Neoadjuvant toripalimab plus CapeOX in locally advanced Epstein-Barr virus-associated gastric or gastroesophageal...

Area of Science:

• Oncology
• Gastroenterology
• Immunotherapy

Background:

• Epstein-Barr virus-associated gastric cancer (EBVaGC) is a distinct subtype.
• Locally advanced EBVaGC presents treatment challenges.
• Neoadjuvant therapy aims to improve surgical outcomes and survival.

Purpose of the Study:

• To evaluate the efficacy and safety of neoadjuvant toripalimab combined with chemotherapy in patients with locally advanced EBVaGC.
• To assess pathological response rates, including major pathological response (MPR) and pathological complete response (pCR).
• To explore associations between treatment response and tumor microenvironment markers like PD-L1 expression and CD8+ T-cell density.

Main Methods:

• A phase 2 clinical trial (NCT04744649) involving 17 patients with locally advanced EBVaGC.
• Patients received four cycles of neoadjuvant toripalimab plus capecitabine/oxaliplatin.
• Paired pre- and post-treatment tumor tissues were analyzed using immunofluorescence to assess tumor microenvironment changes.

Main Results:

• 16 out of 17 patients underwent curative resection.
• Major pathological response (MPR) was observed in 37.5% of patients, and pathological complete response (pCR) in 25.0%.
• Higher MPR rates were noted in patients with PD-L1 expression ≥20% (57.1%) and were associated with higher pretreatment CD8+ T-cell density. Grade 3-4 adverse events occurred in 35.3% of patients.

Conclusions:

• Neoadjuvant toripalimab plus chemotherapy demonstrates favorable efficacy in locally advanced EBVaGC.
• The treatment regimen shows a manageable safety profile.
• Tumor microenvironment markers like PD-L1 and CD8+ T-cell density may predict treatment response.