Xu Steven Xu

Summary

Affiliation: Johnson and Johnson Pharmaceutical Research and Development
Country: USA

Publications

  1. doi request reprint Mixed-effects beta regression for modeling continuous bounded outcome scores using NONMEM when data are not on the boundaries
    Xu Steven Xu
    Model Based Drug Development, Janssen Research and Development, 920 Route 202, Raritan, NJ, USA
    J Pharmacokinet Pharmacodyn 40:537-44. 2013
  2. pmc Shrinkage in nonlinear mixed-effects population models: quantification, influencing factors, and impact
    Xu Steven Xu
    Advanced PKPD Modeling and Simulation, Clinical Pharmacology, Janssen Research and Development, Titusville, New Jersey, USA
    AAPS J 14:927-36. 2012
  3. doi request reprint Analysis of dose-response in flexible dose titration clinical studies
    Xu Steven Xu
    Advanced PK PD Modeling and Simulation, Clinical Pharmacology, Janssen Research and Development, Titusville, NJ, USA
    Pharm Stat 11:280-6. 2012
  4. doi request reprint Pharmacokinetic and pharmacodynamic modeling of opioid-induced gastrointestinal side effects in patients receiving tapentadol IR and oxycodone IR
    Xu Steven Xu
    Clinical Pharmacology, Advanced PK PD Modeling and Simulation, Janssen Research and Development, Raritan, New Jersey, USA
    Pharm Res 29:2555-64. 2012
  5. pmc Population pharmacokinetics and pharmacodynamics of rivaroxaban in patients with acute coronary syndromes
    Xu Steven Xu
    Clinical Pharmacology, Advanced PK PD Modeling and Simulation, Janssen Research and Development, Titusville, NJ 08560, USA
    Br J Clin Pharmacol 74:86-97. 2012
  6. doi request reprint Population pharmacokinetics of tapentadol immediate release (IR) in healthy subjects and patients with moderate or severe pain
    Xu Steven Xu
    Advanced PK PD Modeling and Simulation, Clinical Pharmacology, Johnson and Johnson Pharmaceutical R and D, Raritan, New Jersey 08869, USA
    Clin Pharmacokinet 49:671-82. 2010
  7. doi request reprint Modeling delayed drug effect using discrete-time nonlinear autoregressive models: a connection with indirect response models
    Xu Steven Xu
    Clinical Pharmacology, Advanced PK PD Modeling and Simulation, Johnson and Johnson Pharmaceutical R and D, Raritan, NJ, USA
    J Pharmacokinet Pharmacodyn 38:353-67. 2011
  8. doi request reprint Impact of low percentage of data below the quantification limit on parameter estimates of pharmacokinetic models
    Xu Steven Xu
    Clinical Pharmacology, Advanced PK PD Modeling and Simulation, Johnson and Johnson Pharmaceutical R and D, Raritan, NJ, USA
    J Pharmacokinet Pharmacodyn 38:423-32. 2011

Detail Information

Publications8

  1. doi request reprint Mixed-effects beta regression for modeling continuous bounded outcome scores using NONMEM when data are not on the boundaries
    Xu Steven Xu
    Model Based Drug Development, Janssen Research and Development, 920 Route 202, Raritan, NJ, USA
    J Pharmacokinet Pharmacodyn 40:537-44. 2013
    ..In addition, the NONMEM run time for the mixed beta regression models appeared to be much shorter compared to SAS, i.e., 1-2 versus 20-40 s for the model and data used in the manuscript. ..
  2. pmc Shrinkage in nonlinear mixed-effects population models: quantification, influencing factors, and impact
    Xu Steven Xu
    Advanced PKPD Modeling and Simulation, Clinical Pharmacology, Janssen Research and Development, Titusville, New Jersey, USA
    AAPS J 14:927-36. 2012
    ..As expected, sample size has very limited impact on shrinkage of the PK parameters of the two-compartment model. Assessment of estimation error suggested an average 1:1 relationship between shrinkage and median estimation error of EBEs...
  3. doi request reprint Analysis of dose-response in flexible dose titration clinical studies
    Xu Steven Xu
    Advanced PK PD Modeling and Simulation, Clinical Pharmacology, Janssen Research and Development, Titusville, NJ, USA
    Pharm Stat 11:280-6. 2012
    ..Therefore, DLME may be an appropriate modeling option in identifying dose-response when data from fixed-dose studies are absent or a fixed-dose design is unethical to be implemented...
  4. doi request reprint Pharmacokinetic and pharmacodynamic modeling of opioid-induced gastrointestinal side effects in patients receiving tapentadol IR and oxycodone IR
    Xu Steven Xu
    Clinical Pharmacology, Advanced PK PD Modeling and Simulation, Janssen Research and Development, Raritan, New Jersey, USA
    Pharm Res 29:2555-64. 2012
    ..To understand the relationship between the risk of opioid-related gastrointestinal adverse effects (AEs) and exposure to tapentadol and oxycodone as well as its active metabolite, oxymorphone, using pharmacokinetic/pharmacodynamic models...
  5. pmc Population pharmacokinetics and pharmacodynamics of rivaroxaban in patients with acute coronary syndromes
    Xu Steven Xu
    Clinical Pharmacology, Advanced PK PD Modeling and Simulation, Janssen Research and Development, Titusville, NJ 08560, USA
    Br J Clin Pharmacol 74:86-97. 2012
    ..Population pharmacokinetics and pharmacodynamics of rivaroxaban have been characterized in healthy subjects and in patients with total venous thromboembolism, deep vein thrombosis or atrial fibrillation...
  6. doi request reprint Population pharmacokinetics of tapentadol immediate release (IR) in healthy subjects and patients with moderate or severe pain
    Xu Steven Xu
    Advanced PK PD Modeling and Simulation, Clinical Pharmacology, Johnson and Johnson Pharmaceutical R and D, Raritan, New Jersey 08869, USA
    Clin Pharmacokinet 49:671-82. 2010
    ....
  7. doi request reprint Modeling delayed drug effect using discrete-time nonlinear autoregressive models: a connection with indirect response models
    Xu Steven Xu
    Clinical Pharmacology, Advanced PK PD Modeling and Simulation, Johnson and Johnson Pharmaceutical R and D, Raritan, NJ, USA
    J Pharmacokinet Pharmacodyn 38:353-67. 2011
    ..Further extensions of the proposed nonlinear AR models are warranted to model irregular and sparse PK/PD data...
  8. doi request reprint Impact of low percentage of data below the quantification limit on parameter estimates of pharmacokinetic models
    Xu Steven Xu
    Clinical Pharmacology, Advanced PK PD Modeling and Simulation, Johnson and Johnson Pharmaceutical R and D, Raritan, NJ, USA
    J Pharmacokinet Pharmacodyn 38:423-32. 2011
    ..Understanding the model structure and the distribution of BQL data (percentage and location of BQL data) allows selection of an appropriate and effective modeling approach for handling low percentages of BQL data...