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Aim: To evaluate the safety, pharmacokinetics and antitumor activity of OPB-31121, a signal transducer and activator of transcription-3 inhibitor, in patients with advanced hepatocellular carcinoma (HCC). Methods: HCC patients of Child--Pugh A or B who progressed on, or were intolerant to, sorafenib were eligible for this phase 1 trial. We used a standard 3 + 3 dose-escalation design with a 28-day cycle at dose levels of 50, 100, 200 and 400mg/day. Tumor responses were assessed using the modified Response Evaluation Criteria in Solid Tumors. Results: Twenty-four patients were enrolled, of whom 23 received OPB-31121 (20 males; median age, 65 years). The most common adverse drug reactions were nausea (87.0%), vomiting (82.6%), diarrhea (69.6%), fatigue/malaise (52.2%), anorexia (47.8%) and peripheral sensory neuropathy (26.1%). The recommended dose for OPB-31121 was determined to be 200mg. Six patients had stable disease for 8 weeks or more, resulting in disease control rates of 25.0-42.9%. In the 200-mg dose cohort, three of seven patients had stable disease and a median time to progression of 61.0 days. The maximum concentration and area under the plasma concentration--time curve of OPB-31121 were dose proportional. Conclusion: OPB-31121 demonstrated insufficient antitumor activity for HCC. Furthermore, peripheral nervous system-related toxicities may negatively affect long-term administration of OPB-31121. Therefore, it was deemed difficult to continue the clinical development of OPB-31121 for treating advanced HCC and further investigation is expected in the agent with favorable profile in this category. [ABSTRACT FROM AUTHOR]

Purpose OPB-31121 is an oral STAT3 inhibitor with a good preclinical antitumor activity. This phase I dose-escalation study of OPB-31121 was conducted to determine maximum-tolerated dose (MTD), safety, pharmacokinetics, and preliminary antitumor efficacy in patients with advanced solid tumors. Materials and Methods Patients received OPB-31121 once daily for 28 days of each cycle followed by 2 weeks rest. A standard 3+3 design was used for dose-escalation. Safety and response were evaluated by the National Cancer Institute-Common Terminology Criteria for Adverse Events (NCICTCAE) ver. 3.0 and Response Evaluation Criteria in Solid Tumor (RECIST) ver. 1.0, respectively. Results Twenty-five patients were treated with OPB-31121 at five dose levels: 100 mg (n=4), 200 mg (n=3), 400 mg (n=3), 600 mg (n=7), and 800 mg (n=8). Seven patients discontinued treatment during cycle 1 for various reasons other than study drug-related adverse events. Among 18 patients who were evaluable for dose-limiting toxicity (DLT), three DLTs were observed: one DLT (grade 3 vomiting) at 600 mg and two DLTs (grade 3 vomiting, grade 3 diarrhea) at 800 mg. The MTD was determined as 800 mg/day. Common adverse events were gastrointestinal adverse event including nausea (84%), vomiting (80%), and diarrhea (72%). Pharmacokinetics did not demonstrate dose-proportionality of OPB-31121. Eight patients had stable disease and 10 patients had disease progression. Two patients (1 colon cancer, 1 rectal cancer) showed tumor shrinkage. One gastric cancer patient continued treatment up to cycle 13 before disease progression. Conclusion This study demonstrates feasibility of STAT3 inhibition in patients with advanced solid tumor. OPB-31121, at the MTD of 800 mg/day, was safe and relatively well tolerated, and has a preliminary antitumor activity. [ABSTRACT FROM AUTHOR]

Purpose: To determine the maximum tolerated dose (MTD) and biologic activity of OPB-31121, an oral inhibitor of STAT3, administered twice daily (BID) to subjects with advanced solid tumors. Methods: .Subjects received escalating doses of OPB-31121 BID for the first 21 days of each 28-day cycle in a standard 3 + 3 design. Dose-limiting toxicities (DLTs), safety, pharmacokinetics, and antitumor activity were assessed. Results: Thirty subjects were treated twice daily with OPB-31121 at 6 dose levels: 50 mg ( n = 4); 70 mg ( n = 3); 140 mg ( n = 3); 200 mg ( n = 4); 300 mg ( n = 9); 350 mg ( n = 7). There were no DLTs observed until 300 mg BID (Grade 3 lactic acidosis). At the next dose level (350 mg BID), two subjects had DLTs (Grade 3 vomiting and Grade 3 diarrhea). Thus, 300 mg BID was declared the MTD. OPB-31121-related adverse events included nausea (80 %), vomiting (73 %), diarrhea (63 %), and fatigue (33 %), all of which were primarily grade 1/2. Pharmacokinetics demonstrated high inter-subject variability with exposures 146- to 4,788-fold lower than target concentrations from tumor-bearing mouse models. No objective responses were observed, and all subjects who completed two cycles of treatment had disease progression at their first assessment. Conclusions: Twice-daily administration of OPB-31121 was feasible up to doses of 300 mg. The pharmacokinetic profile was unfavorable, and no objective responses were observed. [ABSTRACT FROM AUTHOR]

Abstract: We investigated the mechanisms of action and antitumor effects of OPB-31121, a novel STAT3 inhibitor, in gastric cancer cells. OPB-31121 downregulated JAK2 and gp130 expression and inhibited JAK2 phosphorylation which leads to inhibition of STAT3 phosphorylation. OPB-31121 inhibited constitutively activated and IL-6-induced JAK/STAT signaling pathway. OPB-31121 decreased cell proliferation in both gastric cancer cells and in a xenograft model, induced the apoptosis of gastric cancer cells, inhibited the expression of antiapoptotic proteins, and showed synergism with 5-fluorouracil and cisplatin. Taken together, our study suggests that STAT3 inhibition with OPB-31121 can be tested in patients with gastric cancer. [Copyright &y& Elsevier]

Purpose: OPB-31121 is an oral STAT3 inhibitor with a good preclinical antitumor activity. This phase I dose-escalation study of OPB-31121 was conducted to determine maximum-tolerated dose (MTD), safety, pharmacokinetics, and preliminary antitumor efficacy in patients with advanced solid tumors., Materials and Methods: Patients received OPB-31121 once daily for 28 days of each cycle followed by 2 weeks rest. A standard 3+3 design was used for dose-escalation. Safety and response were evaluated by the National Cancer Institute-Common Terminology Criteria for Adverse Events (NCI-CTCAE) ver. 3.0 and Response Evaluation Criteria in Solid Tumor (RECIST) ver. 1.0, respectively., Results: Twenty-five patients were treated with OPB-31121 at five dose levels: 100 mg (n=4), 200 mg (n=3), 400 mg (n=3), 600 mg (n=7), and 800 mg (n=8). Seven patients discontinued treatment during cycle 1 for various reasons other than study drug-related adverse events. Among 18 patients who were evaluable for dose-limiting toxicity (DLT), three DLTs were observed: one DLT (grade 3 vomiting) at 600 mg and two DLTs (grade 3 vomiting, grade 3 diarrhea) at 800 mg. The MTD was determined as 800 mg/day. Common adverse events were gastrointestinal adverse event including nausea (84%), vomiting (80%), and diarrhea (72%). Pharmacokinetics did not demonstrate dose-proportionality of OPB-31121. Eight patients had stable disease and 10 patients had disease progression. Two patients (1 colon cancer, 1 rectal cancer) showed tumor shrinkage. One gastric cancer patient continued treatment up to cycle 13 before disease progression., Conclusion: This study demonstrates feasibility of STAT3 inhibition in patients with advanced solid tumor. OPB-31121, at the MTD of 800 mg/day, was safe and relatively well tolerated, and has a preliminary antitumor activity.