The effect of two atypical antipsychotics on QTc intervals (heart rate-corrected QT interval) was evaluated. Patients (N=109) with schizophrenia (79%) or schizoaffective disorder (21%) were randomly ...assigned in 2 : 2 : 1 ratio to paliperidone extended release (ER), quetiapine, or placebo. Doses of 12 and 18 mg/day of paliperidone ER were compared with quetiapine 800 mg/day. Least-squares mean change from baseline in population-specific linear-derived correction method from baseline to days 6-7 at individual tmax was 5.1 ms less 90% confidence interval: -9.2 to -0.9 with paliperidone ER 12 mg/day than with quetiapine 800 mg/day. On the basis of a prespecified 10-ms noninferiority margin, paliperidone ER was thus declared noninferior to quetiapine (primary analysis). Mean change in population-specific linear-derived correction method from baseline to days 11-12 at individual tmax was 2.3 ms less (90% confidence interval: -6.8 to 2.3) with paliperidone ER 18 mg/day than with quetiapine 800 mg/day. Treatment-emergent adverse events occurred in 36 (82%) patients treated with paliperidone ER, 41 (95%) patients treated with quetiapine, and 14 (64%) patients treated with placebo. No adverse events of a proarrhythmic nature were noted. The effect on the QTc interval in patients with schizophrenia or schizoaffective disorder was comparable between paliperidone ER 12 mg/day (maximum recommended dose), paliperidone ER 18 mg/day (supratherapeutic dose), and quetiapine 800 mg/day.
Given the potential concomitant use of carbamazepine and paliperidone extended‐release (ER) in the treatment of schizophrenia or schizoaffective disorder, this open‐label, two‐treatment sequential ...study investigated the effect of repeated administration of carbamazepine on the steady‐state pharmacokinetics of paliperidone. Sixty‐four patients with a diagnosis of schizophrenia or bipolar‐I disorder received the following treatments in a fixed sequential order, without washout between treatments: (i) paliperidone ER 6 mg tablet once daily for 7 days, and (ii) paliperidone ER 6 mg once daily concomitantly with carbamazepine 200 mg twice daily for the subsequent 21 days. Upon coadministration with carbamazepine, paliperidone steady‐state total exposure (AUC24 h) and peak plasma concentrations (Cmax) decreased by approximately 37% LSM ratio—AUC24 h: 63.4 (90% CI: 57.19; 70.29); Cmax: 62.47 (90% CI: 55.77; 69.98). This decrease is accounted for to a substantial degree by a 35% increase in renal clearance of paliperidone, likely as a result of induction of renal P‐glycoprotein by carbamazepine. A 14% decrease in the amount of drug excreted unchanged in the urine suggests that carbamazepine coadministration has a limited effect on the intestinal absorption or cytochrome metabolism of paliperidone.
Starting in December 2013, West Africa was overwhelmed with the deadliest outbreak of Ebola virus known to date, resulting in more than 27,500 cases and 11,000 deaths. In response to the epidemic, ...development of a heterologous prime-boost vaccine regimen was accelerated and involved preparation of a phase 3 effectiveness study. While individually randomized controlled trials are widely acknowledged as the gold standard for demonstrating the efficacy of a candidate vaccine, there was considerable debate on the ethical appropriateness of these designs in the context of an epidemic. A suitable phase 3 trial must convincingly ensure unbiased evaluation with sufficient statistical power. In addition, efficient evaluation of a vaccine candidate is required so that an effective vaccine can be immediately disseminated. This manuscript aims to present the statistical and modeling considerations, design rationale and challenges encountered due to the emergent, epidemic setting that led to the selection of a cluster-randomized phase 3 study design under field conditions.
Paliperidone palmitate (PP) is a once‐monthly long‐acting injectable antipsychotic approved for the treatment of schizophrenia in many countries. To evaluate the different injection‐site options, we ...compared the pharmacokinetic profile of paliperidone after multiple injections of PP 100 mg eq. (156 mg of PP, equivalent to 100 mg of paliperidone) on days 1, 8, 36, and 64 into the deltoid (n = 24) or gluteal muscle (n = 25) in patients with schizophrenia. After four injections in the deltoid muscle, paliperidone exposure was higher for AUCτ and Cmax, compared with the gluteal muscle (geometric mean AUCτ‐based ratio: 120% 90% CI: 93.1–154.7%, and geometric mean Cmax‐based ratio: 130% 90% CI: 100.6–168.9%). The mean SD fluctuation index was higher, with a larger interpatient variability, after deltoid‐injections (75.9% 30.9%) than gluteal‐injections (58.5% 14.3%). The median tmax was similar for both sites. PP was generally tolerable in patients, with more favorable local‐site tolerability for gluteal‐injection. In conclusion, to achieve therapeutic‐concentrations quickly, the first‐two injections of PP are best administered into the deltoid muscle, whereas thereafter maintenance‐injections can be administered either in the deltoid or gluteal muscle.
A Phase 2a, open-label study (NCT01724086) was conducted to assess the efficacy and safety of a once-daily, 2-direct-acting-antiviral-agent (2-DAA) combination of simeprevir + TMC647055/ritonavir ± ...ribavirin and of the 3-DAA combination of simeprevir + TMC647055/ritonavir + JNJ-56914845 in chronic hepatitis C virus genotype (GT)1-infected treatment-naïve and prior-relapse patients.
The study comprised four 12-week treatment panels: Panel 1 (n = 10; GT1a) and Panel 2-Arm 1 (n = 12; GT1b): simeprevir 75 mg once daily + TMC647055 450 mg once daily/ritonavir 30 mg once daily + ribavirin 1000-1200 mg/day; Panel 2-Arm 2 (n = 9; GT1b): simeprevir 75 mg + TMC647055 450 mg/ritonavir 30 mg without ribavirin; Panel 3: simeprevir 75 mg + TMC647055 600 mg/ritonavir 50 mg with (Arm 1: GT1a; n = 7) or without (Arm 2: GT1b; n = 8) ribavirin; Panel 4: simeprevir 75 mg + TMC647055 450 mg/ritonavir 30 mg + JNJ-56914845 30 mg once daily (Arm 1: n = 22; GT1a/GT1b) or 60 mg once daily (Arm 2: n = 22; GT1a/GT1b). Primary endpoint was sustained virologic response 12 weeks after end of treatment (12 weeks of combination treatment; SVR12).
In Panel 1 and Panel 2-Arm 1, 5/10 and 6/12 (50%) GT1a/GT1b + ribavirin patients achieved SVR12, versus 3/9 (33%) GT1b without ribavirin patients in Panel 2-Arm 2. In Panel 3-Arm 1 and Panel 3-Arm 2, 6/7 (86%) GT1a + ribavirin and 4/8 (50%) GT1b without ribavirin patients, respectively, achieved SVR12. In Panel 4, 10/14 (71%) and 14/15 (93%) GT1a patients in Arms 1 and 2 achieved SVR12 compared with 8/8 and 7/7 (100%) GT1b patients in each arm, respectively. No deaths, serious adverse events (AEs), Grade 4 AEs or AEs leading to treatment discontinuation occurred.
The 2- and 3-DAA combinations were well tolerated. High SVR rates of 93% and 100% in GT1a- and GT1b-infected patients, respectively, were achieved in this study by combining simeprevir with JNJ-56914845 60 mg and TMC647055/ritonavir.
NCT01724086 (date of registration: September 26, 2012).
When choosing estimands and estimators in randomized clinical trials, caution is warranted as intercurrent events, such as - due to patients who switch treatment after disease progression, are often ...extreme. Statistical analyses may then easily lure one into making large implicit extrapolations, which often go unnoticed. We will illustrate this problem of implicit extrapolations using a real oncology case study, with a right-censored time-to-event endpoint, in which patients can cross over from the control to the experimental treatment after disease progression, for ethical reasons. We resolve this by developing an estimator for the survival risk ratio contrasting the survival probabilities at each time t if all patients would take experimental treatment with the survival probabilities at those times t if all patients would take control treatment up to time t, using randomization as an instrumental variable to avoid reliance on no unmeasured confounders assumptions. This doubly robust estimator can handle time-varying treatment switches and right-censored survival times. Insight into the rationale behind the estimator is provided and the approach is demonstrated by re-analyzing the oncology trial.
Dapoxetine is a short‐acting selective serotonin reuptake inhibitor developed for the on‐demand treatment of premature ejaculation and is approved in some European Union countries, as well as Mexico ...and Korea, for this indication. The pharmacokinetics of dapoxetine 30 mg and 60 mg in healthy Chinese (single dose), Japanese, and Caucasian men (single and multiple dose) were assessed in 2 studies. In the 3 ethnic groups, dapoxetine was rapidly absorbed following oral administration, with peak plasma concentrations evident approximately 1 hour after dosing, independent of dose, dosing frequency (single or multiple dosing), or ethnicity. Dapoxetine was eliminated in a biphasic manner with an apparent mean terminal half‐life of 14 to 17 hours. There was a dose‐proportional increase in dapoxetine maximum plasma concentration (Cmax) and area under concentration‐time curves (AUCs). The single‐dose pharmacokinetic parameters of dapoxetine metabolites were also similar for the 3 ethnic groups, as were the pharmacokinetics of dapoxetine and its metabolites following single and multiple dosing in Caucasian and Japanese men. Dapoxetine was well tolerated by all 3 ethnic groups.
Drug–drug interactions between canagliflozin, a sodium glucose co‐transporter 2 inhibitor, and glyburide, metformin, and simvastatin were evaluated in three phase‐1 studies in healthy participants. ...In these open‐label, fixed sequence studies, participants received: Study 1‐glyburide 1.25 mg/day (Day 1), canagliflozin 200 mg/day (Days 4–8), canagliflozin with glyburide (Day 9); Study 2‐metformin 2,000 mg/day (Day 1), canagliflozin 300 mg/day (Days 4–7), metformin with canagliflozin (Day 8); Study 3‐simvastatin 40 mg/day (Day 1), canagliflozin 300 mg/day (Days 2–6), simvastatin with canagliflozin (Day 7). Pharmacokinetic parameters were assessed at prespecified intervals. Co‐administration of canagliflozin and glyburide did not affect the overall exposure (maximum plasma concentration Cmax and area under the plasma concentration–time curve AUC) of glyburide and its metabolites (4‐trans‐hydroxy‐glyburide and 3‐cis‐hydroxy‐glyburide). Canagliflozin did not affect the peak concentration of metformin; however, AUC increased by 20%. Though Cmax and AUC were slightly increased for simvastatin (9% and 12%) and simvastatin acid (26% and 18%) following coadministration with canagliflozin, compared with simvastatin administration alone; however, no effect on active 3‐hydroxy‐3‐methyl‐glutaryl‐CoA (HMG‐CoA) reductase inhibitory activity was observed. There were no serious adverse events or hypoglycemic episodes. No drug–drug interactions were observed between canagliflozin and glyburide, metformin, or simvastatin. All treatments were well‐tolerated in healthy participants.
The interpretation of randomised clinical trial results is often complicated by intercurrent events. For instance, rescue medication is sometimes given to patients in response to worsening of their ...disease, either in addition to the randomised treatment or in its place. The use of such medication complicates the interpretation of the intention-to-treat analysis. In view of this, we propose a novel estimand defined as the intention-to-treat effect that would have been observed, had patients on the active arm been switched to rescue medication if and only if they would have been switched when randomised to control. This enables us to disentangle the treatment effect from the effect of rescue medication on a patient's outcome, while avoiding the strong extrapolations that are typically needed when inferring what the intention-to-treat effect would have been in the absence of rescue medication. We develop an inverse probability weighting method to estimate this estimand under specific untestable assumptions, in view of which we propose a sensitivity analysis. We use the method for the analysis of a clinical trial conducted by Janssen Pharmaceuticals, in which chronically ill patients can switch to rescue medication for ethical reasons. Monte Carlo simulations confirm that the proposed estimator is unbiased in moderate sample sizes.
PDF
