Determination of starting dose of the T cell-redirecting bispecific antibody ERY974 targeting glypican-3 in first-in-human clinical trial.

Currently, ERY974, a humanized IgG4 bispecific T cell-redirecting antibody recognizing glypican-3 and CD3, is in phase I clinical trials. After a first-in-human clinical trial of an anti-CD28 agonist monoclonal antibody resulting in severe life-threatening adverse events, the minimal anticipated biological effect level approach has been considered for determining the first-in-human dose of high-risk drugs. Accordingly, we aimed to determine the first-in-human dose of ERY974 using both the minimal anticipated biological effect level and no observed adverse effect level approaches. In the former, we used the 10% effective concentration value from a cytotoxicity assay using the huH-1 cell line with the highest sensitivity to ERY974 to calculate the first-in-human dose of 4.9 ng/kg, at which maximum drug concentration after 4 h of intravenous ERY974 infusion was equal to the 10% effective concentration value. To determine the no observed adverse effect level, we conducted a single-dose study in cynomolgus monkeys that were intravenously infused with ERY974 (0.1, 1, and 10 µg/kg). The lowest dose of 0.1 µg/kg was determined as the no observed adverse effect level, and the first-in-human dose of 3.2 ng/kg was calculated, considering body surface area and species difference. For the phase I clinical trial, we selected 3.0 ng/kg as a starting dose, which was lower than the first-in-human dose calculated from both the no observed adverse effect level and minimal anticipated biological effect level. Combining these two methods to determine the first-in-human dose of strong immune modulators such as T cell-redirecting antibodies would be a suitable approach from safety and efficacy perspectives.Clinical trial registration: JapicCTI-194805/NCT05022927.

EOS789, a novel pan-phosphate transporter inhibitor, is effective for the treatment of chronic kidney disease-mineral bone disorder.

Chronic kidney disease is characterized as impaired renal function along with the imbalance and dysregulation of mineral metabolism; recognized as chronic kidney disease-mineral and bone disorder. Hyperphosphatemia, characterized by altered phosphate homeostasis along with elevated fibroblast growth factor-23 and intact parathyroid hormone, is such an alteration of mineral metabolism. We discovered a novel inhibitor, EOS789, that interacts with several sodium-dependent phosphate transporters (NaPi-IIb, PiT-1, and PiT-2) known to contribute to intestinal phosphate absorption. This inhibitor dose-dependently increased the fecal phosphorus excretion rate and inversely decreased the urinary phosphorus excretion rate in normal rats, suggesting inhibition of intestinal phosphorus absorption. In rats with adenine-induced hyperphosphatemia, EOS789 markedly decreased the serum phosphate, fibroblast growth factor-23, and intact parathyroid hormone below values found in normal control rats. Notably, this pan-phosphate transporter inhibitor exhibited a more potent effect on serum phosphate than a NaPi-IIb-selective inhibitor in rats with hyperphosphatemia indicating that PiT-1 and PiT-2 play important roles in intestinal phosphate absorption. Moreover, in a long-term study, EOS789 sustained the suppression of serum phosphorus in parallel with fibroblast growth factor-23 and intact parathyroid hormone and ameliorated ectopic calcification of the thoracic aorta. Additionally, EOS789 treatment also ameliorated kidney deterioration in rats with progressive kidney injury, probably due to the strict phosphate control. Thus, EOS789 has potent efficacy against hyperphosphatemia and its complications and could provide a significant benefit to patients who are ineffectively treated with phosphate binders.

Histopathological, immunohistochemical and ultrastructural studies of a renal mesenchymal tumor in a young beagle dog.

A 15-month-old male beagle dog used in a toxicity study had a primary renal mesenchymal tumor. Macroscopically, the tumor was a gray-white mass which was found in the right kidney, and extended from the capsule to a position slightly compressing the medulla. Microscopically, most of the tumor cells showed a myxoid pattern, in which the matrix was positive for alcian blue staining. In the other parts of the tumor, a fascicular and wavy pattern was observed, and the matrix was full of collagen fibrils. Immunohistochemically, tumor cells were positive for vimentin and fibronectin, and negative for cytokeratin, desmin, α-smooth muscle actin, Von Willebrand factor, cyclooxigenase-2 and myelin basic protein. As a result, we diagnosed this case to be a renal mesenchymal tumor. Based on the microscopic findings, interstitial characteristics and immunohistochemical features, the present case was classified as a congenital mesoblastic tumor.

Susceptibility of primary culture neurons from rats of different ages to encephalomyocarditis (EMC) virus infection.

The changes in susceptibility of neurons to the D variant of EMC virus (EMC-D) (10(6) PFU/well) were investigated in developing hippocampal primary cultures from postnatal days of 1, 7, and 56 Fischer 344 rats (P1, P7, and P56) for up to 12 h after infection (12 HAI). The virus titer of primary culture neurons increased at 1 HAI, decreased at 2 HAI, increased at 3 HAI, peaked at 8 HAI, and decreased at 12 HAI in all age groups. The titers at 1 and 8 HAI were lowest in P56 cultures. The virus titer of neurons was always higher than that of culture media, especially at 1 HAI, in P1 cultures, whereas the former was lower than the latter from 2 to 3 HAI in P7 cultures and from 2 to 4 HAI in P56 cultures, respectively. Signals of viral RNA detected by in situ hybridization were first observed in the peripheral cytoplasm of neurons at 1 HAI in P1 and P7 cultures and at 4 HAI in P56 cultures, respectively. The signals spread to a large or whole area of cytoplasm and also to processes thereafter. The number of viral RNA-positive neurons and the amount of signals decreased with age. The present results indicated that the susceptibility of primary culture neurons to EMC-D decreased with age but viral replication still occurred in P56 cultures.

Immunohistochemical study on inducible type of nitric oxide (iNOS), basic fibroblast growth factor (bFGF) and tumor growth factor-beta1 (TGF-beta1) in arteritis induced in rats by fenoldopam and theophylline, vasodilators.

Arteritis induced in rats by vasodilators, fenoldopam and theophylline, was examined immunohistochemically for expressions of inducible type of nitric oxide synthase (iNOS), basic fibroblast growth factor (bFGF) and tumor growth factor-beta1 (TGF-beta1). Rats were administered fenoldopam for 24 hours by intravenous infusion with or without following repeated daily oral administrations of theophylline. Irrespective of theophylline administration, iNOS antigens were remarkably abundant in ED-1-positive cells on day 5 and 8 post-fenoldopam-infusion (DPI); bFGF antigens were remarkably abundant in ED-1-positive cells on 1 and 3 DPI; TGF-beta1 antigens were observed in ED-1-positive cells on and after 5 DPI. These results suggest that the peak expression of iNOS antigen was followed by that of bFGF antigen, and bFGF may have a suppressive effect on iNOS expression in these rat arteritis models. On the other hand, TGF-beta1 was not considered to have a suppressive effect on iNOS expression in these models.