1058P - Intraperitoneal nivolumab for malignant ascites in patients with advanced gastrointestinal or pancreaticobiliary tract cancer

Background

Malignant ascites occur in 10 – 15% of patients with cancers from gastrointestinal tract, and it leads to impaired quality of life and declined performance. The abundance of immune cells in the peritoneum and ascites, as well as the immune escaped circumstance created by cancer cells in the peritoneum, suggest the potential use of intraperitoneal (IP) immune checkpoint inhibitors to control malignant ascites.

Methods

Patients with cancers from gastrointestinal or pancreaticobiliary tract who had cytologically confirmed malignant ascites were enrolled. Twenty mg of nivolumab diluted in 100 ml of saline was infused into the peritoneal cavity in 10 minutes after paracentesis. IP therapy was repeated after each paracentesis until ineffectiveness of therapy judged by physician, unacceptable toxicity, or patient’s refusal. The clinical response and adverse effects were recorded. The cellular components of malignant ascites sampled prior each paracentesis were analyzed by flow cytometry.

Results

Totally, 9 patients with a median age of 55 years were treated with IP nivolumab. The cancer types were pancreatic cancer in 4, biliary tract cancer in 3, and gastric cancer in 2 patients. Systemic anticancer treatments were given for 3 lines in 2, 2 lines in 2, and 1 line in 4 patients before the administration of IP nivolumab. After a median of 3 (2 – 5) cycles of treatment, 7 (77%) patients had clinical response as evidenced by reduced ascites and less frequent paracentesis. The change of tumor cell number in serial ascites, instead of the change of lymphocyte counts and lymphocyte percentage, correlated with the clinical response. There was only grade 1 tenderness over the puncture site as the adverse effect. The reasons of stop IP were death due to disease progression in 5, patient’s wish in 2, and clinical unresponsiveness in 2 patients, respectively.

Conclusions

IP administration of nivolumab was a safe and effective method to control malignant ascites from gastrointestinal or pancreaticobiliary tract cancer. Further validation of the application in larger population and other types of cancer, as well as biomarkers study are needed.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

The National Health Research Institutes, Taiwan (NHRI-112A1-CACO-13232302) China Medical University Hospital (DMR-112-195) Ministry of Science and Technology, Taiwan (MOST110-2314-B-039-034-MY3).

Disclosure

All authors have declared no conflicts of interest.