The design of this study is based on other PK studies.4–8
Study Setting
This is a comparative, randomized, open, crossover, bicentre clinical trial (Pain and PC Department of University Hospital and Regional PC Unit, Fondation de la Miséricorde, Caen, France) with SC and IV paracetamol injections successively given to each patient.
Eligibility Criteria
Inclusion Criteria
1- Patients ≥ 18 years old, hospitalized
2- Patients in a PC situation
3- Patients having an IV device with the presence of a venous reflux (implantable venous site, PICC line, central track)
4- Patients having spontaneous pain, not related to care, with a numeric pain rate scale (NPRS) > 3/10, or having a systematic prescription of paracetamol in the usual treatment
5- Patients able to do an auto-evaluation of their pain by NPRS
6- No contraindications of paracetamol
7- No contraindications of alternative antalgic (low and strong opioids, non-steroidal anti-inflammatory)
8- Possibility to not take paracetamol in the previous 24 hours before inclusion
9- Patients with a blood test dating back less than 7 days, without severe renal (DFG > 30 or hepatic failure (SGPT/SGOT > 350 UI/L, Bilirubin > 40 µmol/L, TP <50%)
10- Patients related with a French social security regime
11- Patients accept to participate in the study, with written consent
Exclusion criteria
1- Patients under legal protection
2- Patients who participate in another study less than 30 days before
3- Patients weighing less than 50 kg
4- Patients having a contraindication to the SC route
5- Pregnant or breastfeeding woman
6- Patients having a paracetamol administration less than 24 hours before the beginning of the inclusion
7- Patients having a low opioid less than 2 hours before or a strong opioid less than one hour before the beginning of administration of paracetamol
8- Patients having a fever
9- No possibility of communication
Experimental Plan / Intervention
Patients will be screened by investigators according to eligibility criteria. Patients will be randomly assigned (by using an informatic software) to SC before IV route paracetamol injection or IV before SC with a washout period of 24 hours between the injections.
Protocol Steps
The study design is described in figure 1
Figure 1:Study design
All steps are resumed in table 1, with the SPIRIT advice.
Patients will be screened by investigators according to eligibility criteria. Patients will sign a consent form after receiving oral and written information from a physician investigator involved in this project.
After inclusion, they will be randomly assigned (by using Ennov clinical® software) to SC before IV route paracetamol injection or IV before SC with a washout period of 24 hours between the injections.
Day (D) -1
- Verification of eligibility criteria
- Explanation of the study to patients: information about predictable modalities, constraints and risks of the study
- Collect the signed consent
- Informatic Randomization (Group SC-IV or Iv-SC)
- Stop paracetamol
- Alternative antalgics prescription
Day (D) 0:
- Collect the patient characteristics: Temperature; Weight; Size; Gender, Liver and kidney history, Main disease.
- Collect all current treatments
- Adapt pain management treatment and if the patient has paracetamol in his treatment, the practitioner has to prescribe alternative antalgics
- Plan for collection of alternative antalgics from D-1 to D2: hours of administration; dosage.
- First blood test: Albumin, Liver function tests (glutamic-oxaloacetic transaminase serum (SGOT), glutamic pyruvic transaminase (SGPT), gamma-glutamyltransferase (GGT); alkaline phosphatase); kidney function tests (creatinine, glomerular filtration rate (GFR)), human chorionic-gonadotropin, beta subunit (βhCG) (only childbearing woman).
D1:
- Dosage of paracetamol in blood before any administration (=TO). The blood sample has to be done at the precise timetable specified in the protocol.
-Administration of 1000 mg of paracetamol, by the first route of administration designated by randomization and with infusion pump Volumat® or Volumed® at the rate of 100 ml in 30 min (200 mL/hour).
-Carry out blood quantitative analysis of paracetamol, according to the following parameters and depending on the route done first:
- IV way: (after paracetamol administration and every blood puncture, rinsing the central track by 10 mL of physiological serum) 0.75, 1, 1.5, 2, 4 and 8 hours
-SC way: (after every blood puncture, rinsing the central track by 10 mL of physiological serum): 0.25, 0.5, 0.75, 1, 1.5, 2, 4, 6 and 8 hours.
-At each blood test, the patient will undergo a NPRS and an assessment of the tolerance.
D2:
Twenty-four hours after first administration of paracetamol (washout)
The patient will receive paracetamol by the second route of administration according to the randomization in the same timeline as D1.
In any moment, if pain is not well controlled, the investigator practitioner has to prescribe alternative drugs, and all treatment that he will consider necessary to obtain relief. Any adverse events, other unidentified effects of trial intervention and any alternative drugs used have to be listed in the electronic Case Report Form (eCRF) of the patient and declared to the promoter, following the procedure described in the protocol.
Every Patient will have an exam on the fourth and the thirtieth day of the protocol for safety monitoring of the subcutaneous route of administration. In case of adverse events, long term monitoring will be proposed and a specialist opinion will be requested if the investigating physician or the promoter deems it necessary.
Visits
|
VS
(D-1)
|
VI
(D0)
|
V1
(D1)
|
V2
(D2)
|
V4
(D4)
|
V6
(D30)
|
Collect the eligibility criteria
|
X
|
X
|
|
|
|
|
Informed consent
|
|
X
|
|
|
|
|
Collect patients’ characteristics
|
|
X
|
|
|
|
|
Allocation (IV-SC or SC-IV)
|
|
X
|
|
|
|
|
First blood test
|
|
X
|
|
|
|
|
Paracetamol IV administration
|
|
|
X or
|
X
|
|
|
Paracetamol SC Administration
|
|
|
X or
|
X
|
|
|
Plasmatic paracetamol concentrations
|
|
|
X
|
X
|
|
|
Prescription of alternative pain drugs
|
X
|
X
|
X
|
X
|
|
|
Temperature
|
|
X
|
X
|
X
|
|
|
Central track monitoring
|
|
|
X
|
X
|
|
|
Pain monitoring
|
|
X
|
X
|
X
|
X
|
X
|
Tolerance monitoring
|
|
|
X
|
X
|
X
|
X
|
Adverse events monitoring
|
|
X
|
X
|
X
|
X
|
X
|
Table 1: Protocol Steps and Intervention-SPIRIT Figure
Outcomes
The main objective is to demonstrate a PK equivalence between the two modes of administration. The secondary objectives are to compare the efficacy of the two modes of administration on pain and to explore global and cutaneous tolerance of paracetamol used by the SC route.
The main judgement test will be the blood concentration of paracetamol.
Curves will be established for each patient, and we’ll determine and compare for each route of administration and for each patient AUC0-t, AUC0-¥, Cmax, and Vd et t1/2. Data will also permit us to compare PK characteristics between all of the patients.
Secondary evaluation criteria will be the pain evaluation by NPRS throughout the duration of the protocol, and the evaluation of safety by the nurse.
Data Collection Methods
Every participant will be assigned a unique electronic- Case Report Form (eCRF).
Pharmacokinetic Data
Pharmacokinetic sampling procedure.
Blood samples (2 ml) will be collected in dry tubes free of gel at 0.75, 1, 1.5, 2, 4 and 8 hours after paracetamol intravenous administration or 0.25, 0.5, 0.75, 1, 1.5, 2, 4, 6 and 8 hours after SC administration. They will be rapidly transported to the laboratory.
Assay method.
After centrifugation, serum samples will be immediately used for quantification of acetaminophen with the EMIT tox TM Acetaminophen Assay, which is a homogeneous enzyme immunoassay performed in AU 5800 clinical chemistry systems (Beckman Coulter, France). The limit of quantification is 0.12 mg/L. Precision is better than 6% for three quality control levels.
Pharmacokinetic calculations.
Paracetamol concentrations obtained after IV and subcutaneous administration will be analysed using a 1-compartment open model. The apparent first-order rate constant (ke) and the corresponding apparent elimination half-life (t1/2 = Ln2/ke) will be determined by least squares regression analysis of the terminal phase of the serum concentration-time curve. The apparent first-order rate constant (ka) and the corresponding apparent resorption half-life (t1/2 = Ln2/ka) will be determined by least squares regression analysis of the resorption phase from the serum concentration-time curve obtained after subcutaneous administration. The maximum observed serum concentration (Cmax) and the time required to reach Cmax (Tmax) will be calculated using the following formula: Tmax = Ln(Ka/Ke) / (Ka-Ke) and Cmax=C0.(e-Ke.Tmax- e-Ka.Tmax). The AUC 0-infinity will be calculated using the linear trapezoidal rule over the interval of 0 to 8 h (AUC -8 h) and extrapolated to infinity with the following equation: AUC 0-infinity = AUC 0-8 h + C8 h/ke. The bioavailability (f) corresponds to the ratio AUC 0-infinity (after SC administration) / AUC 0-infinity (after IV administration). The volume of distribution will be evaluated with the equations Vd = D/C0 (IV) and Vd = f.D/C0 (SC). The total clearance (CL) will be calculated from the equation CL = Ke.Vd.
Adverse Events Data
All adverse events will be collected, from consent to the end of patient participation, and reported to the sponsor. Serious adverse reactions (SAR) will be qualified as expected or unexpected by the sponsor. Expected SAR related to paracetamol are thrombocytopenia, leucopenia, neutropenia, hypersensitivity, hypotension, increased transaminases, malaise, tachycardia, flushing, pruritus and erythema. Other SAR will be considered as unexpected.
A Data Safety Monitoring Board (DSMB) will review the safety independently. The DSMB will include three experts: one pharmacologist, one physician pain specialist, and one dermatologist. The sponsor will request DSMB advice in case of Suspected Unexpected Serious Adverse Reaction or any new safety information. The DSMB is charged with providing advices to the sponsor recommendations that include (a) continuation of the study, (b) continuation with modification, and (c) termination of the study.
Data Analysis
The following PK parameters: AUC0-t, AUC0-¥, Cmax, Vd, and T1/2, whose distributions are known to be approximately log-normal, will be described for the 2 modes of administration in the form of geometric means with geometric coefficients of variation. Tmax will be summarized by a median and quartiles.
The parameters AUC0-t, AUC0-¥, Cmax, Vd and T1/2 will then be log-transformed and compared between the 2 modes of administration using a linear regression model taking into account the following effects: treatment sequence (IV – SC or SC – IV), subjects (nested in the treatment sequence), treatment period (period 1 or period 2) and treatment (mode of administration: IV or SC). For each parameter, the difference between the two modes of administration will be tested, based on the P-value associated with the treatment effect. A non-parametric test (Wilcoxon signed-rank test) will be used for Tmax.
The bioequivalence between the 2 modes of administration will be tested for AUC0-t, AUC0-¥ and Cmax, based on the 90% confidence interval of the ratio of the geometric means (SC vs IV). According to the recommendations of the European Medicines Agency,9 we can conclude bioequivalence if the confidence interval is fully within the range [80%-125%].
Pain scores will be compared between the 2 modes of administration by paired T-tests or Wilcoxon signed-rank tests, depending on the form of the distribution.
Statistical significance will be set at P < 0.05. Data will be analysed at the Biostatistics and Clinical Research Unit of Caen University Hospital, with SPSS and R software.
Sample Size
No sample size calculations were performed due to the pilot nature of the study. Furthermore, we could not find any information in the literature on the variability of PK parameters in a palliative care population.
We therefore relied on the number of subjects included in clinical studies with a similar methodology4,10–13 and decided to include 20 patients. This number is also in line with the recommendations of the European Medicines Agency9 which sets at 12 the minimum number of patients to be included in a bioequivalence trial.