VITAL phase 2 study: Upfront 5-fluorouracil, mitomycin-C, panitumumab and radiotherapy treatment in nonmetastatic squamous cell carcinomas of the anal canal (GEMCAD 09-02)

Abstract

Aim: VITAL, a phase II single-arm study, aimed to evaluate efficacy and safety of panitumumab addition to 5-fluorouracil (5-FU), mitomycin-C (MMC) and radiotherapy (RT) in patients with localized squamous cell carcinoma of the anal canal (SCCAC).

Methods: Adult, treatment-naïve SCCAC patients (Stage T2-T4, any N, M0) and ECOG-PS ≤2, received panitumumab (6 mg/kg, day 1 and Q2W; 8 weeks), 5-FU (1000 mg/m² /d, days 1-4 and 29-32), MMC (10 mg/m² , days 1 and 29) and RT 45 Gy (1.8 Gy/fraction) to the primary tumor and mesorectal, iliac and inguinal lymph nodes, plus 10-15 Gy boost dose to the primary tumor and affected lymph nodes. The primary objective was disease free survival rate (DFS) at 3-years (expected 3-year DFS rate: 73.7 ± 12%).

Results: Fifty-eight patients (31 women; median age: 59 years; ECOG-PS 0-1:98%; TNM II [29%] (T2 or T3/N0/M0)/IIIA (T1-T3/N1/M0 or T4/N0/M0) [21%]/IIIB (T4/N1/M0 or any T/N2 or N3/M0) [47%]/nonevaluable [4%]) were included. The median follow-up was 45 months. The 3-year DFS rate was 61.1% (95% CI: 47.1, 72.4). The 3-year overall survival rate was 78.4% (95% CI: 65.1, 87.1). Eighteen patients (31.0%) required a colostomy within 2 years posttreatment. Grade 3-4 toxicities were experienced by 53 (91%) patients. Most common grade 3-4 treatment-related events were radiation skin injury (40%) and neutropenia (24%). No toxic deaths occurred. Improved efficacy in colostomy-free survival and complete response rate was observed in human papilloma virus positive patients.

Conclusions: Panitumumab addition to MMC-5FU regimen in SCCAC patients increases toxicity and does not improve patients' outcomes. RT plus MMC-5FU remains the standard of care for localized SCCAC patients.

Keywords: chemotherapy; radiotherapy; rectal cancer; target therapy.