A population pharmacokinetic/pharmacodynamic model of thrombocytopenia characterizing the effect of trastuzumab emtansine (T-DM1) on platelet counts in patients with HER2-positive metastatic breast cancer

作者：Bender Brendan C; Schaedeli Stark Franziska; Koch Reinhold; Joshi Amita; Chu Yu Waye; Rugo Hope; Krop Ian E; Girish Sandhya^*; Friberg Lena E; Gupta Manish

来源：Cancer Chemotherapy and Pharmacology, 2012, 70(4): 591-601.

DOI：10.1007/s00280-012-1934-7

• Trastuzumab emtansine
• T-DM1
• Thrombocytopenia
• Population pharmacokinetic/pharmacodynamic model
• Semimechanistic
• Cumulative TCP

Trastuzumab emtansine (T-DM1) is an antibody-drug conjugate in the development for the treatment of human epidermal growth factor receptor 2-positive cancers. Thrombocytopenia (TCP) is the dose-limiting toxicity of T-DM1. A semimechanistic population pharmacokinetic/pharmacodynamic (PK/PD) model was developed to characterize the effect of T-DM1 on patient platelet counts. %26lt;br%26gt;A PK/PD model with transit compartments that mimic platelet development and circulation was fit to concentration-platelet-time course data from two T-DM1 single-agent studies (TDM3569g; N = 52 and TDM4258g; N = 112). NONMEMA (R) 7 software was used for model development. Data from a separate phase II study (TDM4374g; N = 110) were used for model evaluation. Patient baseline characteristics were evaluated as covariates of model PD parameters. %26lt;br%26gt;The model described the platelet data well and predicted the incidence of grade a parts per thousand yen3 TCP. The model predicted that with T-DM1 3.6 mg/kg given every 3 weeks (q3w), the lowest platelet nadir would occur after the first dose. Also predicted was a patient subgroup (46 %) having variable degrees of downward drifting platelet-time profiles, which were predicted to stabilize by the eighth treatment cycle to platelet counts above grade 3 TCP. Baseline characteristics were not significant covariates of PD parameters in the model. %26lt;br%26gt;This semimechanistic PK/PD model accurately captures the cycle 1 platelet nadir, the downward drift noted in some patient platelet-time profiles, and the similar to 8 % incidence of grade a parts per thousand yen3 TCP with T-DM1 3.6 mg/kg q3w. This model supports T-DM1 3.6 mg/kg q3w as a well-tolerated dose with minimal dose delays or reductions for TCP.

• 出版日期2012-10