Dicycloplatin, a Novel Platinum Analog in Chemotherapy: Synthesis of Chinese Pre-clinical and Clinical Profile and Emerging Mechanistic Studies

Abstract

Dicycloplatin (DCP) has better solubility and stability than both cisplatin and carboplatin. Pre-clinical and phase I studies demonstrated significant antitumor activity and fewer adverse events than carboplatin. Phase II clinical trials in advanced non-small cell lung cancer found efficacy and safety of DCP-plus-paclitaxel comparable to carboplatin-plus-paclitaxel but better tolerability. This article summarizes and reviews pre-clinical and clinical data for dicycloplatin from the Chinese medical literature. We also report on new mechanistic findings in our laboratory in West Virginia, USA. Patient blood samples were collected for DCP-prototype determination by liquid chromatography mass spectrometry (LC-MS/MS). Molecular studies of ovarian cancer cells treated with DCP or cisplatin were carried out for gene-signature profiling using immunoblotting. Pharmacokinetic mass-spectrometry showed different spectrum profiles of DCP and carboplatin in plasma. Plasma concentration of DCP prototype was 17.1 μg/ml 2h after administration, with a peak concentration of 26.9 μg/ml at 0.5 h. Immunoblotting showed DCP-induced activation of DNA damage pathways, including double-phosphorylated checkpoint kinase 2 (CHK2) and breast cancer 1 (BRCA1) and triple-phosphorylated p53, compared to controls. Cisplatin produced a similar profile, with increased p53 protein. DCP and cisplatin activate DNA-damage response through similar pathways. DCP may be more soluble and stable, and better-tolerated.