Phase II study of pre-operative panitumumab and external pelvic radiotherapy (RT) in locally advanced rectal cancer (LARC) patients (pts) (RaP/STAR-03 Study): Preliminary report of safety and treatment compliance.

e14502 Background: The treatment with fluoropyrimidines and concomitant RT is the standard care inLARC preoperative chemoradiation. The aim of RaP/STAR-03 study is to evaluate the activity and safety of panitumumab single agent in LARC preoperative treatment. Methods: RaP/STAR-03 is a phase II study with panitumumab and concomitant RT followed by TME surgery and adjuvant chemotherapy (ACT) in LARC pts. The inclusion criteria are: diagnosis of adenocarcinoma of the mid-low rectum; KRAS wild-type; stage cT3N-M0 or cT2-T3N+M0; CRM-. Panitumumab is administered by IV infusion at a dose of 6 mg/kg once Q2W for 3 cycles concomitant to RT delivered up to a dose of 50.4 Gy in daily fractions of 1.8 Gy (day 1-38). Rectal surgery is performed 6-8 weeks after the end of pre-operative treatment. ACT regimen is FOLFOX4 (12 cycles). Primary end-point is pCR rate. The sample size is calculated using Simon's two-stage design. A pCR of 16% is considered to qualify the experimental treatment for further testing. The first ...