Personalization of AntiTB Treatment: Evaluation of Pharmacological Determinants of Treatment Response
Personalization of AntiTB Treatment: Evaluation of Pharmacological Determinants of Treatment Response
The aim of the study is to investigate the possible correlation of plasma drug concentrations
 with Time To Positivity (TTP) in liquid culture in patients with active pulmonary multi
 sensitive TB in the first two weeks of treatment. Secondary aims are: the correlation between
 plasma drug concentrations and hepato/neuro toxicity; the impact of different allelic
 variants on PK data, toxicity and TTP in liquid culture; the feasibility of using dried
 blood/plasma spots to measure plasma concentrations of anti-TB drugs and determine genetic
 polymorphisms.
A longitudinal observational multicentred study will be conducted in patients with diagnosis
 of active pulmonary TB.

 The following variables will be recorded:

 -  demographic variables: age, gender, ethnicity, SNPs for NAT2, SLCO1B1, ABCB1 and VDR;

 -  clinical variables: weight, height, renal function tests, liver function tests, vitamin
 D (25-OH vitamin D) level, albuminemia, serology for HIV, HCV, presence of comorbidities
 (e.g. diabetes mellitus), visual acuity test, presence of neuropathic symptoms;

 -  microbiological variables: phenotypic and genotypic drug sensitivity test results,
 sputum Mycobacterium tuberculosis DNA (PCR), microscopy, culture, Time To Positivity
 (TTP) in liquid culture, IGRA test (if performed), history of previous treatments,
 location of pulmonary lesions, presence of extra-pulmonary locations;

 -  therapeutic variables: start/end of treatment, treatment interruptions, dose mg/kg,
 route of administration.

 The patients will received standard antitubercular drugs according to international
 guidelines (RIF 10 mg/kg, INH 5 mg/kg maximum dose 300 mg, ETB 15-20 mg/kg, PZA 25 mg/kg
 maximum dose 2000 mg) in fasten condition, once daily.

 To measure plasma concentrations four blood samples (Lithium heparin 7 ml tubes) will be
 collected at 0, 2, 4 and 6 hours post dose. This analysis will be performed at 7 and 14 days
 after the beginning of anti-TB treatment.

 For the pharmacogenetic analysis a blood sample (EDTA 4 ml tube) will be collected at the
 baseline.

 Sputum samples will be collected at baseline, 7 and 14 days for Mycobacterial culture.

 Medical visits and blood samples (for LFTs) will be performed at baseline, 7 and 14 days to
 investigate neuro and hepato- toxicity.

 Pharmacokinetics After the collection the samples will be centrifugated (3000 rev min-1 at
 4°C for 10 min) and plasma will be frozen at - 20°C in 2 aliquots (1 mL of volume) and will
 be delivered to the Laboratory of Pharmacokinetics and Pharmacogenetics of the University of
 Torino Amedeo di Savoia Hospital, ASLTO2, Torino, Italy.

 Plasma concentrations of all four drugs will be measured using liquid chromatography coupled
 with tandem mass-spectroscopy (allowing high sensitivity despite small sample volumes).
 Collected concentration-time data will be evaluated by a non-compartmental approach to
 characterize the pharmacokinetic properties at steady-state. AUC, maximum (Cmax) and minimum
 (Cmin) drug levels and plasma elimination half-life will be used to assess the enzymatic
 induction properties of these drugs. Pharmacogenomics (PG) DNA will be extracted from whole
 blood using QIamp DNA Mini Kit (Quiagen, Valencia, CA). Purified and eluted DNA will be
 directly used for real-time PCR (BIORAD, Milano, Italia) reaction. The allelic discrimination
 analysis will be performed using the TaqMan assays (Applied Biosystems, Foster City, CA).

 Analyzed SNPs will be:

 ABCB1 3435C>T (rs1045642), OATP1B1 521T>C (rs4149056) e OATP1B1 85-7793T>C (rs4149032), PXR
 63396C>T (rs2472677), BsmI G>A (rs1544410).

 and NAT2 G>A (rs1799930). Dried blood spots (DBSs) and Dried plasma spots (DPSs) Method for
 the determination of plasma concentrations on DPSs will be developed and validated by our
 laboratory. In the study, the blood samples for evaluation on DPSs will be obtained only from
 subjects of our institute. After centrifugation (3000 rev min-1 at 4°C for 10 min) 100 μ l
 plasma will be spotted onto each glass filter (purchased from Laboratori Biomicron srl,
 Italy) and used for pharmacokinetic (PK) analysis. The remaining plasma will be used as
 controls in the analysis.

 For the pharmacogenetic (PG) analysis venous blood samples will be obtained from all subjects
 and whole blood (50 μ l per spot) will be spotted on DBS Whatman 903 protein saver cards (VWR
 International, Milan, Italy).

 DBS will be inserted in a foil bag with desiccant (Foil Bag and Desiccant Packs, purchased
 from Laboratori Biomicron srl, Italy) and then stored at room temperature. After a maximum of
 30 days samples will be delivered to the Laboratory of Pharmacokinetics and Pharmacogenetics
 of the University of Torino Amedeo di Savoia Hospital, ASLTO2, Torino, Italy. They will be
 stored at - 20°C until analysis will be performed (within 3 months from collection).

 Time To Positivity Time to positivity on sputum cultures at baseline, 7 and 14 days will be
 calculated using software BD Epicenter integrated in BACTEC MGIT System (Mycobacteria Growth
 Indication Tube) 960. Default time is 42 days.
Inclusion Criteria:

 -  signed informed consent

 -  age >=18 years;

 -  pulmonary tuberculosis defined by positive sputum microscopy (waiting for culture
 confirmation)

 -  sensitivity to first-line anti-TB drugs;

 -  normal liver and renal function.

 Exclusion Criteria:

 -  severe malnutrition;

 -  HIV infection