A Study of Evorpacept (ALX148) in Patients with Advanced Gastric Cancer

Prior treatment

• Patients with known symptomatic CNS metastases or leptomeningeal disease requiring steroids. Patients with previously diagnosed brain metastases are eligible if they have completed their treatment and have recovered from the acute effects of radiation therapy or surgery prior to study entry, have discontinued corticosteroid treatment for these metastases and are clinically stable off anticonvulsants for at least 4 weeks and are neurologically stable before enrollment
• Prior radiotherapy within 2 weeks of start of study treatment. Note: Participants must have recovered from all radiation-related toxicities, not require corticosteroids, and not have had radiation pneumonitis. A 1-week washout is permitted for palliative radiation (≤2 weeks of radiotherapy) to non-CNS disease
• Prior treatment with anti-CD47 or anti-SIRPα agent or ramucirumab or any other systemic anticancer therapy within 4 weeks of starting study treatment
• Any Grade 3-4 GI bleeding or history of deep vein thrombosis (DVT), pulmonary embolism (PE), arterial thrombosis or any other significant thromboembolism (venous port or catheter thrombosis or superficial venous thrombosis are not considered "significant") within 3 months prior to first dose of Cycle 1 Day 1
• Prior history of GI perforation/fistula (within 6 months of first dose of protocol therapy) or risk factors for perforation

Other illness

• Cirrhosis at a level of Child-Pugh B (or worse) or cirrhosis (any degree) and a history of hepatic encephalopathy or clinically meaningful ascites resulting from cirrhosis. Clinically meaningful ascites is defined as ascites from cirrhosis requiring diuretics or paracentesis

• Age ≥18 years (except in regions in which the minimum age for subject participation is >18 years)
• Patients with HER2-overexpressing advanced or metastatic gastric or gastroesophageal junction (GEJ) adenocarcinoma that has progressed on or after a prior HER2-directed agent and fluoropyrimidine- or platinum-containing chemotherapy (2nd-line or 3rd-line). Phase 2: HER2 overexpression determined by an FDA-approved test for gastric/GEJ cancer. If safe and feasible, it is recommended that patient eligibility be based on a biopsy obtained after prior trastuzumab treatment. Phase 3: HER2 overexpression determined by HER2 protein overexpression and/or HER2 gene amplification in tumor specimens assessed with FDA-approved (and local regulatory authority approved) tests specific for gastric cancer. (HER2 positivity will be centrally assessed for eligibility in Phase 3)
• Patients must have at least one measurable lesion as defined by RECIST version 1.1. Lesions situated in a previously irradiated area are considered measurable if progression has been demonstrated in such lesions
• Adequate bone marrow, renal, liver, cardiac (via ECG), clotting (INR/PT and PTT) function
• Eastern Cooperative Oncology Group (ECOG) Performance Status (PS) must be 0 or 1
• Resolved acute effects of any prior therapy
• Patients of childbearing potential must be non-pregnant and must agree to use a highly effective method of contraception throughout the study
• Consent to the study and study procedures