Trilaciclib: First Approval.

Trilaciclib (Cosela™) is a small-molecule, short-acting, inhibitor of cyclin-dependent kinases (CDK) 4 and 6 developed by G1 Therapeutics for its myeloprotection and potential antitumor efficacy and safety benefits in combination with cancer chemotherapy. CDKs govern cell cycle progression, and trilaciclib induces a transient, reversible G1 cell cycle arrest of proliferating haematopoietic stem and progenitor cells in bone marrow, thus protecting them from damage during chemotherapy. In February 2021, trilaciclib received its first approval in the USA to decrease the incidence of chemotherapy-induced myelosuppression in adult patients when administered prior to a platinum/etoposide-containing regimen or topotecan-containing regimen for extensive-stage small cell lung cancer (ES-SCLC). Clinical studies in breast cancer, colorectal cancer and small cell lung cancer are underway in several countries. This article summarizes the milestones in the development of trilaciclib leading to this first approval.