Population pharmacokinetics of zanidatamab, an anti-HER2 biparatopic antibody, in patients with advanced or metastatic cancer.

PURPOSE: To characterize the pharmacokinetics (PK) of zanidatamab including evaluation of the impact of intrinsic and extrinsic patient factors. To investigate alternative dosing regimens to improve caregiver convenience and reduce zanidatamab wastage. METHODS: Serum zanidatamab concentrations were obtained from 305 patients with advanced or metastatic breast cancer, gastroesophageal adenocarcinoma (GEA), biliary tract cancer, and other HER2-expressing cancers from four ongoing phase I and II clinical trials. Zanidatamab PK were described using population methods. The exposure of alternative dosing regimens and the impact of dose delay was estimated by model simulation. RESULTS: A two-compartment model with parallel linear and nonlinear clearance from the central compartment adequately described zanidatamab PK. At the recommended dose regimens of 20 mg/kg Q2W and 30 mg/kg Q3W, zanidatamab clearance was primarily linear at steady state. At steady state, 30 mg/kg Q3W zanidatamab returns within 10% of the steady state trough after 2 subsequent doses following either a 1-week or 2-week dose delay. Statistically significant covariates included in the final model were body weight, sex, albumin, GEA cancer type, baseline tumor size, and presence of post-baseline anti-drug antibodies, all of which resulted in less than 30% impact on exposure. Model simulation predicts weight-based and two-tiered flat dosing will result in similar exposure and variability. CONCLUSION: The identified significant covariates were not considered clinically meaningful. Both weight-based (30 mg/kg Q3W) and two-tiered flat dosing (1800/2400 mg Q3W, 70 kg threshold) strategies are expected to provide similar exposures of zanidatamab.

Recombinant thrombin: safety and immunogenicity in burn wound excision and grafting.

This study evaluated the safety, immunogenicity, and hemostatic effect of recombinant human Thrombin (rThrombin), in patients undergoing skin grafting for burns. This was a phase 2 multiple site, single-arm, open-label study in patients receiving partial- or full-thickness autologous grafts. rThrombin was applied using a spray applicator to newly excised wounds of 1 to 4% body surface area at 5 minutes intervals for up to 20 minutes, after point source bleeding was stopped. Adverse events, skin graft survival, and formation of anti-rThrombin antibodies were measured at baseline and Day 29. There were no deaths or study drug discontinuations. Adverse events occurred in 63 of 72 patients (88%), and were typical of sequelae of skin grafting. Hemostasis was achieved within 20 minutes after application of rThrombin in 65 of 71 patients (91.5%). Skin graft failure occurred in 4 patients (6%). At the day 29 evaluation, for those patients who returned, 88.9% had > or =90% graft survival. One patient (1 of 70, 1.4%) had specific, low titer antibodies to rThrombin at baseline, but no increase in titer posttreatment; a second patient (1 of 62, 1.6%), developed antibodies to rThrombin at day 29. None of the antibodies neutralized native human thrombin. In excised burn wounds, hemostasis at 20 minutes was achieved in 91.5% of patients and skin graft survival was excellent. There was a low rate of antibodies to rThrombin at baseline (1.4%) and a low rate of anti-rThrombin antibody formation at day 29 (1.6%). rThrombin was well tolerated when administered with a pump spray.