SAPPHIRE: a randomised phase II study of planned discontinuation or continuous treatment of oxaliplatin after six cycles of modified FOLFOX6 plus panitumumab in patients with colorectal cancer.

BACKGROUND: Fluorouracil (5-FU), leucovorin (LV) and oxaliplatin (FOLFOX) plus panitumumab therapy is a commonly used first-line chemotherapy for metastatic colorectal cancer (mCRC). However, the long-term administration of oxaliplatin is associated with peripheral neuropathy (PN). We investigated whether the planned discontinuation of oxaliplatin after FOLFOX plus panitumumab therapy can maintain efficacy and reduce PN incidence. PATIENTS AND METHODS: Chemotherapy-naive patients with RAS wild-type mCRC, aged ≥20 years, were enrolled and received six cycles of modified FOLFOX6 (mFOLFOX6) plus panitumumab as induction therapy. Patients who completed induction therapy without progression were randomised to mFOLFOX6 plus panitumumab (group A) or to 5-FU/LV plus panitumumab (group B). The primary end-point was the progression-free survival (PFS) rate at 9 months after randomisation. The secondary end-points were PFS, overall survival (OS), time to treatment failure (TTF), response rate (RR) and safety. RESULTS: In total, 164 patients were enrolled; of whom, 113 patients were then randomised (group A, n = 56; group B, n = 57). The median follow-up after randomisation was 19.6 months. The PFS rates at 9 months and median PFS were 46.4% (80% confidence interval [CI], 38.1-54.9) and 9.1 months (95% CI, 8.6-11.1) in group A, compared with 47.4% (80% CI, 39.1-55.8) and 9.3 months (95% CI, 6.0-13.0) in group B, respectively. RR, OS and TTF were also similar in both groups. Grade ≥2 PN incidence was lower in group B (9.3%) than in group A (35.7%). CONCLUSION: Planned discontinuation of oxaliplatin after six cycles of mFOLFOX6 plus panitumumab is a potential treatment option in patients with mCRC, achieving similar efficacy while reducing oxaliplatin-associated PN compared with mFOLFOX6 plus panitumumab. TRIAL REGISTRATION NUMBER: NCT02337946.