Pharmacokinetics and Safety of Brexpiprazole Following Multiple-Dose Administration to Japanese Patients With Schizophrenia.

Brexpiprazole is currently approved in the United States for the treatment of schizophrenia and as adjunctive treatment of major depressive disorder. In Canada, it is approved for the treatment of schizophrenia. This study evaluated the pharmacokinetics (PK) and safety of brexpiprazole in Japanese patients with schizophrenia. This phase 1 study comprised a 14-day multiple-dose administration of brexpiprazole 1, 4, and 6 mg/day (n = 7, 8, and 6, respectively). Plasma concentrations and PK parameters and the influence of CYP2D6 polymorphisms (intermediate metabolizers [IMs] and extensive metabolizers [EMs]) on PK were evaluated. Adverse events (AEs) were recorded. The Cmax and AUC24h of brexpiprazole and its metabolite, DM-3411, showed dose-proportionality. The Cmax and AUC24h of brexpiprazole showed accumulation of about 2.5- to 5.5-fold on day 14, compared with those on day 1. The median tmax and the mean elimination half-life of brexpiprazole were 4-5 and 52-92 hours, respectively, across all doses on day 14. The C24h of brexpiprazole reached steady state after day 10 in all dose groups. The dose-normalized Cmax and AUC24h of brexpiprazole on day 14 were higher in IM patients than in EM patients. AEs were generally mild to moderate, with transient serum prolactin increase being the most common event. No clinically significant changes were observed for other clinical laboratory values. Brexpiprazole was safe and well tolerated in the studied Japanese patients with schizophrenia.

Phase 1 study of OCV-C02, a peptide vaccine consisting of two peptide epitopes for refractory metastatic colorectal cancer.

OCV-C02 is a peptide vaccine consisting of two peptide epitopes derived from ring finger protein 43 (RNF43) and translocase of outer mitochondrial membrane 34 (TOMM34). This Phase 1 study assessed the safety, preliminary efficacy and immunological responses following OCV-C02 administration in patients with advanced or relapsed colorectal cancer who were intolerant or refractory to standard chemotherapy. Primary endpoint was any occurrence of dose-limiting toxicity (DLT) during cycle 1. Secondary endpoints were treatment-emergent adverse events, efficacy and immunological responses. Efficacy was evaluated based on overall response rate, disease control rate, time to treatment failure and overall survival. Immunological responses were evaluated by measuring CTL, delayed-type hypersensitivity (DTH) and regulatory T cells (Tregs). Twenty-four patients who were HLA-A*24:02-positive were enrolled and grouped into four cohorts of six patients each: cohorts 1, 2, 3, and 4 which received s.c. OCV-C02 (emulsifying agent: Montanide™ ISA 51 VG) 0.3, 1, 3, and 6 mg/body, respectively. After cycle 1, patients who were eligible and willing to continue vaccination proceeded to the extended treatment period. No DLT occurred in cycle 1 and no major safety problems were reported throughout the trial. One patient in cohort 2, three patients in cohort 3 and two patients in cohort 4 achieved stable disease. CTL and DTH responses following vaccination were also observed across the four cohorts. OCV-C02 at 0.3 to 6 mg/body was found to be safe and well tolerated. TRIAL REGISTRATIONS: JAPIC clinical trials registry (ID: JapicCTI-132075) and ClinicalTrials.Gov (ID: NCT01801930).

Identification of AIM2 as a downstream target of JAK2V617F.

BACKGROUND: The gain-of-function mutation JAK2V617F is frequently found in Philadelphia-chromosome-negative myeloproliferative neoplasm (MPN) patients. However, the tumorigenic properties of JAK2V617F have mostly been characterized in in vivo and in vitro murine models due to the lack of appropriate human cell lines. METHODS: Using the multipotent hematologic cell line UT-7/GM, we established D9, a novel human cell line that expresses JAK2V617F upon tetracycline addition. We assessed cellular differentiation in UT-7/GM cells when JAK2V617F was induced, and we used microarrays to analyze changes in mRNA expression caused by JAK2V617F. RESULTS: Using the human D9 cell line, we demonstrated that the induction of JAK2V617F leads to cytokine-independent cell growth with increased STAT activation and erythroid differentiation, mimicking the characteristics observed in polycythemia vera, making it a suitable in vitro model for studying this disorder. Interestingly, JAK2V617F-dependent erythroid cell differentiation was blocked when GM-CSF was added to the culture, suggesting that the GM-CSF pathway antagonizes JAK2V617F-induced erythroid cell differentiation. Our microarray analysis identified several genes involved in inflammasome activation, such as AIM2, IL1B, and CASP1, which were significantly up-regulated in JAK2V617F-induced cells. CONCLUSIONS: The observed inflammasome activation following JAK2V617F induction is consistent with a recent report demonstrating the involvement of IL1B in myelofibrosis development in a JAK2V617F model mouse. These results indicate that the D9 cell line should be useful for characterizing the signaling pathways downstream of JAK2V617F, allowing for the identification of effector molecules that contribute to the development of MPN.

Inhibition of the NAD-dependent protein deacetylase SIRT2 induces granulocytic differentiation in human leukemia cells.

Sirtuins, NAD-dependent protein deacetylases, play important roles in cellular functions such as metabolism and differentiation. Whether sirtuins function in tumorigenesis is still controversial, but sirtuins are aberrantly expressed in tumors, which may keep cancerous cells undifferentiated. Therefore, we investigated whether the inhibition of sirtuin family proteins induces cellular differentiation in leukemic cells. The sirtuin inhibitors tenovin-6 and BML-266 induce granulocytic differentiation in the acute promyelocytic leukemia (APL) cell line NB4. This differentiation is likely caused by an inhibition of SIRT2 deacetylase activity, judging from the accumulation of acetylated α-tubulin, a major SIRT2 substrate. Unlike the clinically used differentiation inducer all-trans retinoic acid, tenovin-6 shows limited effects on promyelocytic leukemia-retinoic acid receptor α (PML-RAR-α) stability and promyelocytic leukemia nuclear body formation in NB4 cells, suggesting that tenovin-6 does not directly target PML-RAR-α activity. In agreement with this, tenovin-6 induces cellular differentiation in the non-APL cell line HL-60, where PML-RAR-α does not exist. Knocking down SIRT2 by shRNA induces granulocytic differentiation in NB4 cells, which demonstrates that the inhibition of SIRT2 activity is sufficient to induce cell differentiation in NB4 cells. The overexpression of SIRT2 in NB4 cells decreases the level of granulocytic differentiation induced by tenovin-6, which indicates that tenovin-6 induces granulocytic differentiation by inhibiting SIRT2 activity. Taken together, our data suggest that targeting SIRT2 is a viable strategy to induce leukemic cell differentiation.

Quantitative structure--activity relationship analysis and molecular dynamics simulation to functionally validate nonsynonymous polymorphisms of human ABC transporter ABCB1 (P-glycoprotein/MDR1).

Several preclinical and clinical studies suggest the importance of naturally occurring polymorphisms of drug transporters in the individual difference of drug response. To functionally validate the nonsynonymous polymorphisms of ABCB1 (P-glycoprotein/MDR1) in vitro, we generated SNP variant forms (i.e., S400N, R492C, R669C, I849M, A893P, A893S, A893T, M986V, A999T, P1051A, and G1063A) and expressed them in Sf9 cells. The kinetic properties (Km and Vmax) of those variants were analyzed by measuring the ATPase activity to obtain the ATPase profile for each variant toward structurally unrelated substrates. On the basis of the experimental data, we determined the substrate specificity of ABCB1 WT and its variants by the quantitative structure-activity relationship (QSAR) analysis method. While several SNP variants appeared to influence the substrate specificity of ABCB1, the nonsynonymous polymorphisms of 2677G > T, A, or C at amino acid position 893 (Ala > Ser, Thr, or Pro) have great impacts on both the activity and the substrate specificity of ABCB1. The A893P variant (2677G > C), a rare mutation, exhibited markedly high activity of ATPase toward different test compounds. Molecular dynamics (MD) simulation based on a three-dimensional structural model of human ABCB1 revealed that multiple kinks are formed in the intracellular loop between transmembrane domains 10 and 11 of the A893P variant (2677G > C) protein. The polymorphisms of 2677G, 2677T, and 2677A exhibit wide ethnic differences in the allele frequency, and these nonsynonymous polymorphisms are suggested to be clinically important because of their altered ATPase activity and substrate specificity toward different drugs.