Evaluation of Deutetrabenazine's Potential to Delay Cardiac Repolarization Using Concentration-QTc Analysis

Deutetrabenazine (Austedo) is indicated in adults for chorea associated with Huntington disease and tardive dyskinesia. Escalating deutetrabenazine doses were administered to healthy volunteers who were cytochrome P450 2D6 extensive/intermediate metabolizers (EMs) or poor metabolizers (PMs) to determine pharmacokinetic exposure of parent drug and active metabolites (α-dihydrotetrabenazine [α-HTBZ] and β-dihydrotetrabenazine [β-HTBZ]), and collect corresponding electrocardiograms (ECGs) for evaluation of the cardiodynamic effect using concentration-QTc (C-QTc) modeling. Participants (12 EMs, 24 PMs) received placebo or single doses of deutetrabenazine (24, 48, and 72 mg) to achieve plasma concentrations exceeding therapeutic range in both cohorts. Pharmacokinetic samples were obtained over 72 hours after dosing and were time matched with 12-lead ECGs extracted from continuous ECG recordings. C-QTc analysis, using linear mixed-effects modeling and model selection procedure, characterized the relationship between plasma concentrations of deutetrabenazine, deuterated α-HTBZ and β-HTBZ, and the change from baseline in QT interval corrected using Fridericia's formula. Deutetrabenazine exhibited linear kinetics, and a C-QTc model with deuterated α-HTBZ and β-HTBZ was selected to best describe the C-QTc relationship in pooled EM and PM data. This model predicted a placebo-corrected Fridericia corrected QT interval prolongation higher than 10 milliseconds can be excluded at concentrations associated with the maximum recommended doses in both populations. Adverse events increased with higher exposure as reflected by the higher event number in the PM cohort receiving 48 and 72 mg doses. No subject discontinued due to cardiac-related adverse events and no clinically relevant ECG findings were reported. Thus, this study found that deutetrabenazine does not have a clinically relevant effect on QT prolongation at maximum recommended doses in either cytochrome P450 2D6 EMs or PMs.

The effect of potent CYP2D6 inhibition on the pharmacokinetics and safety of deutetrabenazine in healthy volunteers

Purpose

Deutetrabenazine is a deuterated form of tetrabenazine with a confirmed lower rate of CYP2D6 metabolism of the active metabolites, α- and β-HTBZ. In this study, we assessed the effect of paroxetine, a potent CYP2D6 inhibitor, on the pharmacokinetics and safety of deutetrabenazine and its metabolites.

Methods

In this open-label sequential drug-drug-interaction study, 24 healthy adults who were CYP2D6 extensive or intermediate metabolizers received a single deutetrabenazine 22.5-mg oral dose on days 1 and 11 and a single paroxetine 20-mg oral daily dose on days 4–12. Pharmacokinetics of deutetrabenazine and its metabolites were assessed on days 1–4 and 11–14. Paroxetine trough concentrations were obtained pre-dose on days 9–13. Safety examinations occurred throughout the study.

Results

Paroxetine administered under steady-state conditions, increased exposure of the deuterated active metabolites, α-HTBZ (1.2-fold C_max and 1.8-fold AUC_0–∞) and β-HTBZ (2.1-fold C_max and 5.6-fold AUC_0–∞), and correspondingly, 1.6-fold C_max and threefold AUC_0–∞ for total (α + β)-HTBZ. Sixteen subjects reported 45 adverse events and most were mild. Headache was the most common AE reported 8 times by 7 subjects (5 following paroxetine alone; 2 following deutetrabenazine + paroxetine).

Conclusions

Paroxetine-induced increases in exposure to the active deutetrabenazine metabolites were less than those previously reported for tetrabenazine, a finding expected to reduce the burden of drug interaction. In addition, single doses of 22.5 mg deutetrabenazine, when given alone or in the presence of steady-state paroxetine (20 mg daily), were safe.

Supplementary information

The online version contains supplementary material available at 10.1007/s00228-021-03202-0.

A Pharmacokinetic Bioequivalence Study of Fremanezumab Administered Subcutaneously Using an Autoinjector and a Prefilled Syringe

Fremanezumab (AJOVY; Teva Pharmaceutical Industries Ltd, Netanya, Israel), approved for the preventive treatment of migraine, is available as a subcutaneous injection either once a month or once every 3 months using an autoinjector or a prefilled syringe. The present study evaluated the pharmacokinetic (PK) bioequivalence of a single subcutaneous injection of fremanezumab 225 mg administered using an autoinjector compared to a prefilled syringe in healthy volunteers. Blood samples for PK and antidrug antibodies were collected before and after dosing. Safety and tolerability assessments included physical examinations, adverse event reporting, laboratory evaluations, and immunogenicity. Following single-dose administration, the mean concentration-time profiles for the 2 treatment groups (autoinjector, n = 106; and prefilled syringe, n = 110) were similar. The point estimates for the back-transformed ratio (autoinjector/prefilled syringe) of geometric least squares means of maximum plasma concentration, area under the plasma concentration-time curve from time 0 to the time of the last measurable drug concentration, and area under the plasma concentration-time curve from time 0 extrapolated to infinity were 1.03, 1.04, and 1.05, respectively, with the 90% confidence intervals entirely contained within bioequivalence margins of 0.8 to 1.25. For both groups, median time to maximum observed concentration was 5 days and mean terminal elimination half-life was approximately 29 days. Treatment-related adverse events were reported by 39 (36%) subjects in the autoinjector group and 26 (24%) in the prefilled syringe group, and the majority were nonserious injection site reactions. The incidence of treatment-emergent antidrug antibody response was low and evenly distributed between the autoinjector (n = 3; 3%) and prefilled syringe (n = 4; 4%) groups. These results indicate that the fremanezumab autoinjector presentation provides an easy-to-use bioequivalent PK profile with a similar safety and tolerability profile to that of the prefilled syringe.

Pharmacokinetics of Deutetrabenazine and Tetrabenazine: Dose Proportionality and Food Effect

Deutetrabenazine (Austedo, Teva), an approved treatment of chorea in Huntington's disease and tardive dyskinesia in adult patients, is a rationally designed deuterated form of tetrabenazine. Two studies assessed the pharmacokinetics and safety of deutetrabenazine compared with tetrabenazine, and the effects of food on absorption of the deuterated active metabolites, α‐dihydrotetrabenazine (α‐HTBZ) and β‐dihydrotetrabenazine (β‐HTBZ). One study was an open‐label 2‐part study in healthy volunteers; the first part included a crossover single dose of two 15 mg candidate deutetrabenazine formulations in fed and fasted states compared with tetrabenazine 25 mg in the fasted state, and the second part included single and repeated dosing of the commercial formulation of deutetrabenazine (7.5, 15, and 22.5 mg) compared with tetrabenazine 25 mg. The second study was an open‐label 5‐way crossover study in healthy volunteers (n = 32) to evaluate relative bioavailability of 4 dose levels of the commercial formulation of deutetrabenazine (6, 12, 18, and 24 mg) with a standard meal and 18 mg with a high‐fat meal. Both studies confirmed longer half‐lives for active metabolites and lower peak‐to‐trough fluctuations for the sum of the metabolites (total [α+β]‐HTBZ) following deutetrabenazine compared with tetrabenazine (3‐ to 4‐fold and 11‐fold, respectively) in steady‐state conditions. Deutetrabenazine doses estimated to provide total (α+β)‐HTBZ exposure comparable to tetrabenazine 25 mg were 11.4‐13.2 mg. Food had no effect on exposure to total (α+β)‐HTBZ, as measured by AUC. Although the total (α+β)‐HTBZ C_max of deutetrabenazine was increased by ≈50% in the presence of food, it remained lower than that of tetrabenazine.

The Effect of CYP3A Induction and Inhibition on the Pharmacokinetics of Laquinimod, a Novel Neuroimmunomodulator

Laquinimod, a neuroimmunomodulator, is extensively metabolized by cytochrome P450 (CYP) 3A4, and modulations of CYP3A4 activity may lead to alterations in the pharmacokinetics and/or clinical effects of laquinimod. To determine the drug-drug interaction potential of laquinimod with CYP3A inhibitors and inducers, interaction assessments were conducted in healthy volunteers using single-dose administration of laquinimod before and after multiple dosing of CYP3A inhibitors (ketoconazole, fluconazole, and cimetidine) or a CYP3A4 inducer (rifampin). For ketoconazole, subjects (n = 14) received laquinimod 0.6 mg following 1 day of ketoconazole (400 mg daily) pretreatment, a single concomitant dose, and 28 additional days. For fluconazole, subjects (n = 14) received laquinimod 0.6 mg after a single fluconazole dose of 400 mg followed by 200-mg daily fluconazole administration for 20 additional days. For cimetidine, subjects (n = 14) received laquinimod 0.6 mg following 1 day of cimetidine (800 mg twice daily) pretreatment, a single concomitant dose, and 21 additional days. For rifampin, subjects (n = 14) received laquinimod 0.6 mg following 9 days of rifampin (600 mg daily) pretreatment, a single concomitant dose, and 12 additional days. Coadministration of laquinimod with CYP3A inhibitors, ketoconazole, fluconazole, and cimetidine increased laquinimod area under the plasma concentration-time curve from time zero to infinity by approximately 3.1-, 2.5-, and 1.1-fold, respectively. Coadministration of laquinimod with rifampin decreased laquinimod area under the plasma concentration-time curve from time zero to infinity by 5-fold. These results indicate that coadministration of laquinimod with moderate to strong inhibitors of CYP3A or strong inducers of CYP3A may give rise to significant pharmacokinetic drug interactions.

Pharmacokinetic and Metabolic Profile of Deutetrabenazine (TEV-50717) Compared With Tetrabenazine in Healthy Volunteers

Deutetrabenazine (Austedo, Teva Pharmaceuticals) is a deuterated form of tetrabenazine. It is the first deuterated drug to receive US regulatory approval and is approved for treatment of chorea in Huntington's disease and tardive dyskinesia. Two oral single dose studies comparing deutetrabenazine (25 mg) with tetrabenazine (25 mg) in healthy volunteers evaluated the impact of deuteration on pharmacokinetics of the active metabolites, alpha-dihydrotetrabenazine (α-HTBZ) and beta-dihydrotetrabenazine (β-HTBZ), metabolite profile, safety, and tolerability. In the two-way, cross-over study, the mean elimination half-life of deuterated total (α + β)-HTBZ was doubled compared with nondeuterated total (α + β)-HTBZ, with a twofold increase in overall mean exposure (area under the concentration-time curve from zero to infinity (AUC_0-inf )) and a marginal increase in mean peak plasma concentration (C_max ). In the mass balance and metabolite profiling study, there were no novel plasma or urinary metabolites of [¹⁴ C]-deutetrabenazine relative to [¹⁴ C]-tetrabenazine. Specific deuteration in deutetrabenazine resulted in a superior pharmacokinetic profile and an increased ratio of active-to-inactive metabolites, attributes considered to provide significant benefits to patients.

Quantification of Motor Function in Huntington Disease Patients Using Wearable Sensor Devices

Previous studies have demonstrated the feasibility and promise of wearable sensors as objective measures of motor impairment in Parkinson disease and essential tremor. However, there are few published studies that have examined such an application in Huntington disease (HD). This report provides an evaluation of the potential to objectively quantify chorea in HD patients using wearable sensor data. Data were derived from a substudy of the phase 2 Open-PRIDE-HD study, where 17 patients were screened and 15 patients enrolled in the substudy and ultimately 10 patients provided sufficient wearable sensor data. The substudy was designed to provide high-resolution data to inform design of predictive algorithms for chorea quantification. During the entire course of the 6-month study, in addition to chorea ratings from 18 in-clinic assessments, 890 home assessments, and 1,388 responses to daily reminders, 33,000 h of high-resolution accelerometer data were captured continuously from wearable smartwatches and smartphones. Despite its limited sample size, our study demonstrates that arm chorea can be characterized using accelerometer data during static assessments. Nonetheless, the small sample size limits the generalizability of the model. The sensor-based model can quantify the chorea level with high correlation to the chorea severity reported by both clinicians and patients. In addition, our analysis shows that the chorea digital signature varies between patients. This work suggests that digital wearable sensors have the potential to support clinical development of medications in patients with movement disorders, such as chorea. However, additional data would be needed from a larger number of HD patients with a full range of chorea severity (none to severe) with and without intervention to validate this potentially predictive technology.

Fremanezumab for preventive treatment of migraine: Functional status on headache-free days

Objective

To evaluate the effect of fremanezumab on the functional status on headache-free days in phase 2 episodic migraine (EM) and chronic migraine (CM) studies.

Methods

Functional status data were collected prospectively via the electronic headache diary on all headache-free days by patients answering questions regarding work/school/household chore performance, speed of work completion, concentration, and feeling of fatigue. Individuals with EM receiving monthly doses of fremanezumab 225 mg (n = 96) or 675 mg (n = 97) or placebo (n = 104) were compared. Individuals with CM receiving fremanezumab 675 mg followed by monthly 225 mg (n = 88) and 900 mg (n = 86) were also independently compared to those receiving placebo (n = 89).

Results

In patients with EM, compared to patients receiving placebo, those receiving fremanezumab experienced an increased number of headache-free days with normal function in work/school/household chore performance and concentration/mental fatigue measures compared to their baseline over the entire treatment period (all p < 0.005). An increased number of headache-free days with normal functional performance for some measures was also found in the CM group in those treated with fremanezumab.

Conclusion

There was an increased number of headache-free days with normal functional performance on all measures for the patients with EM and some measures for patients with CM in the fremanezumab-treated groups. Further research is required to confirm these findings in a prospective study and to clarify the underlying mechanism(s).

ClinicalTrials.gov identifier:

NCT02025556 and NCT02021773.

Classification of evidence

This study provides Class II evidence that for patients with migraine, fremanezumab increases normal functional performance on headache-free days.

Pharmacokinetics, metabolism and safety of deuterated L-DOPA (SD-1077)/carbidopa compared to L-DOPA/carbidopa following single oral dose administration in healthy subjects

AIMS

SD-1077, a selectively deuterated precursor of dopamine (DA) structurally related to L-3,4-dihydroxyphenylalanine (L-DOPA), is under development for treatment of motor symptoms of Parkinson's disease. Preclinical models have shown slower metabolism of central deuterated DA. The present study investigated the peripheral pharmacokinetics (PK), metabolism and safety of SD-1077.

METHODS

Plasma and urine PK of drug and metabolites and safety after a single oral 150 mg SD-1077 dose were compared to 150 mg L-DOPA, each in combination with 37.5 mg carbidopa (CD) in a double-blind, two-period, crossover study in healthy volunteers (n = 16).

RESULTS

Geometric least squares mean ratios (GMRs) and 90% confidence intervals (90% CI) of SD-1077 vs. L-DOPA for C_max , AUC_0-t , and AUC_0-inf were 88.4 (75.9-103.1), 89.5 (84.1-95.3), and 89.6 (84.2-95.4), respectively. Systemic exposure to DA was significantly higher after SD-1077/CD compared to that after L-DOPA/CD, with GMRs (90% CI) of 1.8 (1.45-2.24; P = 0.0005) and 2.06 (1.68-2.52; P < 0.0001) for C_max and AUC_0-t and a concomitant reduction in the ratio of 3,4-dihydroxyphenylacetic acid/DA confirming slower metabolic breakdown of DA by monoamine oxidase (MAO). There were increases in systemic exposures to metabolites of catechol O-methyltransferase (COMT) reaction, 3-methoxytyramine (3-MT) and 3-O-methyldopa (3-OMD) with GMRs (90% CI) for SD-1077/CD to L-DOPA/CD for 3-MT exposure of 1.33 (1.14-1.56; P = 0.0077) and 1.66 (1.42-1.93; P < 0.0001) for C_max and AUC_0-t , respectively and GMRs (90% CI) for 3-OMD of 1.19 (1.15, 1.23; P < 0.0001) and 1.31 (1.27, 1.36; P < 0.0001) for C_max and AUC_0-t . SD-1077/CD exhibited comparable tolerability and safety to L-DOPA/CD.

CONCLUSIONS

SD-1077/CD demonstrated the potential to prolong exposure to central DA at comparable peripheral PK and safety to the reference L-DOPA/CD combination. A single dose of SD-1077 is safe for further clinical development in Parkinson's disease patients.

Sustained reductions in migraine days, moderate-to-severe headache days and days with acute medication use for HFEM and CM patients taking fremanezumab: Post-hoc analyses from phase 2 trials

BACKGROUND

In phase 2 and 3 studies, fremanezumab, a monoclonal CGRP antibody, was an effective preventive treatment for high-frequency episodic migraine (HFEM) and chronic migraine (CM).

OBJECTIVE

Post-hoc analyses evaluated population-wise 50%, 75% and 100% responder rates, and the extent to which individual responders sustained a 50%, 75% and 100% reduction in migraine days, moderate-to-severe (M/S) headache days and days of acute medication use during all three treatment months of the fremanezumab phase 2 studies.

DESIGN/METHODS

HFEM patients received either placebo or three once-monthly injections of 225 mg or 675 mg. CM patients received either placebo or three once-monthly injections of 900 mg, or an initial loading dose of 675 mg and subsequent injections of 225 mg. Patients reported headache-related data daily using an electronic diary.

RESULTS

In the HFEM study, the percent of patients on fremanezumab doses 225 mg and 675 mg were greater compared to the percent of placebo patients with sustained 50% reduction in migraine days (39% and 35% vs. 10% for placebo, both p < 0.0001), M/S headache days (36% and 38% vs. 16% placebo, p = 0.0017 and p = 0.0007 respectively), and acute medication use days (36% and 27% vs. 8% placebo, p < 0.0001 and p = 0.0003). Likewise, although there were fewer patients with sustained 75% reduction, there were increases in the percent of patients on fremanezumab 225 mg and 675 mg in the HFEM study relative to placebo patients in migraine days (19% and 11% vs. 3% placebo, p = 0.0002 and p = 0.0176), M/S headache days (19% and 15% vs. 2% placebo, p = 0.0001 and p = 0.0011) and days of acute medication use (16% and 8% vs. 2% placebo, p = 0.0005 and p = 0.0377). In the CM study, there were increases in the percent of patients on fremanezumab 675/225 mg and 900 mg with 50% sustained reduction in M/S headache days (32% and 40% vs. 15% placebo, p = 0.0058 and p = 0.0002) and days of acute medication use (26% and 22% vs. 11% placebo, p = 0.0098 and p = 0.0492). There were also increases in the percent of patients on fremanezumab 675/225 mg and 900 mg compared to patients on placebo with 75% sustained reduction in M/S headache days (10% and 13% vs. 3%, p = 0.0665 and p = 0.0203). Few patients had 100% sustained reductions in these parameters in either study.

CONCLUSIONS

Post-hoc results must be interpreted with caution; nonetheless, a statistically significant percentage of patients who initially responded to fremanezumab within 1 month sustained this response over the subsequent 2 months. Sustained reduction in individual patients may provide a novel patient-centric, clinically meaningful endpoint for future trials assessing the effectiveness of preventive migraine treatments. Trials are registered as http://clinical trials.gov as NCT02025556 and NCT02021773.

A phase 1 study to assess the pharmacokinetics, safety, and tolerability of fremanezumab doses (225 mg, 675 mg and 900 mg) in Japanese and Caucasian healthy subjects

OBJECTIVES

The primary and secondary objectives of this phase 1 study were to evaluate the pharmacokinetic profile, safety, and immunogenicity of fremanezumab subcutaneous (sc) doses tested in phase 2 and 3 trials (225 mg, 675 mg and 900 mg) following single administration in Japanese (n = 32) and Caucasian (n = 32) healthy subjects.

METHODS

Japanese and matched Caucasian healthy subjects were enrolled into one of four cohorts and were randomly assigned to one of four treatments: 225, 675, or 900 mg fremanezumab, or placebo. Pharmacokinetic and immunogenicity sampling, and safety and tolerability assessments occurred at one inpatient visit and 12 ambulatory visits during the 36-week study.

RESULTS

Pharmacokinetic analyses included those randomized to fremanezumab (n = 24 for each ethnic group) and safety analyses included all subjects enrolled in the study (n = 32 for each ethnic group). Fremanezumab concentration-time profiles and pharmacokinetic parameters per dose were similar for Japanese and Caucasians at all dose levels. Geometric mean ratios (GMRs) for C_max for Japanese to Caucasian subjects were 0.91, 1.04 and 1.14 for the 225 mg, 675 mg and 900 mg fremanezumab doses. GMRs for AUC_0-inf were 0.96, 1.09, and 0.98, respectively. Median T_max (range 5-11 days) and mean half-lives (range 31-39 days) were similar across doses for both ethnicities. Most frequently occurring adverse events were injection site reactions, abdominal pain, headache, upper respiratory tract infection, constipation and nasopharyngitis. There was no development of anti-drug-antibodies and no clinically meaningful changes in laboratory findings.

CONCLUSION

The results of the pharmacokinetic exposure parameters and safety measures were similar for Japanese and Caucasians and support the once monthly and once quarterly sc injections of fremanezumab.

Placebo-controlled evaluation of a bioengineered, cocaine-metabolizing fusion protein, TV-1380 (AlbuBChE), in the treatment of cocaine dependence

BACKGROUND

TV-1380 (AlbuChE) is a novel recombinant fusion protein of mutated butyrylcholinesterase (BChE) that has increased catalytic efficiency for cocaine metabolism compared to wild-type BChE.

METHODS

Intra-muscular injections of TV-1380 (150mg or 300mg) or placebo were administered once weekly to participants (n=66-69 per group) in a randomized, double-blind study to evaluate the ability of TV-1380 to facilitate abstinence in treatment-seeking, cocaine-dependent individuals. The primary endpoint was the proportion of participants achieving abstinence from cocaine during the last three weeks of the 12 week treatment phase, based on daily self-report of "no use" confirmed by urine testing.

RESULTS

Although there were no significant differences between the TV-1380 treatment groups and placebo for the primary endpoint, 6% of participants in the 150mg and 300mg TV-1380 groups and no participants in the placebo group achieved abstinence. For the only declared secondary endpoint, there was a dose-dependent increase in the group mean percentage of urine samples testing negative for cocaine metabolites during weeks 5-12 (8.1% and 14.6% for the 150mg and 300mg TV-1380 groups, respectively, compared to 4.7% for the placebo group; p=0.0056 for 300mg vs. placebo). No meaningful differences in adverse events were seen between treatment groups.

CONCLUSIONS

While the apparent reduction in cocaine use may be of insufficient magnitude to justify further trials of TV-1380 in cocaine dependence, the results argue for development of improved enzymes with greater catalytic activity.

TEV-48125 for the preventive treatment of chronic migraine: Efficacy at early time points

Objective:

To evaluate the onset of efficacy of TEV-48125, a monoclonal antibody against calcitonin gene-related peptide, recently shown to be effective for the preventive treatment of chronic migraine (CM) and high-frequency episodic migraine.

Methods:

A randomized placebo-controlled study tested once-monthly injections of TEV-48125 675/225 mg or 900 mg vs placebo. Headache information was captured daily using an electronic headache diary. The primary endpoint was change from baseline in the number of headache hours in month 3. Herein, we assess the efficacy of each dose at earlier time points.

Results:

The sample consisted of 261 patients. For headache hours, the 675/225-mg dose separated from placebo on day 7 and the 900-mg dose separated from placebo after 3 days of therapy (p = 0.048 and p = 0.033, respectively). For both the 675/225-mg and 900-mg doses, the improvement was sustained through the second (p = 0.004 and p < 0.001) and third (p = 0.025 and p < 0.001) weeks of therapy and throughout the study (month 3, p = 0.0386 and p = 0.0057). For change in weekly headache days of at least moderate intensity, both doses were superior to placebo at week 2 (p = 0.031 and p = 0.005).

Conclusions:

TEV-48125 demonstrated a significant improvement within 1 week of therapy initiation in patients with CM.

Classification of evidence:

This study provides Class II evidence that for patients with CM, TEV-48125 significantly decreases the number of headache hours within 3 to 7 days of injection.

Safety, tolerability, and efficacy of TEV-48125 for preventive treatment of chronic migraine: a multicentre, randomised, double-blind, placebo-controlled, phase 2b study

BACKGROUND

Benefits of calcitonin-gene related peptide (CGRP) inhibition have not been established in chronic migraine. Here we assess the safety, tolerability, and efficacy of two doses of TEV-48125, a monoclonal anti-CGRP antibody, in the preventive treatment of chronic migraine.

METHODS

In this multicentre, randomised, double-blind, double-dummy, placebo-controlled, parallel-group phase 2b study, we enrolled men and women (aged 18-65 years) from 62 sites in the USA who had chronic migraine. Using a randomisation list generated by a central computerised system and an interactive web response system, we randomly assigned patients (1:1:1, stratified by sex and use of concomitant preventive drugs) to three 28-day treatment cycles of subcutaneous TEV-48125 675/225 mg (675 mg in the first treatment cycle and 225 mg in the second and third treatment cycles), TEV-48125 900 mg (900 mg in all three treatment cycles), or placebo. Investigators, patients, and the funder were blinded to treatment allocation. Daily headache information was captured using an electronic diary. Primary endpoints were change from baseline in the number of headache-hours during the third treatment cycle (weeks 9-12) and safety and tolerability during the study. Secondary endpoint was change in the number of moderate or severe headache-days in weeks 9-12 relative to baseline. Efficacy endpoints were analysed for the intention-to-treat population. Safety and tolerability were analysed using descriptive statistics. This trial is registered with ClinicalTrials.gov, number, NCT02021773.

FINDINGS

Between Jan 8, 2014, and Aug 27, 2014, we enrolled 264 participants: 89 were randomly assigned to receive placebo, 88 to receive 675/225 mg TEV-48125, and 87 to receive 900 mg TEV-48125. The mean change from baseline in number of headache-hours during weeks 9-12 was -59.84 h (SD 80.38) in the 675/225 mg group and -67.51 h (79.37) in the 900 mg group, compared with -37.10 h (79.44) in the placebo group. The least square mean difference in the reduction of headache-hours between the placebo and 675/225 mg dose groups was -22.74 h (95% CI -44.28 to -1.21; p=0.0386), whereas the difference between placebo and 900 mg dose groups was -30.41 h (-51.88 to -8.95; p=0.0057). Adverse events were reported by 36 (40%) patients in the placebo group, 47 (53%) patients in the 675/225 mg dose group, and 41 (47%) patients in the 900 mg dose group, whereas treatment-related adverse events were recorded in 15 (17%) patients, 25 (29%) patients, and 28 (32%) patients, respectively. The most common adverse events were mild injection-site pain and pruritus. Four (1%) patients had serious non-treatment-related adverse events (one patient in the placebo group, one patient in the 675/225 mg group, and two patients in the 900 mg group); no treatment-related adverse events were serious and there were no relevant changes in blood pressure or other vital signs.

INTERPRETATION

TEV-48125 given by subcutaneous injection every 28 days seems to be tolerable and effective, thus supporting the further development of TEV-48125 for the preventive treatment of chronic migraine in a phase 3 trial.

FUNDING

Teva Pharmaceuticals.

Safety, tolerability, and efficacy of TEV-48125 for preventive treatment of high-frequency episodic migraine: a multicentre, randomised, double-blind, placebo-controlled, phase 2b study

BACKGROUND

Calcitonin gene-related peptide (CGRP) is a validated target for the treatment of episodic migraine. Here we assess the safety, tolerability, and efficacy of TEV-48125, a monoclonal anti-CGRP antibody, in the preventive treatment of high-frequency episodic migraine.

METHODS

In this multicentre, randomised, double-blind, placebo-controlled, phase 2b study, we enrolled men and women (aged 18-65 years) from 62 sites in the USA who had migraine headaches 8-14 days per month. Using a randomisation list generated by a central computerised system and an interactive web response system, we randomly assigned patients (1:1:1; stratified by sex and use of concomitant preventive drugs) after a 28 day run-in period to three 28 day treatment cycles of subcutaneous 225 mg TEV-48125, 675 mg TEV-48125, or placebo. Investigators, patients, and the funder were blinded to treatment allocation. Patients reported headache information daily using an electronic diary. Primary endpoints were change from baseline in migraine days during the third treatment cycle (weeks 9-12) and safety and tolerability. The secondary endpoint was change relative to baseline in headache-days during weeks 9-12. Efficacy endpoints were analysed for the intention-to-treat population. Safety and tolerability were analysed using descriptive statistics. This trial is registered at ClinicalTrials.gov, number NCT02025556.

FINDINGS

Between Jan 8, 2014, and Oct 15, 2014, we enrolled 297 participants: 104 were randomly assigned to receive placebo, 95 to receive 225 mg TEV-48125, and 96 to receive 675 mg TEV-48125. The least square mean (LSM) change in number of migraine-days from baseline to weeks 9-12 was -3.46 days (SD 5.40) in the placebo group, -6.27 days (5.38) in the 225 mg dose group, and -6.09 days (5.22) in the 675 mg dose group. The LSM difference in the reduction of migraine-days between the placebo and 225 mg dose groups was -2.81 days (95% CI -4.07 to -1.55; p<0.0001), whereas the difference between the placebo and 675 mg dose group was -2.64 days (-3.90 to -1.38; p<0.0001). LSM differences in the reduction of headache-days were -2.63 days (-3.91 to -1.34; p<0.0001) between the placebo group and 225 mg dose group and -2.58 days (-3.87 to 1.30; p <0.0001) between the placebo group and the 675 mg dose group. Adverse events occurred in 58 (56%) patients in the placebo group, 44 (46%) patients in the 225 mg dose group, and 57 (59%) patients in the 675 mg dose group; moderate or severe adverse events were reported for 29 (27%) patients, 24 (25%) patients, and 26 (27%) patients, respectively.

INTERPRETATION

TEV-48125, at doses of 225 mg and 675 mg given once every 28 days for 12 weeks, was safe, well tolerated, and effective as a preventive treatment of high-frequency episodic migraine, thus supporting advancement of the clinical development programme to phase 3 clinical trials.

FUNDING

Teva Pharmaceuticals.

Kinetic assessment of the effects of task difficulty, microencephaly, and a response manipulandum alteration on the rate of fixed-ratio discrimination acquisition

Fixed-ratio discrimination (FRD) training session-accuracy curves were constructed using first-order, nonlinear regression and probit analyses to determine maximal (asymptotic) accuracy and the number of sessions required to reach half-maximal accuracy. Increased FRD difficulty (reductions in the differences between the 2 fixed-ratio values to be discriminated) and a training parameter change each increased the number of sessions required to reach half-maximal accuracy and decreased maximal FRD accuracy (i.e., session-accuracy curves were shifted down and to the right) regardless of analysis procedure. These findings indicate that the above manipulations induced mixed competitive-noncompetitive inhibition of the rate of FRD learning. Microencephalic rats were more sensitive to increases in FRD difficulty, whereas control rats were more sensitive to the training parameter change.

Fixed ratio discrimination training increases in vivo striatal dopamine in neonatal 6-OHDA-lesioned rats

Massed training in the conditional discrimination task, the fixed ratio discrimination (FRD) task led to elevated extracellular dopamine (DA) concentrations in the neonatal 6-hydroxydopamine (6-OHDA)-treated rat, a model of Lesch-Nyhan disease (LND). Rats neonatally treated with 6-OHDA or its vehicle were, as adults, implanted with microdialysis probes and assessed for basal pretraining concentrations of DA and its major metabolites. Subsequently, microdialysis samples were collected each day following three separate FRD training periods (trained group) or three separate periods of noncontingent food presentations (untrained group). The present study found that there were significant increases in extracellular DA in the caudate-putamen from basal pretraining concentrations in the repeated sample collections of trained 6-OHDA-lesioned animals but not in the samples of untrained 6-OHDA-lesioned animals. Consistent with previous studies [Brain Res. 508 (1990) 30.], there was an increase in the extracellular concentrations as compared to tissue concentrations of DA and 3,4-dihydroxyphenylacetic acid (DOPAC). Similar to our previous studies with long-term FRD training [Pharmacol. Biochem. Behav. 51 (1995) 861; Brain Res. 713 (1996) 246.], there was also an indication of an increase in cortical and striatal tissue concentration of DA in the trained 6-OHDA-lesioned animals as compared to the untrained 6-OHDA-lesioned animals. The elevations in striatal DA concentrations following operant performance in the present study illustrate how operant procedures of the behavior therapy used with individuals with LND and other mental retardation syndromes may interact with the modulation of dopaminergic function by the pharmaceutical application of DA antagonists to suppress aberrant behaviors.

Dopamine re-uptake inhibitor GBR-12909 induction of aberrant behaviors in animal models of dopamine dysfunction

Many individuals with mental retardation exhibit chronic aberrant behaviors (CABs) that includes hyperactive, stereotyped, aggressive, and self-injurious behaviors. Brain imaging studies have found that several of these individuals have abnormalities in their dopaminergic neurotransmitter systems that are thought to be responsible in part, for the development of these behaviors. The present study evaluated the effects of a selective dopamine re-uptake blocker, GBR-12909 in three animal models of varying striatal dopamine concentrations. The three animal models included the neonatal 6-hydroxydopamine (6-OHDA)-lesioned rat, a model of dopamine neuronal depletion, the prenatal methylazoxymethanol (MAM)-exposed rat, a model of hyper-dopaminergic innervation and control rats, a model of normal dopaminergic function. The animals were given five daily injections of GBR-12909 and videotaped observations were conducted immediately following the injections and 6h later. The results of the study indicate that the MAM-treated rats exhibited more hyperactive behaviors than either the 6-OHDA or the control animals in response to the GBR-12909 injections. However, the 6-OHDA and control rats exhibited more self-injurious behaviors than the MAM rats. Interestingly, the topography of the self-injurious behavior exhibited differed from that we have previously observed in 6-OHDA lesioned rats following dopamine agonists and resembles the mouthing behaviors seen in some individuals with mental retardation, in particular those with Rett syndrome. These findings indicate the models of varying dopaminergic function interact differently with a dopamine re-uptake blocker than dopamine agonists and that the partially dopamine depleted model may model the behaviors seen in individuals with Rett syndrome.

Cross-sensitization between footshock stress and apomorphine on self-injurious behavior and neostriatal catecholamines in a rat model of Lesch-Nyhan syndrome

The effects of footshock sensitization (priming), apomorphine (APO) priming and their combination on behavior and neostriatal and cortical catecholamines were examined in adult rats which had neonatally received bilateral intracerebroventricular injections with 6-hydroxydopamine (6-OHDA; a model of Lesch-Nyhan syndrome (LNS)) or vehicle (unlesioned rats). Lesioned (6-OHDA-treated) rats displayed self-biting (SB; 7/20 rats) and self-injurious behavior (SIB; 1/20 rats) during APO priming, but not during footshock priming. During subsequent acute cumulative APO dosing, 20-30% of lesioned rats primed with APO alone or footshock alone displayed SB and SIB. However, SB and SIB incidence in APO+footshock-primed lesioned rats was nearly tripled. Dopamine (DA) synthesis, metabolism and extracellular concentrations (disposition) in unlesioned rats and in cortices of lesioned animals were unaffected by priming. In lesioned rats primed with APO alone or footshock alone, only neostriatal 3-methoxytyramine (3-MT) was significantly increased. However, neostriatal DA and metabolite concentrations (and norepinephrine (NE)) were all significantly elevated in lesioned rats primed with both APO and footshock. These results confirm that neonatal 6-OHDA-induced neostriatal catecholamine depletion can be antagonized by experiential change, suggest that behavioral and neurochemical cross-sensitization between APO and footshock in such rats is unidirectional and support the view that stress can exacerbate the incidence of SIB in LNS.

Effects of neuroleptic and anticonvulsant drugs on repeated acquisition learning in microencephalic and normal rats

Neuroleptic and anticonvulsant drugs are used to reduce the occurrence of aberrant behaviors, seizures, or both in individuals with mental retardation. However, their use may disrupt the learning of desired skills, and the extent to which anatomical (e.g., microencephaly) or biochemical abnormalities or both in such individuals alter the effects of drugs on learning is not known. In this study, the effects of neuroleptics and anticonvulsants on learning and performance in a repeated acquisition task in methylazoxymethanol-induced microencephalic and saline control rats were assessed. Thioridazine was more potent in microencephalic rats than in control rats in increasing errors and decreasing response rates. Clozapine was equally potent in both microencephalic and control rats in increasing errors and decreasing response rates. The effect of carbamazepine was biphasic in both rat groups: Low doses decreased errors and increased response rates, whereas higher doses did the opposite.

FR discrimination training effects in SHR and microencephalic rats

Fixed-ratio (FR) discrimination learning in adult male spontaneously hypertensive rats (SHR), methylazoxymethanol-induced microencephalic Sprague-Dawley (MAM), and Sprague-Dawley control rats was examined. SHR and MAM rats had little problem learning incrementally more difficult FR discriminations (FR1 vs. FR16, FR4 vs. FR16, and FR8 vs. FR16) that resulted in parallel increases in errors in all animals, and displayed only modest learning deficits during a subsequent FR4 vs. FR16 position reversal. When training involved nonincremental changes in difficulty (FR8 vs. FR16, FR4 vs. FR16, FR8 vs. FR16, FR12 vs. FR16, and FR14 vs. FR16), SHR and MAM rats evidenced relatively large learning deficits during the initial FR8 vs. FR16 discrimination but had no difficulty with the last two discriminations. Furthermore, training selectively and significantly elevated hippocampal weight in MAM rats. These findings: a) question prior suggestions that MAM and SHR model separate human developmental disabilities; b) indicate that manifestation of learning deficits in even markedly brain-damaged organisms depends on initial task difficulty and can be overcome by experience; and c) are the first indicating that training-induced antagonism of prenatally induced hippocampal hypoplasia and its consequences is possible.

Reversal of 6HD-induced neonatal brain catecholamine depletion after operant training

Rats received either vehicle (controls) or 100 micrograms of 6-hydroxydopamine (6HD) base intracisternally on postnatal day 5. At 3 mo of age, striatal and cortical catecholamine and metabolite levels were determined in some animals. Others were subjected to 4.5 mo of training on incrementally more difficult fixed-ratio (FR) discriminations; 2 mo later, their levels were determined. Learning was essentially unaffected by 6HD even though errors in all animals increased with increases in discrimination difficulty and 6HD had markedly depleted levels in the 3-mo-old animals. Moreover, an initial response-rate deficit in 6HD-treated rats disappeared with training. However, after training, levels in 6HD-treated rats were not only not depleted, they were as much as 661% of those in controls. These and others of our findings indicate that FR discrimination training can induce persistent increases in brain catecholamine utilization. They also appear to be the first to suggest that at least some neurochemical effects of neonatal 6HD are not necessarily irreversible, and that such a reversal can be experientially induced and possibly functionally beneficial.