Phase II study of preoperative panitumumab, 5-fluorouracil, and oxaliplatin with concurrent radiotherapy in locally advanced rectal cancer: Preliminary safety results (StarPan /STAR-02 Study)
4110 Background: The aim of this phase II study is to assess the activity of preoperative external radiotherapy combined with panitumumab, oxaliplatin and 5-fluorouracil in locally advanced rectal cancer patients (pts). Methods: Pts entering the study had histologically-proven rectal adenocarcinoma, either uT3N+ or T4 N-/+ stage, with location <12 cm from the anal margin. Panitumumab was administered at a dose of 6 mg/kg IV, 2 weeks before the start of chemoradiotherapy, and then in combination with chemoradiotherapy, every 2 weeks for 3 times. 5-fluorouracil and oxaliplatin were administered according to an established schedule of STAR-01 Study (oxaliplatin 60 mg/m2 IV weekly for six times, and 5- fluorouracil 225 mg/m2/day continuous infusion IV d 1–38). Radiotherapy was delivered up to a dose of 50.4 Gy in daily fractions of 1.8 Gy. Rectal surgery was performed 7–8 weeks after the end of neoadjuvant treatment. Eight courses of adjuvant chemotherapy with FOLFOX4 plus panitumumab at a dose of 6 mg/kg, every 2 weeks, were given after surgery. The primary endpoint of the study was the complete pathological response rate. Results: From February 2007 to December 2008, 35 out of the 55 planned pts were enrolled. Twenty nine pts completed neoadjuvant treatment and 20 underwent surgery (15 pts ongoing). The characteristics of 29 pts were: males 19 (65.5%) and females 10 (34.5%); median age 58 years (range 39–78); median Karnofsky PS 100 (range 70–100); stage: uT3N+ 22 (75.9%), uT4N- 3 (10.3%), uT4N+ 4 (13.8%). The most frequent grade 1–4 side-effects were acneiform rash (96.2%), diarrhea (51.7%) and fatigue (14.3%). Grade 3 diarrhea was registered in 35.7% pts, and grade 3–4 cutaneous toxicity in 51.8%. No grade 3–4 hematological toxicity was found. The median cumulative dose of delivered radiotherapy was 50.4 Gy. The planned dose of panitumumab, 5-fluourouracil and oxaliplatin was administered in 83%, 72% and 67% of pts, respectively. Conclusions: Despite the moderate increase of diarrhea, these early results demonstrate that panitumumab can be safety added to 5-fluorouracil/oxaliplatin-based chemoradiotherapy, without compromising the concurrent radiotherapy dose. No significant financial relationships to disclose.