ALX Oncology to Present ALX148 Clinical Data at the ESMO 23rd World Congress on Gastrointestinal Cancer

Updated results will be presented from ASPEN-01, the ongoing Phase 1b Study of ALX148 in combination trastuzumab, ramucirumab and paclitaxel in patients with gastric or gastroesophageal junction cancerBURLINGAME, Calif., April 21, 2021 (GLOBE NEWSWIRE) — ALX Oncology Holdings Inc., (“ALX Oncology”) (Nasdaq: ALXO), a clinical-stage immuno-oncology company developing therapies that block the CD47 checkpoint pathway, today announced that our Phase 1b study of ALX148 in patients with advanced gastric or gastroesophageal junction cancer has been selected for a short oral presentation at the ESMO 23rd World Congress on Gastrointestinal Cancer to be held virtually from June 30 – July 3, 2021. Oral Presentation Information Title: ASPEN-01: A phase 1 study of ALX148, a CD47 blocker, in combination with trastuzumab, ramucirumab and paclitaxel in patients with 2nd line HER2-positive advanced gastric or gastroesophageal junction (G/GEJ) cancer Abstract Number: SO-31 Session Name: Session X: Esophageal and Gastric Cancers Date and Time: Saturday, July 3, 2021, 15:01 – 15:08 CEST About ALX Oncology ALX Oncology is a publicly traded, clinical-stage immuno-oncology company focused on helping patients fight cancer by developing therapies that block the CD47 checkpoint pathway and bridge the innate and adaptive immune system. ALX Oncology’s lead product candidate, ALX148, is a next generation CD47 blocking therapeutic that combines a high-affinity CD47 binding domain with an inactivated, proprietary Fc domain. ALX148 has demonstrated promising clinical responses across a range of hematologic and solid malignancies in combination with a number of leading anti-cancer agents. ALX Oncology intends to continue clinical development of ALX148 for the treatment of a range of solid tumor indications as well as MDS and AML. For more information, please visit ALX Oncology’s website at www.alxoncology.com. Cautionary Note Regarding Forward-Looking Statements This press release contains “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995, as amended. Such forward-looking statements are based on ALX Oncology’s beliefs and assumptions and on information currently available to it on the date of this press release. Forward-looking statements may involve known and unknown risks, uncertainties and other factors that may cause ALX Oncology’s actual results, performance or achievements to be materially different from those expressed or implied by the forward-looking statements. These and other risks are described more fully in ALX Oncology’s filings with the Securities and Exchange Commission (“SEC”), including ALX Oncology’s Annual Report on Form 10-K, filed with the SEC on March 18, 2021, and other documents ALX Oncology subsequently files with the SEC from time to time. Except to the extent required by law, ALX Oncology undertakes no obligation to update such statements to reflect events that occur or circumstances that exist after the date on which they were made. CONTACT: Investor Contact:

Peter Garcia
Chief Financial Officer, ALX Oncology
(650) 466-7125 Ext. 113
[email protected]

Argot Partners
(212)-600-1902
[email protected]

Media Contact:

Karen Sharma
MacDougall
(781) 235-3060
[email protected]