A study of second-line irinotecan plus cisplatin vs. irinotecan alone in platinum-naïve patients with early relapse of gastric cancer refractory to adjuvant S-1 monotherapy: exploratory subgroup analysis of the randomized phase III TRICS trial

Abstract

Backgrounds

Many patients with gastric cancer relapse during or early after adjuvant chemotherapy. The standard treatment for early relapse patients is a second-line chemotherapy (SLC) based on irinotecan, taxanes, or a platinum-based chemotherapy. The platinum-containing biweekly irinotecan plus cisplatin (IRI/CDDP) combination was assumed to be promising in several reports of clinical trials as SLC. TRICS trial, a randomized phase III study of IRI/CDDP vs. IRI in platinum-naïve gastric cancers refractory to S-1 monotherapy, revealed that both irinotecan-based chemotherapies were effective and well tolerated.

Methods

This study analyzed 108 patients in the TRICS trial who experienced early relapse. Patients receiving IRI/CDDP (IRI, 60 mg/m²; CDDP, 30 mg/m², q2w) versus IRI (150 mg/m², q2w) were compared regarding overall survival (OS), progression-free survival (PFS), overall response rate (ORR), and safety.

Results

The OS was 14.0 (95% confidence interval [CI]: 11.0–21.2) and 14.0 (95% CI: 10.7–16.5) months for IRI/CDDP and IRI, respectively (hazard ratio [HR]: 0.782; 95% CI: 0.515–1.188, P = 0.249). No significant differences were observed for PFS (5.0 vs. 4.5 months, respectively; HR: 0.802; 95% CI: 0.543–1.185, P = 0.268) or ORR (19.6% [95% CI: 9.4–33.9%] vs. 23.3% [95% CI: 11.8–38.6%], respectively). The incidence of grade 3–4 anemia was higher for IRI/CDDP than for IRI (20% vs. 0%, respectively; P = 0.0006).

Conclusion

Our study showed no significant survival differences between IRI/CDDP and IRI in platinum-naïve patients who relapsed during or within 6 months after S-1 adjuvant therapy; therefore, IRI may be a good option in this population.

Clinical trial information

UMIN 000002571.

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