Phase 2, Multicenter, Open-label, Nonrandomized Study of Neoadjuvant Chemotherapy Liposomal Irinotecan With 5-Fluorouracil, Leucovorin, and Oxaliplatin, Followed by Chemoradiotherapy in Patients With Rectal Cancer in a Watch-and-Wait Program.

Objective: To evaluate the efficacy of neoadjuvant chemotherapy combination with liposomal irinotecan, 5-fluorouracil, leucovorin, and oxaliplatin in patients with locally advanced rectal cancer.

Methods: This was a phase 2, nonrandomized, multicenter study in adults with stage II or III rectal cancer and an Eastern Cooperative Oncology Group performance status of 0 to 1. Total neoadjuvant therapy (TNT) consisted of neoadjuvant chemotherapy combination with liposomal irinotecan (60 mg/m2), oxaliplatin (60 mg/m2), leucovorin (400 mg/m2), and fluorouracil (2400 mg/m²), followed by chemoradiotherapy [ie, capecitabine (825 mg/m2) and radiotherapy according to the standard of care]. The primary efficacy endpoint was the proportion of patients who achieved clinical complete response (cCR), defined as the normalization of pelvic magnetic resonance imaging, rectoscopy, computed tomography scan, and tumor markers.

Results: The median follow-up was 32.3 months. Of the 30 patients who underwent TNT and were evaluated, 6 (20.0%; 95% CI: 5.2%-34.8%) patients achieved a cCR. There were no deaths. The median disease-free survival (DFS) for patients with cCR was not reached after a follow-up of 32 months; the 1-year DFS rate was 90.0% (95% CI: 71.0%-100%), and the 2-year and 3-year DFS rates were 80.0% (95% CI: 55.0%-100%). No grade ≥4 adverse events (AEs) were observed. Grade 3 AEs occurred in 18 patients (60%), most frequent was diarrhea (n = 9, 30%). Eleven (36.7%) patients experienced serious AEs, with diarrhea being the most frequent (n = 6, 20.0%).

Conclusion: TNT with 5-fluorouracil, leucovorin, and oxaliplatin and chemoradiation is a safe and effective therapeutic alternative for the management of locally advanced rectal cancer.