Syndax Pharmaceuticals, Inc. announced that investigators at The University of Texas MD Anderson Cancer Center Department of Breast Medical Oncology have initiated a phase 1/2 study combining Syndax's lead product entinostat with lapatinib ditosylate (Tykerb) in patients with locally recurrent or distant relapsed metastatic breast cancer previously treated with trastuzumab (Herceptin®). The study sponsored by MD Anderson is being conducted in collaboration with the National Cancer Institute (NCI) Division of Cancer Treatment and Diagnosis and Glaxo Smith Kline (GSK). Preclinical data has demonstrated that entinostat, a novel, selective histone deacetylase inhibitor can overcome acquired resistance to HER2 targeted therapies when combined with lapatinib.
"Based on preclinical work conducted by Syndax's collaborators, GSK scientists and our own laboratory, we believe entinostat may be effective in tackling the resistance pathways that contribute to the reduced efficacy of HER2-targeted agents in breast cancer patients progressing on such therapies," said Naoto T. Ueno, MD, PhD, FACP, Section Chief, Section of the Translational Breast Cancer Research Department of Breast Medical Oncology, Executive Director of the Morgan Welch Inflammatory Breast Cancer Program and Clinic, MD Anderson Cancer Center and principal investigator. "With the data we have generated, we are particularly excited to test this combination in patients with inflammatory breast cancer, a subset of breast cancer often expressing HER2 for whom there are few effective treatment options.
The phase 1 portion of the study will characterize the safety profile of the combination and identify the appropriate dosing regimen to be used in the phase 2 portion. Translational studies will provide valuable insight into the mechanism of action for the combination in tumor cells while potentially identifying biomarkers for patient selection in subsequent studies.
"This study represents our continued commitment to work with the NCI and our industry and academic collaborators to expand the ENCORE (ENtinostat Combinations Overcoming REsistance) platform aimed at overcoming resistance to targeted therapies in breast cancer and other solid tumors," said Joanna Horobin, MD, president and chief executive officer of Syndax. "With our recently reported positive data in ENCORE 301 targeting ER+ breast cancer and the NCI sponsored study NCT01234532 combining entinostat with Arimidex in ER-, PR-, HER2- triple negative breast cancer we are pleased to be in a position to provide proof-of-concept clinical data across all segments of breast cancer."