Panitumumab added to 5-FU/LV effective as maintenance therapy in patients with mCRC

Progression-free survival in patients with RAS wildtype metastatic colorectal cancer (mCRC) improved with the addition of panitumumab to maintenance therapy with 5-FU/LV versus 5-FU/LV alone, demonstrated results from the phase 3 PANAMA trial.

Currently, the preferred maintenance therapy regimen in mCRC is fluoropyrimidine ± bevacizumab, with improved progression-free but not overall survival [1]. Maintenance concepts in the context of EGFR monoclonal antibody-based first-line therapy are still the subject of scientific debate. Although EGFR-antibodies may provide activity during maintenance therapy, 5-FU/LV appears necessary [2].

The phase 3 PANAMA trial (NCT01991873) evaluated the efficacy and safety of maintenance therapy with panitumumab plus 5-FU/LV versus 5-FU/LV alone in patients with RAS wildtype mCRC who showed a clinical response on induction therapy with 6 cycles of FOLFOX (5-FU/LV, oxaliplatin) plus panitumumab. The primary endpoint was progression-free survival. Prof. Dominik Modest (Charité Universitätsmedizin Berlin, Germany) presented the first results [3].

Of the 377 patients treated with induction therapy, 248 were randomised to receive maintenance therapy with either 5-FU/LV plus panitumumab (n=125) or 5-FU/LV alone (n=123). At data cut-off, median progression-free survival was improved with 5-FU/LV plus panitumumab versus 5-FU/LV alone (8.8 vs 5.7 months; HR 0.72; 80% CI 0.60–0.85; P=0.014). Data for the key secondary endpoint of overall survival is immature, but currently shows a small trend towards a better outcome with 5-FU/LV plus panitumumab. Re-induction therapy was initiated less frequently in the 5-FU/LV plus panitumumab arm and was also associated with less objective responses compared to the 5-FU/LV alone arm. Maintenance therapy with 5-FU/LV plus panitumumab was well tolerated, with expected adverse events with special interest to panitumumab.

1. Sonbol MB, et al. JAMA Oncol. 2020 Mar 1;6(3):e194489
2. Pietrantonio F, et al. JAMA Oncol. 2019;5:1268-1275.
3. Modest DP, et al. Maintenance therapy with 5-fluoruracil/leucovorin (5FU/LV) plus panitumumab (pmab) or 5FU/LV alone in RAS wildtype (WT) metastatic colorectal cancer (mCRC) - the PANAMA trial (AIO KRK 0212). Abstract 3503, ASCO 2021 Virtual Meeting, 4–8 June.

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Posted on 12 August 202117 May 2024