The company will present the following two assets during the AACR Annual Meeting 2025:

1. AT65474 is a highly selective anti-CLDN6 ADC with a proprietary payload

Session Category: Experimental and Molecular Therapeutics

Session Title: Antibody-Based Cancer Therapeutics 4

Session Date and Time: April 30, 2025, 9:00 AM to 12:00 PM (Local Time)

Location: Poster Section 16

Poster Board Number: 7

Published Abstract Number: 6741

CLDN6 is a membrane-bound oncofetal protein and a promising target for cancers such as ovarian and testicular cancer. AT65474 is an antibody drug conjugate (ADC) candidate composed of a highly selective humanized anti-CLDN6 antibody conjugated to a proprietary payload, namely TCS132, with a drug-to-antibody (DAR) ratio of 4. The antibody is engineered to incorporate AxcynCYSTM technology for site-specific conjugation which can reproducibly achieve high DAR4 ratios of greater than 97% by HIC analysis.

The payload, TCS132, is derived from an FDA approved drug and when compared to the parent drug, demonstrates increased potency with broad sub-nanomolar activities across a wide range of cancer cell lines including those resistant to paclitaxel, DM1, MMAE and DXd. Additionally, TCS132 was chemically optimized for better PK properties and demonstrates a much-improved safety profile despite its increased potency over the parent drug.

2. AT2604 is a highly efficacious ADC targeting alkaline phosphatases ALPP and ALPPL2​

Session Category: Experimental and Molecular Therapeutics

Session Title: Antibody-Based Cancer Therapeutics 4

Session Date and Time: April 30, 2025, 9:00 AM to 12:00 PM (Local Time)

Location: Poster Section 16

Poster Board Number: 17

Published Abstract Number: 6751

Placental alkaline phosphatases, ALPP and ALPPL2, are highly homologous, membrane-bound proteins involved in fetal development. Despite having limited expression in normal tissues, they are highly differentiated in multiple tumor cells making them ideal targets for antibody drug conjugate (ADC) development.

AT2604 is an ADC incorporating an anti-ALPP/ALPPL2 antibody conjugated to monomethyl auristatin E (MMAE) with high DAR 4 homogeneity; and displays strong tumor growth inhibition at low doses in CDX models of gastric and pancreatic cancer. In patient-derived xenograft models of gastric cancer with moderate- and low-antigen expression, AT2604 achieves near-complete tumor regression at 3 and 6 mg/kg (QWx3), respectively. A preliminary toxicity assessment in non-human primates concluded a well-tolerated dose of 10 mg/kg (Q3Wx3) without exhibiting any non-reversible adverse effects and good plasma stability;  implying that AT2604 possesses an improved safety profile over other vedotin-based ADCs.

Email us at BD@axcynsis.com if you are interested to learn more about our Pipelines and Leading assets.