Population Pharmacokinetics of MCLA-128, a HER2/HER3 Bispecific Monoclonal Antibody, in Patients with Solid Tumors.

BACKGROUND AND OBJECTIVES: MCLA-128 is a bispecific monoclonal antibody targeting the HER2 and HER3 receptors and is in development to overcome HER3-mediated resistance to anti-HER2 therapies. The aims of this analysis were to characterize the population pharmacokinetics of MCLA-128 in patients with various solid tumors, to evaluate patient-related factors that affect the disposition of MCLA-128, and to assess whether flat dosing is appropriate. METHODS: MCLA-128 concentration data following intravenous administration were collected in a phase I/II clinical trial. Pharmacokinetic data were analyzed using non-linear mixed-effects modeling. Different compartmental models were evaluated. Various body size parameters including body weight, body surface area, and fat-free mass were evaluated as covariates in addition to age, sex, HER2 status, and tumor burden. RESULTS: In total, 1115 serum concentration measurements were available from 116 patients. The pharmacokinetics of MCLA-128 was best described by a two-compartment model with linear and non-linear (Michaelis-Menten) clearance. Fat-free mass significantly affected the linear clearance and volume of distribution of the central compartment of MCLA-128, explaining 8.4% and 5.6% of inter-individual variability, respectively. Tumor burden significantly affected the non-linear clearance capacity. Simulations demonstrated that dosing based on body size parameters resulted in similar area under the plasma concentration-time curve for a dosing interval (AUC0-τ), maximum and trough concentrations of MCLA-128, compared to flat dosing. CONCLUSIONS: This analysis demonstrated that the pharmacokinetics of MCLA-128 exhibits similar disposition characteristics to other therapeutic monoclonal antibodies and that a flat dose of MCLA-128 in patients with various solid tumors is appropriate.

Translational PK-PD modeling analysis of MCLA-128, a HER2/HER3 bispecific monoclonal antibody, to predict clinical efficacious exposure and dose.

Introduction MCLA-128 is a bispecific monoclonal antibody targeting the HER2 and HER3 receptors. Pharmacokinetics (PK) and pharmacodynamics (PD) of MCLA-128 have been evaluated in preclinical studies in cynomolgus monkeys and mice. The aim of this study was to characterize the PK and PD of MCLA-128 and to predict a safe starting dose and efficacious clinical dose for the First-In-Human study. Methods A PK-PD model was developed based on PK data from cynomolgus monkeys and tumor growth data from a mouse JIMT-1 xenograft model. Allometric scaling was used to scale PK parameters between species. Simulations were performed to predict the safe and efficacious clinical dose, based on AUCs, receptor occupancies and PK-PD model simulations. Results MCLA-128 PK in cynomolgus monkeys was described by a two-compartment model with parallel linear and nonlinear clearance. The xenograft tumor growth model consisted of a tumor compartment with a zero-order growth rate and a first-order dying rate, both affected by MCLA-128. Human doses of 10 to 480 mg q3wk were predicted to show a safety margin of >10-fold compared to the cynomolgus monkey AUC at the no-observed-adverse-effect-level (NOAEL). Doses of ≥360 mg resulted in predicted receptor occupancies above 99% (Cmax and Cave). These doses showed anti-tumor efficacy in the PK-PD model. Conclusions This analysis predicts that a flat dose of 10 to 480 mg q3wk is suitable as starting dose for a First-in-Human study with MCLA-128. Flat doses ≥360 mg q3wk are expected to be efficacious in human, based on receptor occupancies and PK-PD model simulations.

JNJ-26481585, a novel "second-generation" oral histone deacetylase inhibitor, shows broad-spectrum preclinical antitumoral activity.

PURPOSE: Histone deacetylase (HDAC) inhibitors have shown promising clinical activity in the treatment of hematologic malignancies, but their activity in solid tumor indications has been limited. Most HDAC inhibitors in clinical development only transiently induce histone acetylation in tumor tissue. Here, we sought to identify a "second-generation" class I HDAC inhibitor with prolonged pharmacodynamic response in vivo, to assess whether this results in superior antitumoral efficacy. EXPERIMENTAL DESIGN: To identify novel HDAC inhibitors with superior pharmacodynamic properties, we developed a preclinical in vivo tumor model, in which tumor cells have been engineered to express fluorescent protein dependent on HDAC1 inhibition, thereby allowing noninvasive real-time evaluation of the tumor response to HDAC inhibitors. RESULTS: In vivo pharmacodynamic analysis of 140 potent pyrimidyl-hydroxamic acid analogues resulted in the identification of JNJ-26481585. Once daily oral administration of JNJ-26481585 induced continuous histone H3 acetylation. The prolonged pharmacodynamic response translated into complete tumor growth inhibition in Ras mutant HCT116 colon carcinoma xenografts, whereas 5-fluorouracil was less active. JNJ-26481585 also fully inhibited the growth of C170HM2 colorectal liver metastases, whereas again 5-fluorouracil/Leucovorin showed modest activity. Further characterization revealed that JNJ-26481585 is a pan-HDAC inhibitor with marked potency toward HDAC1 (IC(50), 0.16 nmol/L). CONCLUSIONS: The potent antitumor activity as a single agent in preclinical models combined with its favorable pharmacodynamic profile makes JNJ-26481585 a promising "second-generation" HDAC inhibitor. The compound is currently in clinical studies, to evaluate its potential applicability in a broad spectrum of both solid and hematologic malignancies.