Vepafestinib is a pharmacologically advanced RET-selective inhibitor with high CNS penetration and inhibitory activity against RET solvent front mutations.

RET receptor tyrosine kinase is activated in various cancers (lung, thyroid, colon and pancreatic, among others) through oncogenic fusions or gain-of-function single-nucleotide variants. Small-molecule RET kinase inhibitors became standard-of-care therapy for advanced malignancies driven by RET. The therapeutic benefit of RET inhibitors is limited, however, by acquired mutations in the drug target as well as brain metastasis, presumably due to inadequate brain penetration. Here, we perform preclinical characterization of vepafestinib (TAS0953/HM06), a next-generation RET inhibitor with a unique binding mode. We demonstrate that vepafestinib has best-in-class selectivity against RET, while exerting activity against commonly reported on-target resistance mutations (variants in RETL730, RETV804 and RETG810), and shows superior pharmacokinetic properties in the brain when compared to currently approved RET drugs. We further show that these properties translate into improved tumor control in an intracranial model of RET-driven cancer. Our results underscore the clinical potential of vepafestinib in treating RET-driven cancers.

Modulation of tumor immune microenvironment by TAS-115, a multi-receptor tyrosine kinase inhibitor, promotes antitumor immunity and contributes anti-PD-1 antibody therapy.

TAS-115 is an oral multi-receptor tyrosine kinase inhibitor that strongly inhibits kinases implicated in antitumor immunity, such as colony stimulating factor 1 receptor and vascular endothelial growth factor receptor. Because these kinases are associated with the modulation of immune pathways, we investigated the immunomodulatory activity of TAS-115. An in vitro cytokine assay revealed that TAS-115 upregulated interferon γ (IFNγ) and interleukin-2 secretion by T cells, suggesting that TAS-115 activated T cells. Gene expression analysis suggested that TAS-115 promoted M1 macrophage differentiation. In in vivo experiments, although TAS-115 exerted a moderate antitumor effect in the MC38 mouse colorectal cancer model under immunodeficient conditions, this effect was enhanced under immunocompetent conditions. Furthermore, combination of TAS-115 and anti-PD-1 antibody exhibited greater antitumor activity than either treatment alone. Flow cytometry analysis showed the increase in IFNγ- and granzyme B (Gzmb)-secreting tumor-infiltrating T cells by TAS-115 treatment. The combination treatment further increased the percentage of Gzmb+CD8+ T cells and decreased the percentage of macrophages compared with either treatment alone. These results highlight the potential therapeutic effect of TAS-115 in combination with PD-1 blockade, mediated via activation of antitumor immunity by TAS-115.

Estimation of Changes in Kidney Volume Growth Rate in ADPKD.

INTRODUCTION: In the Mayo Imaging Classification (MIC) for autosomal dominant polycystic kidney disease (ADPKD), the height-adjusted total kidney volume (HtTKV) growth rate is estimated for classification. Estimated HtTKV slope, termed as eHTKV-α, is calculated by the equation [HtTKV at age t] = K(1+α/100)(t-A), where K = 150 and A = 0 are used in MIC. If eHTKV-α is nearly stable during a standard-of-care period, the change in eHTKV-α from baseline can be used for estimation of the treatment effect on the HtTKV slope. METHODS: The constancy of eHTKV-α (A = 0 and K = 150) was evaluated using 453 placebo-assigned subjects in the Tolvaptan Efficacy and Safety in Management of ADPKD and Its Outcomes (TEMPO) 3:4 trial. A and K were sought out respectively by a converged pattern of regression lines of log10(HtTKV) plotted against age for subgroups divided according to MIC, and by change in eHTKV-α from baseline. A total of 239 standard-of-care patients from the Kyorin University Cohort (KUC) served as validation. Changes in eHTKV-α from baseline were evaluated in 809 tolvaptan-treated subjects in TEMPO 3:4. RESULTS: In placebo-assigned subjects, eHTKV-α (A = 0 and K = 150) changed significantly from baseline at the third year. As regression lines of placebo-assigned subgroups converged around age 0, A was set as 0, which was confirmed by KUC. K = 130 was selected because of minimal change in eHTKV-α from baseline. The KUC validated the constancy of eHTKV-α (A = 0 and K = 130) but not that of eHTKV-α (A=0 and K=150). In tolvaptan-treated subjects, eHTKV-α remained significantly lower than baseline for 3 years. CONCLUSIONS: eHTKV-α (A = 0 and K = 130) was nearly stable from baseline through follow-up in standard-of-care adults. Treatment effects on the HtTKV slope can be estimated by changes in eHTKV-α from baseline.

Identification of inhibitors of dengue viral replication using replicon cells expressing secretory luciferase.

Dengue virus (DENV) is the causative agent of dengue fever (DF), dengue haemorrhagic fever (DHF), and dengue shock syndrome (DSS) and continues to be a public health problem in the tropical and subtropical areas. However, there is currently no antiviral treatment for DENV infection. In this study, our aim was to develop a stable reporter replicon cell system that supports constant viral RNA replication in cultured cells. The isolated replicon cells exhibited high levels of luciferase activity in the culture supernatant concomitant with expression of virus-encoded NS1, NS3 and NS5 proteins in the cells. The NS1, NS3 proteins and dsRNA were detected in the replicon cells by immunofluorescence analysis. Furthermore, the anti-DENV inhibitors ribavirin and bromocriptine significantly reduced the luciferase activity in a dose-dependent manner. High-throughput screening with a compound library using the stably-transfected replicon cells showed a Z' factor value of 0.57. Our screening yielded several candidates including one compound that has already shown anti-DENV activity. Taken together, our results demonstrate that this DENV subgenomic replicon cell system expressing a secretory luciferase gene can be useful for the high-throughput screening of anti-DENV compounds and the analysis of the replication mechanism of the DENV RNA.

Age- and height-adjusted total kidney volume growth rate in autosomal dominant polycystic kidney diseases.

BACKGROUND: The Mayo Clinic Image Classification (MIC) was proposed as a renal prognosis prediction model for autosomal dominant polycystic kidney disease (ADPKD). MIC is based on the assumption of exponential constant increase in height-adjusted total kidney volume (HtTKV). HtTKV growth rate is calculated by one-time measurement of HtTKV and age. We named it as an age-adjusted HtTKV growth rate (AHTKV-α). AHTKV-α was compared with HtTKV slope measured by at least two HtTKV values. METHODS: Comparison of repeatability between AHTKV-α and HtTKV slope, correlation of subgroups divided according to baseline AHTKV-α and HtTKV slope with disease manifestations, estimated glomerular filtration rate (eGFR) slope, and renal survival were analyzed in 296 patients with ADPKD. PKD genotype influences were compared between AHTKV-α and HtTKV slope in 88 patients with characterized PKD mutations. RESULTS: Absolute differences between baseline and follow-up measures were significantly larger for the HtTKV slope than for AHTKV-α (P < 0.0001). From baseline AHTKV-α-based subgroups A-E according to MIC, disease manifestations occurred earlier and future eGFR slopes became steeper (P < 0.0001). Multivariate hazard ratios of renal survival differed significantly among baseline AHTKV-α-based subgroups. Inter-subgroup differences in these predictors were less evident during baseline HtTKV slope-based classification. AHTKV-α values, but not HtTKV slopes, were significantly higher for PKD1 mutation carriers than for PKD2 mutation carriers (P < 0.0001). CONCLUSION: MIC is a good renal prediction model applicable to Japanese patients also. AHTKV-α can be a more sensitive and reliable indicator in TKV growth rate than HtTKV slope.

Optimal equation for estimation of glomerular filtration rate in autosomal dominant polycystic kidney disease: influence of tolvaptan.

BACKGROUND: The reliability of various equations for estimating the GFR in ADPKD patients and the influence of tolvaptan on the resulting estimates have not been examined when GFR is calculated on the basis of inulin clearance. METHODS: We obtained baseline and on-tolvaptan measured GFRs (mGFRs), calculated on the basis of inulin clearance, in 114 ADPKD, and these mGFRs were compared with eGFRs calculated according to four basic equations: the MDRD, CKD-EPI, and JSN-CKDI equations and the Cockcroft-Gault formula, as well as the influence of tolvaptan and of inclusion of cystatin C on accuracy of the results. Accuracy of each of the seven total equations was evaluated on the basis of the percentage of eGFR values within mGFR ± 30% (P30). RESULTS: mGFRs were distributed throughout CKD stages 1-5. Regardless of the CKD stage, P30s of the MDRD, CKD-EPI, and JSN-CKDI equations did not differ significantly between baseline values and on-tolvaptan values. In CKD 1-2 patients, P30 of the CKD-EPI equation was 100.0%, whether or not the patient was on-tolvaptan. In CKD 3-5 patients, P30s of the MDRD, CKD-EPI, and JSN-CKDI equations were similar. For all four equations, regression coefficients and intercepts did not differ significantly between baseline and on-tolvaptan values, but accuracy of the Cockcroft-Gault formula was inferior to that of the other three equations. Incorporation of serum cystatin C reduced accuracy. CONCLUSIONS: The CKD-EPI equation is most reliable, regardless of the severity of CKD. Tolvaptain intake has minimal influence and cystatin C incorporation does not improve accuracy.

A potentially crucial role of the PKD1 C-terminal tail in renal prognosis.

BACKGROUND: Autosomal dominant polycystic disease (ADPKD) often results in renal failure. Recently, allelic influences of PKD1 mutation types on renal survival were extensively investigated. Here, we analyzed integrated influences of PKD1 mutation types and positions on renal survival. METHODS: We included 338 (82 pedigrees) and 72 (12 pedigrees) patients with PKD1 and PKD2 mutations, respectively, identified through comprehensive gene analysis of 101 probands with ADPKD. Genetic testing was performed using next-generation sequencing, long-range PCR, and multiplex ligation-dependent probe amplification. Pathogenic mutations were identified by a software package-integrated seven databases and provided access to five cloud-based computing systems. RESULTS: Mean renal survivals of carriers with PKD1 non-truncating-type mutations at positions upstream of G-protein-coupled receptor proteolytic site (GPS-upstream domain), transmembrane domain, or cytoplasmic C-terminal tail (CTT) domain were 70.2, 67.0, and 50.1 years, respectively (P < 0.0001); renal survival was shorter for mutation positions closer to CTT domain, suggesting its crucial role in renal prognosis. Furthermore, in truncating-type mutations, strong inactivation is anticipated on nucleotides downstream from the mutation site, implying CTT domain inactivation irrespective of mutation site. Shorter mean renal survival was found for PKD1 truncating-type than non-truncating-type mutation carriers (P = 0.0348); mean renal survival was not different between PKD1 3'- and 5'-region truncating-type mutation carriers (P = 0.4375), but was shorter in PKD1 3'-region than in 5'-region non-truncating-type mutation carriers (P = 0.0014). Variable strength of CTT domain inactivation might account for these results. CONCLUSIONS: Aforementioned findings indicate that CTT domain's crucial role in renal prognosis needs further investigation by larger studies (ClinicalTrials.gov; NCT02322385).

Relationship between intracranial aneurysms and the severity of autosomal dominant polycystic kidney disease.

BACKGROUND: Autosomal dominant polycystic kidney disease (ADPKD) is a hereditary kidney disease characterized by the progressive enlargement of innumerable renal cysts. Although the association of intracranial aneurysms (ICANs) with ADPKD is well known, the relationship between the ICAN and the disease severity including total kidney volume (TKV) and estimated glomerular filtration rate (eGFR) is poorly understood. METHODS: We screened 265 patients with ADPKD (mean age, 48.8 years; range, 14.9-88.3 years) with MR angiography. The patients with a past history related to ICANs were excluded from the study. The incidence and characteristics of ICAN in patients with ADPKD were evaluated. TKV was measured by volumetric analyses of MR imaging. RESULTS: We detected 65 ICANs in 49 patients (37 women and 12 men, mean age, 52.7 years; range, 20.4-86 years). The incidence of ICANs was 18.5% and female patients had was higher incidence (23.1%) than male patients (11.4%) (p = 0.02). An age of those with ICANs was significantly higher than those without (p = 0.006), and the cumulative risk of diagnosis of ICANs increased with age. TKV was significantly larger in those with ICANs than those without (p = 0.001), but eGFR was not different between two groups (p = 0.07). By multivariate analyses, only TKV was significantly related to the development of ICANs (p = 0.02). CONCLUSIONS: The incidence of ICANs increased with age, was higher in females, and correlated with kidney enlargement in patients with ADPKD. Necessity of screening ICANs would be particularly high in elderly women with large kidneys.

Optimal Imaging Parameters and the Advantage of Renal Artery Image Using Time-spatial Labeling Inversion Pulse at 3 Tesla Magnetic Resonance Imaging: Comparison of Image Quality for 1.5 Tesla Magnetic Resonance Imaging.

With the recent spread of three tesla (3 T) magnetic resonance imaging (MRI), time-spatial labeling inversion pulse (Time-SLIP) technique at high magnetic field can be used. The purpose of this study was to determine appropriate renal artery imaging parameters and to compare with the 1.5 T MRI image quality of a renal artery using the Time-SLIP technique. The imaging sequence was 3D true steady-state free precession (True SSFP), and using respiratory gated by the voice instructions of breath interval 2, 4, 6 seconds. We measured the fat signals when changing the values of short TI inversion recovery (STIR TI), the renal artery and renal parenchyma signals when changing the values of black blood time interval (BBTI), and contrast-to-noise ratio (CNR) between renal artery and background in 11 healthy volunteers. Visual evaluation using a 4-stage score at renal artery in clinical cases was performed. 3 T MRI is compared with a 1.5 T MRI, and the null point of STIR TI value is 60 ms extension, null point of BBTI value in the renal parenchyma was an extension of 250 ms in any of the breath interval. In flow effect, there is no difference in the 1.5 T MRI and 3 T MRI, peaked at BBTI value 1500 ms. CNR and visual evaluation were better than 3 T MRI. 3 T MRI showed a better image quality by the background signal suppression effect of the extension of the T1 value.

Kidney volume estimations with ellipsoid equations by magnetic resonance imaging in autosomal dominant polycystic kidney disease.

BACKGROUND: Kidney volume (KV) becomes clinically relevant in autosomal dominant polycystic kidney disease (ADPKD) management. KV can be conveniently estimated (ceKV) using ellipsoid volume equations with three axes measurements; however, the accuracy and reliability are unknown. METHODS: KVs of 347 kidneys in 177 consecutive ADPKD patients were determined with a volumetric method (standard-KV), and ceKV was calculated using six different ellipsoid equations with three axes measurements using magnetic resonance imaging. The inter- and intraobserver reliabilities were analyzed using intraclass correlation coefficients (ICCs). Ellipsoid-KVs were obtained by linear regression analysis between standard-KV and ceKVs, and six ellipsoid-KVs were validated with a bootstrap model. RESULTS: The ICCs of intra- and interobserver reliabilities in standard-KV and axes measurements were highly reliable. All ceKVs underestimated standard-KV and % differences between ceKV and standard-KV were reduced by ellipsoid-KVs. Bootstrap analyses suggested that six ellipsoid-KVs reliably simulated standard-KV. CONCLUSION: Among six ellipsoid-KVs, ellipsoid-KV3 = 84 + 1.01 x π/24 × Length × (sum of two width measurements)(2) relatively accurately simulated the standard-KV. Kidney volume estimation using ellipsoid equations is reliably applied to clinical management of ADPKD while recognizing wide scattering in the difference between estimated and volumetrically measured kidney volume.

Safety study of somatostatin analogue octreotide for autosomal dominant polycystic kidney disease in Japan.

BACKGROUND: The total kidney volume (TKV) and total liver volume (TLV) increase and renal function decreases progressively in patients with autosomal dominant polycystic kidney disease (ADPKD). Somatostatin analogues, such as octreotide, reduce these increases in TKV and TLV. The aim of this study was to examine the safety of the short-term administration of octreotide long-acting release (octreotide-LAR) in a small number of cases. METHODS: Four ADPKD patients with an estimated glomerular filtration rate (eGFR) > 45 mL/min/1.73 m(2), TKV > 1,000 mL, and TLV > 3,000 mL were enrolled. Two 20-mg octreotide-LAR intramuscular injections were repeated every 4 weeks for 24 weeks. Laboratory and clinical assessments were repeated every 4 weeks, and TKV and TLV were measured by magnetic resonance imaging before and after the study. RESULTS: In the laboratory tests, there was no abnormal variable except for a significant decrease of alanine aminotransferase. The means of TKV and TLV decreased from 2,007 to 1,903 mL and from 9,197 to 8,866 mL, respectively, but the changes were not significant. eGFR did not change significantly. Adverse events involved loose stools in two patients, as well as injection site granuloma and abdominal pain in one patient each, which resolved spontaneously. CONCLUSION: Octreotide-LAR may be safe and effective for preventing TKV and TLV increases (UMIN000009214).

Does increased water intake prevent disease progression in autosomal dominant polycystic kidney disease?

BACKGROUND: The clinical effects of increased water intake on autosomal dominant polycystic kidney disease (ADPKD) progression are unknown. METHODS: ADPKD patients with creatinine clearance ≧ 50 mL/min/1.73 m(2) were divided into high (H-, n = 18) and free (F-, n = 16) water-intake groups, mainly according to their preference. Prior to the study, 30 patients underwent annual evaluation of total kidney volume (TKV) and 24-h urine for an average of 33 months. During the 1-year study period, TKV and 24-h urine were analyzed at the beginning and end of the study and every 4 months, respectively. RESULTS: During the pre-study period, urine volume (UV) in the H-group was higher (P = 0.034), but TKV and kidney function and their slopes were not significantly different between the two groups. After the study commenced, UV further increased (P < 0.001) in the H-group but not in the F-group. During the study period, TKV and kidney function slopes were not significantly different between the two groups (primary endpoint). Plasma copeptin was lower (P = 0.024) in the H-group than in the F-group. TKV and kidney function slopes became worse (P = 0.047 and 0.011, respectively) after high water intake (H-group) but not in the F-group. High UV was associated with increased urine sodium, and urine sodium positively correlated with the % TKV slope (P = 0.014). CONCLUSIONS: Although the main endpoint was not significant, high water intake enhanced disease progression in the H-group when compared with the pre-study period. These findings necessitate a long-term randomized study before drawing a final conclusion.

The application of the chemical array for biological study.

The identification of specific interactions between small molecules and human proteins of interest is a fundamental step in chemical biology and drug development. The small molecules that bind to specific proteins can be used as tools to study the functions of proteins and biological processes in cells. We have developed an efficient method to obtain novel binding ligands of human proteins by a chemical array approach. Our method includes the use of cell lysates that express proteins of interest fused with red fluorescent protein (RFP) and high-throughput screening by merged display analysis, which removes false positive signals from array experiments. To demonstrate large-scale ligand screening for various human proteins of interest, the gene library GLORIA (Gene Library of Osada Laboratory at RIKEN for chemical array analysis) has been established. Using the systematic platform, we detected novel inhibitors of carbonic anhydrase II. We also have shown that this screening method is useful not merely for ligand screening of proteins of interest, but also for gaining insight into structure-affinity relationships (SARs) and for studies of "fragment-based approach."Traditional fragment-based ligand discoveries have been demonstrated by using several technologies, such as NMR spectroscopy and X-ray crystallography and mass spectrometry. We present initial studies of fragment-based approach to binding assay by using the chemical array format.

A small-molecule inhibitor shows that pirin regulates migration of melanoma cells.

The discovery of small molecules that bind to a specific target and disrupt the function of proteins is an important step in chemical biology, especially for poorly characterized proteins. Human pirin is a nuclear protein of unknown function that is widely expressed in punctate subnuclear structures in human tissues. Here, we report the discovery of a small molecule that binds to pirin. We determined how the small molecule bound to pirin by solving the cocrystal structure. Either knockdown of pirin or treatment with the small molecule inhibited melanoma cell migration. Thus, inhibition of pirin by the small molecule has led to a greater understanding of the function of pirin and represents a new method of studying pirin-mediated signaling pathways.

Structure-affinity relationship study of bleomycins and Shble protein by use of a chemical array.

The photocrosslinked chemical array format is useful not merely for screening protein ligands, but also for gaining insight into structure-affinity relationships (SARs). By probing an array of 2000 natural products, containing 50 bleomycin (BLM) derivatives, with cell lysates that overexpress RFP-fused Shble protein, we successfully observed interactions between Shble protein and BLMs on the array. Among the BLM derivatives, those that had long C-terminal tails were found to bind strongly. The binding signal intensities observed on the chemical array correlated well with the association constants, which were determined by isothermal titration carolimetry (ITC) experiments (r(2)=0.663), showing that the on-chip results were not an artifact of ligand immobilization. In addition to the C-terminal tails, the propionamide moieties in pyrimidoblamic acid (PBA) also appeared to be important for binding. The contributions of the propionamide moieties of PBA to binding were further supported by the X-ray structure of the complex of Shble protein and BLM A(6). These results provide insight into the structural requirements for recognition of BLMs by Shble protein.

Robust and systematic drug screening method using chemical arrays and the protein library: identification of novel inhibitors of carbonic anhydrase II.

The identification of specific interactions between small molecules and human proteins of interest is a fundamental step in chemical biology and drug development. Here we describe an efficient method to obtain novel binding ligands of human proteins by a chemical array approach. Our method includes large-scale ligand screening with two libraries, proteins and chemicals, the use of cell lysates that express proteins of interest fused with red fluorescent protein, and high-throughput screening by merged display analysis, which removes false positive signals from array experiments. Using our systematic platform, we detected novel inhibitors of carbonic anhydrase II. It is suggested that our systematic platform is a rapid and robust approach to screen novel ligands for human proteins of interest.