Abstract 48P
Background
Rechallenge therapy for RAS WT/MSS refractory metastatic colorectal cancer (mCRC) is an emerging therapeutic approach. CAVE and AVETUXIRI showed it could be promising to treat such kind of patients with CET,CPT-11 and PD-L1 inhibitor. We had explored some cases with ICE regimen (irinotecan plus cetuximab and envafolimab, envafolimab is a new PD-L1 which was used by subcutaneous injection) and found it had good ORR and PFS.
Methods
This was the exploratory part of ICE study and conducted in Beijing Hospital. Patients with MSS/pMMR and RAS/BRAF WT (according to liquid biopsy at baseline) mCRC who had received at least two lines treatment. The front lines treatment should be included irinotecan and cetuximab and pts had a clinical benefit (complete or partial response) from both of them, no matter whether they had treated by any PD-1 inhibitor before. ICE regimen is Irinotecan 150mg/m2 Q2W, cetuximab 500mg/m2 Q2W, envafolimab 200mg Q2W. The primary endpoint was Progression-Free Survival (PFS). The Secondary endpoints included Overall Survival (OS), objective response rate (ORR) and disease control rate (DCR).
Results
From Jul 2022 to Apr 2023, 8 patients were treated with ICE regimen. The median age was 60 years (range 43-74), 4 pts with left colon tumors and 4 pts with rectal tumors, and 50% pts had both liver and lung metastases. Median prior lines of therapy was 2.5(range 2-6). The ORR was 50% (4/8), and the DCR was 87.5% (7/8). By the data cut-off date, with a median follow-up time of 13.1 months, 62.5% (5/8) pts were still responding. The longest PFS was 13.8 months, and the longest OS was 20.2months, either the median PFS or OS has been reached. The most common adverse events grade≥3 were skin rash (3/8). Table: 48P
| Best overall response | N=6 |
| CR | 0 |
| PR | 4 |
| SD | 3 |
| PD | 1 |
| ORR | 50% |
| DCR | 87.5% |
Conclusions
This exploratory study of ICE regimen shows an inspiring clinical efficacy in refractory MSS/pMMR and RAS/BRAF wild-type mCRC pts. It seems to have longer PFS and OS than any other standard third-line treatment.
Clinical trial identification
NCT06321081.
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.