In an Italian phase II trial (IMPROVE) reported in the Journal of Clinical Oncology, Avallone et al found that intermittent panitumumab and FOLFIRI (fluorouracil, leucovorin, and irinotecan) was associated with promising progression-free survival as first-line treatment in patients with RAS/BRAF wild-type metastatic colorectal cancer.
Study Details
In the noncomparative multicenter trial, 137 patients were randomly assigned between May 2018 and June 2021 to receive: continuous FOLFIRI plus panitumumab until disease progression (n = 69); or induction treatment for 8 cycles of the same regimen followed by a treatment-free interval until disease progression, when another treatment period of up to 8 cycles was restarted (intermittent group, n = 68). Both groups received panitumumab every 2 weeks at 6 mg/kg followed by irinotecan at 180 mg/m2, leucovorin at 200 mg/m2, and fluorouracil as a 400 mg/m2 bolus followed by 2,400 mg/m2 as a 48-hour continuous infusion. The primary endpoint was progression-free survival on treatment at 12 months. The null hypothesis for median progression-free survival-on treatment was < 7 months.
Key Findings
Median follow-up was 43.2 months. Median progression-free survival on treatment was 11.2 months in the continuous group and 17.5 months in the intermittent group. Rates of 12-month progression-free survival on treatment were 45.7% and 58.5%. Overall response rates were 68.1% and 61.2%. Median overall survival was 36.3 months and 35.1 months.
In the intermittent group, median treatment-free interval between the end of treatment induction and the first round of treatment reinduction was 4 months (range = 2–46 months).
The overall rates of grade >2 skin panitumumab-related adverse events were 30.3% and 17.9%.
The investigators concluded: “Intermittent FOLFIRI plus [panitumumab] after the induction phase was feasible, and the primary end point was met with reduced toxicity while allowing patients more time off treatment.”
Antonio Avallone, MD, of the Istituto Nazionale Tumori-IRCCS-Fondazione G. Pascale, Napoli, is the corresponding author of the Journal of Clinical Oncology article.
Disclosure: The study was supported by Amgen and the Istituto Nazionale Tumori-IRCCS-Fondazione G.Pascale. For full disclosures of the study authors, visit ascopubs.org.
