Trilaciclib, a CDK4/6 Inhibitor, in Patients With Early-Stage Triple Negative Breast Cancer

The purpose of this study is to evaluate the mechanism of action, as well as the safety and efficacy of trilaciclib in combination with standard of care treatment in the neoadjuvant setting of early-stage triple negative breast cancer (TNBC). This study will have four phases: 1) Screening Phase, 2) Trilaciclib Lead-In Phase, 3) Treatment Phase, and 4) Surgery and Follow-Up Phase. After a screening phase of up to 21 day, each participant will receive trilaciclib single-dose monotherapy during the lead-in phase, followed by a tumor biopsy. During the treatment phase, each participant will receive trilaciclib with standard of care chemotherapy. Immunotherapy may be included during the treatment phase, per standard of care. 3-5 weeks following conclusion of the treatment phase, each participant will undergo definitive surgery. A 30-day Safety Follow-up Visit will occur 30 days after the last dose of trilaciclib and an End of Study Visit will occur within 14 days after definitive surgery.