Synaffix Sees Competitive Early In Vivo Data from ADCs Based on Proprietary Exatecan Linker-Payload

  • In vivo efficacy on a par with gold standard deruxtecan-based ADCs
  • Poster to be presented at World ADC meeting on 17 September 2020

AMSTERDAM–(BUSINESS WIRE)–Synaffix B.V., a biotechnology company enabling antibody-drug conjugates (ADCs) with best-in-class therapeutic index, based on proprietary GlycoConnect™, HydraSpace™ and toxSYN™ technology platforms, announces promising findings from its latest in vivo benchmarking study.

In this mouse BT-474 xenograft study, trastuzumab-based ADCs prepared using Synaffix’s proprietary SYNtecan E™ linker-payload demonstrated an efficacy profile equivalent to deruxtecan-based ADCs. SYNtecan E™ is an exatecan-based linker-payload that contains the HydraSpace™ polar spacer technology, a conventional dipeptide cleavable linker and is conjugated, in this study, to the native antibody glycan using GlycoConnect™. Deruxtecan is the linker-payload used in Enhertu®, the FDA-approved ADC indicated for previously treated, HER-2 positive unresectable or metastatic breast cancer.

Following just a single dose, both HER-2-targeting ADCs, which have the same drug-to-antibody ratio (DAR) and administered at the same dose level, achieved complete tumor regression.

A poster of the data will be presented at the World ADC Digital conference on Thursday, 17 September 2020 at 3:30p-4:00p EDT.

Floris van Delft, CSO of Synaffix said:

“Given the recent clinical and commercial success observed with deruxtecan-based ADCs, we have been very excited with our first data for ADCs with the same mechanism of action.”

“Exatecan mesylate has completed Phase 3 studies as a single agent already and comes with a well-understood toxicology profile. That said, its relatively challenging biophysical properties have likely contributed to limited exploration within the ADC context to date, despite its high potency and putative bystander killing potential. We have resolved the ADC aggregation issue by combining exatecan with our highly polar HydraSpace™ technology, providing highly stable and efficacious ADCs. We look forward to presenting further data on this new linker-payload and introducing it to our collaborators in due course.”

Deruxtecan and SYNtecan E™ both belong to the family of camptothecins and are potent DNA topoisomerase 1 inhibitors that release DXd and exatecan as the active catabolite respectively.

SYNtecan E™ represents one of multiple options within the toxSYN™ linker-payload platform, which spans multiple mechanisms of action and can be evaluated in combination with GlycoConnect™ and HydraSpace™ technologies. This consolidated ADC platform enables any company with an antibody to rapidly co-discover an ADC with Synaffix and then develop and market the resulting ADC as part of its own pipeline under a license agreement.

Notes to Editors

About GlycoConnect™ and HydraSpace™

The clinical-stage GlycoConnect™ and HydraSpace™ technologies enable best-in-class ADCs lacking effector function with significantly enhanced efficacy and tolerability. GlycoConnect™ is the conjugation technology that exploits the native antibody glycan for site-specific and stable payload attachment, tailored to DAR1, DAR2 or DAR4 format. HydraSpace™ is a compact and highly polar spacer technology that accommodates hydrophobic payloads and further enhances therapeutic index. These technologies can be applied directly to any existing antibody without any protein sequence engineering and are compatible with all ADC payload classes.

The growing experience of Synaffix and its collaboration partners continues to confirm the ability of GlycoConnect™ and HydraSpace™ to consistently generate ADCs with enhanced therapeutic index compared to the three major clinical-stage conjugation technologies.

About Synaffix B.V.

Synaffix B.V. is a biotechnology company that enables best-in-class ADC product candidates using its clinical-stage, site-specific ADC technology platform. In addition to GlycoConnect™ and the ADC-enhancing HydraSpace™ technology, the extension of the platform with toxSYN™ payloads provides a fully complementary technology platform that enables any company with an antibody to develop proprietary ADC products.

The Synaffix platform comes with an IND-ready CMC package to support a rapid timeline to the clinic. Granted patents covering Synaffix’ technology provide end-to-end protection of the platform technology as well as of the resulting products through at least 2035. The business model of Synaffix is target-specific technology out-licensing, as exemplified through its existing deals with Shanghai Miracogen, Mersana Therapeutics and ADC Therapeutics.

Synaffix is backed by a top tier, European, life science-focused investor syndicate that includes Aravis, BioGeneration Ventures, BOM Capital and M Ventures.

For more information, please visit the website at


Synaffix BV
Anthony DeBoer

Director, Business Development

Instinctif Partners
Melanie Toyne-Sewell / Phil Marriage

Tel: +44 207 457 2020

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