Will “personalized medicine” need personalized laboratory approach?

Individualizing the dosage of Methylphenidate in children with attention deficit hyperactivity disorder

BACKGROUND

Attention deficit hyperactivity disorder (ADHD) is one of the most common childhood mental health disorders. Stimulant drugs as the most commonly used treatment and first-line therapy for ADHD have side effects. One of the newest approaches to select the best choices and optimize dosages of medications is personalized medicine.

METHODS

This historical cohort study was carried out on the data taken from the period of 2008 to 2015. Eligible subjects were included in the study randomly. We used mixed-effects logistic regression models to personalize the dosage of Methylphenidate (MPH) in ADHD. The patients' heterogeneity was considered using subject-specific random effects, which are treated as the realizations of a stochastic process. To recommend a personalized dosage for a new patient, a two-step procedure was proposed. In the first step, we obtained estimates for population parameters. In the second step, the dosage of the drug for a new patient was updated at each follow-up.

RESULTS

Of the 221 children enrolled in the study, 169 (76.5%) were male and 52 (23.5%) were females. The overall mean age at the beginning of the study is 82.5 (± 26.5) months. In multivariable mixed logit model, three variables (severity of ADHD, time duration receiving MPH, and dosage of MPH) had a significant relationship with improvement. Based on this model the personalized dosage of MPH was obtained.

CONCLUSIONS

To determine the dosage of MPH for a new patient, the more the severity of baseline is, the more of an initial dose is required. To recommend the dose in the next times, first, the estimation of random coefficient should be updated. The optimum dose increased when the severity of ADHD increased. Also, the results show that the optimum dose of MPH as one proceeds through the period of treatment will decreased.

Measurement of the new anticoagulants

New oral anticoagulants are given at fixed daily doses without laboratory dose adjustment for prevention of venous thromboembolism following elective total knee- and hip replacement, for treatment and prevention of recurrent events of acute venous thromboembolism, and for prevention of embolic events in atrial fibrillation. However, it may be necessary to determine the anticoagulant effect of new oral anticoagulants in special patient populations such as in elderly, for renal impairment, before operation, bleeding or thrombotic episodes and to monitor self-compliance. Oral factor Xa and oral thrombin inhibitors influence dose dependently global and specific coagulation assays. Standardization of assays is currently undertaken. Determination of the new oral anticoagulants in serum samples would facilitate blood sampling and analysis from samples taken and stored for creatinine or other biochemical parameters. Point of care methods from plasma or urine for the new oral anticoagulants would improve patient care. First data demonstrate the feasibility of such assays in urine.

Modeling complex workflow in molecular diagnostics: design specifications of laboratory software for support of personalized medicine

One of the hurdles to achieving personalized medicine has been implementing the laboratory processes for performing and reporting complex molecular tests. The rapidly changing test rosters and complex analysis platforms in molecular diagnostics have meant that many clinical laboratories still use labor-intensive manual processing and testing without the level of automation seen in high-volume chemistry and hematology testing. We provide here a discussion of design requirements and the results of implementation of a suite of lab management tools that incorporate the many elements required for use of molecular diagnostics in personalized medicine, particularly in cancer. These applications provide the functionality required for sample accessioning and tracking, material generation, and testing that are particular to the evolving needs of individualized molecular diagnostics. On implementation, the applications described here resulted in improvements in the turn-around time for reporting of more complex molecular test sets, and significant changes in the workflow. Therefore, careful mapping of workflow can permit design of software applications that simplify even the complex demands of specialized molecular testing. By incorporating design features for order review, software tools can permit a more personalized approach to sample handling and test selection without compromising efficiency.

Improved Statistical Methods are Needed to Advance Personalized Medicine

Common methods of statistical analysis, e.g. Analysis of Variance and Discriminant Analysis, are not necessarily optimal in selecting therapy for an individual patient. These methods rely on group differences to identify markers for disease or successful interventions and ignore sub-group differences when the number of sub-groups is large. In these circumstances, they provide the same advice to an individual as the average patient. Personalized medicine needs new statistical methods that allow treatment efficacy to be tailored to a specific patient, based on a large number of patient characteristics. One such approach is the sequential k-nearest neighbor analysis (patients-like-me algorithm). In this approach, the k most similar patients are examined sequentially until a statistically significant conclusion about the efficacy of treatment for the patient-at-hand can be arrived at. For some patients, the algorithm stops before the entire set of data is examined and provides beneficial advice that may contradict recommendations made to the average patient. Many problems remain in creating statistical tools that can help individual patients but this is an important area in which progress in statistical thinking is helpful.

Glanzmann thrombasthenia: an update

Glanzmann thrombasthenia (GT) is a rare autosomal recessive disorder characterized by qualitative or quantitative abnormalities of the platelet membrane glycoprotein (GP) IIb/IIIa. Physiologically, this platelet receptor normally binds several adhesive plasma proteins, and this facilitates attachment and aggregation of platelets to ensure thrombus formation at sites of vascular injury. The lack of resultant platelet aggregation in GT leads to mucocutaneous bleeding whose manifestation may be clinically variable, ranging from easy bruising to severe and potentially life-threatening hemorrhages. In this review we discuss the main characteristics of GT, focusing on molecular defects, diagnostic evaluation and treatment strategies.