Abstract OT2-28-01: A phase 2 study of sitravatinib in metastatic, pre-treated, triple negative breast cancer, NCT # 04123704

Abstract

Abstract Background:Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer, disproportionally affecting African American and Hispanic patients, and germline BRCA1/2 mutation carriers. Prognosis of relapsed, metastatic disease is extremely poor and effective well-tolerated therapies are urgently needed. Our collaborators have discovered that TNBCs often lose feedback control of receptor tyrosine kinases (RTKs) including PDGFR and MET, locking these receptors in a chronically active state. These receptors share a common negative regulator called Protein Tyrosine Phosphatase, Non-Receptor Type 12 (PTPN12). Baylor investigators have shown that PTPN12- deficient TNBCs may be responsive to combined RTK inhibition. Sitravatinib is a spectrum selective RTK inhibitor that has shown strong antitumor activity in patient derived xenografts (PDXs) of TNBC with low levels of PTPN12. We have therefore designed a phase II, multi-institution, two cohort trials to evaluate the efficacy of sitravatinib in patients with metastatic TNBC (mTNBC). Methods: Patients with diagnosis of mTNBC who have received at least one line of chemotherapy +/- atezolizumab for advanced disease would be considered for enrollment. Patients would need to have tissue from metastatic site available for evaluation or agree to undergo biopsy if banked tumor tissue is not available. Sitravatinib at 100 mg daily, the recommended phase 2 dose for sitravatinib monotherapy, will be started at the initiation of the study and continued until progression or unacceptable toxicity. The study will employ a modified optimal Simon’s two stage design. Patients will be recruited into two cohorts: PTPN12 low or PTPN12 high/normal cohorts simultaneously and independently. Seven patients will be enrolled to each arm during the first stage. After the first stage, depending on the observed number of responses, the study will proceed to the 2nd stage. The primary endpoint is progression-free survival status at 24 weeks (PFS24). Current Trial status: The trial is funded by Mirati Therapeutics and opened to enrollment at Dan L Duncan Comprehensive Cancer Center (DLDCCC) clinics as of 6/8/21. Trial is due to open at UT Southwestern Dallas by 11/2021. The correlative science is funded by an institutional SPORE grant. Conclusion: This trial aims to show that sitravatinib is safe and to investigate whether it could be a treatment option in mTNBC. Citation Format: Maryam Nemati Shafaee, Kristen Otte, Nicholas J Neill, Kent C Osborne, Thomas F Westbrook, Susan Hilseneck, Matthew J Ellis. A phase 2 study of sitravatinib in metastatic, pre-treated, triple negative breast cancer, NCT # 04123704 [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr OT2-28-01.