Trilaciclib is an intravenously administered CDK4/6 inhibitor that was expected to reduce myelosuppression (neutropenia or bone marrow suppression) when added to gemcitabine/carboplatin chemotherapy. In a phase II study conducted by Joyce O'Shaughnessy, MD and published in The Lancet Oncology, Trilaciclib failed to significantly reduce myelosuppression. Link from clinicaltrials.gov. However, patients with mTNBC appeared to have a survival benefit of more than 5 months. Researchers still believe that Trilaciclib improved overall tolerability of chemotherapy and reduced the incidence of transfusions and severe thrombocytopenia (low platelets). These results certainly warrant further investigation especially since no increase in side-effects were noted.