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

Abstract

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.

Conflict of interest statement

All authors are employees of Chugai Pharmaceutical Co., Ltd., and Chugai Pharmaceutical Co., Ltd. is involved in the research and development of medicines. This study was funded by Chugai Pharmaceutical Co., Ltd.

© 2022. The Author(s).

Figures

Figure 1

Strategy to determine the FIH dose of ERY974. Pharmacology data exploiting the MABEL approach and toxicology data in cynomolgus monkeys to determine the NOAEL were combined to determine FIH dose of ERY974. FIH, first-in-human; MABEL, minimal anticipated biological effect level; NOAEL, observed adverse effect level.

Figure 2

huH-1 is the most sensitive cell line to ERY974. (a) GPC3 expression level on the surface of HepG2, PC-10, and huH-1 cells. ABC for each cell line is shown. (b) The EC10 values of cytotoxicity and T cell activation assay of ERY974 in HepG2, PC-10, and huH-1. The PBMCs from four independent donors were used as effector cells. EC10 was calculated using the sigmoid Emax model. Data are shown as mean ± SD (n = 3). ABC means antigen-binding capacity.

Figure 3

Various in vitro assays to observe the pharmacological effect of ERY974 using huH-1 and PBMCs. (a) Cytotoxicity assay for ERY974 in huH-1. The cytotoxicity was calculated by measuring LDH release from huH-1. (b) Induction of CD25 and CD69 expression in T cells treated with ERY974. T cell activation by ERY974 is measured using cytometric analysis for T cell activation markers CD25 and CD69. (c) Production of IL-2, IL-4, IL-6, IL-10, TNFα, and IFNγ induced by ERY974. The level of each cytokine was measured using the cytometric analysis. In all assays, PBMCs from 10 independent donors were used as effector cells, and huH-1 was used as the target cell line. Data are shown as mean ± SD (n = 3). (d) Cytotoxicity assay is the most sensitive assay of ERY974 in huH-1. The mean EC10 values of cytotoxicity, T cell activation, and cytokine production of ERY974 using the 10 PBMC samples from different donors are shown. The sigmoid Emax model was used to calculate EC10 for each in vitro assay. More precisely, estimated values of EC50, Emax and Hill coefficient were used for the calculation of EC10 where each pharmacological activity reaches 10% of maximum. (e) The RO of ERY974 to GPC3 and CD3 antigens. The RO was calculated using the following formula: RO (%) = [mAb]/([KD] + [mAb]) × 100. RO, receptor occupancy.

Figure 4

Cynomolgus monkey is a suitable species to study the safety of ERY974. (a) Cytotoxicity assay for ERY974 using human PBMCs. (b) Cytotoxicity assay for ERY974 using cynomolgus monkey PBMCs. PBMCs from four independent donors are used as effector cells, and SK-pca13a was used as the target cell. Data are shown as mean ± SD (n = 3). (c) Summary of tissue cross-reactivity of ERY974 in human and cynomolgus monkeys. Frozen sections of various normal tissues from human and cynomolgus monkeys were stained with biotinylated ERY974. Tissues positive for ERY974 staining are shown with “P,” and tissues negative for ERY974 staining are shown with “-.” Cyno means cynomolugus monkey.

Figure 5

Calculation of the FIH dose from MABEL and NOAEL. The FIH dose from MABEL and NOAEL. The FIH dose from MABEL was calculated as the dose at which the Cmax after 4 h of i.v. infusion of ERY974 is equal to the EC10 value of cytotoxicity assay, combining PK data, and the FIH dose from NOAEL was calculated considering species differences. FIH, first-in-human; MABEL, minimal anticipated biological effect level; NOAEL, observed adverse effect level.