Utilizing total neoadjuvant therapy (TNT) in rectal cancer: NRG-GI002, a phase II clinical trial platform.

Abstract

TPS814 Background: Improvements in outcomes for locally advanced rectal cancer (LARC) have plateaued due to an inability to consistently deliver adjuvant therapy and thus far ineffective novel therapies. Systematic testing of new chemotherapy and radiation sensitizers are needed to advance treatment outcomes. This randomized phase II modular clinical trial platform utilizes Total Neoadjuvant Therapy (TNT) with parallel experimental arms in LARC. The experimental arms are not intended for direct comparison, but to test a variety of sensitizers or hypotheses in a consistent and relatively homogenous high-risk patient (pt) population with correlative biomarkers. Success of any given experimental arm will be determined by achievement of pathologic endpoints compared to a control arm. Methods: This NCTN multi-arm randomized phase II trial serves as a modular platform to assess novel sensitizers to neoadjuvant chemotherapy and/or chemoradiotherapy (chemoRT) in LARC. Eligibility includes LARC as defined by any ONE of the following criteria: distal location (cT3-4 ≤5cm from the anal verge, any N); bulky (any cT4 or tumor within 3mm of the mesorectal fascia); high risk for metastatic disease (cN2); or not a candidate for sphincter-sparing surgical resection. After randomization, all pts receive neoadjuvant FOLFOX x 4mo → chemoRT (capecitabine with 50.4Gy) → surgical resection 8-12 wks later. Based on promising phase I results, the first experimental arm will assess the activity of veliparib added to standard chemoRT (capecitabine + RT). Primary endpoint is to demonstrate an improvement in Neoadjuvant Rectal Cancer (NAR) score for the experimental arm vs control representing a 20% relative risk reduction in DFS HR and 3-4% absolute OS improvement. Secondary endpoints include comparisons of OS, DFS, toxicity, pCR, cCR, therapy completion, negative surgical margins, sphincter preservation, sphincter function including quality of life, and exploratory assessments of molecular and radiographic predictors of response and distant failure. Target accrual is 79 evaluable pts per arm with additional arms added through rolling protocol amendments. Support: U10 CA-180868, -180822, UG-189867; AbbVie. Clinical trial information: NCT02921256.