Bidirectional pharmacodynamic interaction between pegylated liposomal CKD-602 (S-CKD602) and monocytes in patients with refractory solid tumors.

Background: STEALTH® liposomal CKD-602 (S-CKD602), a camptothecin analog, is eliminated by the reticuloendothelial system (RES), which consists of cells, including monocytes. We evaluated the relationship between monocyte and absolute neutrophil counts (ANCs) in the blood and pharmacokinetic disposition of S-CKD602 and nonliposomal CKD-602 (NL-CKD602) in patients.Methods: As part of a phase I study of S-CKD602 and phase I and II studies of NL-CKD602, the percent decreases in ANC and monocytes at their nadir were calculated. After S-CKD602, the amount of CKD-602 recovered in urine was measured.Results: For S-CKD602 in patients  0.05). For S-CKD602, the relationship between the percent decrease in mo...