PULSAR Combined With Immunotherapy for Unresectable Locally Advanced Gastric Cancer

Samsung Medical Center

Status: Enrolling

Conditions: Unresectable Gastric Cancer; Locally Advanced Gastric Cancer; Stomach Neoplasms; Gastric Adenocarcinoma

Treatments: Radiation: PULSAR; Radiation: PULSAR (Personalized Ultrafractionated Stereotactic Adaptive Radiation Therapy)

Study type: Interventional

Funder types: Other

Identifiers

NCT07607119

PULSAR-GC-1.2

Details and patient eligibility

About

The purpose of this prospective, single-center, phase II study is to evaluate the clinical efficacy and safety of combining first-line systemic therapy plus immunotherapy with personalized ultrafractionated stereotactic adaptive radiation therapy (PULSAR) in patients with unresectable locally advanced gastric cancer.

Full description

Standard first-line treatment for unresectable locally advanced gastric cancer is systemic chemotherapy combined with immunotherapy, but the overall prognosis remains poor, and local complications like bleeding or obstruction frequently occur.

ULSAR delivers a high dose of radiation per fraction using a 3-to-4 week interval. This extended fraction interval allows normal tissue recovery and provides an opportunity for adaptive replanning before each fraction to minimize gastrointestinal toxicities while maximizing tumor dose delivery. Furthermore, this unique scheduling allows seamless integration with systemic immunotherapy without interrupting the regular chemotherapy cycle. This study specifically aims to evaluate if PULSAR can improve local control, conversion to surgery, and progression-free survival in HER-2 negative, EBV negative, and MSS gastric cancer patients whose tumors have not progressed after at least 3 cycles of first-line immunotherapy-containing systemic regimens.

Enrollment: 53 estimated patients

Sex: All

Ages: 19+ years old

Volunteers: No Healthy Volunteers

Inclusion criteria

Age 19 or more years. Eastern Cooperative Oncology Group (ECOG) Performance Status of 0-2. Histologically confirmed gastric adenocarcinoma. Tumor biomarker status: HER-2 negative, EBV negative, and Microsatellite Stable (MSS).

Unresectable, locally advanced extent at initial staging (Para-aortic lymph node [PALN] and Supraclavicular lymph node [SCN] metastases are allowed).

Has completed 3 or more cycles of first-line systemic therapy combined with immunotherapy without evidence of disease progression.

Presence of at least one evaluable lesion according to RECIST v1.1 that is deemed safely irradiable by the investigator.

Voluntary written informed consent provided by the subject.

Exclusion criteria

Pregnant or lactating women. Presence of brain metastases or leptomeningeal involvement. Prior history of radiation therapy to the intended target site. Severe uncontrolled comorbidities that, in the investigator's opinion, limit study participation or treatment compliance (e.g., uncontrolled infection, heart failure, arrhythmia, psychiatric illness).

Inability or unwillingness to comply with the study protocol procedures. Any condition deemed inappropriate for study participation by the principal investigator or attending physician.

Trial design

Primary purpose: Treatment

Allocation: N/A

Interventional model: Single Group Assignment

Masking: None (Open label)

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53 participants in 1 patient group

Experimental Group (PULSAR + Immunotherapy)

Experimental group

Description:

Patients with unresectable locally advanced gastric cancer who did not progress after 3 or more cycles of first-line immunotherapy-containing systemic therapy will receive personalized ultrafractionated stereotactic adaptive radiation therapy (PULSAR)

Treatment:

Radiation: PULSAR (Personalized Ultrafractionated Stereotactic Adaptive Radiation Therapy)

Radiation: PULSAR