Ambrx to Present Preliminary ARX517 First-in-Human Safety, Efficacy, and Pharmacokinetics Data at ESMO 2023

Presentations represent the first time clinical data regarding ARX517 will be presented at a medical meeting

SAN DIEGO, July 28, 2023 (GLOBE NEWSWIRE) -- Ambrx Biopharma Inc., Ambrx (or the “Company”) (NASDAQ: AMAM), today announced the acceptance of four abstracts for poster presentation at the European Society for Medical Oncology (ESMO) Congress 2023, being held October 20-24, 2023 in Madrid, Spain. Posters will feature preliminary safety, efficacy, and pharmacokinetic (PK) data from APEX-01 (NCT04662580), evaluating Ambrx’s proprietary anti-PSMA antibody drug conjugate (ADC), ARX517, in metastatic castration resistant prostate cancer (mCRPC) patients. This will be the first presentation of clinical data regarding ARX517 at a medical congress.   

APEX-01 is a Phase 1/2, first-in-human, open label dose escalation and dose expansion trial enrolling patients with mCRPC whose tumors have progressed on at least two prior FDA-approved treatments and who have met at least one of the following three criteria: PSA progression defined by a minimum of two rising PSA values or radiographic progression by RECIST v1.1 or disease progression by the presence of new bone lesions. APEX-01 opened for enrollment July 2021 and is the only ongoing clinical trial in the United States targeting PSMA with an ADC.

Presentation details:

Title: APEX-01: First-in-human phase 1/2 study of ARX517, an anti- prostate-specific membrane antigen (PSMA) antibody-drug conjugate (ADC), in patients (pts) with metastatic castration-resistant prostate cancer (mCRPC)
Presentation number: 1804P

Title: ARX517, a next generation anti-PSMA antibody drug conjugate (ADC), demonstrates notable stability and pharmacokinetic (PK) profile in the ARX517 phase 1 clinical trial (APEX-01)
Presentation number: 1828P

Title: Evaluation of ARX517, a next-generation anti-PSMA antibody drug conjugate for prostate cancer treatment, in preclinical enzalutamide-resistant and enzalutamide-sensitive pharmacology models and in toxicology models
Presentation number: 41P

Title: Preclinical characterization of ARX305, a next-generation anti-CD70 antibody drug conjugate for the treatment of CD70-expressing cancers
Presentation number: 71P

About Ambrx Biopharma Inc.

Ambrx is a clinical stage biopharmaceutical company using an expanded genetic code technology platform to discover and develop next generation antibody drug conjugates (ADCs) and other engineered therapies to modulate the immune system. Ambrx is advancing a focused portfolio of clinical and preclinical programs designed to optimize efficacy and safety in multiple cancer indications, including ARX517, its proprietary antibody-drug conjugate (ADC) targeting the prostate-specific membrane antigen (PSMA) and ARX788, its proprietary ADC targeting HER2. In addition, Ambrx has preclinical and clinical collaborations with multiple partners on drug candidates generated using Ambrx technology. Ambrx spun out of The Scripps Research Institute in 2003 and has several other product candidates involving ADCs and other aspects of Ambrx’s protein engineering technology. For more information, please visit Ambrx routinely posts information that may be important to investors on its website.

Forward-Looking Statements

This press release includes certain “forward-looking statements” intended to qualify for the “safe harbor” from liability established by the Private Securities Litigation Reform Act of 1995, as amended. Forward-looking statements may be identified by the words “intend,” “plan,” and similar expressions. Forward-looking statements are based on Ambrx’s current expectations and are subject to inherent uncertainties, risks and assumptions that are difficult to predict. Factors that could cause actual results to differ include, but are not limited to, those risks and uncertainties associated with: the continuing impact of the COVID-19 pandemic and other public health-related risks and events on Ambrx’s business, operations, strategy, goals and anticipated milestones; Ambrx’s ability to execute on its strategy including with respect to the timing of its R&D efforts, initiation of clinical trials and other anticipated milestones; risks associated with development and marketing approval of novel therapeutics, including potential delays in clinical trials and regulatory submissions and the fact that future clinical trial results/data may not be consistent with interim, initial or preliminary results/data or results/data from prior preclinical studies or clinical trials; Ambrx’s ability to fund operations as anticipated; and the additional risks and uncertainties set forth more fully under the caption “Risk Factors” in Ambrx’s Quarterly Report on Form 10-Q filed with the SEC on May 11, 2023, and elsewhere in Ambrx’s filings and reports with the SEC, including the prospectus supplement to be filed in connection with the Offering. Forward-looking statements contained in this press release are made as of this date, and Ambrx undertakes no duty to publicly update or revise any forward-looking statements, whether as a result of new information, future events or otherwise, except as may be required under applicable law.


Mike Moyer
LifeSci Advisors

Mike Tattory
Account Supervisor
LifeSci Communications

Source: Ambrx Biopharma, Inc.