A Phase 2/3 interventional study of PF-08634404 and Chemotherapy in Untreated Advanced or Metastatic Gastric, Gastroesophageal Junction , or Esophageal Adenocarcinoma, Metastatic Gastric Cancer and Gastroesophageal Junction Cancer, sponsored by Pfizer. Recruiting at 102 sites in 10 countries. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-10-13.
Sponsored by Pfizer · Phase 2/3, Interventional, and Treatment
Help build ClinicalTrials.gg — short surveys, remote interviews or testing, in your language. Take part →
Among 27 studies in Stomach Neoplasms by Pfizer — 5 open to participants now, 7 under way, 1 of them phase 3. Stomach Neoplasms · Pfizer.
Among the 27 studies in Stomach Neoplasms by Pfizer, this one is the 3rd largest by planned enrollment of the 25 interventional ones that give a count, is one of 2 that started in 2026, is the only one in phase 2/3, and was the 26th registered.
3,401 studies on the registry are indexed under Stomach Neoplasms; 993 are open to participants now.
Browse Stomach Neoplasms studies →5 of the 27 studies in Stomach Neoplasms by Pfizer are open now, in 12 countries. Recruiting first, the newest first:
Pfizer · Sites in United States
Ages 18+
Seagen, a wholly owned subsidiary of Pfizer · Sites in United States, Canada, China and 7 more countries
Ages 18+
Seagen, a wholly owned subsidiary of Pfizer · Sites in United States, Belgium, Canada and 8 more countries
Ages 18+
Seagen, a wholly owned subsidiary of Pfizer · Sites in United States, France, Korea, Republic of and 4 more countries
Ages 18+
By country, each count listing its studies:
Of the 704 Stomach Neoplasms studies recruiting now, 376 (53%) set no upper age limit and 194 (28%) stop at 75 or younger; 28 take children under 18; 69 take healthy volunteers.
This study: 18 Years and older · all sexes · no healthy volunteers.
The full table on the hub →This tab as a report to print or save as PDF → With an account.
27 studies; the count open now beside each. This study's row is marked.
A study in two phases is counted once above. Listed by phase, each with its combined phases: Phase 1 19 · Phase 2 6 · Phase 3 2
First in 2002; this study’s year is marked. 2 started in 2026.
By drug class, each counting the studies that test any of its medicines:
This study's planned enrollment of 840 is above the median of 66 across 2,500 interventional studies indexed under Stomach Neoplasms.
Median enrollment 79 across the 25 interventional studies, 30,936 across the 2 observational. Of the 20 that completed or were terminated, 10 (50%) have results posted.
This tab as a report to print or save as PDF → With an account.
Pfizer is the lead sponsor of 3,337 studies on the registry; 150 are open to participants now.
Of its 601 completed or terminated interventional studies of FDA-regulated products, 392 (65%) have results posted.
1 of the studies in Stomach Neoplasms by Pfizer that are under way reach primary completion within a year, 0 of them phase 3. Phase 3 first, then by date:
| Study | Primary completion |
|---|---|
| NCT04389632Seagen, a wholly owned subsidiary of PfizerA Study of Sigvotatug Vedotin in Advanced Solid Tumors | 2027-06-16 |
Add it to your calendar (.ics) → With an account.
Among the 27 studies in Stomach Neoplasms by Pfizer, from their registry updates:
This tab as a report to print or save as PDF → With an account.
This study is being done to learn more about a new medicine called PF-08634404 and how well it works when given with chemotherapy to people with gastroesophageal cancer that is locally advanced (spread to nearby tissues) or has spread to other parts of the body.
To join the study, participants must meet the following conditions:
Be 18 years or older. Have locally advanced or metastatic gastric, gastroesophageal junction or esophageal adenocarcinoma Be treatment naïve for advanced or metastatic disease Be in good physical condition and have healthy organs based on medical tests.
The study has two parts:
The treatment will be given in repeated time periods called cycles.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.
A scale of how much an illness limits everyday activity. For people being assessed to join a study, scores run from 0 (fully active) to 4; lower is more active.
Studies most often ask for 0–1 or 0–2. Your doctor gives the score; the WHO scale uses the same steps. The full scale also has 5, which records death.
HER2 is a protein, made from the ERBB2 gene, that drives the growth of some cancers. A study may look for a level of the protein, extra copies of the gene, or a particular change in it.
In breast cancer, protein tests are read as HER2-positive, HER2-low or HER2-negative; other cancers use their own rules. Check which test result the study requires.
PD-1, PD-L1 and CTLA-4 are proteins that act as brakes on the immune system. Checkpoint inhibitors, such as pembrolizumab or nivolumab, block them so the immune system can attack a cancer.
PD-L1 can also be measured in a tumour sample. Some scores count stained tumour cells only (TPS); others also count certain immune cells (CPS). The study names the score and the minimum it uses.
Cancer deposits in the brain from a cancer that started elsewhere in the body (CNS metastases include the spinal cord).
Studies differ: some leave out any brain metastases, some accept ones treated and stable for some weeks. Check what this study allows.
Cancer that has spread to the leptomeninges, the thin layers covering the brain and spinal cord, and the fluid between them. It is not the same as brain metastases.
Criteria often treat it separately, and many studies leave it out even where treated brain metastases are allowed.
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Stem cell (bone marrow) transplants. Allogeneic uses cells from a donor; autologous uses your own cells, collected earlier and given back.
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
Metastases
Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ECOG performance status
A scale of how much an illness limits everyday activity. For people being assessed to join a study, scores run from 0 (fully active) to 4; lower is more active.
Studies most often ask for 0–1 or 0–2. Your doctor gives the score; the WHO scale uses the same steps. The full scale also has 5, which records death.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HER2
HER2 is a protein, made from the ERBB2 gene, that drives the growth of some cancers. A study may look for a level of the protein, extra copies of the gene, or a particular change in it.
In breast cancer, protein tests are read as HER2-positive, HER2-low or HER2-negative; other cancers use their own rules. Check which test result the study requires.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
PD-1, PD-L1 and checkpoint inhibitors
PD-1, PD-L1 and CTLA-4 are proteins that act as brakes on the immune system. Checkpoint inhibitors, such as pembrolizumab or nivolumab, block them so the immune system can attack a cancer.
PD-L1 can also be measured in a tumour sample. Some scores count stained tumour cells only (TPS); others also count certain immune cells (CPS). The study names the score and the minimum it uses.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Brain metastases
Cancer deposits in the brain from a cancer that started elsewhere in the body (CNS metastases include the spinal cord).
Studies differ: some leave out any brain metastases, some accept ones treated and stable for some weeks. Check what this study allows.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Leptomeningeal disease
Cancer that has spread to the leptomeninges, the thin layers covering the brain and spinal cord, and the fluid between them. It is not the same as brain metastases.
Criteria often treat it separately, and many studies leave it out even where treated brain metastases are allowed.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Allogeneic and autologous transplant
Stem cell (bone marrow) transplants. Allogeneic uses cells from a donor; autologous uses your own cells, collected earlier and given back.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Autoimmune disease
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
PF-08634404 + Chemotherapy
Biological: PF-08634404 · Drug: Chemotherapy
PF-08634404 + Chemotherapy
Biological: PF-08634404 · Drug: Chemotherapy
Nivolumab + Chemotherapy
Drug: Chemotherapy · Biological: Nivolumab
Participants will receive PF-08634404 intravenously.
Also known as: SSGJ-707
Participants will receive PF-08634404 intravenously in combination with Chemotherapy.
Participants will receive Nivolumab intravenously.
Phase 2: Confirmed Objective response rate (ORR) using RECIST 1.1 as assessed by investigator
Confirmed ORR by investigator is defined as the proportion of participants with confirmed Complete Response (CR) or Partial Response (PR) per RECIST v1.1 as assessed by investigator.
Time frame: Approximately 4 years
Phase 2: Number of participants with treatment-emergent adverse events
Adverse Events (AEs) as characterized by type, frequency, severity (as graded by NCI CTCAE version 5.0), timing, seriousness, and relationship to study intervention.
Time frame: Through 90 days after the last study intervention; Approximately 4 years
Phase 3: Progression Free Survival (PFS) using RECIST 1.1 as assessed by BICR
PFS by BICR is defined as the time from the date of randomization to the date of first documented disease progression per RECIST 1.1 as assessed by BICR, or death due to any cause, whichever occurs first.
Time frame: Approximately 4 years
Phase 3: Overall Survival (OS)
OS is defined as the time from the date of randomization to the date of death due to any cause.
Time frame: Approximately 4 years
Phase 2: Duration of Response (DOR) using RECIST 1.1 as assessed by investigator
DOR by investigator is defined as the time from the first documentation of objective response (CR or PR that is subsequently confirmed) to the date of first documented disease progression per RECIST 1.1 as assessed by investigator, respectively, or death due to any cause, whichever occurs first.
Time frame: Approximately 4 years
Phase 2: Progression Free Survival (PFS) using RECIST 1.1 as assessed by investigator
PFS by investigator is defined as the time from the date of first dose to the date of first documented disease progression per RECIST 1.1 as assessed by investigator, or death due to any cause, whichever occurs first.
Time frame: Approximately 4 years
Phase 2: Overall Survival (OS)
OS is defined as the time from the date of first dose to the date of death due to any cause.
Time frame: Approximately 4 years
Phase 2: Number of participants with laboratory abnormalities
Laboratory abnormalities as characterized by type, frequency, severity (as graded by NCI CTCAE version 5.0), and timing. For laboratory tests without CTCAE grade definitions, results will be categorized as normal, high, low, or not done and be listed.
Time frame: Through 90 days after the last study intervention; Approximately 4 years
Phase 2: Serum concentrations of PF-08634404
Predose and postdose concentrations of PF-08634404
Time frame: Approximately 21 months
Phase 2: Incidence of Anti-Drug Antibody (ADA) against PF-08634404
Time frame: Approximately 21 months
Phase 3: ORR using RECIST 1.1 as assessed by BICR
ORR by BICR is defined as the proportion of participants with a Best Overall Response (BOR) of confirmed CR or confirmed PR per RECIST 1.1 as assessed by BICR.
Time frame: Approximately 4 years
Phase 3: ORR using RECIST 1.1 as assessed by investigator
ORR by investigator is defined as the proportion of participants with a BOR of confirmed CR or confirmed PR per RECIST 1.1 as assessed by investigator.
Time frame: Approximately 4 years
Phase 3: Progression free survival (PFS) using RECIST 1.1 as assessed by investigator
PFS by investigator is defined as the time from the date of randomization to the date of first documented disease progression per RECIST 1.1 as assessed by investigator, or death due to any cause, whichever occurs first
Time frame: Approximately 4 years
Phase 3: DOR using RECIST 1.1 as assessed by BICR
DOR is defined as the time from the first documentation of objective response (CR or PR that is subsequently confirmed) to the date of first documented disease progression per RECIST 1.1 as assessed by BICR, respectively, or death due to any cause, whichever occurs first.
Time frame: Approximately 4 years
Phase 3: DOR using RECIST 1.1 as assessed by investigator
DOR is defined as the time from the first documentation of objective response (CR or PR that is subsequently confirmed) to the date of first documented disease progression per RECIST 1.1 as assessed by investigator, respectively, or death due to any cause, whichever occurs first.
Time frame: Approximately 4 years
Phase 3: PFS2 (PFS after next-line therapy) by investigator
PFS2 is defined as the time from the date of randomization to the date of second objective disease progression or death due to any cause, whichever occurs first
Time frame: Approximately 4 years
Phase 3: Number of participants with treatment-emergent adverse events
AEs as characterized by type, frequency, intensity as graded by NCI CTCAE version 5.0, timing, seriousness, and relationship to study intervention(s)
Time frame: Through 90 days after the last study intervention; Approximately 4 years
Phase 3: Number of participants with laboratory abnormalities
Laboratory abnormalities as characterized by type, frequency, severity (as graded by NCI CTCAE version 5.0), and timing. For laboratory tests without CTCAE grade definitions, results will be categorized as normal, high, low, or not done and be listed.
Time frame: Through 90 days after the last study intervention; Approximately 4 years
Phase 3: Serum concentrations of PF-08634404
Predose and postdose concentrations of PF-08634404
Time frame: Approximately 21 months
Phase 3: Incidence of ADA against PF-08634404
Time frame: Approximately 21 months
Phase 3: Change from baseline in Functional Assessment of Cancer Therapy - Gastric (FACT-Ga) Total score
Time frame: Approximately 4 years
Phase 3: Time to definitive deterioration in FACT-Ga Total score
Time frame: Approximately 4 years
Phase 3: Time to definitive deterioration in Gastric Cancer Subscale (GaCS) score
Time frame: Approximately 4 years
Showing the first 100 of 102 sites across 10 countries. Choose a country and city above to see the rest.
Plan to share: Yes — Pfizer will provide access to individual de-identified participant data and related study documents (e.g. protocol, Statistical Analysis Plan (SAP), Clinical Study Report (CSR)) upon request from qualified researchers, and subject to certain criteria, conditions, and exceptions. Further details on Pfizer's data sharing criteria and process for requesting access can be found at: https://www.pfizer.com/science/clinical_trials/trial_data_and_results/data_requests.
Data sharing details ↗ · www.pfizer.com
Started May 2026 (actual). Primary completion is estimated for Jul 2031, 62 months after the start.
Of 26 phase 2/3 interventional studies under Stomach Neoplasms, half reached primary completion within 49 months of starting (the median), counting those still running; a quarter within 28 and three quarters within 52. This study's planned 62 months is above that.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
Contact study teamGet an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
Studies of the drug tested here: Anti-PD-1/Anti-VEGF Bispecific Antibody PF-08634404