Phase II Study (NO LIMIT, WJOG13320G) of First-Line Nivolumab Plus Low-Dose Ipilimumab for Microsatellite Instability–High Advanced Gastric or Esophagogastric Junction Cancer
Mené sur 29 patients atteints d'un cancer de la jonction oesogastrique ou de l'estomac présentant une haute instabilité des microsatellites et de stade avancé (durée médiane de suivi : 9 mois), cet essai de phase II évalue l'efficacité, du point de vue du taux de réponse globale, et la toxicité d'un traitement de première ligne combinant nivolumab et faibles doses d'ipilimumab
Purpose: Microsatellite instability–high (MSI-H) advanced gastric or esophagogastric junction cancer (AGC), accounting for 5%-6% of all AGC cases, has shown an enhanced responsiveness to immunotherapy. We performed a single-arm phase II study to evaluate the combination of nivolumab (NIVO) and low-dose (LD) ipilimumab (IPI) for first-line treatment of MSI-H AGC.
Patients and Methods: Patients with MSI-H AGC received NIVO (240 mg once every 2 weeks) and IPI (1 mg/kg once every 6 weeks). The primary end point was overall response rate (ORR) assessed by blinded independent central review. Secondary end points included disease control rate (DCR), progression-free survival (PFS), overall survival (OS), safety, and biomarker analysis. MSI-H status was confirmed with an MSI-IVD Kit (Falco).
Results: Twenty-nine patients were enrolled. The ORR was 62.1% (95% CI, 42.3 to 79.3), with a complete response rate of 10.3%. The DCR was 79.3% (95% CI, 60.3 to 92.0). Treatment-related adverse events (TRAEs) of any grade occurred in 93.1% of patients, with those of grade ≥3 manifesting in 37.9% of patients. At the data cutoff (median follow-up of 9.0 months), treatment had been discontinued in 21 patients, with such discontinuation being due to TRAEs in 12 (41.4%) patients. However, after exclusion of one patient with progressive disease, the remaining 11 patients showed long-term antitumor efficacy after treatment discontinuation (range of response duration, 0.9+ to 15.6+ months). The median PFS was 13.8 months (95% CI, 13.7 months to not reached [NR]) and the median OS was NR (95% CI, 13.7 months to NR), with a 12-month OS rate of 79.5%.
Conclusion: NIVO plus LD-IPI showed robust and durable antitumor efficacy as a first-line treatment for MSI-H AGC. Although TRAEs often led to treatment discontinuation, treatment efficacy was subsequently sustained in most patients.
Journal of Clinical Oncology , résumé, 2025