Clinical efficacy of the optimal biological dose in early-phase trials of anti-cancer targeted therapies

•Optimal biological dose (OBD) is the lowest dose associated with biological efficacy in early-phase trials.•OBDs were insufficiently reported in early-phase trials of targeted therapies.•When selected as recommended phase II trial doses, OBDs were frequently consistent with Food and Drug Administration–approved doses.•OBD may be a relevant end-point for drug development of novel targeted therapies.