An 84.1% four-year overall survival rate emerged from updated findings of the NEONIPIGA trial published in JAMA Oncology, evaluating neoadjuvant nivolumab and ipilimumab followed by surgery and adjuvant nivolumab for localized dMMR/MSI-H gastric or gastroesophageal junction adenocarcinoma, according to The ASCO Post.
Long-Term Survival Rates Hold Steady Above 84%
- Sustained Survival: Four-year follow-up data shows long-term survival rates holding steady at over 84% in the intention-to-treat group.
Trial Design and Patient Demographics
The study enrolled thirty-two individuals with histologically confirmed cT2–T4NXM0 dMMR/MSI-H gastroesophageal junction or gastric adenocarcinoma who qualified for surgical intervention. The median age of the cohort was 65 years, with 72% identified as male, and cases split evenly between gastric and gastroesophageal junction adenocarcinoma, as reported by The ASCO Post.
One patient with metastatic disease was inadvertently included in this single-arm trial. Participants received six cycles of neoadjuvant nivolumab plus two cycles of ipilimumab before surgery, followed by nine cycles of adjuvant nivolumab. Eighty-four percent completed the neoadjuvant phase, while 44% completed all planned treatment protocols.
Survival Outcomes and Pathologic Responses
Within the intention-to-treat population of 32 patients, the four-year overall survival rate reached 84.1%. Among the 31 patients eligible for surgery, the four-year event-free survival rate stood at 83.5%, according to The ASCO Post data. One patient experienced a relapse involving cerebral metastases.
Six total deaths occurred during the extended follow-up period after a median of 48.3 months. Two deaths related directly to gastric cancer or its treatment—one from postoperative complications and another linked to cerebral metastases—while four deaths stemmed from unrelated causes. Pathologic complete response was achieved in 59% of patients who underwent surgery.
| Clinical Endpoint | Trial Results | Patient Population |
|---|---|---|
| 4-Year Overall Survival | 84.1% | Intention-to-Treat (n = 32) |
| 4-Year Event-Free Survival | 83.5% | Surgery-Eligible (n = 31) |
| Pathologic Complete Response | 59.0% | Patients Undergoing Surgery |
Adverse Events and Nonoperative Management
Grade 3 or 4 adverse events linked to neoadjuvant and adjuvant treatment were documented in 19% and 17% of participants, respectively, and prolonged monitoring revealed no subsequent late toxicities. Three patients did not undergo surgery, which included the participant with metastatic disease alongside two individuals who declined surgical intervention.
All patients who bypassed surgery achieved a clinical complete response following immune checkpoint inhibitor therapy. One of these nonoperative patients was among the four individuals who ultimately died from causes unrelated to cancer.
The high [pathologic complete response] and sustained outcomes raise the question of whether chemotherapy-free, immune checkpoint inhibitor–based approaches could be considered in this setting,
the investigators wrote, as reported by The ASCO Post.
Future Research and Funding Disclosures
Thierry André, of Hôpital Saint-Antoine, Assistance Publique–Hôpitaux de Paris, serves as the corresponding author of the article published in JAMA Oncology. Financial support for the study was provided by BMS, GERCOR, and the ARCAD (Aide et Recherche en Cancérologie Digestive) Foundation.
Further studies, including randomized trials, are warranted to refine patient selection, optimize response assessment, and evaluate organ-preserving strategies, including nonoperative management,
the research team concluded, according to The ASCO Post.
References
- Samaille, et al. Extended Follow-up of Nivolumab Plus Ipilimumab in Localized dMMR/MSI-H Gastric or GEJ Cancer. JAMA Oncology. Available at: JAMA Network.
- The ASCO Post. Updated Findings on Neoadjuvant Immunotherapy in Gastric Cancer.
