546C-CL-0201: A Phase 1b/2 Open-label Study to Assess the Safety and Efficacy of ASP546C in Participants with CLDN18.2-expressing Locally Advanced Unresectable or Metastatic Gastroesophageal Adenocarcinoma, Pancreatic Adenocarcinoma or Other Solid Tumor T

The primary objective of this multicohort phase 1b/2 study is to determine the RP2D of ASP546C (XNW27011) monotherapy based on the totality of efficacy, safety and PK data collected at 2 different dose levels. The secondary objectives include evaluation of the efficacy, safety, PK and immunogenicity of ASP546C monotherapy. Safety and tolerability will be assessed via AEs, SAEs, ECOG performance status, vital signs and other laboratory results.

Inova Schar Cancer
8081 Innovation Park Drive 
Fairfax, VA 22031

• Participant is ≥ 18 years of age at the time of signing informed consent.
• Participant has a histologically confirmed diagnosis of gastroesophageal (gastric/GEJ/esophageal) adenocarcinoma, pancreatic adenocarcinoma, or pan-tumor (cholangiocarcinoma, colorectal adenocarcinoma, NSCLC [adenocarcinoma], SCLC, ovarian mucinous carcinoma or invasive breast cancer [ER/PR+HER2-; ER/PR-HER2+;
  ER/PR+HER2+ (triple positive); ER/PR-HER2- (triple negative)] as determined by local testing).
• Participant has radiologically confirmed uLA/m gastroesophageal (gastric/GEJ/esophageal) adenocarcinoma, pancreatic adenocarcinoma or pan-tumor within 28 days prior to the first dose of study intervention.
• Cohorts 1 to 3 only: Participant has measurable disease according to RECIST v1.1 per investigator assessment within 28 days prior to the first dose of study intervention. For participants with only 1 measurable lesion and prior radiotherapy, the lesion must be outside the field of prior radiotherapy or must have documented progression following radiation therapy.
•  Cohort 4 only: Participant has radiologically evaluable disease (measurable and/or non-measurable) according to RECIST v1.1, per investigator assessment, within 28 days prior to the first dose of study intervention. For participants with only 1 evaluable lesion and prior radiotherapy, the lesion must be outside the field of prior radiotherapy or must have documented progression following radiation therapy.

• Cohorts 1, 2 and 3 only: Participant's disease is of the non-adenocarcinoma histology or mixed histology containing adenocarcinoma.
• Cohorts 1, 2 and 3 only: Participant has received > 2 prior lines of therapy for uLA/m disease.
  • Participants in Cohort 4 (pan-tumor) may enroll regardless of the number of prior lines of therapy, if they are not eligible for, decline, or do not have any available SoC treatment options.
• Participant has complete gastric outlet syndrome or a partial gastric outlet syndrome with persistent recurrent vomiting.
• Participant has significant gastric bleeding or had a significant bleeding episode from the gastrointestinal tract within 3 months prior to the first dose of study intervention and/or an untreated peptic ulcer disease that would preclude the participant from participation per investigator's judgment.
• Participant has significant bleeding disorders or has had vasculitis within 3 months prior to the first dose of study intervention.
• Participant has a history of gastrointestinal perforation and/or fistula within 6 months prior to the first dose of study intervention.
• Participant has symptomatic, untreated brain metastases or meningeal carcinomatosis (carcinomatous meningitis) from the primary malignancy. A participant with stable central nervous system metastases for > 3 months without need of steroids for ≥ 2 weeks prior to the first dose of study intervention is eligible.