A phase II clinical trial platform for sensitization testing using total neoadjuvant therapy (TNT) in rectal cancer: Nrg-GI002.

TPS721 Background: Locally advanced rectal cancer (LARC) improvements have plateaued due to an inability to consistently deliver adjuvant therapy and effective novel therapies. Systematic testing of new chemotherapy and radiation sensitizers is needed to advance treatment outcomes. This NCTN multi-arm randomized phase II modular clinical trial platform utilizes TNT with parallel experimental arms (EA) in LARC. The EAs are not intended for direct comparison, but rather to test a variety of sensitizers or hypotheses in a consistent and homogenous high-risk patient (pt) population with correlative biomarkers. Success of any EA will be determined by achievement of pathologic endpoints compared to a control arm. Methods: The NRG-GI002 trial serves as a modular platform to assess novel sensitizers to neoadjuvant chemotherapy and/or chemoradiotherapy (chemoRT) in LARC. Eligibility includes LARC with any ONE of the following: distal location (cT3-4 ≤ 5 cm from anal verge, any N); bulky (any cT4 or tumor within 3 mm of the mesorectal fascia); high risk for metastatic disease (cN2); or not a candidate for sphincter-sparing surgical resection. After randomization, pts receive neoadjuvant FOLFOX x 4 mo→chemoRT (capecitabine with 50.4 Gy)→surgical resection 8-12 wks later. The first EA will assess activity of veliparib with standard chemoRT. Enrollment to this EA is complete (results anticipated late 2019). The second EA, testing pembrolizumab concurrently with and following chemoRT, is currently active, with several other EAs in development. Primary endpoint is demonstrated improvement in Neoadjuvant Rectal Cancer score for the EA v 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 QOL, and exploratory assessments of molecular and radiographic predictors of response and distant failure. Target accrual is 79 evaluable pts/arm with additional EAs added through protocol amendments. NCT02921256. Support: U10CA180868, -180822, UG1-189867, U24-196067; AbbVie, Merck. Clinical trial information: NCT02921256.