Neoadjuvant cadonilimab plus FLOT chemotherapy in locally advanced gastric/gastroesophageal junction adenocarcinoma: A multicenter, phase 2 study.

Background: Treatment with cadonilimab and chemotherapy has shown promise as a first-line treatment for gastric or gastroesophageal junction (G/GEJ) adenocarcinoma. However, its application in neoadjuvant settings has not yet been documented.

Methods: This multicenter, phase 2 trial (ChiCTR2200066893) was conducted at four hospitals across China. Treatment-naive patients with locally advanced G/GEJ adenocarcinoma (cT3/4, N+, M0) and who were human epidermal growth factor receptor 2 negative received 3-cycle or 4-cycle neoadjuvant treatment of cadonilimab plus FLOT (5-fluorouracil, leucovorin, oxaliplatin, and docetaxel) chemotherapy, followed by gastrectomy and 4-cycle adjuvant FLOT chemotherapy. The primary endpoint was the pathological complete response (pCR) rate. Secondary endpoints included major pathological response (MPR), overall response rate (ORR), disease control rate (DCR), R0 resection rate, downstaging rate, and safety.

Results: Between December 23, 2022, and December 15, 2023, 32 of 38 patients completed the scheduled treatment, achieving an R0 resection rate of 100% (32/32). The pCR rate was 21.1% (8/38, 90% confidence interval [CI]: 9.7-32.4), and the MPR rate was 44.7% (17/38, 90% CI: 30.9-58.5). Radiological evaluations were available for 28 of 38 patients by blinded independent central review. The ORR was 60.7% (17/28, 90% CI: 44.7-76.7), and the DCR was 100.0% (28/28, 90% CI: 100.0-100.0). Tumor downstaging occurred in 71.9% of patients (23/32), with consistent efficacy across all populations observed in the subgroup analysis. Grade 3 adverse events occurred in 31.6% of patients without severe safety issues.

Conclusions: Neoadjuvant cadonilimab plus FLOT chemotherapy treatment exhibits promising efficacy with manageable toxicities in locally advanced G/GEJ adenocarcinoma, providing preliminary evidence for further investigation. Background: This study was funded by Akeso Biopharma.