Dolasynthen:A Novel, Homogeneous Auristatin F Hydroxypropyl Amide Antibody-Drug Conjugate Platform

Dorin Toader, Marc Damelin, Anouk Dirksen, Shawn P. Fessler, Scott D. Collins, Barrett J. Nehilla, Jian Xu, Ling Xu, Kalli C. Catcott, Alex Uttard, Winnie Lee, Susan Clardy, Cheri A. Stevenson, LiuLiang Qin, Patrick R. Conlon, Mariya V. Kozytska, Chen-Ni Chin, David H. Lee, Timothy B. Lowinger

2019 AACR Annual MeetingAtlanta, GA, March 29-April 3, 2019

Overview of the talkDolasynthen ADC Platform

• Dolasynthen is a novel, fully synthetic ADC platform based on the AF-HPA payload

• Optimization in 3 Phases:– Phase 1 – Scaffold optimization– Phase 2 – Impact of Bioconjugation Technologies– Phase 3 – Applicability across antibodies and targets

• Herein we demonstrate that Dolasynthen platform enables – Precise modulation of the drug-to-antibody ratio (DAR)– Flexibility with bioconjugation technology– Selection of optimal ADCs for clinical development

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Proprietary Auristatin DolaLock Payload with Unique Pharmacology

No Bystander KillingNot a Pgp substrateBystander Killing

MetabolicConversion

in Tumor Cell

Auristatin F-HPA (AF-HPA) Auristatin F (AF)

AF-HPA AF

OO N

Ph HNO

O

N

OO

ON

O

NH

LegendAntigen +

Antigen -

Presented at the AACR, Chicago, 2018, Abstract No.754 3

• Vary linker and hydrophilic moiety

• Determine optimal scaffold in vivo

Phase 1: Modular Scaffold Optimization

Pharmacokinetics in NHPAnti-Tumor Efficacy in Xenografts

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Optimized Dolasynthen Trimeric Scaffold

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• Trastuzumab was used as a model to synthesize – ADCs with DAR6 (n=2 site specific, n=2-4 stochastic) and DAR12 (n=4 site specific, n=2-8 stochastic)– Stochastic maleimide ADCs– Site specific ADCs with a variety of technologies and sites of conjugation

Phase 2: Screening BioconjugationTechnologies and Sites

ADC 1 ADC 2 ADC 3 ADC 4 ADC 5 ADC 6 ADC 7

Bioconjugation A B A C C D A

DAR 6 6 6 6 6 12 12

Site specific

NH

OO

HN

NH

OO

HN

ONH

HN

NH

HN

OHN

O

O

O

O

O

OO

OHO

O

NH

NH

O

HN

O

3

O

O

OO

O

NH

O

NH

OO

OO

O

OO

O

O NH

N PhHN

OOMe

N

OOMe

O

NO

HN

n

N

O

O

, other

maleimide

(site 1) (site 2)

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Differentiated Pharmacokinetics Enabled Selection of Lead Technologies

0 2 1 4 2 6 3 8 4

D a y s p o s t t r e a t m e n t

Efficacy JIMT1 Breast Xenograft Model (0.067 mg/kg payload single dose)

0 2 1 4 2 6 3 8 4

D a y s p o s t t r e a t m e n t

0 2 1 4 2 6 3 8 4

D a y s p o s t t r e a t m e n t

0 2 1 4 2 6 3 8 4

D a y s p o s t t r e a t m e n t

0 2 1 4 2 6 3 8 4

D a y s p o s t t r e a t m e n t

0 2 1 4 2 6 3 8 4

D a y s p o s t t r e a t m e n t

PK in tumor bearing mice (0.133 mg/kg payload single dose)7

Phase 3 Explore Applicability Across mAbs and Targets

Efficacy, tolerability and PK were key parameters that were used to understand the clinical potential of the Dolasynthen platform

DAR6 DAR6 DAR12

Target 1

Target 2

DAR6 DAR6

= AF HPA

=Sulfur

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Site Specific Dolasynthen ADC was Superior to Stochastic ADCs for Target 1

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Efficacy: CDX Toxicology parameter in Rats

Days Post TreatmentSingle Dose: 0.1 mg/kg AF HPA

Exposure, Conjugated AF HPA (Day * ng/mL)Single Dose

Normalized AUCinfconjugated AF HPA

Stochastic Dolasynthen DAR 6.6

Site Specific Dolasynthen DAR 6

Stochastic Dolasynthen DAR 12.1

Exposure (day*ng/mL)

Stochastic Dolasynthen DAR 6.6

Site Specific Dolasynthen DAR 6

Stochastic Dolasynthen DAR 12.1

Site Specific Dolasynthen ADCs Showed Consistently Improved In Vivo Performance Against Target 2

Efficacy: CDX Toxicology parameter in RatsExposure (day*ng/mL)

Normalized AUCinfconjugated AF HPA

Exposure, conjugated drug (day*ng/mL)Single Dose at 4 Dose Levels

Stochastic Dolasynthen DAR 6.6

Site Specific Dolasynthen DAR 6

Stochastic Dolasynthen DAR 6.6

Site Specific Dolasynthen DAR 6

Days Post TreatmentSingle Dose at 0.033 mg/kg AF HPA

Mea

n Tu

mor

Vol

ume

(mm

3 )

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Dolasynthen– Novel ADC platform based on the DolaLock payload – Flexibility and precision enables ADC optimization for

each target

– Significant potential for clinical application

Conclusions

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