverage). DAR 4 and 'humanized mAb, vc-MMAE, cleavable linker' confirmed by ESMO 2025 press release / OncLive coverage.