A Phase 1b/2 Multicenter, Open-label, Dose-escalation and Dose-expansion Study to Evaluate the Safety, Tolerability, Pharmacokinetics, Immunogenicity, and Antitumor Activity of Trastuzumab Deruxtecan (T-DXd) Monotherapy and Combinations in Adult Participants With HER2-expressing Gastric Cancer (DESTINY-Gastric-03)
Summary
DESTINY-Gastric03 will investigate the safety, tolerability, pharmacokinetics, immunogenicity, and preliminary antitumor activity of trastuzumab deruxtecan (T-DXd) alone or in combination with chemotherapy and/or immunotherapy in HER2-expressing advanced/metastatic gastric/gastroesophageal junction (GEJ) and esophageal adenocarcinoma patients. Study hypotheses: Combination of T-DXd with cytotoxic chemotherapy and/or immunotherapy administered to subjects at the recommended phase 2 dose will show manageable safety and tolerability and preliminary anti-tumor efficacy so as to permit further clinical testing. T-DXd in combination with cytotoxic chemotherapy or immune checkpoint inhibitor administered to HER2-expressing gastric, GEJ and esophageal cancer patients who have not received prior treatment for advanced/metastatic disease will show preliminary evidence of anti-tumour activity and the potential to become a therapeutic option for this patient population.
Arms & interventions
- DrugFluorouracil (5-FU)
5-FU: administered as an IV infusion
- DrugCapecitabine
Capecitabine: administered orally
- BiologicalDurvalumab
Durvalumab: administered as an IV infusion
- DrugOxaliplatin
Oxaliplatin: administered as an IV infusion
- BiologicalTrastuzumab
Trastuzumab: administered as an IV infusion
- DrugTrastuzumab deruxtecan
T-DXd: administered as an IV infusion
- DrugCisplatin
Cisplatin: administered as an IV infusion
- BiologicalPembrolizumab
Pembrolizumab: administered as an IV infusion
- BiologicalVolrustomig
Volrustomig: administered as an IV infusion
- BiologicalRilvegostomig
Rilvegostomig: administered as an IV infusion
Outcome measures
Primary
Part 1: Occurrence of adverse events (AEs) and serious adverse events (SAEs), graded according to NCI CTCAE v5.0
Occurrence of AEs and SAEs graded according to NCI CTCAE v5.0
Time frame: Safety will be assessed up to the follow-up period, approximately 24 months.
Part 1: Ocurrence of dose-limiting toxicities (DLTs)
Occurrence of dose limiting toxicities
Time frame: Safety will be assessed up to the follow-up period, approximately 24 months.
Part 1: Changes from baseline in laboratory parameters
Changes in laboratory parameters (every in appropriate units) compared to baseline results.
Time frame: Safety will be assessed up to the follow-up period, approximately 24 months.
Part 1: Changes from baseline in vital signs
Changes in vital signs results compared to baseline results.
Time frame: Safety will be assessed up to the follow-up period, approximately 24 months.
Part 1: Changes from baseline in electrocardiogram (ECG) results
Changes in ECG results compared to baseline results.
Time frame: Safety will be assessed up to the follow-up period, approximately 24 months.
Part 2, Part 3, Part 4 and Part 5: Endpoint assessed by Investigator per RECIST v1.1: Confirmed Objective Response Rate (ORR)
Confirmed ORR per RECIST 1.1 is the percentage of patients with Complete Response or Partial Response that is subsequently confirmed.
Time frame: (Endpoint: ORR) Efficacy will be assessed at an average of approximately 12 months
Secondary
Part 1: Objective Response Rate (ORR)
Time frame: Efficacy will be assessed at an average of approximately 12 months
Part 2, Part 3, Part 4 and Part 5: Occurrence of adverse events (AEs) and serious adverse events (SAEs)
Time frame: Safety will be assessed up to follow-up period, approximately 24 months
Part 2, Part 3, Part 4 and Part 5: Changes from baseline in laboratory parameters
Time frame: Safety will be assessed up to follow-up period, approximately 24 months
Part 2, Part 3, Part 4 and Part 5: Changes from baseline in vital signs
Time frame: Safety will be assessed up to follow-up period, approximately 24 months
Part 2, Part 3 , Part 4 and Part 5: Changes from baseline in body weight
Time frame: Safety will be assessed up to follow-up period, approximately 24 months
Part 2, Part 3, Part 4 and Part 5: Changes from baseline in electrocardiogram (ECG) results
Time frame: Safety will be assessed up to follow-up period, approximately 24 months
Duration of Response (DoR)
Time frame: Until progression or death, efficacy (DoR) will be assessed up to approximately 24 months
Disease Control Rate (DCR)
Time frame: Efficacy will be assessed at an average of approximately 12 months
Progression Free Survival (PFS)
Time frame: Until progression or death, efficacy (PFS) will be assessed up to approximately 24 months
Overall survival (OS)
Time frame: Until death, efficacy (OS) will be assessed up to approximately 24 months
Serum concentration of T-DXd, total anti-HER2 antibody, and MAAA-1181a in all arms
Time frame: While on study drug up to study completion, approximately 24 months
Serum concentration of durvalumab in study arms including T-DXd in combination with durvalumab
Time frame: While on study drug up to study completion, approximately 24 months
Presence of ADAs for T-DXD, durvalumab, volrustomig and rilvegostomig (in study arms including T-DXd and durvalumab, and T-DXd and volrustomig, and T-DXd and rilvegostomig respectively)
Time frame: While on study drug up to study completion, approximately 24 months
Serum concentrations of volrustomig and rilvegostomig in study arms including T-DXd in combination with volrustomig and T-DXd in combination with rilvegostomig
Time frame: While on study drug up to study completion, approximately 24 months
Comparison of ORR
Time frame: While on study drug up to study completion, approximately 24 months
Comparison of DCR
Time frame: While on study drug up to study completion, approximately 24 months
Comparison of DoR
Time frame: While on study drug up to study completion, approximately 24 months
Comparison of PFS
Time frame: While on study drug up to study completion, approximately 24 months
Comparison of OS
Time frame: While on study drug up to study completion, approximately 24 months
Eligibility criteria
Study locations (10)
Research Site
Santa Monica, California, 90404
Research Site
Westwood, Kansas, 66205
Research Site
Baltimore, Maryland, 21287
Research Site
Boston, Massachusetts, 02114
Research Site
Boston, Massachusetts, 02215
Research Site
Ann Arbor, Michigan, 48109
Research Site
New York, New York, 10065
Research Site
Durham, North Carolina, 27710
Research Site
Houston, Texas, 77090
Research Site
Fairfax, Virginia, 22031
References
- Yu J, Mehta R. Biomarker-Driven Approach to the Treatment of Metastatic Gastric or Gastroesophageal Adenocarcinoma. J Natl Compr Canc Netw. 2025 May;23(5):e257036. doi: 10.6004/jnccn.2025.7036.(PubMed)