rx-3117 and Pancreatic-Neoplasms

Background RX-3117 is an oral small molecule antimetabolite, cyclopentyl pyrimidyl nucleoside that is activated by cancer cells over-expressing uridine cytidine kinase 2 (UCK2). Single agent RX-3117 demonstrated efficacy in a phase I trial in patients with metastatic (met) pancreatic adenocarcinoma (PC). RX-3117 plus nab-paclitaxel (nab-Pac) was evaluated as a first line treatment in met-PC cancer. Methods This was a multicenter open label phase I/II 2-stage study investigating the combination of RX3117 plus nab-Pac in the frontline treatment of patients with met-PC. The phase I portion comprised a dose de-escalation design with primary objectives of determining the safety, tolerability and recommended phase 2 dose (RP2D) of RX-3117 (orally 700, 600, or 500 mg/day for 5 consecutive days with 2 days off/week) plus nab-Pac (intravenous (IV) 125 mg/m2 once weekly) for 3 weeks with 1 week off per a 4-week cycle. The primary objective was to determine the antitumor efficacy. Results 46 patients were enrolled (22 male/24 female; median age 67; 91% Caucasian). The RP2D of RX-3117 plus nab-Pac was 700 mg/day. No dose-limiting toxicities were observed (DLTs). The overall response rate (ORR) was 23.1% and disease control rate (DCR) 74.4%. RX-3117 pharmacokinetics (PK) results were similar to previously reported monotherapy phase 1 trial. All patients experienced a treatment emergent adverse event (TEAE) with the most common diarrhea, nausea, and fatigue.10.9% of patients experienced a serious adverse event (SAE) related to the combination. Conclusion RX-3117 plus nab-Pac in newly diagnosed met-PC patients demonstrated tolerability, safety, and early treatment efficacy.

Topics: Adenocarcinoma; Aged; Aged, 80 and over; Albumins; Antineoplastic Combined Chemotherapy Protocols; Area Under Curve; Cytidine; Dose-Response Relationship, Drug; Drug Administration Schedule; Female; Half-Life; Humans; Male; Maximum Tolerated Dose; Metabolic Clearance Rate; Middle Aged; Paclitaxel; Pancreatic Neoplasms

The novel cytidine analog RX-3117, which is activated by uridine-cytidine kinase 2 (UCK2), shows encouraging activity in pancreatic and bladder cancer Phase IIa studies. In this study we highlight the potential role of UCK2 as a biomarker for selecting patients for RX-3117 treatment.. The online genomics analysis and visualization platform, R2, developed by the Oncogenomics department at the AMC (Amsterdam, The Netherlands) was used for in silico UCK2-mRNA correlation with overall survival of pancreatic cancer patients, while UCK2 protein expression was evaluated by immunohistochemistry on pancreatic tumor formalin-fixed-paraffin-embedded sections from independent pancreatic cancer patients. mRNA expression was also determined for SUIT-2, PANC-1 and PDAC-3. Lastly, the drug sensitivity to RX-3117 was investigated using the Sulforhodamine-B cytotoxicity assay.. The in silico data showed that a high UCK2-mRNA expression was correlated with a shorter overall survival in pancreatic cancer patients. Moreover, UCK2 protein expression was high in 21/25 patients, showing a significantly shorter mean. Overall Survival (8.4 versus 34.3 months, p=0.045). Sensitivity to RX-3117 varied between 0.6 and 11 μM.. Pancreatic cancer cells are sensitive to pharmacologically achievable RX-3117 concentrations and UCK2 might be exploited as a biomarker for patient treatment selection.

Topics: Adenocarcinoma; Aged; Antineoplastic Agents; Biomarkers, Tumor; Cell Line, Tumor; Cytidine; Female; Humans; Male; Pancreatic Neoplasms; RNA, Messenger; Uridine Kinase