Phase II study of panitumumab, oxaliplatin, 5-fluorouracil, and concurrent radiotherapy as preoperative treatment in high-risk locally advanced rectal cancer patients (StarPan/STAR-02 Study)

Abstract

BackgroundThe aim of this phase II study was to assess the activity of panitumumab in combination with oxaliplatin, 5-fluorouracil, and external radiotherapy (RT) as preoperative treatment in locally advanced rectal cancer patients. Patients and methodsPatients had rectal adenocarcinoma, cT3N+ or cT4N-/+ stage, located <12 cm from the anal margin. Panitumumab was administered before the start of chemo-RT, and every 2 weeks in combination with 5-fluorouracil–oxaliplatin with concurrent RT. Rectal surgery was carried out 7–8 weeks after the end of neoadjuvant treatment. The primary end point was a pathological complete response rate of 25%. ResultsSixty patients were enrolled from February 2007 to October 2009. Fifty-five (91.7%) patients underwent surgery. Rate of pathological complete response was 21.1% (95% confidence interval 10.4% to 31.6%). Pathological downstaging occurred in 33 of 57 (57.9%) patients. Grade 3–4 toxicity during neoadjuvant treatment was diarrhea (38.9%), cutaneous reactions (18.6%), nausea (5.1%), asthenia (3.4%), anorexia (3.4%), and neutropenia (1.7%). One toxic death was observed for diarrhea. ConclusionsIn our study, the primary end point is not reached and panitumumab combination treatment was associated with high incidence of grade 3–4 diarrhea. The higher pathological complete response rate in comparison with the results of previous neoadjuvant rectal cancer trials with anti-epidermal growth factor receptor monoclonal antibodies supports further studies necessary to understand the possibility of optimal regimens and sequences with chemo-RT.