Practical Management of Zolbetuximab Administration: The Project VYLOY Initiative.

Background: Zolbetuximab, a monoclonal antibody targeting claudin-18.2 (CLDN18.2), which was recently approved as first-line treatment for advanced gastric cancer (AGC), presents unique safety challenges, particularly infusion-related gastrointestinal toxicity and hypoalbuminemia. This study aimed to present our experience with zolbetuximab administration in patients with AGC, focusing on the safety and management effectiveness of our adapted protocol in routine clinical practice. Methods: This study presents our single-institution real-world experience implementing a proactive management protocol ("Project VYLOY") using zolbetuximab to mitigate these toxicities. We adopted a standardized stepwise infusion protocol and antiemetic premedication to reduce infusion-related nausea and vomiting. Patients with CLDN18.2-positive advanced gastric or gastroesophageal junction adenocarcinoma who received zolbetuximab combined with chemotherapy were included. Results: Twenty-four patients were included. The median infusion duration was 215 min, with an interruption rate of 25.0%. In cycle 1, 62.5% experienced infusion-associated adverse events, primarily grade 1 nausea (54%) and vomiting (25%). Hypoalbuminemia (grade ≥ 2) occurred in 57% of first-line patients, potentially linked to zolbetuximab-induced gastritis and gastrointestinal protein loss. Proactive antiemetic support and infusion rate adjustments substantially reduced infusion interruptions in subsequent cycles (10.9%). Patients without prior gastrectomy had higher nausea and vomiting rates, confirming the stomach's role in mediating toxicity. Conclusions: Our results suggest that proactive management can improve the safety and tolerability of zolbetuximab, especially by reducing infusion-related toxicity in real-world practice.