A Randomized Phase II/III Trial of Intraperitoneal Paclitaxel Plus Systemic Treatment vs Systemic Treatment Alone in Gastric Carcinomatosis – STOPGAP II

Gastric cancer, also known as stomach cancer, occurs in the cells lining the stomach. At diagnosis, about 30% of patients already have cancer that has spread to the peritoneum—the tissue lining the abdominal cavity. This condition, known as gastric carcinomatosis, is metastatic (stage IV) and, even with the best systemic treatments, is associated with a dismal prognosis. More effective therapies are needed to improve survival outcomes for these patients.

One possible strategy is to combine systemic and regional, or localized, therapies. Of the regional therapies, the most studied is NIPEC (normothermic intraperitoneal chemotherapy) with paclitaxel. Whereas systemic treatment targets cancer cells throughout the body, NIPEC entails delivering paclitaxel directly into the peritoneal cavity through a surgically placed port. It may reach more cancer cells and has been shown to improve survival rates in other types of cancer. This procedure can be performed either in the hospital or in an outpatient setting.

The ECOG-ACRIN Cancer Research Group has opened the EA2234/STOPGAP II clinical trial to test if adding paclitaxel with NIPEC to systemic treatment improves survival compared to systemic therapy alone. This study addresses a critical gap for patients with gastric carcinomatosis: in the United States, no randomized clinical trials currently exist for this population. Additionally, many metastatic gastric cancer studies specifically exclude these patients.

Participants in the study will be randomized to receive either three months of standard-of-care systemic therapy or three months of systemic therapy plus paclitaxel with NIPEC. After this period, patients will have their cancer restaged using CT scans and diagnostic laparoscopy. If their cancer is stable or responding to treatment, they may continue their assigned therapy and will undergo restaging every 12 weeks. Treatment will continue until the disease progresses, unacceptable side effects occur, or surgery is required.

Patients are eligible for EA2234/STOPGAP II if they have gastric cancer or gastroesophageal junction (GEJ) adenocarcinoma (Siewert 3) with synchronous cytology-positive disease or peritoneal carcinomatosis and no visceral metastases. They must have received at least 3 months—but no more than 6 months—of first-line systemic treatment without disease progression. They must have MSS (microsatellite stable) or pMMR (mismatch repair proficient) disease to be eligible.

Learn more about EA2234/STOPGAP II at ecog-acrin.org.

The study chair for this trial is Maheswari Senthil, MD (University of California, Irvine). The co-chair is Nataliya V. Uboha, MD, PhD (University of Wisconsin/Carbone Cancer Center), the surgical co-chair is Shishir K. Maithel, MD (Emory University/Winship Cancer Institute), and the community co-chair is Xin Yao, MD (Cleveland Clinic).