Gastric Cancer Clinical Trial Landscape

Why gastric cancer trial monitoring matters in 2026

Gastric and gastroesophageal junction (GEJ) adenocarcinoma is the fifth most common cancer worldwide, with over one million new cases annually. While incidence is declining in Western populations, it remains extremely prevalent in East Asia (Japan, Korea, China), and the majority of patients present with advanced disease and poor prognosis.

The gastric cancer pipeline in 2026 is undergoing a transformation driven by several converging targets:

• CLDN18.2 (Claudin 18.2) — zolbetuximab (Vyloy) received FDA approval in 2024 for CLDN18.2-positive, HER2-negative gastric/GEJ cancer. This marks the validation of CLDN18.2 as a key target; ADCs, bispecifics, and CAR-T cells targeting CLDN18.2 are now pouring into trials
• HER2-targeted ADCs — trastuzumab deruxtecan (T-DXd / Enhertu) has shown transformative activity in HER2-positive gastric cancer, displacing standard HER2 therapy. Multiple next-gen HER2 ADCs are in development
• PD-1/PD-L1 combinations — nivolumab (CheckMate 649), pembrolizumab, and tislelizumab are now first-line standards in high CPS tumors; ongoing trials are defining maintenance, combination, and biomarker strategies
• FGFR2b inhibitors — bemarituzumab (anti-FGFR2b) showed Phase 3 activity in FGFR2b-overexpressing tumors; approval expected imminently
• VEGFR2 and anti-angiogenic — ramucirumab remains active; combinations with IO being explored
• EGFR and MET-targeted agents — in molecularly selected subpopulations

Active Phase 3 gastric cancer trials (2026)

27 Phase 3 programs are active in gastric/GEJ cancer, spanning FGFR2b, HER2, CLDN18.2, PD-1/TIGIT, and novel chemotherapy combinations:

What we monitor for gastric cancer

Our system pulls from the ClinicalTrials.gov API every day. For a gastric cancer watch profile, you can configure alerts for:

• Condition keywords: "gastric cancer", "stomach cancer", "gastroesophageal junction", "GEJ adenocarcinoma", "gastric adenocarcinoma", "gastroesophageal cancer"
• Drug/target keywords: "CLDN18.2", "claudin 18", "zolbetuximab", "HER2 gastric", "trastuzumab deruxtecan", "FGFR2b", "bemarituzumab", "ramucirumab" — any drug or target you're tracking
• Phase filter: Phase 1 for early programs, Phase 2/3 for competitive commercial data
• Sponsor type: Industry only or all sponsors including major academic sites in East Asia and the US
• Status changes: New registrations, enrollment opens, status updates, and results postings

Bemarituzumab (FGFR2b) — Phase 3 complete, approval decision approaching

Bemarituzumab (Amgen) is an anti-FGFR2b antibody that blocks fibroblast growth factor receptor 2b signaling. Approximately 30% of gastric/GEJ adenocarcinomas overexpress FGFR2b — a molecularly selected population. The FIGHT Phase 3 trial (NCT05052801) completed enrollment and compares bemarituzumab + mFOLFOX6 versus placebo + mFOLFOX6 in first-line FGFR2b-overexpressing gastric/GEJ cancer.

Phase 2 (FIGHT-101 and FIGHT-302) demonstrated meaningful survival benefit in the FGFR2b-selected population, with 24-month OS around 38% vs 25% for chemotherapy alone. The biomarker selection (FGFR2b overexpression by IHC or FISH) creates a distinct patient segment — approximately 5,000 new patients annually in the US. BLA filing and FDA review are anticipated in 2026.

The FGFR2b program represents one of the few positive Phase 3 results in gastric cancer outside PD-1 and HER2 targeting, validating a third biomarker-defined subtype for treatment selection alongside HER2 and MSI-H status.

T-DXd redefining HER2-positive gastric cancer — from 2nd-line to 1st-line quadruplet

Trastuzumab deruxtecan (T-DXd, Enhertu; Daiichi Sankyo/AstraZeneca) received approval in HER2-positive gastric/GEJ cancer based on DESTINY-Gastric01 (Japan/Korea, 40.5% ORR vs 11.3% for standard), extending to global approval with DESTINY-Gastric02. In 2026, the T-DXd program is moving into the first-line setting:

• DESTINY-Gastric04 (NCT06731478): 1L quadruplet — T-DXd + chemotherapy + pembrolizumab + trastuzumab vs current standard (trastuzumab + chemo + pembrolizumab). If positive, would represent the most aggressive displacement of a standard-of-care in HER2+ gastric cancer
• Rationale: ToGA established trastuzumab + chemo; CheckMate 649 established nivolumab + chemo ± trastuzumab; KEYNOTE-811 established pembrolizumab + trastuzumab + chemo. Adding T-DXd to this triplet tests whether ADC-mediated HER2-directed cytotoxicity adds further survival benefit

HER2 amplification occurs in approximately 15–20% of gastric/GEJ adenocarcinomas — the highest-prevalence molecularly defined subtype — making HER2 programs the most commercially significant in the indication. Multiple competitors are racing to displace trastuzumab: T-DXd (Daiichi Sankyo), zanidatamab (Jazz/Zymeworks), disitamab vedotin (RemeGen), KN026 (JMT-Bio), HLX22 (Henlius), and SHR-A1811 (Hengrui).

SHR-A1811 (Hengrui/Suncadia): A new entry to the 1L HER2+ gastric Phase 3 race. SHR-A1811 is Hengrui's proprietary HER2 ADC — the same molecule showing activity in breast cancer — now in a Phase 3 trial (NCT07118527) combining it with chemotherapy and adebrelimab (Hengrui's PD-L1 antibody) vs. standard of care in previously untreated HER2-positive gastric or GEJ adenocarcinoma. This is a distinctly Chinese commercial strategy: Hengrui controls both the ADC and the PD-L1 checkpoint, enabling a single-sponsor triplet without partnership royalties. For global competitive intelligence teams, SHR-A1811's gastric Phase 3 join a crowded 1L space but represent a significant internal Chinese market opportunity.

CLDN18.2: zolbetuximab approved, ADC race enters Phase 3

The 2024 approval of zolbetuximab (Vyloy; Astellas) in CLDN18.2-positive, HER2-negative gastric/GEJ cancer validated Claudin 18.2 as the third major targetable biomarker after HER2 and MSI-H status. Approximately 38% of gastric cancers express CLDN18.2 at moderate-high levels. The CLDN18.2 competition is now moving toward ADCs and beyond the monoclonal antibody:

• Sonesitatug vedotin (AZD0901, AstraZeneca): CLDN18.2 ADC in two Phase 3 trials — as 2nd-line monotherapy vs investigator's choice (NCT06346392) and as 1st-line combination with capecitabine ± rilvegostomig (NCT07431281, the PD-1/TIGIT bispecific)
• JS107 (Junshi Bioscience): CLDN18.2 ADC vs investigator's choice in 2nd-line Phase 3 (NCT07284134)
• CMG901 (AstraZeneca/Keymed): Phase 1/2 CLDN18.2 ADC with strong early signals
• CAR-T cells: CLDN18.2-directed CAR-T programs in Phase 1/2 in China — potential "functional cure" approach in a small patient subset

AstraZeneca alone has three separate CLDN18.2/PD-1 combination trials in Phase 3, making gastric cancer one of the most active oncology programs in AZ's pipeline.

Rilvegostomig (PD-1/TIGIT bispecific) — AstraZeneca's multi-indication bet

Rilvegostomig is a bispecific antibody blocking both PD-1 and TIGIT on a single molecule (compared to combination of separate antibodies). TIGIT is an inhibitory checkpoint expressed on tumor-infiltrating T cells; co-blockade with PD-1 enhances T-cell activation in a synergistic mechanism distinct from anti-CTLA-4. AstraZeneca is testing rilvegostomig in multiple gastric cancer contexts in 2026:

• 1L HER2+ gastric + trastuzumab + fluoropyrimidine (NCT06764875) — testing PD-1/TIGIT in the HER2+ setting
• 1L CLDN18.2+ gastric alongside sonesitatug vedotin + capecitabine (NCT07431281) — CLDN18.2 ADC + PD-1/TIGIT combination

The rilvegostomig program reflects the broader industry question of whether combined PD-1+TIGIT co-blockade on a single molecule provides meaningful advantages over adding separate anti-TIGIT antibodies to PD-1/PD-L1 therapy — a question that failed for tiragolumab (Roche) in lung cancer but remains open for other indications and molecules.

Who uses gastric cancer trial monitoring

• GI oncology BD teams — tracking CLDN18.2, HER2, and FGFR2b competitor programs for partnering and pipeline decisions
• Oncology investors — monitoring Phase 2/3 initiations and enrollment milestones in gastric cancer
• GI oncologists and research sites — staying current on available trials for patients with advanced gastric/GEJ cancer
• CROs with GI oncology practices — tracking competing enrollment across the major Phase 3 gastric programs
• Academic researchers in gastric oncology — following the global competitive landscape including East Asian programs

Frequently asked questions