Interim Data from Ambrx’s Study of ARX788 selected for Spotlight Poster Discussion at the 2022 San Antonio Breast Cancer Symposium

Investigators to present efficacy and safety data of ARX788 treatment in patients with HER2+ metastatic breast cancer who have progressed following treatment with T-DM1

SAN DIEGO, Nov. 29, 2022 (GLOBE NEWSWIRE) — ​Ambrx Biopharma Inc., or Ambrx, (NYSE: AMAM), a clinical stage biopharmaceutical company using its proprietary Engineered Precision Biologics (EPBs) platform to create antibody drug conjugates (ADCs), today announced that interim data from its safety and efficacy study of ARX788 have been selected for a Spotlight Poster Discussion at the 2022 San Antonio Breast Cancer Symposium (SABCS) being held December 6^th to 10^th, 2022, in San Antonio, TX. ACE-Breast-03 (NCT04829604) is a Phase 2, single-arm clinical study evaluating ARX788 in patients with HER2+ metastatic breast cancer (mBC) whose disease progressed following T-DM1, T-DXd and/or tucatinib-containing regimens. Ambrx’s abstract was selected as a Spotlight Poster Discussion session, which features oncology experts discussing the most prominent topics and latest findings in breast cancer research. Each Spotlight session will include a live 15-minute Q&A session with Spotlight discussants and poster presenters. The Spotlight Poster Discussion will provide efficacy and safety data in the post T-DM1 patient population treated with ARX788.

ARX788 is an anti-HER2 antibody drug conjugate currently being studied in several registrational trials in breast cancer and gastric/GEJ cancer by Ambrx’s partner, NovoCodex Biopharmaceuticals, in China. Pursuant to its recently announced strategic reprioritization, Ambrx has paused the internal development of ARX788 and is seeking to partner ARX788 outside of China.

Details for the Spotlight Poster Discussion poster presentation are shown below:

Date: Friday December 9, 2022
Time: 7:00 AM – 8:15 AM
Title: ACE-Breast-03: Efficacy and safety of ARX788 in patients with HER2+ metastatic breast cancer previously treated with T-DM1
Poster Number: PD18-09
Presenter: Sarah Hurvitz, M.D.

About Ambrx Biopharma Inc. (Ambrx)
Ambrx is a clinical stage biopharmaceutical company using an expanded genetic code technology platform to discover and develop Engineered Precision Biologics. These include 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 its lead product candidate ARX517, a prostate-specific membrane antigen (PSMA) targeting ADC. In addition, Ambrx has clinical collaborations with multiple partners on drug candidates generated using Ambrx technology. For more information, please visit www.ambrx.com.

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 “anticipate,” “believe,” “estimate,” “expect,” “intend,” “plan,” “project,” “may,” “will,” “could,” “should,” “seek,” “potential” and similar expressions, and include, without limitation, express or implied statements regarding Ambrx’s beliefs and expectations regarding the advancement and potential benefits of its product candidates, clinical development and strategic plans, the timing of program updates and milestones related to its product candidates. 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 of novel therapeutics, including potential delays in clinical trials and regulatory submissions and the fact that future clinical trial results may not be consistent with preliminary results or results 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 Annual Report on Form 20-F filed with the United States Securities and Exchange Commission (SEC) on April 26, 2022, and elsewhere in Ambrx’s filings and reports with the SEC. 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.

Contacts

INVESTORS
Mike Moyer
LifeSci Advisors
617-308-4306
mmoyer@lifesciadvisors.com

MEDIA
Mike Tattory
Account Supervisor 
LifeSci Communications 
mtattory@lifescicomms.com

Source: Ambrx