The Efficacy of FOLFIRI Plus Ramucirumab in Recurrent Colorectal Cancer Refractory to Adjuvant Chemotherapy with...

FOLFIRI (5-FU + leucovorin + irinotecan) plus ramucirumab is one of the standards in second-line metastatic colorectal cancer (CRC) patients progressing after treatment with oxaliplatin/fluoropyrimidine with bevacizumab, but there is no evidence on its efficacy without prior bevacizumab. Moreover, VEGF-D has not been confirmed as a predictive biomarker for ramucirumab's efficacy, either.

The RAINCLOUD study was a multicenter, single-arm, phase II trial conducted in Japan. Patients with recurrent CRC pretreated with fluoropyrimidine and oxaliplatin without bevacizumab were analyzed. The primary endpoint was progression-free survival (PFS). The secondary endpoints measured were overall survival (OS), overall response rate (ORR), and safety.

A total of 48 patients were enrolled from 15 sites between September 2017 and September 2020. Their median age was 63.5 years (25~77), 20.1% had a right-sided tumor, and 68.8% had RAS-mutant cancer. The median PFS was 8.9 months (90% CI: 6.3-11.8), so the primary endpoint was met. Their median OS and ORR were 22.3 months (95% CI: 17.4-NA) and 41.7% (95% CI: 4.9-7.6), respectively. An incidence of grade 3/4 adverse events that reached over 5% applied to neutropenia (44%), leucopenia (10%), and hypertension (8%). In the biomarker analysis, the serum VEGF-D levels post-treatment were higher than those pre-treatment, but the PFS in those with high VEGF-D levels trended towards being worse than that in those with low VEGF-D (7.6M/5.6M (p = 0.095; HR: 0.56)). Instead, those with low TSP-2 had a better PFS than those with high TSP-2 (7.5M/4.3M (p = 0.022; HR: 0.45)).

Our data suggested that FOLFIRI plus ramucirumab was effective and tolerable for CRC refractory to fluoropyrimidine and oxaliplatin without anti-angiogenesis. Serum VEGF-D levels may not be predictive but TSP-2 may be a potential prognostic biomarker for ramucirumab's efficacy.