Aston Sci pushes AST-301 gastric vaccine readout to February 2027
The trial's primary completion date shifted 16 months as enrollment finished at its 24-patient target, leaving an immunogenicity and safety readout for a vaccine with no direct competitor at its target and indication.
Executive Summary
- Aston Sci. Inc. pushed back the primary completion date for its Phase 2 gastric cancer vaccine trial by more than a year, with the readout now targeted for early 2027.
- Enrollment closed at its original target with no cut or expansion, and the trial moved to a non-recruiting status consistent with that closure.
- The trial's dual primary endpoints measure the vaccine's immune response and its safety profile in patients who have completed standard adjuvant treatment for gastric cancer.
- The vaccine sits without a same-target Phase 2 peer in gastric cancer, with the nearest comparable programs testing related biology in breast cancer rather than this indication.
The registry change
The trial, registered as NCT05771584 and known by the acronym Conerstone3, updated its primary completion date on July 22, 2026, moving it from October 15, 2025 to February 9, 2027. The trial's overall completion date also moved, from June 15, 2026 to May 31, 2027. The same registry update recorded the trial's status changing from Recruiting to Active, not recruiting. This is the second time the primary completion date has moved since the trial's 2023 registration: it shifted once before, from October 2023 to October 2025, in July 2024. NCT05771584Therapeutic Cancer Vaccine (AST-301, pNGVL3-hICD) in Gastric CancerNCT05771584
Probability of SuccessBased on the AppliedXL Probability of Success model. For more information about the methodology, read the research here.
What the trial tests
AST-301, also known as pNGVL3-hICD, is being tested in 24 patients with stage II or III gastric cancer who have completed curative surgery and standard adjuvant treatment. The trial runs in Taiwan under a randomized, open-label design with two arms. Its two primary endpoints measure the vaccine's immunologic efficacy, assessed by an interferon-gamma ELISpot assay, and the incidence of treatment-related adverse events graded by NCI CTCAE criteria. Secondary endpoints include one-year and end-of-study disease-free survival rates and changes in central memory T-cell populations between the trial's two arms. NCT05771584Therapeutic Cancer Vaccine (AST-301, pNGVL3-hICD) in Gastric CancerNCT05771584
Enrollment and status
Enrollment reached its target of 24 patients with no increase or shortfall against the original plan, a change the trial's own operational threshold treats as routine. The status move to Active, not recruiting followed that enrollment closure, the expected sequence once a small trial reaches its planned patient count. The primary completion date now sits about 16 months past its most recent guidance, extending the window before the immunogenicity and safety data become available. NCT05771584Therapeutic Cancer Vaccine (AST-301, pNGVL3-hICD) in Gastric CancerNCT05771584
The competitive frame
AST-301 targets the CSF2 receptor through GM-CSF receptor activation, and no other industry trial has reached Phase 2 with that target in gastric cancer. The closest comparable programs, Cancer Insight's trastuzumab and nelipepimut-S vaccine trials sharing the same target biology, are tested in breast cancer rather than gastric cancer. Within gastric cancer itself, the active competitive field is dominated by antibody and bispecific programs against different targets, including Astellas' ASP2138 against CLDN18.2 and Shanghai JMT-Bio's anbenitamab against HER2, both in Phase 3. Against that backdrop, a vaccine approach testing immune activation rather than direct tumor-antigen targeting stands apart mechanistically, and the readout will be informative mainly for whether that immune-activation approach produces a measurable disease-free survival signal in this adjuvant setting. NCT01570036
This analysis was produced using AI-assisted reporting systems, AppliedXL data, and official public records. These systems undergo editorial review, quality checks, and regular audits by human experts. Errors may still occur, as with any automated system. Always consult the linked primary sources. Read our AI Editorial Policy.