Abstract OT2-07-01: Phase 1/2 trial of the oncolytic virus, talimogene laherparpvec, in combination with neoadjuvant chemotherapy in stage II/III triple negative breast cancer

Abstract

Abstract Background: The host anti-tumor immune response plays an important role in determining natural history and therapy response for early stage breast cancer. Tumors with high levels of lymphocytic infiltration appear to have a superior prognosis and response rate to neoadjuvant chemotherapy. However, these tumors are in the minority so methods to enhance tumor lymphocyte infiltration should be identified. The oncolytic virus, talimogene laherparpvec (TVEC) is a genetically modified HSV1 virus which selectively replicates in transformed cells while sparing normal tissue. This leads to lysis of infected tumor cells along with co-expression of GM-CSF to elicit an enhanced anti-tumor immune response. Prior data has shown TVEC can be safely combined with chemotherapy in other indications, so we launched an investigator initiated study to determine the safety and efficacy of combining TVEC with neoadjuvant dose dense chemotherapy in stage II-III TNBC. Study design: The study is a phase 1 (2 dose levels of TVEC, 3+3 design) and phase 2 single arm Simon two stage combination trial. Primary endpoints of phase 1 is safety of intratumoral TVEC (DL1=106 PFU x 5 injections, DL2=106 PFU x 1 then 108 PFU x 4 injections) administered q2-3 weeks concurrently with weekly paclitaxel followed by standard dose dense AC x 4 and local therapy as indicated. Phase 2 primary endpoint is pCR rate of the study treatment, secondary endpoints include DFS, OS, immune correlates in resected tumor specimens. Eligibility criteria includes females >17 years old, newly diagnosed T2-3N0-3 TNBC, adequate organ function, primary tumor amenable to injection with TVEC, no immunosuppressive or autoimmune conditions, no inflammatory or bilateral/multifocal disease. Sample size is up to 49 patients (12 phase 1, 37 phase 2) with 80% power to detect increase in pCR rate from 30% to 50% with one sided p=.1 in phase 2. Study status: This novel Amgen supported investigator initiated study activated to accrual 3/2017 and first patient on study was on 5/2017. The study is currently open only at the Moffitt Cancer Center. Target study completion date 8/2021. (NCT02779855) Citation Format: Soliman HH, Hogue D, Han H, Lee C, Ismail-Khan R, Khong H, Niell B, Czerniecki B. Phase 1/2 trial of the oncolytic virus, talimogene laherparpvec, in combination with neoadjuvant chemotherapy in stage II/III triple negative breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr OT2-07-01.