Phase 3 trilaciclib CDK4/CDK6 inhibitor tests myeloprotection in limited-stage SCLC.

This Phase 3 randomized, double-blind, placebo-controlled, parallel-group trial sponsored by Pharmacosmos A/S tests whether trilaciclib—a small-molecule CDK4/CDK6 inhibitor that transiently arrests hematopoietic stem/progenitor cells in G1—can reduce chemotherapy-related myelosuppression in limited-stage small cell lung cancer (LS-SCLC). Participants are randomized to receive IV trilaciclib versus IV placebo (0.9% saline) given prophylactically around planned curative-intent therapy, with the primary endpoint focused on severe neutropenia (duration/occurrence) over roughly the first 4 months on study. Secondary endpoints track practical consequences of marrow toxicity such as chemo dose reductions, G-CSF use, febrile neutropenia, hospitalizations for myelosuppression/sepsis, and RBC transfusions. The commercial/scientific angle is a supportive-care, regimen-agnostic “marrow shield” approach in LS-SCLC, where today’s care is concurrent chemoradiation with platinum + etoposide (followed by prophylactic cranial irradiation in selected patients), and treatment intensity is often limited by cytopenias rather than tumor control.