146P - Neoadjuvant adebrelimab combined with chemotherapy for adenocarcinoma of esophagogastric junction: A single-arm, single-center, phase II clinical trial

Background

The CROSS and NEOCRTEC-5010 trials established neoadjuvant chemoradiotherapy (nCRT) as the standard for locally advanced esophageal cancer (EC). The ESCORT-NEO study showed the efficacy and safety of neoadjuvant immunotherapy combined with chemotherapy in locally advanced esophageal squamous cell carcinoma (LA-ESCC). However, reports on the combined approach in adenocarcinoma of the esophagogastric junction (AEG) are lacking. This phase II trial evaluates the efficacy and safety of neoadjuvant adebrelimab with nab-paclitaxel, lobaplatin, and S-1 in resectable locally advanced AEG.

Methods

Treatment-naive patients with cT_3-4N_anyM₀ resectable locally advanced AEG and ECOG PS 0-1 received adebrelimab (1200 mg IV) on Day 1, nab-paclitaxel (180-200 mg IV) on Day 1, lobaplatin (50 mg IV 2h) on Day 1, and S-1 (40 mg, bid po) every 3 weeks for 2 cycles, followed by surgery and investigator's choice of adjuvant treatment. The primary endpoint was the pathologic complete response (pCR) rate; secondary endpoints included R0 resection rate, overall response rate (ORR), event-free survival (EFS), disease-free survival (DFS), safety.

Results

From November 2023 to June 2024, 15 patients were enrolled and completed neoadjuvant treatment; 2 patients were lost to follow-up, and 5 refused surgery. Among the 8 patients who underwent surgery, 1 (12.5%) achieved pCR, and all achieved R0 resection. Tumor regression grades (TRG) observed were TRG0 in 1 (12.5%), TRG2 in 5 (62.5%), and TRG3 in 2 (25.0%) patients. Of the 13 evaluable patients, 8 (62%) achieved partial response (PR) and 5 (38%) had stable disease (SD). ORR and DCR were 62% (8/13) and 100.0% (13/13), respectively. Treatment-related adverse events (TRAEs) occurred in 100% of patients, but no grade 3-5 TRAEs were observed. Toxicity and post-surgery complications were limited, and surgical feasibility was not impacted.

Conclusions

Neoadjuvant adebrelimab combined with chemotherapy, followed by surgery and adjuvant treatment, demonstrated good efficacy and safety in patients with resectable locally advanced AEG, offering a promising treatment option for this patient population.

Clinical trial identification

NCT06198465.

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.