Adcentrx Therapeutics to Showcase Novel STEAP1 and NaPi2b ADCs with Oral and Poster Presentations at AACR 2025

On March 25, 2025 Adcentrx Therapeutics ("Adcentrx"), a clinical-stage biotechnology company redefining Antibody-Drug Conjugate (ADC) therapies for cancer treatment and other life-threatening diseases, reported it will present new data at the American Association for Cancer Research (AACR) (Free AACR Whitepaper) Annual Meeting 2025, (April 25-30, 2025) in Chicago, IL (Press release, Adcentrx Therapeutics, MAR 25, 2025, View Source [SID1234651430]).

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The company will deliver an oral presentation on ADRX-0405, its clinical-stage STEAP1 ADC, and a poster presentation on ADRX-0134, its preclinical NaPi2b ADC. The presentations will underscore the versatility of Adcentrx’s ADC platform, showing advancements in therapeutic window expansion, bystander effect optimization, and payload delivery improvements for targeted cancer therapy. These innovations are powered by Adcentrx’s proprietary i-Conjugation technology, which integrates stable conjugation chemistry and a cleavable linker to optimize ADC properties, ensuring optimal payload delivery and therapeutic efficacy.

ADRX-0405, Adcentrx’s second clinical program and potential first-in-class STEAP1 ADC, has the opportunity to expand treatment options for metastatic castration-resistant prostate cancer (mCRPC) and other STEAP1-expressing tumors, where targeted therapy options remain limited. Featuring a novel topoisomerase inhibitor linker-payload, ADRX-0405 represents a distinct therapeutic approach for this disease with a high unmet need for more tolerable and effective therapies.

ADRX-0134 is a preclinical NaPi2b ADC incorporating AP052, the same clinically validated microtubule inhibitor payload used in Adcentrx’s lead program, ADRX-0706 (Nectin-4 ADC), currently enrolling patients in Phase 1b (NCT06036121). ADRX-0134 offers a differentiated approach for patients with lung and ovarian cancers, where few viable treatment options are available.

Details of the oral and poster presentations are as follows:

Oral Presentation
Title: Preclinical characterization of a novel STEAP1 antibody-drug conjugate ADRX-0405 for the treatment of mCRPC
Abstract Number: 1159
Session Date & Time: Sunday, April 27, 3:25 p.m. – 3:40 p.m. CST
Session Title: Antibody-Based Cancer Therapeutic Agents

Poster Presentation
Title: ADRX-0134 as a novel auristatin-based NaPi2b antibody-drug conjugate with widened therapeutic window
Abstract Number: 1563
Session Date & Time: Monday, April 28, 9:00 a.m. – 12:00 p.m. CST
Session Title: Antibody-Based Cancer Therapeutics 1

About i-Conjugation Technology
Adcentrx’s proprietary i-Conjugation technology platform is an important component in the design of the company’s ADCs. The platform utilizes protease-cleavable linkers and stable conjugation chemistry to enhance payload delivery. This advanced technology ensures a highly stable ADC with the desired linker-payload.

About ADRX-0405
ADRX-0405 is a clinical-stage next-generation ADC targeting six-transmembrane epithelial antigen of the prostate 1 (STEAP1), a cell surface protein that is upregulated in prostate cancer and certain other cancers with limited expression in normal healthy tissue. The ADC is composed of a humanized IgG1 antibody and novel topoisomerase inhibitor linker-payload conjugated at a drug-to-antibody ratio of eight (DAR 8) to maximize payload delivery to solid tumors. ADRX-0405 preclinical studies have demonstrated its favorable pharmacokinetics, safety profile, and significant efficacy across multiple animal tumor models. ADRX-0405 is currently being evaluated in a Phase 1a/b clinical trial.

For more information about the ADRX-0405 Phase 1a/b clinical trial, please refer to the Study ID NCT06710379 on ClinicalTrials.gov.

About ADRX-0134
ADRX-0134 is a state-of-the-art preclinical ADC targeting NaPi2b, a cell surface sodium-dependent phosphate transporter expressed in lung and ovarian cancers with minimal expression in normal healthy tissues. The ADC is a human IgG1 antibody conjugated at DAR8 with Adcentrx’s clinically validated AP052 tubulin inhibitor payload, substantially expanding the therapeutic window of auristatin-based ADCs beyond existing vedotin technology. ADRX-0134 preclinical studies have demonstrated strong efficacy in lung and ovarian tumor models, and the ADC’s pharmacokinetics and safety profile are also favorable.