PFS difference is small. But argument can be made for a younger patient who desires aggressive therapy and toxicities have been manageable.
The randomized PANAMA trial investigated the efficacy of panitumumab (Pmab) when added to maintenance therapy with fluorouracil and folinic acid (FU/FA) in patients with RAS wild-type metastatic colorectal cancer.
Following first-line induction therapy with six cycles of FU/FA and oxaliplatin plus Pmab, responding patients (stable disease or partial or complete remission) were randomly assigned (1:1, open-label) to maintenance treatment with either FU/FA plus Pmab or FU/FA alone. The primary objective was to demonstrate superiority of progression-free survival (PFS, time from random assignment until progression or death) in favor of FU/FA plus Pmab with a hazard ratio (HR) of 0.75, a power of 80%, and a significance level of 10%. Secondary end points included overall survival, objective response rate of maintenance therapy, and toxicity. Survival end points were analyzed by the Kaplan-Meier method and compared by log-rank test and Cox regressions. Dichotomous variables were compared by Fisher’s exact test; odds ratios were indicated when appropriate. The trial is registered with ClinicalTrials.gov (NCT01991873).
Overall, 248 patients were randomly assigned and received maintenance therapy with either FU/FA plus Pmab (125 patients) or FU/FA alone (123 patients). At data cutoff, with 218 events (of 218 needed), PFS of maintenance therapy was significantly improved with FU/FA plus Pmab (8.8 months v 5.7 months; HR, 0.72; 80% CI, 0.60 to 0.85; P = .014). Overall survival (event rate 54%) numerically favored the FU/FA plus Pmab arm (28.7 months v 25.7 months; HR, 0.84; 95% CI, 0.60 to 1.18; P = .32). Objective response rates were 40.8% in patients receiving FU/FA plus Pmab versus 26.0% in patients receiving FU/FA alone (odds ratio, 1.96; 95% CI, 1.14 to 3.36; P = .02). The most frequent Common Terminology Criteria for Adverse Event grade ≥ 3 event during maintenance therapy was skin rash (7.2%).
In RAS wild-type metastatic colorectal cancer, maintenance therapy with FU/FA plus Pmab induced a significantly superior PFS compared with FU/FA alone. If active maintenance therapy is aspired following induction therapy with FU/FA and oxaliplatin plus Pmab, FU/FA plus Pmab appears to be the most favorable option.
Epi and nivo for mismatch repair-deficient (dMMR) colon cancer had 98% response rate with 68% complete response, non-recurred with a median of follow up of 26 months. Does this mean bye-bye surgery??? Probably. We will need to assess those who have complete response and have a close follow up. CtDNA may play big role here, along with a need for randomized trials.
COLOXIS is an interesting computer-based learning model that seems to be able to predict which patients are likely to benefit from adjuvant chemotherapy in colorectal cancer. This, along with ctDNA tests, may change whom we choose to offer adjuvant chemotherapy.
Negative study for the use of HIPEC in the adjuvant setting of high-risk or locally advanced colorectal cancers, including those with perforation and peritoneal invasion. HIPEC doesn’t seem to reduce the risk of peritoneal recurrence after potentially curative resection.
Stopping oxaliplatinum and cont. of 5FU is better than stopping all chemotherapy. An option for patients with worsening neuropathy or other oxaliplatinum toxicity.
Get your patients moving, even in the adjuvant setting! Of course, a lot of bias is possible here, but there was nearly a 10% difference in cure at three years.
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1 thought on “Panitumumab Plus Fluorouracil and Folinic Acid Versus Fluorouracil and Folinic Acid Alone as Maintenance Therapy in RAS Wild-Type Metastatic Colorectal Cancer: The Randomized PANAMA Trial (AIO KRK 0212)”
I understand toxicity is greater with with FU/FA plus Pmab and I will question where we will find the space to use it once the routine use of Bev. is the standard in my view.