Farletuzumab ecteribulin

Investigational

MORAb-202; FZEC; ER-001159569; VCP-Eribulin; eribulin/farletuzumab ADC

Target

Folate receptor alpha · FOLR1

Sponsor

Eisai (Morphotek); Bristol Myers Squibb

Indication

FOLR1+ platinum-resistant ovarian cancer

Target family

GPI-anchored

RP2D dose

0.9 mg/kg

Q3WRP2D

Multi-organ toxicity

Fingerprint & organ drill-down

Also reported

0%severity100%

Assessed · clear

true 0%

No data

never assessed

3 adverse-event terms

Ocular

Any-grade

G3+

RP2D

sagittal schematic · Reversible

↳

Tissues shaded by reported adverse-event rate.

Cornea

Express.

0.02%

Limbus

Express.

0.07%

Conjunctiva

Express.

0.19%

Lens

Express.

Retina / RPE

Express.

3.21%

0.4 nTPM

Dominant tissue

Unknown

Surface subtype

Unknown

Reversibility

Reversible

Reported ocular events

Cataract14.3%

n=21

Eye disorders (SOC, PT not specified)9%

n=22

Eye disorders (SOC)-

G3+ 0%n=22

Per-trial detail

Adverse events by trial

MORAb-202 vs Investigator's Choice chemo in PROC ovarian (NCT05613088)Phase 225 mg/m^2 Q3Wn=70CTCAE not reported (MedDRA 2B

ClinicalTrials.gov posted results NCT05613088 NCT05613088

48 adverse-event terms · 12 systems · expand a system below

GI8

Constipation

24.3%

17/70

Nausea

24.3%

17/70

Vomiting

12.9%

9/70

Diarrhoea

11.4%

8/70

Abdominal pain upper

2.9%

2/70

Abdominal discomfort

1.4%

1/70

Gastrooesophageal reflux disease

0/70

Stomatitis

0/70

Investigations7

Dermatologic6

Metabolic4

Musculoskeletal4

Neurologic (other)4

Hematologic3

General3

Pulmonary3

Infections2

Psychiatric2

Vascular2

Construct

Molecular anatomy

Antibody

IgG1/kappa

Humanized

Linker

Cleavable

DAR

Payload

Eribulin

Tubulin inhibitor

Linker structureC29H42N6O9

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

Payload structureC40H59NO11

C[C@@H]1C[C@@H]2CC[C@H]3C(=C)C[C@@H](O3)CC[C@]45C[C@@H]6[C@H](O4)[C@H]7[C@@H](O6)[C@@H](O5)[C@@H]8[C@@H](O7)CC[C@@H](O8)CC(=O)C[C@H]9[C@H](C[C@H](C1=C)O2)O[C@@H]([C@@H]9OC)C[C@@H](CN)O

Antibody

Antibody & Fc engineering

Antibody

Farletuzumab

Isotype

IgG1/kappa

Origin

Humanized

Fc modifications

None

Glycoengineering

Standard

Effector silencing

None

FcγR binding

Retained

C1q binding

Retained

Target KD (nM)

Linker & conjugation

Linker chemistry

Linker profile

Linker

Mal-PEG2-Val-Cit-PAB

Class

Cleavable

Cleavage

Cleavable

Attachment

Cysteine (interchain)

Conjugation

Conventional interchain Cys (maleimide; reduced disulfides; ADCdb 'Random Cysteines')

Symmetry

Symmetric

DAR (mean)

DAR homogeneity

Heterogeneous

Plasma t½

Cleavage trigger

Cathepsin B (Val-Cit)

Release control

Conditional

Hydrophilicity mask

Discrete-PEG-spacer

%HMW aggregate

1.2 %

Cell line

CHO-K1SV

Formula

C29H42N6O9

Linker MW

618.688 Da

Linker TPSA

223.69 Å²

Linker xLogP

-0.6966

ADCdb linker

LIN0KCWDR

In-vitro stability

Stability note

Serum-stable; <30% released eribulin detectable, most below LLOQ; cleaves intracellularly via cathepsin B

Payload

Payload & physicochemistry

Payload profile

Payload

Eribulin

Class

Microtubule (other)

Mechanism

Tubulin inhibitor

Released catabolite

Eribulin (free base)

Mechanistic subtype

Tubulin-other

Stereochem / salt

Conjugated as eribulin mesylate; releases free-base eribulin (single stereoisomer, 19 chiral centres)

Bystander

Yes

PAMPA rank

729.9 Da

XLogP3

1.1

logD₇.₄

TPSA

146 Å²

pKa

Charge pH 7.4

H-bond donors

H-bond acceptors

IC50 (HCEC)

Formula

C40H59NO11

PubChem CID

11354606

ADCdb payload

PAY0JAEKD

Potency IC50 (nM)

0.001

Plasma protein binding (%)

49 %

Bioactivity note

ADCdb reports ADC cytotoxicity IC50: IGROV-1 (ovarian) 0.01 pM / 0.02 nM; NCI-H2110 (lung) 0.74 pM / 0.42 nM; Caov-3 (ovarian) 0.43 nM; OVCAR-3 (ovarian) 0.75 nM (FOLR1-dependent, sub-nM to pM potency).

Dosing & regimen

Dosing

RP2D dose

0.9 mg/kg

Schedule

Q3W

Route

Fractionated

n at RP2D

Dose basis

TBW

Trial phase

Phase 1

Dose-OAE available

Yes

Tox summary basis

RP2D

ADA rate (%)

3 %

Ocular & expression

Ocular profile & eye-tissue target expression

Target profile

OAE any-grade

9 %

OAE grade 3+

0 %

OAE data status

reported

Severity (weighted)

2.7

Keratopathy

Conjunctival

Dry eye

Blurred vision

Dominant tissue

Unknown

Surface subtype

Unknown

Grading scale

CTCAE v4.03

Reversibility

Reversible

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

Cornea (central)

0.02 %

Cornea (limbal)

0.07 %

Conjunctiva

0.19 %

RPE

3.21 %

Retina (HPA)

0.4 nTPM

Cross-trial comparability · source-verified

Ascertainment: Symptom-driven reportingScale: CTCAE v4Denominator: RP2D⚠ Not comparable: symptom-driven ascertainment

Dose & schedule → ocular toxicity · ocular AE (any-grade) by cohort

0.9 mg/kg

Q3W

8.3%

n=24 · MORAb-202 PROC expansion

1.2 mg/kg

Q3W

14.3%

n=21 · MORAb-202 PROC expansion

0.3-1.2 mg/kg

Q3W

n=22 · MORAb-202 FIH Ph1

Per-cohort rates from the per-trial extraction, sorted by dose. Cross-trial comparison is subject to ascertainment / scale differences (see comparability above) — e.g. an early symptom-driven trial can read lower than a later systematic-exam trial at a higher dose.

Ocular AE grading reference — interspecialty consensus · 6 scales + dose modification

Identity & registry

Identifiers, registry & notes

ADC id

farletuzumab-ecteribulin

Approval status

Investigational

Approval year

UniProt

P15328

ADCdb ADC

DRG0HPUIL

ADCdb antibody

ANI0TZBRZ

ADCdb target

TAR0QHAVI

Primary source

Shimizu CCR 2021;27(14):3905 (FIH Ph1, n=22); Yonemori IJGO 2026, doi 10.1002/ijgo.70676 (PROC expansion, n=45)

Aliases & development codes

MORAb-202; FZEC; ER-001159569; VCP-Eribulin; eribulin/farletuzumab ADC

Notes

NEW conjugate row, distinct from the existing naked-Ab row 'farletuzumab' (MORAb-003). MORAb-202 = humanized anti-FRalpha IgG1/kappa farletuzumab + cathepsin-B-cleavable Mal-PEG2-Val-Cit-PAB linker + eribulin (DAR 4, random interchain-Cys/maleimide). 'RP2D'-tagged toxicity rows = the FIH Ph1 pooled cohort (Shimizu CCR 2021, n=22, 0.3-1.2 mg/kg Q3W, NCT03386942) — the primary/qualifying OAE cohort: eye disorders 2/22 (9%), all grade 1, markedly lower than the FRalpha comparator mirvetuximab (blurred vision ~42-48%, keratopathy ~33-36%). Recommended expansion doses were 0.9 & 1.2 mg/kg (Yonemori IJGO 2026 PROC expansion, Cohort 1 n=24 + Cohort 2 n=21); in the expansion the ONLY ocular PT reported was cataract (8.3% at 0.9, 14.3% at 1.2 mg/kg) — a lens finding likely age/steroid-confounded in this PROC population, not an ocular-surface ADC signal; hence ocular_surface_subtype/dominant_ae_tissue = Unknown. Key AE of interest = ILD/pneumonitis (FIH 23% G1-2; expansion 37.5% at 0.9 mg/kg, 66.7% at 1.2 mg/kg incl. 1 G3). NOTE neutropenia discrepancy by cohort: FIH 45% (10/22; escalation incl. higher doses) vs expansion 4.4% (2/45) at recommended doses. Later PK/E-R modelling (Hayato JCP 2025) supports 33 mg/m2 BSA-based Q3W. Eribulin released as membrane-permeable free base -> strong bystander (>140-fold). Thrombocytopenia and infusion-reaction rates NOT reported in available sources (left blank, not zero). FOLR1 not corneal/conjunctival-expressed (HCA ~0.02-0.19%), consistent with the low ocular-surface signal. Cross-refs: adcdb_adc_id DRG0HPUIL, linker LIN0KCWDR (PubChem CID 155889591), payload eribulin PAY0JAEKD/PubChem CID 11354606, ChEMBL4802212.