A Bayesian method for safety signal detection in ongoing blinded randomised controlled trials.

Sponsors have a responsibility to minimise risk to participants in clinical studies through safety monitoring. The FDA Final Rule for IND Safety Reporting requires routine aggregate safety evaluation, including in ongoing blinded studies. We are interested in estimating the probability that the true adverse event rate in the experimental arm exceeds that in the control arm. We developed a Bayesian approach that specifies an informative meta-analytic predictive prior on the event probability in the control arm and an uninformative prior on that in the experimental arm. We combined these priors with a mixture likelihood that considers each patient in the ongoing blinded study may belong to the experimental or control arm. This allowed us to estimate the quantity of interest without unblinding. We evaluated our method by simulation, pairing scenarios that differed only in whether a safety signal was present or missing, and quantifying the ability of our model to discriminate using signal detection theory. Our approach shows benefit. It detects safety signals more reliably with greater sample sizes and for common rather than rare events. Performance does not deteriorate markedly when historical studies exhibit heterogeneous hazards or non-constant hazards. Our method will allow us to monitor safety signals in ongoing blinded studies with the goal of earlier identification and risk mitigation. Our method could be adapted to use informative priors on both arms or predictive covariates where pertinent data exist. We stress that ongoing safety monitoring should involve a multi-disciplinary team where statistical methods are paired with medical judgement.

Safety and efficacy of adjunctive lacosamide among patients with partial-onset seizures in a long-term open-label extension trial of up to 8 years.

Long-term (up to 8 years of exposure) safety and efficacy of the antiepileptic drug lacosamide was evaluated in this open-label extension trial (SP615 [ClinicalTrials.gov identifier: NCT00552305]). Patients were enrolled following participation in a double-blind trial or one of two open-label trials of adjunctive lacosamide for partial-onset seizures. Dosage adjustments of lacosamide (100-800 mg/day) and/or concomitant antiepileptic drugs were allowed to optimize tolerability and seizure reduction. Of the 370 enrolled patients, 77%, 51%, and 39% had >1, >3, or >5 years of lacosamide exposure, respectively. Median lacosamide modal dose was 400mg/day. Common treatment-emergent adverse events (TEAEs) were dizziness (39.7%), headache (20.8%), nausea (17.3%), diplopia (17.0%), fatigue (16.5%), upper respiratory tract infection (16.5%), nasopharyngitis (16.2%), and contusion (15.4%). Dizziness (2.2%) was the only TEAE that led to discontinuation in >2% of patients. Ranges for median percent reductions in seizure frequency were 47-65%, and those for ≥ 50% responder rates were 49-63% for 1-, 3-, and 5-year completer cohorts. Exposure to lacosamide for up to 8 years was generally well tolerated, with a safety profile similar to previous double-blind trials, and efficacy was maintained.

Long-term safety and efficacy in patients with uncontrolled partial-onset seizures treated with adjunctive lacosamide: results from a Phase III open-label extension trial.

PURPOSE: To evaluate the long-term (up to 5 years exposure) safety and efficacy of lacosamide as adjunctive therapy in patients with uncontrolled partial-onset seizures taking one to three concomitant antiepileptic drugs (AEDs) in open-label extension trial SP756 (NCT00522275). METHODS: Patients who completed the double-blind trial SP754 (NCT00136019) were eligible to participate in this open-label extension trial (SP756). At the conclusion of trial SP754, patients had transitioned to lacosamide 200 mg/day. Subsequent dosage adjustments of lacosamide (100-800 mg/day) and/or concomitant AEDs were allowed to optimize tolerability and seizure reduction. Treatment-emergent adverse events (TEAEs), vital signs, body weight, clinical laboratory data, electrocardiography studies, and seizure frequency were evaluated. KEY FINDINGS: A total of 308 patients received open-label lacosamide and 138 patients (44.8%) completed the long-term trial. The median modal dose (defined as the daily lacosamide dose a patient received for the longest duration during the treatment period) was 500 mg/day. The percentages of patients with lacosamide exposure >1, >2, >3, or >4 years were 75%, 63%, 54%, and 29%, respectively. Primary reasons for discontinuation were lack of efficacy (26%) and adverse events (11%). Common TEAEs (≥15%) were dizziness, headache, contusion, nausea, convulsion, nasopharyngitis, fall, vomiting, and diplopia. TEAEs that led to discontinuation in ≥1.0% of patients were dizziness (1.6%) and convulsion (1.0%). The median percent reductions from baseline of trial SP754 in 28-day seizure frequency were 53.4%, 55.2%, 58.1%, and 62.5%, respectively, for 1-, 2-, 3-, and 4-year completers. The ≥50% responder rates were 52.8%, 56.5%, 58.7%, and 62.5% for 1-, 2-, 3-, and 4-year completers, respectively. Seven of eight patients on lacosamide monotherapy for ≥12 months were deemed 50% responders. Of patients exposed to lacosamide ≥2 years, 3.1% remained seizure-free for a period ≥2 years. SIGNIFICANCE: Long-term (up to 5 years) lacosamide treatment was generally well tolerated. The safety profile of lacosamide observed in this trial is consistent with that established in previous double-blind, placebo-controlled trials. Although the open-label trial design limits the analysis of efficacy, long-term reduction in seizure frequency and maintenance of efficacy was observed.

Conversion to brivaracetam monotherapy for the treatment of patients with focal seizures: Two double-blind, randomized, multicenter, historical control, Phase III studies.

Brivaracetam (BRV), a selective, high-affinity ligand for synaptic vesicle protein 2A, is a new antiepileptic drug (AED) approved for monotherapy (in the USA) and adjunctive treatment of focal (partial-onset) seizures in adults, at a dose range of 50-200 mg/day taken in two equal doses, with a recommended starting dose of 100 mg/day. Two Phase III, randomized, double-blind, multicenter, historical-controlled, conversion-to-monotherapy studies (N01276, NCT00698581; N01306, NCT00699283) were conducted to evaluate the efficacy, safety, and tolerability of conversion to BRV 50 mg/day monotherapy in adults with uncontrolled focal seizures. Patients aged 16-75 years, with 2-40 focal seizures per 4 weeks during an 8-week baseline, and on stable doses of 1-2 AEDs were enrolled. Patients were randomized to BRV 50 or 100 mg/day (3:1) in two equal doses without titration. The treatment period comprised 1-week BRV add-on, 8-week baseline AED tapering, and 8-week BRV monotherapy periods. Primary efficacy endpoint was Kaplan-Meier estimate of the cumulative exit rate due to pre-defined exit criteria at Day 112 (50 mg/day, efficacy population). The upper 95% confidence interval (CI) was compared with the historical control threshold (0.722). Safety and tolerability assessments included treatment-emergent adverse events (TEAEs; intent-to-treat population). After randomization of 150 patients (N01276: 88; N01306: 62), both studies were terminated due to the confounding effects of a higher-than-expected discontinuation rate. For BRV 50 mg/day, ≥1 exit criterion was met by 26/67 (38.8%) patients (study N01276) and 18/45 (40.0%) patients (study N01306). In both studies, the cumulative exit rate was lower than the historical control threshold (N01276: 0.487, 95% CI 0.347, 0.626; N01306: 0.474, 95% CI 0.310, 0.638). However, with maximum 10% censoring due to early withdrawal (sensitivity analysis), cumulative exit rates were above historical control (N01276: 0.652, 95% CI 0.532, 0.772; N01306: 0.704, 95% CI 0.563, 0.844). Overall incidence of TEAEs was 110/150, 73.3% (treatment period); 78/147, 53.1% (baseline AED tapering period); 41/84, 48.8% (BRV monotherapy period). In conclusion, BRV 50 mg/day monotherapy demonstrated an exit rate lower than historical control. Results should be interpreted with caution as, following termination of both studies, patient numbers were too low to evaluate the efficacy of BRV monotherapy. These are the first published safety and tolerability data for BRV monotherapy. Monotherapy was well tolerated, with a relatively low incidence of TEAEs, though this should be interpreted with the caveat that the majority of common TEAEs were likely to have occurred earlier in the course of treatment with BRV. No new safety concerns were identified, supporting the favorable safety profile of BRV observed in adjunctive studies.

Adjunctive lacosamide for focal epilepsy: an open-label trial evaluating the impact of flexible titration and dosing on safety and seizure outcomes.

To evaluate the safety and effectiveness of lacosamide in a real-life setting with the use of a flexible dose titration schedule and individualised maintenance doses up to the maximum approved dose of 400 mg/day. Adults with a diagnosis of focal seizures, with or without secondary generalization, were enrolled in this open-label Phase IV trial (NCT01235403). Lacosamide was initiated at 100 mg/day (50 mg bid) and uptitrated over a 12-week period to 200, 300 or 400 mg/day, based on safety and seizure control. Although dose increases were to be in increments of 100 mg/day, intermediate doses were permitted at each escalation step for one week for patients known to be particularly sensitive to starting new AEDs. After receiving a stable, effective dose for three weeks, patients entered the 12-week maintenance period. Primary outcomes were incidence of treatment-emergent adverse events (TEAEs) and withdrawal due to TEAEs. Seizure outcomes, all secondary, were median focal seizure frequency, ≥50% reduction in focal seizure frequency, and seizure freedom. One hundred patients with a mean age of 44 years were enrolled and 74 completed the trial. The incidence of TEAEs was 64.0% (n=100), with the most frequently reported (≥5% of patients) being dizziness, headache, and asthenia. Fourteen patients withdrew due to TEAEs, most frequently due to dizziness (six patients; 6.0%), vomiting (two patients; 2%), and tremor (two patients; 2%). Among patients with baseline and maintenance phase seizure data (n=75), median reduction in focal seizure frequency from baseline was 69.7% and the ≥50% responder rate was 69.3%. Among 74 patients who completed the maintenance phase, 21 (28.4%) were seizure-free. Flexible lacosamide dosing in this open-label trial was associated with a favourable tolerability and safety profile; the nature of the TEAEs was consistent with that observed in previous pivotal trials. Treatment with lacosamide was also associated with effective seizure control.

Levetiracetam extended release for the treatment of patients with partial-onset seizures: A long-term, open-label follow-up study.

This was an open-label study (N01281 [NCT00419393]) assessing the long-term safety of extended-release levetiracetam (LEV XR) in patients with partial-onset seizures (POS); the study was a follow-up to a double-blind, randomized, historical controlled, multicenter, conversion to monotherapy study (N01280 [NCT00419094]). Eligible patients initially received LEV XR 2000 mg/day; dose adjustments and the addition of other antiepileptic drugs (AEDs) were permitted. Overall, 190 patients were enrolled, 189 (99.5%) received LEV XR (safety and efficacy populations) and 166 patients (87.4%) completed the study. The study duration in completed patients was 5.5-24.6 months. Mean daily dose of LEV XR was 2131 mg/day. Treatment-emergent adverse events (TEAEs) occurred in 126 patients (66.7%); most were of mild or moderate severity. Five patients (2.6%) had a TEAE that led to treatment discontinuation. Treatment-emergent serious adverse events occurred in 22 patients (11.6%). Twenty-six patients (13.8%) experienced a psychiatric TEAE. The median 7-day normalized POS frequency was: 1.38 at N01280 study baseline; 0.50 at the first visit of N01281 (last visit of N01280); and 0.00-0.36 between all subsequent visits. Overall, 171 patients (90.5%) entered the N01281 study on LEV XR monotherapy; 65.3% (32/49) of patients remained on monotherapy for 12 months and 47.1% (8/17) for 18 months. While remaining on LEV XR monotherapy, 27/139 patients (19.4%) were seizure-free at 6 months and 8/49 (16.3%) at 12 months. In conclusion, LEV XR was well tolerated when administered as long-term monotherapy or in combination with other AEDs in patients with inadequately controlled POS.

Levetiracetam extended release conversion to monotherapy for the treatment of patients with partial-onset seizures: a double-blind, randomised, multicentre, historical control study.

This double-blind, randomised, multicentre, conversion to monotherapy, historical control study (N01280; NCT00419094) evaluated the efficacy, safety and tolerability of levetiracetam extended release (LEV XR) 2000mg/day once daily for the treatment of patients with partial-onset seizures compared with a historical control. Patients aged 12-75 years with 2-40 partial-onset seizures per 4 weeks, taking 1-2 antiepileptic drugs (AEDs) and receiving a stable dosage for ≥4 weeks prior to screening were randomised in a 3:1 ratio to LEV XR 2000 or 1000 mg/day. The study comprised baseline (8 weeks), LEV XR up-titration (2 weeks), baseline AED tapering (6 weeks), LEV XR monotherapy (10 weeks), and entry into open-label follow-up study or down-titration (1 week). The primary efficacy variable was the cumulative exit rate at Day 112 due to predefined exit criteria compared with the historical control. Of the 171 patients randomised to LEV XR 2000 mg/day and 57 randomised to 1000 mg/day, 141 (82.5%) and 50 (87.7%) completed the study. The cumulative exit rate for patients on LEV XR 2000 mg/day (0.375 [95% CI 0.297, 0.453]) was significantly lower than historical control (0.653). Both LEV doses were well tolerated. The most common adverse events during the treatment period were somnolence (21.9%), headache (19.7%) and convulsion (14.9%).