ALX Oncology Reports ASPEN-03 and ASPEN-04 Phase 2 Trials Evaluating Evorpacept with a Checkpoint Inhibitor for the Treatment of Head and Neck Cancers Did Not Meet Primary Endpoints

Core Insights - ALX Oncology announced topline data from Phase 2 ASPEN-03 and ASPEN-04 clinical trials, revealing that the investigational CD47-blocker evorpacept did not meet primary endpoints for improved objective response rates when combined with Merck's KEYTRUDA® in advanced head and neck squamous cell carcinoma [1][6] - Despite the trial outcomes, the company remains committed to advancing evorpacept in combination with other anti-cancer antibodies based on previous positive clinical data [4][6] Group 1: Clinical Trial Results - The ASPEN-03 and ASPEN-04 trials evaluated evorpacept combined with KEYTRUDA® with or without chemotherapy in patients with advanced head and neck squamous cell carcinoma [7] - The primary endpoints for both trials were objective response rates compared to historical controls, with key secondary endpoints including safety, duration of response, progression-free survival, and overall survival [7] - The combination demonstrated a manageable safety profile consistent with previous reports for pembrolizumab and chemotherapy [1][4] Group 2: Mechanism of Action - Evorpacept functions by blocking the 'don't eat me' signal from CD47 on cancer cells, allowing macrophages to target cancer cells selectively [2][9] - The drug is designed to enhance T-cell priming and stimulate the adaptive immune system, although the trials did not support advancing this combination into registrational studies [3][6] Group 3: Future Directions - The company will continue to explore evorpacept in combination with various anti-cancer antibodies in other cancer types, including colorectal cancer, breast cancer, non-Hodgkin lymphoma, and multiple myeloma [2][4] - ALX Oncology is prioritizing its established anti-cancer antibody combination program, which has shown positive results in other studies [4][6] - Evorpacept has received Fast Track designation from the FDA for second-line treatment of HER2-positive gastric or GEJ carcinoma, indicating its potential in the oncology pipeline [9][10]