Neoadjuvant nivolumab shows therapeutic potential in resectable gastric cancer

Neoadjuvant treatment with nivolumab appears to induce a major pathologic response in selected patients with resectable gastric cancer, in addition to having an acceptable safety profile, according to the results of a phase I trial.

A total of 31 untreated patients (median age 69 years, 68 percent male) with resectable gastric adenocarcinomas were treated with two doses of nivolumab prior to gastrectomy. The primary tumour site was the stomach in the majority of the population (97 percent) and the esophagogastric junction in a few (3 percent). Of the patients, 32 percent had lymph node metastasis and 68 percent had stages I or II disease.

Except for one patient who discontinued before the planned surgical intervention because of a newly emerging liver metastasis, the rest (97 percent) underwent surgery with curative intent. Seven patients (23 percent) developed nivolumab treatment-related adverse events (AEs), and one patient had a grade 3–4 treatment-related AE.

The primary endpoint of the incidence of AEs of special interest ranged from 0 percent to 6 percent. As for surgical complications, there were two cases of grade 3 anastomotic leakage and two cases of pancreatic fistula.

Five patients (16 percent) achieved major pathologic response, of which one had a pathologic complete response. Response was mostly observed in patients with positive PD-L1 expression, high microsatellite instability, and/or high tumour mutation burden.