The following is a summary of “Intermittent or Continuous Panitumumab Plus Fluorouracil, Leucovorin, and Irinotecan for First-Line Treatment of RAS and BRAF Wild-Type Metastatic Colorectal Cancer: The IMPROVE Trial,” published in the November 2024 issue of Oncology by Avallone et al.    

Intermittent treatment after induction with fluorouracil (5-FU), leucovorin (LV), irinotecan (IRI), and panitumumab (PAN) may reduce resistance and improve safety and compliance in patients with unresectable RAS/BRAF wild-type metastatic colorectal cancer (mCRC).  

Researchers conducted a prospective study to evaluate intermittent FOLFIRI plus PAN treatment’s impact on progression-free survival (PFS) and safety in patients with unresectable RAS/BRAF wild-type mCRC.  

They assigned patients with unresectable RAS/BRAF wild type mCRC (1:1) to continuous FOLFIRI plus PAN (arm A) or intermittent FOLFIRI plus PAN (arm B) until progression, toxicity, or death. The primary endpoint was PFS on treatment (PFSot) at 12 months, requiring 65 patients per arm to achieve 80% power.  

The results showed that at a median follow-up of 43.2 months (IQR, 35.0-50.5), the median PFSot was 11.2 months in arm A and 17.5 months in arm B. The 12-month PFSot rates were 45.7% in arm A and 58.5% in arm B. The overall response rates were 68.1% in arm A and 61.2% in arm B. The median overall survival (OS) was 36.3 months in arm A and 35.1 months in arm B. Grade >2 skin PAN-related AEs occurred in 30.3% of patients in arm A and 17.9% in arm B.  

They concluded that intermittent FOLFIRI plus PAN after induction was feasible, reduced toxicity, and provided patients with more treatment-free time.  

Source: ascopubs.org/doi/10.1200/JCO.24.00979