ADC TOXICITY ATLAS
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PF-06650808

Discontinued
PF 6650808; PF-6650808; PF06650808
Sponsor
Pfizer
Indication
Advanced solid tumors (incl. triple-negative breast cancer)
Target family
Notch ligand
RP2D dose
2.4 mg/kg
Q3W (Day 1 of every 21-day cycle)RP2D
01
Multi-organ toxicity

Fingerprint & organ drill-down

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

Ocular

Any-grade
5%
G3+
-
RP2D
sagittal schematic · -

Tissues shaded by reported adverse-event rate.

Cornea
AE
-
Express.
-
Limbus
AE
-
Express.
-
Conjunctiva
AE
5%
Express.
-
Lens
AE
-
Express.
-
Retina / RPE
AE
-
Express.
-
Dominant tissue
Ocular surface
Surface subtype
Mixed
Reversibility
-
Reported ocular events
Vision blurred5%
Conjunctivitis5%
Dry eye2.5%
Foreign body sensation in eyes2.5%
02
Construct

Molecular anatomy

Antibody
Humanized
Linker
Cleavable
4
DAR
Payload
Microtubule / tubulin-polymerization inhibitor (antimitotic)
Linker structureC28H40N6O7
OCc1ccc(NC(=O)[C@@H](NC(=O)[C@@H](NC(=O)CCCCCN2C(=O)C=CC2=O)C(C)C)CCCNC(N)=O)cc1
Payload structureC39H62N6O6S
CC[C@H](C)[C@@H]([C@@H](CC(=O)N1CCC[C@H]1[C@@H]([C@@H](C)C(=O)N[C@@H](CC2=CC=CC=C2)C3=NC=CS3)OC)OC)N(C)C(=O)[C@H](C(C)C)NC(=O)C(C)(C)N
03
Antibody

Antibody & Fc engineering

Antibody
Anti-NOTCH3 mAb hu28
Isotype
-
Origin
Humanized
Fc modifications
-
Glycoengineering
-
Effector silencing
-
FcγR binding
Retained
C1q binding
Retained
04
Linker & conjugation

Linker chemistry

Linker profile
Linker
Mc-Val-Cit-PABC (maleimidocaproyl-valine-citrulline-p-aminobenzyloxycarbonyl)
Class
Peptide
Cleavage
Cleavable
Attachment
Cysteine (interchain)
Conjugation
Reduced interchain cysteine (random cysteine, maleimide); DAR 4
Symmetry
Symmetric
DAR (mean)
4
DAR homogeneity
Heterogeneous
Plasma t½
-
Cleavage trigger
Cathepsin B (lysosomal cysteine protease; cleaves Val-Cit dipeptide)
Release control
Conditional
Hydrophilicity mask
-
Formula
C28H40N6O7
Linker MW
572.663 Da
Linker TPSA
200.03 Ų
Linker xLogP
0.6769
ADCdb linker
LIN0SQEDQ
In-vitro stability
-
05
Payload

Payload & physicochemistry

Payload profile
Payload
Aur0101 (auristatin 0101; PF-06380101)
Class
Auristatin
Mechanism
Microtubule / tubulin-polymerization inhibitor (antimitotic)
Released catabolite
Free Aur0101 (PF-06380101) after Val-Cit proteolysis and PABC 1,6-self-immolation
Mechanistic subtype
Tubulin-auristatin
Stereochem / salt
-
Bystander
-
PAMPA rank
-
MW
743 Da
XLogP3
4.1
logD₇.₄
-
TPSA
184 Ų
pKa
-
Charge pH 7.4
+1
H-bond donors
3
H-bond acceptors
9
IC50 (HCEC)
-
Formula
C39H62N6O6S
PubChem CID
71569947
ADCdb payload
PAY0WDZAK
Bioactivity note
Free payload Aur0101 (PF-06380101) is a Dolastatin 10 analogue / auristatin microtubule (tubulin polymerization) inhibitor; ADCdb reports payload IC50 0.8 nM in HT-29 colon adenocarcinoma cells. Membrane-permeable, giving bystander killing of NOTCH3-negative neighboring cells. PF
06
Dosing & regimen

Dosing

RP2D dose
2.4 mg/kg
Schedule
Q3W (Day 1 of every 21-day cycle)
Route
IV
Fractionated
No
n at RP2D
11
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
5 %
OAE grade 3+
-
OAE data status
reported
Severity (weighted)
-
Keratopathy
-
Conjunctival
5 %
Dry eye
2.5 %
Blurred vision
5 %
Dominant tissue
Ocular surface
Surface subtype
Mixed
Grading scale
CTCAE v4
Reversibility
-
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-06650808
Approval status
Discontinued
Approval year
-
UniProt
Q9UM47
ADCdb ADC
DRG0WRFYU
ADCdb antibody
ANI0UMBRJ
ADCdb target
TAR0PNBPC
Primary source
ClinicalTrials.gov NCT02129205 (posted results) + Rosen et al., Invest New Drugs 2019 (PMID 30887250)
Aliases & development codes
PF 6650808; PF-6650808; PF06650808
Notes
PF-06650808 = humanized anti-Notch3 (NOTCH3) ADC, payload Aur0101 (auristatin 0101 / PF-06380101, a dolastatin-10 analog tubulin inhibitor that retains the thiazole ring and carries a free basic primary amine), cleavable Mc-Val-Cit-PABC linker, interchain-cysteine conjugation, DAR 4. Sponsor Pfizer. ADCdb DRG0WRFYU; linker LIN0SQEDQ; antibody ANI0UMBRJ; payload PAY0WDZAK; antigen TAR0PNBPC. Total-antibody analyte = PF-06460005. CLINICAL: First-in-human Phase 1 NCT02129205 (Rosen et al., Invest New Drugs 2019, PMID 30887250), advanced solid tumors incl. TNBC, N=40, IV on Day 1 of each 21-day cycle (Q3W). Dose escalation 0.2-4.68 mg/kg (per CT.gov cohorts); MTD estimated 2.4 mg/kg (N=11 at that level); Part 2 expansion at 2.4 mg/kg enrolled 0 patients; study TERMINATED for sponsor reprioritization (recruitment suspended Feb 2017). CTCAE v4.03. Protocol DLTs were hematologic (e.g., Grade 4 neutropenia >7 d, febrile neutropenia) and non-heme Grade >=3; no DLTs at <=2.0 mg/kg. Top treatment-related AEs in the publication: fatigue 40.0%, decreased appetite 37.5%, nausea 35.0%, alopecia 32.5%, abdominal pain 25.0%, pruritus 25.0%, vomiting 25.0% (none ocular). OCULAR (reason for inclusion): All ocular figures are ALL-CAUSE from CT.gov posted results (N=40); ocular AEs are NOT mentioned in the peer-reviewed paper -> tier C, causal attribution weak in an advanced-cancer population. Pooled: vision blurred 5.0% (2/40), conjunctivitis 5.0% (2/40, MedDRA Infections SOC), dry eye 2.5% (1/40), foreign-body sensation 2.5% (1/40). No ocular event appeared among serious AEs (no ocular SAE / no G3+ ocular reported; oae_g3plus left blank rather than asserting 0). DOSE STRATIFICATION (notable): at the MTD/RP2D 2.4 mg/kg cohort the ONLY ocular AE was conjunctivitis 2/11 (18.2%); the dry-eye, foreign-body-sensation and one blurred-vision case occurred at sub-MTD doses (0.4 and 2.0 mg/kg). Pooled N=40 reporting follows the wave1 oae_hint and the convention used for sibling Pfizer/Aur0101 ADC entries (PF-06263507, PF-06664178, PF-06804103). line_context tagged 'RP2D' to denote the primary/total safety population (no dedicated RP2D expansion exists); dose fields show the pooling explicitly. CAVEATS/DERIVED: antibody_isotype left blank (not explicitly sourced; most likely humanized IgG1 cysteine-conjugate by class). payload_charge_pH7_4 '+1' is DERIVED from the free basic primary amine (PubChem formal charge 0); payload_pka and logD7.4 not available; payload_bystander left blank (vc-cleavable auristatin is plausibly bystander-capable, but the released free Aur0101 is cationic at pH 7.4, like MMAF -> no definitive source). Payload physchem from PubChem CID 71569947 (MW 743.0, XLogP3 4.1, TPSA 184, HBD 3, HBA 9). Linker physchem from ADCdb (C28H40N6O7, MW 572.663, TPSA 200.03, xLogP 0.6769); linker_smiles given as the clean canonical Mc-Val-Cit-PAB-OH. No infusion-related-reaction PT was reported in the posted AE table (Infusion organ rows therefore omitted rather than recorded as 0; pyrexia 12.5%, chills 7.5%, flushing 5.0% occurred but were not labeled infusion reactions). Toxicity_rows are all-cause (pooled N=40) from CT.gov posted results; G3+ rows use serious AEs as a proxy.