Comparative Analysis of Deutetrabenazine and Valbenazine as VMAT2 Inhibitors for Tardive Dyskinesia: A Systematic Review

Background

Tardive Dyskinesia (TD) is a neurological disorder characterized by involuntary movements, often caused by dopamine receptor antagonists. Vesicular Monoamine Transporter 2 (VMAT2) inhibitors, such as valbenazine and deutetrabenazine, have emerged as promising therapies for TD and several clinical trials have shown their efficacy. This study aims to compare the efficacy and safety profile of VMAT2 inhibitors, focusing on a recent trial conducted in the Asian population.

Methods

We reviewed the PubMed, Cochrane Library, Embase database, and clinicaltrials.gov between January 2017 and October 2023, using the keywords "tardive dyskinesia" AND ("valbenazine" [all fields] OR " deutetrabenazine " [all fields]) AND "clinical trial". The reviewed articles were studied for efficacy and side effects.

Results

An initial search yielded 230 articles, of which 104 were duplicates. Following the title and abstract screening, 25 additional articles were excluded. A full-text review resulted in the exclusion of 96 more articles. Ultimately, four double-blind clinical trials met the inclusion criteria. The deutetrabenazine studies demonstrated significant improvements in Abnormal Involuntary Movement Scale (AIMS) scores compared to placebo, with no difference in adverse events. The valbenazine studies showed favorable results in reducing TD symptoms and were well-tolerated.

Discussion

The studies reviewed in this analysis underscore the potential of deutetrabenazine and valbenazine as valuable treatment options for TD in diverse populations. Both medications demonstrated significant improvements in AIMS scores, suggesting their effectiveness in managing TD symptoms. Additionally, they exhibited favorable safety profiles, with low rates of serious adverse events and no significant increase in QT prolongation, parkinsonism, suicidal ideation, or mortality.

Conclusion

The studies reviewed highlight the promising efficacy and tolerability of deutetrabenazine and valbenazine as treatments for Tardive Dyskinesia, providing new hope for individuals affected by this challenging condition.

Tardive Dyskinesia With Chorea-Ballism Improved by Valbenazine: A Case Report

Tardive dyskinesia (TD) is an involuntary muscle movement typically caused by prolonged exposure to antipsychotic medications. Depending on the symptom severity and the affected body parts, it can cause a terrible decline in patients' daily activities and life quality. TD often persists despite discontinuation of the offending drugs. There was no approved or effective agent to treat the patients until valbenazine, a vesicular monoamine transporter-2 inhibitor, became available. We report the case of a 64-year-old woman who started to take antipsychotics at the age of her late 20s for her schizophrenic symptoms and later developed left arm chorea-ballism in mid-50s. The patient's involuntary movements got progressively worse even after being freed from the medications and caused severe body weight loss due to difficulties in taking meals. Daily treatment with valbenazine gradually mitigated her symptoms, resulting in significant improvement in her feeding activities, body weight, and daily life quality. This is the first report, to our knowledge, describing the therapeutic potential of valbenazine to improve chorea-ballism associated with TD. Our observation highlights that valbenazine may relieve a broader spectrum of antipsychotic-induced involuntary movements.

Huntington's Disease Drug Development: A Phase 3 Pipeline Analysis

Huntington's Disease (HD) is a severely debilitating neurodegenerative disorder in which sufferers exhibit different combinations of movement disorders, dementia, and behavioral or psychiatric abnormalities. The disorder is a result of a trinucleotide repeat expansion mutation that is inherited in an autosomal dominant manner. While there is currently no treatment to alter the course of HD, there are medications that lessen abnormal movement and psychiatric symptoms. ClinicalTrials.gov was searched to identify drugs that are currently in or have completed phase III drug trials for the treatment of HD. The described phase III trials were further limited to interventional studies that were recruiting, active not recruiting, or completed. In addition, all studies must have posted an update within the past year. PubMed was used to gather further information on these interventional studies. Of the nine clinical trials that met these criteria, eight involved the following drugs: metformin, dextromethorphan/quinidine, deutetrabenazine, valbenazine, Cellavita HD, pridopidine, SAGE-718, and RO7234292 (RG6042). Of these drug treatments, four are already FDA approved. This systematic review provides a resource that summarizes the present therapies for treating this devastating condition that are currently in phase III clinical trials in the United States.

Exploring real-world symptom impact and improvement in well-being domains for tardive dyskinesia in VMAT2 inhibitor-treated patients via clinician survey and chart review

Introduction

Two vesicular monoamine transporter 2 (VMAT2) inhibitors are approved in the United States (US) for the treatment of tardive dyskinesia (TD). There is a paucity of information on the impact of VMAT2 inhibitor treatment on patient social and physical well-being. The study objective was to elucidate clinician-reported improvement in symptoms and any noticeable changes in social or physical well-being in patients receiving VMAT2 inhibitors.

Methods

A web-based survey was offered to physicians, nurse practitioners, and physician assistants based in the US who prescribed valbenazine for TD within the past 24 months. Clinicians reported data from the charts of patients who met the inclusion criteria and were allowed to recall missing information.

Results

Respondents included 163 clinicians who reviewed charts of 601 VMAT2-treated patients with TD: 47% had TD symptoms in ≥2 body regions, with the most common being in the head or face and upper extremities. Prior to treatment, 93% of patients showed impairment in ≥1 social domain, and 88% were impaired in ≥1 physical domain. Following treatment, among those with improvement in TD symptoms (n = 540), 80% to 95% showed improvement in social domains, 90% to 95% showed improvement in physical domains, and 73% showed improvement in their primary psychiatric condition.

Discussion

In VMAT2-treated patients with TD symptom improvement, clinicians reported concomitant improvement in psychiatric disorder symptoms and in social and physical well-being. Regular assessment of TD impact on these types of domains should occur simultaneously with movement disorder ratings when evaluating the value of VMAT2 inhibitor therapy.

Efficacy and safety of valbenazine in Japanese patients with tardive dyskinesia: A multicenter, randomized, double-blind, placebo-controlled study (J-KINECT)

AIM

Valbenazine is approved in the US for treatment of tardive dyskinesia (TD); however, efficacy/safety data in Asian populations are lacking. We assessed the efficacy/safety of valbenazine in Japanese patients.

METHODS

This phase II/III, multicenter, randomized, double-blind, placebo-controlled study (NCT03176771) included adult psychiatric patients with TD, who were randomly allocated to receive placebo or valbenazine (once-daily 40- or 80-mg) for a 6-week, double-blind period, after which the placebo group was switched to valbenazine for a 42-week extension. The primary endpoint was change from baseline in Abnormal Involuntary Movement Scale (AIMS) total score at Week 6; clinical global impression of improvement of TD (CGI-TD) was also assessed.

RESULTS

Of 256 patients, 86, 85, and 85 were allocated to the 40-mg valbenazine, 80-mg valbenazine, and placebo groups, respectively. Least-squares mean (95% confidence interval) change from baseline in AIMS score at Week 6 was -2.3 (-3.0 to -1.7) in the valbenazine 40-mg group, -3.7 (-4.4 to -3.0) in the 80-mg group, and -0.1 (-0.8 to 0.5) in the placebo group; both treatment groups showed statistically significant improvements vs. placebo. Patients switched to valbenazine at Week 6 showed similar improvements in AIMS scores, which were maintained to Week 48. Improvements in CGI-TD scores were observed for both treatment groups vs. placebo. Incidence of adverse events was highest in the 80-mg group; common events included nasopharyngitis, somnolence, schizophrenia worsening, hypersalivation, insomnia, and tremor.

CONCLUSION

The efficacy/safety profile of valbenazine was similar to that of previous clinical trials, supporting its use for TD treatment in Japanese patients.

9-Cyclopropylmethoxy-dihydrotetrabenazine and its stereoisomers as vesicular monoamine transporter-2 inhibitors

Aim: To separate and evaluate 9-cyclopropylmethoxy-dihydrotetrabenazine (13a) and its stereoisomers for their high affinity for vesicular monoamine transporter-2 (VMAT2). Method: Stereoisomers of 13a were separated and configurations were ascertained by chiral chromatography and crystal diffraction combined with ¹H-¹H NOESY assay. Possible binding modes of eight stereoisomers and VMAT2 were explored by molecular docking assays. The VMAT2 affinity of the stereoisomers, inhibition in vivo and pharmacokinetics in rats were evaluated. Results: Three stereoisomers were obtained: P1, P2 and P3, and all had similar VMAT2 binding modes. P2 [(2R, 3R, 11bR)-13a] showed the highest potential VMAT2 binding activity (K_i = 0.75 nM), decreased locomotor activity in rats and had an oral absolute bioavailability of 92.0%. Conclusion: P2 has good efficacy and pharmacokinetic properties and warrants further development to treat tardive dyskinesia.

A long-term, open-label study of valbenazine for tardive dyskinesia

BACKGROUND

Individuals with tardive dyskinesia (TD) who completed a long-term study (KINECT 3 or KINECT 4) of valbenazine (40 or 80 mg/day, once-daily for up to 48 weeks followed by 4-week washout) were enrolled in a subsequent study (NCT02736955) that was primarily designed to further evaluate the long-term safety of valbenazine.

METHODS

Participants were initiated at 40 mg/day (following prior valbenazine washout). At week 4, dosing was escalated to 80 mg/day based on tolerability and clinical assessment of TD; reduction to 40 mg/day was allowed for tolerability. The study was planned for 72 weeks or until termination due to commercial availability of valbenazine. Assessments included the Clinical Global Impression of Severity-TD (CGIS-TD), Patient Satisfaction Questionnaire (PSQ), and treatment-emergent adverse events (TEAEs).

RESULTS

At study termination, 85.7% (138/161) of participants were still active. Four participants had reached week 60, and none reached week 72. The percentage of participants with a CGIS-TD score ≤2 (normal/not ill or borderline ill) increased from study baseline (14.5% [23/159]) to week 48 (64.3% [36/56]). At baseline, 98.8% (158/160) of participants rated their prior valbenazine experience with a PSQ score ≤2 (very satisfied or somewhat satisfied). At week 48, 98.2% (55/56) remained satisfied. Before week 4 (dose escalation), 9.4% of participants had ≥1 TEAE. After week 4, the TEAE incidence was 49.0%. No TEAE occurred in ≥5% of participants during treatment (before or after week 4).

CONCLUSIONS

Valbenazine was well-tolerated and persistent improvements in TD were found in adults who received once-daily treatment for >1 year.

Valbenazine for the Treatment of Adults with Tardive Dyskinesia

PURPOSE OF REVIEW

This a comprehensive review of the literature regarding the use of Valbenazine in treating tardive dyskinesia. A primarily oral movement disorder induced by chronic exposure to certain classes of medications, tardive dyskinesia is often resistant to many therapeutic approaches. This review presents the background, evidence, and indications for the use of Valbenazine as a treatment option for this condition.

RECENT FINDINGS

Tardive dyskinesia is a disorder arising from long-term exposure to medications that blocked dopamine receptors, primarily antipsychotics. It is characterized by abnormal movements of the oral-buccal-lingual structures as well as associated pain and hypertrophy. Simply stopping the use of the dopamine blocking agents effectively alleviates the symptoms but is not always reliable hence the need for another therapeutic approach.Valbenazine is thought to function as a highly selective inhibitor of the VMAT2 vesicular monoamine transporter resulting in decreased availability of dopamine in the presynaptic cleft. This leads to decreased dopaminergic activation of the striatal motor pathway. The FDA approved Valbenazine in 2017 to treat tardive dyskinesia in adults and needs to be evaluated with existing therapeutic approaches.

SUMMARY

The chronic use of dopamine receptor blocking agents, most commonly antipsychotics, can lead to a movement disorder called tardive dyskinesia. Once symptom onset has occurred, these movement abnormalities can persist for years to permanently, depending on the speed and effectiveness of treatment. Valbenazine is a relatively newer option for the treatment of tardive dyskinesia in adults. Compared to other pharmaceutical agents, it is more selective and has limited toxicities making it an effective treatment regimen. However, further research, including additional direct comparison studies, should be conducted to fully evaluate this drug's usefulness.

Clinical development of valbenazine for tics associated with Tourette syndrome

Introduction: Significant need exists for effective, well-tolerated pharmacologic treatments for Tourette syndrome (TS). Medications that inhibit vesicular monoamine transporters (i.e. VMAT2 inhibitors) downregulate presynaptic packaging and release of dopamine into the neuronal synapse and are effective in treating hyperkinetic movement disorders such as Huntington's chorea and tardive dyskinesia (TD); thus, they may be useful in treating TS.Areas covered: This review describes the clinical program evaluating the safety and efficacy of valbenazine in the treatment of involuntary tics associated with TS in adult and pediatric subjects. While there was a trend in the 6 completed trials toward greater improvement in valbenazine-treated versus placebo subjects on the primary efficacy endpoint (Yale Global Tic Severity Scale Total Tic Score), this difference did not reach statistical significance. Valbenazine was generally well-tolerated in the studies, and treatment-emergent adverse events were consistent with valbenazine studies in TD.Expert opinion: Due to the failure to meet the primary endpoint in these trials, further investigation of valbenazine for TS is unlikely. Given the need for safe and effective TS therapies and the key role of VMAT2 in modulating dopaminergic activity, it is reasonable for future studies to investigate other VMAT2 inhibitors as potential treatments for TS.

Cost-effectiveness of valbenazine compared with deutetrabenazine for the treatment of tardive dyskinesia

AIMS

To evaluate clinical and economic outcomes associated with valbenazine compared with deutetrabenazine in patients with tardive dyskinesia (TD) using a model that accounts for multiple dimensions of patient health status.

MATERIALS AND METHODS

A discretely integrated condition event model was developed to evaluate the cost-effectiveness of treatment with valbenazine and deutetrabenazine in a synthetic cohort of 1,000 patients with TD who were receiving antipsychotic medication to treat an underlying psychiatric disorder. Clinical inputs were derived from relevant clinical trials or from publicly available sources. Patients were assessed over 1 year using ≥50% improvement from baseline in Abnormal Involuntary Movement Scale (AIMS) total score as the primary definition of response. Response at 1 year using Clinical Global Impression of Change (CGIC) score ≤2 was also assessed. Health outcomes included quality-adjusted life years (QALYs), life years, proportion responding to treatment at 1 year, and number of psychiatric relapses.

RESULTS

Regardless of the definition used for response, patients treated with valbenazine were more likely to have responded to treatment at 1 year, lived longer, and accrued more QALYs than patients who received deutetrabenazine. Using the AIMS response criterion, the incremental cost-effectiveness ratio was $9,951/QALY for valbenazine compared with deutetrabenazine. By comparison, using the CGIC response criterion valbenazine dominated deutetrabenazine with valbenazine-treated patients accumulating more QALYs (3.4 vs 3.3 years) and incurring lower lifetime costs ($252,311 vs $283,208) than deutetrabenazine-treated patients.

LIMITATIONS

There are no head-to-head trials of valbenazine and deutetrabenazine, so probabilities of response used in the model were calculated based on an indirect treatment comparison of results from individual trials with one drug or the other, using only those metrics reported across trials.

CONCLUSIONS

In patients with TD, treatment with valbenazine is highly cost-effective compared with deutetrabenazine.

Valbenazine and deutetrabenazine: Vesicular monoamine transporter 2 inhibitors for tardive dyskinesia

PURPOSE

The purpose of this review is to summarize the current evidence for valbenazine and deutetrabenazine use for the treatment of tardive dyskinesia (TD).

SUMMARY

A literature search was conducted to gather relevant data regarding the use of valbenazine and deutetrabenazine for TD management. PubMed, MEDLINE, and ClinicalTrials.gov were searched using the following keywords and MeSH terms: valbenazine, deutetrabenazine, tardive dyskinesia, VMAT2 inhibitors, and vesicular monoamine transporter 2 inhibitors. Randomized, double-blind, placebo-controlled trials and meta-analyses published in English from April 2015 to August 2019 were included. Valbenazine 40-80 mg and deutetrabenazine 12-36 mg per day have been evaluated for the treatment of TD. Abnormal Involuntary Movement Scale (AIMS) scores decline similarly (by 2-5 points) with use of either agent. AIMS response rates, defined by a 50% decline in symptoms, range from 33% to 50%. Both agents are well tolerated, with somnolence and akathisia reported most frequently (at low rates). Agent selection may be guided by manufacturer labeling recommendations for special populations and cost considerations.

CONCLUSIONS

Valbenazine and deutetrabenazine were demonstrated to be effective in decreasing AIMS scores and were well tolerated in randomized controlled trials. These treatments may be considered as a next-line option when traditional strategies are not feasible or are ineffective. Head-to-head studies are warranted to decipher if either agent is preferable in terms of efficacy or tolerability.

The effects of valbenazine on tardive dyskinesia in older and younger patients

OBJECTIVE

To evaluate the effects of once-daily valbenazine (40 or 80 mg/d) in older and younger adults with tardive dyskinesia (TD).

METHODS

Data were pooled from three 6-week, randomized, double-blind, placebo-controlled (DBPC) studies (KINECT [NCT01688037], KINECT 2 [NCT01733121], and KINECT 3 [NCT02274558]) and two long-term studies (KINECT 3 extension and KINECT 4 [NCT02405091]). Outcomes analyzed in older and younger participants (55 years or older and younger than 55 years, respectively) included Abnormal Involuntary Movement Scale (AIMS) response (threshold of greater than or equal to 50% improvement from baseline in total score [items 1 to 7]) and Clinical Global Impression of Change-Tardive Dyskinesia (CGI-TD) response (score 2 or less ["very much improved" or "much improved"]). Safety assessments included treatment-emergent adverse events (TEAEs).

RESULTS

At week 6 (end of DBPC treatment), the percentage of participants who met the AIMS response threshold was higher with valbenazine versus placebo in both subgroups: 55 years or older (80 mg/d, 39.7% [P < .001]; 40 mg/d, 28.6% [P < .01]; placebo, 9.7%); younger than 55 years (80 mg/d, 39.5% [P < .001]; 40 mg/d, 20.0% [P > .05]; placebo, 10.8%). The percentage of participants with CGI-TD response was also higher with valbenazine versus placebo: 55 years or older (80 mg/d, 41.3% [P < .01]; 40 mg/d, 30.2% [P > .05]; placebo, 19.4%); younger than 55 years (80 mg/d, 39.5% [P < .05]; 40 mg/d, 35.3% [P < .05]; placebo, 18.5%). Responses at week 48 (end of long-term treatment, combined doses) were as follows: 55 years or older (AIMS, 70.7%; CGI-TD, 82.8%); younger than 55 years (AIMS, 58.7%; CGI-TD, 72.3%). No significant differences between older and younger subgroups were found for AIMS or CGI-TD response. No new safety signals or TEAEs of clinical concern were found in older participants who received long-term treatment.

CONCLUSIONS

Valbenazine improved TD and was generally well tolerated in older and younger adults.

Deutetrabenazine for tardive dyskinesia and chorea associated with Huntington's disease: a review of clinical trial data

Introduction: Huntington's disease (HD)-associated chorea and tardive dyskinesia (TD) are hyperkinetic movement disorders that can have deleterious effects on patients' quality of life (QoL). Deutetrabenazine, a vesicular monoamine transporter 2 (VMAT2) inhibitor, was approved by the US Food and Drug Administration (FDA) for the treatment of HD-associated chorea and TD. It is structurally similar to tetrabenazine, an FDA-approved compound for treatment of chorea that is widely used off-label for treatment of TD, but has deuterium modifications that improve its pharmacokinetic profile.Areas covered: Herein, the authors cover the key clinical trials with deutetrabenazine in patients with HD-associated chorea (First-HD and ARC-HD) and in patients with TD (ARM-TD, AIM-TD, and RIM-TD).Expert opinion: Deutetrabenazine demonstrates consistent efficacy across patient types regardless of underlying psychiatric illness, or through use of dopamine-receptor antagonists (DRAs), which are the primary cause of TD. The safety profile of deutetrabenazine in clinical trials is similar to that of placebo. Long-term extension studies in both HD-associated chorea and TD show consistent efficacy and safety. Deutetrabenazine will likely be an integral part of the treatment strategy for HD-associated chorea and TD. Meanwhile, its potential to treat other hyperkinetic movement disorders is still under investigation.

Role of Vesicular Monoamine Transporter 2 Inhibitors in Tardive Dyskinesia Management

Tardive dyskinesia (TD) is a distressing and disabling movement disorder that occurs with the use of chronic neuroleptic medications. TD is defined as involuntary athetoid or choreiform movements of head, trunk or limbs. Tongue, lower face, jaw, and extremities are commonly involved but pharyngeal, diaphragmatic, or truncal muscles are also sometimes involved affecting breathing, swallowing, speech, posture, gait, and mobility of an individual.

TD is a debilitating movement disorder that requires timely intervention. Subtle tongue movements, tic-like facial movements or increased blink frequency could be some of the initial manifestations of TD. Our article is focused on the new advents in treating TD, their efficacy, and tolerability with emphasizing their side effect profile. The implication of a genetic marker vesicular monoamine transporter 2 (VMAT2), helped in investigating VMAT2 inhibitors for alleviating TD. Among the modalities tested, only VMAT2 inhibitors reported efficacy. However, the outcome of long-term use and its side effect profile can only be determined with longer studies utilizing large set data. More clinical trials are required to explore individual drug efficacy and their long-term adverse effects.

We aim to provide an overview of TD management, illustrating the priority of VMAT2 inhibitors and to determine the importance of selecting an optimal medication. A search through PubMed with terms "Tardive dyskinesia" and "VMAT2 inhibitors" was carried out. Several treatment modalities were tested to control the symptoms of TD with limited benefit. However, VMAT2 inhibitors showed improvement in the Abnormal Involuntary Movement Scale (AIMS) rating scale for TD. Valbenazine and deutetrabenazine (d-TBZ) were recently approved by the Food and Drug Administration (FDA) for treating TD in adults.

Abnormal involuntary movement scale in tardive dyskinesia: Minimal clinically important difference

BACKGROUND

A minimal clinically important difference has not been established for the Abnormal Involuntary Movement Scale in patients with tardive dyskinesia. Valbenazine is a vesicular monoamine transporter 2 inhibitor approved for the treatment of tardive dyskinesia in adults. Efficacy in randomized, double-blind, placebo-controlled trials was defined as the change from baseline in Abnormal Involuntary Movement Scale total score (sum of items 1-7).

OBJECTIVES

To estimate an minimal clinically important difference for the Abnormal Involuntary Movement Scale using valbenazine trial data and an anchor-based method.

METHODS

Data were pooled from three 6-week double-blind, placebo-controlled trials: KINECT (NCT01688037), KINECT 2 (NCT01733121), and KINECT 3 (NCT02274558). Valbenazine doses were pooled for analyses as follows: "low dose," which includes 40 or 50 mg/day; and "high dose," which includes 75 or 80 mg/day. Mean changes from baseline in Abnormal Involuntary Movement Scale total score were analyzed in all participants (valbenazine- and placebo-treated) with a Clinical Global Impression of Change-Tardive Dyskinesia or Patient Global Impression of Change score of 1 (very much improved) to 3 (minimally improved).

RESULTS

The least squares mean improvement from baseline to week 6 in Abnormal Involuntary Movement Scale total score was significantly greater with valbenazine (low dose: -2.4; high dose: -3.2; both, P < 0.001) versus placebo (-0.7). An minimal clinically important difference of 2 points was estimated based on least squares mean changes in Abnormal Involuntary Movement Scale total score in participants with a Clinical Global Impression of Change-Tardive Dyskinesia score ≤3 at week 6 (mean change: -2.2; median change: -2) or Patient Global Impression of Change score ≤3 at week 6 (mean change: -2.0; median change: -2).

CONCLUSIONS

Results from an anchor-based method indicate that a 2-point decrease in Abnormal Involuntary Movement Scale total score may be considered clinically important. © 2019 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.

Overcoming barriers to effective management of tardive dyskinesia

Tardive dyskinesia (TD) is a heterogeneous syndrome of involuntary hyperkinetic movements that is often persistent and occurs belatedly during treatment with antipsychotics. Recent approval of two dopamine-depleting analogs of tetrabenazine based on randomized controlled trials offers an evidence-based therapeutic approach to TD for the first time. These agents are optimally used within the context of a comprehensive approach to patient management that includes a practical screening and monitoring program, sensitive and specific criteria for the diagnosis of TD, awareness of the severity and impact of the disorder, informed discussions with patients and caregivers, and a rational basis for prescribing decisions about continued antipsychotic and adjunctive agents. Areas of limited or inconclusive data, bias and misunderstandings about key aspects, and neglect of training about TD in recent years contribute to barriers in providing effective care and promoting patient safety.

A systematic review on treatment of tardive dyskinesia with valbenazine and deutetrabenazine

Recent reports state that the prevalence of tardive dyskinesia (TD) is 32% with typical antipsychotics, and 13% with atypical antipsychotics. Current evidence-based recommendations determine an unmet need for efficacious treatment of TD. This systematic review was planned to update the evidence for TD treatment, comparing two vesicular monoamine transporter 2 (VMAT2) inhibitors, deutetrabenazine (DBZ), and valbenazine (VBZ). Of 75 PubMed search results, 11 studies met the review criteria. Efficacy and tolerability were demonstrated in a series of randomized, placebo-controlled clinical trials in our review study, and the Abnormal Involuntary Movement Scale response of ⩾50% reduction in score was robust for VBZ 80 mg/day in short-term and long-term studies. On the contrary, DBZ was equally efficacious at 12 mg twice daily, but additional information about long-term efficacy and persistence of effect is needed.

Treatment of tardive dyskinesia with VMAT-2 inhibitors: a systematic review and meta-analysis of randomized controlled trials

Aim

The aim of this study was to summarize the characteristics, efficacy, and safety of vesicular monoamine transporter-2 (VMAT-2) inhibitors for treating tardive dyskinesia (TD).

Materials and methods

We conducted a literature search in PubMed, Cochrane Database, and ClinicalTrials.gov, screening for systematic reviews, meta-analyses or double-blind, randomized, placebo-controlled trials (DBRPCTs) reporting efficacy or safety data of VMAT-2 inhibitors (tetrabenazine, deutetrabenazine, and valbenazine) in patients with TD. A random effects meta-analysis of efficacy and safety data from DBRPCTs was performed.

Results

Two acute, 12-week DBRPCTs with deutetrabenazine 12–48 mg/day (n=413) and 4 acute, 4–6-week double-blind trials with valbenazine 12.5–100 mg/day (n=488) were meta-analyzable, without meta-analyzable, high-quality data for tetrabenazine. Regarding reduction in total Abnormal Involuntary Movement Scale (AIMS) scores (primary outcome), both deutetrabenazine (k=2, n=413, standardized mean difference [SMD] =−0.40, 95% confidence interval [CI] =−0.19, −0.62, p<0.001; weighted mean difference (WMD) =−1.44, 95% CI =−0.67, −2.19, p<0.001) and valbenazine (k=4, n=421, SMD =−0.58, 95% CI =−0.26, −0.91, p<0.001; WMD =−2.07, 95% CI =−1.08, −3.05, p<0.001) significantly outperformed placebo. Results were confirmed regarding responder rates (≥50% AIMS total score reduction; deutetrabenazine: risk ratio [RR] =2.13, 95% CI =1.10, 4.12, p=0.024, number-needed-to-treat [NNT] =7, 95% CI =3, 333, p=0.046; valbenazine: RR =3.05, 95% CI =1.81, 5.11, p<0.001, NNT =4, 95% CI =3, 6, p<0.001). Less consistent results emerged from patient-rated global impression-based response (p=0.15) and clinical global impression for deutetrabenazine (p=0.088), and for clinical global impression change for valbenazine (p=0.67). In an open-label extension (OLE) study of deutetrabenazine (≤54 weeks) and a dose-blinded valbenazine study (≤48 weeks), responder rates increased over time. With valbenazine, discontinuation effects were studied, showing TD symptom recurrence towards baseline severity levels within 4 weeks after valbenazine withdrawal. No increased cumulative or specific adverse (AEs) events versus placebo (acute trials) in extension versus acute trial data were observed.

Conclusion

The 2 VMAT-2 inhibitors, valbenazine and deutetrabenazine, are effective in treating TD, both acutely and long-term, without concerns about increased risk of depression or suicide in the TD population. No head-to-head comparison among VMAT-2 inhibitors and no high-quality, meta-analyzable data are available for tetrabenazine in patients with TD.

VMAT2 Inhibitors for Tardive Dyskinesia-Practice Implications

Tardive dyskinesia is a potentially irreversible, debilitating, hyperkinetic movement disorder that can result from dopamine receptor antagonists. Prompt recognition and resolution of symptoms are instrumental in preventing disease irreversibility, though current treatment options have fallen short of robust, effective, and long-term symptom control. In April 2017, the Food and Drug Administration (FDA) approved 2 new vesicular monoamine transporter 2 (VMAT2) inhibitors, deutetrabenazine and valbenazine, for chorea related to Huntington's disease and tardive dyskinesia, respectively. These agents were pharmacologically modified from tetrabenazine, a VMAT2 inhibitor used off-label in the treatment of tardive dyskinesia. Despite FDA-labeled indications of deutetrabenazine and valbenazine, each agent was explored as a treatment option for those with tardive dyskinesia. In this study, the pharmacologic modifications of the 2 new VMAT2 inhibitors are described, with detailed explanation as to how these may impact clinical practice. The associated case series, observational studies, and clinical trials exploring their use in the treatment of tardive dyskinesia are reported with expert opinion on practice implication.

Treatment of tardive dyskinesia with tetrabenazine or valbenazine: a systematic review

Up to 30% of patients taking antipsychotics may develop tardive dyskinesia (TD). Recent evidence-based recommendations demonstrate an unmet need for effective TD management. This systematic review was designed to update the evidence for TD treatment, comparing two vesicular monoamine transporter 2 (VMAT2) inhibitors, tetrabenazine and valbenazine. Of 487 PubMed/Embase search results, 11 studies met the review criteria. Valbenazine efficacy was demonstrated in rigorously designed clinical trials that meet the guidelines for AAN Class I evidence. Due to differences in study designs and a lack of standardized and controlled trials with tetrabenazine, a formal meta-analysis comparing the agents was not possible. However, valbenazine appears to have fewer side effects and a more favorable once-daily dosing regimen for the treatment of TD.

Valbenazine for the treatment of tardive dyskinesia

INTRODUCTION

Tardive dyskinesia (TD) is a hyperkinetic movement disorder that may result from treatment with antipsychotics or other dopamine receptor blocking agents. Underlying pathophysiology is incompletely understood but since the 1970s dopamine depleting agents have been used to reduce involuntary movements. The search for safe, effective treatments for TD is ongoing. Valbenazine, a novel VMAT2 inhibitor, has recently been FDA approved for treatment of TD. Areas covered: An overview of TD, unmet medical needs and current treatment guidelines are presented. The background, chemistry and clinical development of valbenazine to treat TD is detailed. A competitive market is developing as the treatment gap is identified and potential therapies are discussed in context of a broader market overview. Expert opinion: Antipsychotic use is growing among adults and children in the U.S. Consequently, prevalence of TD is expected to rise. Cessation of antipsychotics is often not possible as the psychiatric condition may deteriorate. Increasing doses of an antipsychotic to suppress involuntary movements is not sustainable long term as underlying TD worsens and movements typically recur. There were no FDA approved treatments for TD. The approval of valbenazine to treat TD is a critical step in addressing this gap in neurologic care.

Single Dose and Repeat Once-Daily Dose Safety, Tolerability and Pharmacokinetics of Valbenazine in Healthy Male Subjects

Valbenazine (VBZ) is a vesicular monoamine transporter 2 (VMAT2) inhibitor approved for the treatment of tardive dyskinesia. The safety, tolerability and pharmacokinetics of VBZ following single and repeat once-daily (QD) dosing were evaluated in 2 randomized, single-center, double-blind studies in healthy male subjects. In the first study, 2 cohorts of 8 subjects were administered single doses (SD) of placebo (PBO; N = 2/period) or VBZ (N = 6/period; 1, 2, 5, or 12.5 mg for Cohort 1 and 12.5, 25, 50, or 75 mg for Cohort 2) using a sequential escalation scheme. The second study consisted of 2 phases. In the initial phase, subjects were administered SD PBO (N = 2/period) or VBZ (N = 6/period; 75, 100, 125 or 150 mg) with sequential escalation. In the second phase, subjects received PBO, or 50 or 100 mg VBZ (N = 4:8:8) QD for 8 days (Cohort 1) or PBO or 50 mg VBZ (N = 6:6) QD for 8 days (Cohort 2). For both studies, plasma concentrations of VBZ and its active metabolite, NBI-98782, were determined. Safety was assessed throughout the studies. PK parameters were determined using noncompartmental methods. In both studies, VBZ was rapidly absorbed with peak concentrations typically observed within 1.5 hours. Peak NBI-98782 concentrations were typically observed at 4.0 to 9.0 hours. Terminal elimination half-life for both VBZ and NBI-98782 was ~20 hours. Across the 1 to 150 mg SD range evaluated across the studies, VBZ and NBI-98782 Cmax and AUC increased dose-proportionally from 50 to 150 mg and more than dose-proportionally from 1 to 50 mg. QD VBZ and NBI-98782 Cmax and AUC parameters were also dose-proportional between the 50 and 100 mg doses. Steady-state for both analytes appeared to be achieved by Day 8. The accumulation index was ~1.5 for VBZ and ~2.5 for NBI-98782. Peak to trough fluctuation was approximately 250% for VBZ and 70% for NBI-98782. Across both studies, NBI-98782 exposure was approximately 20%-30% that of VBZ based on molar ratios. In the first study, the maximum-tolerated dose was not achieved; headache (2 events) was the only treatment-emergent adverse event (TEAE) reported by more than one subject. In the second study, fatigue (4 events) was the only TEAE reported by more than one subject following SD VBZ. Following QD VBZ, the TEAEs of fatigue, insomnia, disturbance in attention, and nervousness were dose-dependent; the latter three TEAEs were considered dose-limiting. Subject withdrawals due to TEAEs were 1 each for PBO and 50 mg VBZ QD, and 3 for 100 mg VBZ QD. Clinically relevant effects on laboratory parameters, vital signs or ECGs were limited to increased CPK (SD: 1 each for 5 mg VBZ and PBO), ALT (QD: 1 each for 50 and 100 mg VBZ and PBO), and triglycerides (QD: 1 each for 50 mg VBZ and PBO). VBZ has an acceptable safety profile and predictable pharmacokinetics that result in stable concentrations of active compounds with low peak-to-trough fluctuation following once-daily dosing.

Long-Term Safety and Tolerability of Valbenazine (NBI-98854) in Subjects with Tardive Dyskinesia and a Diagnosis of Schizophrenia or Mood Disorder

BACKGROUND

The short-term safety profile of once-daily valbenazine (NBI-98854) has been evaluated in several double-blind, placebo-controlled (DBPC) trials in adults with tardive dyskinesia (TD) who had a diagnosis of schizophrenia/schizoaffective (SCHZ) disorder or mood disorder. Studies with longer treatment duration (up to 48 weeks) were conducted to evaluate the long-term safety of this novel drug in subjects with TD.

METHODS

The pooled long-term exposure (LTE) population included valbenazine-treated subjects from 3 studies: KINECT (NCT01688037: 6-week DBPC, 6-week open-label); KINECT 3 (NCT02274558: 6-week DBPC, 42-week blinded extension, 4-week drug-free follow-up); KINECT 4 (NCT02405091: 48-week open-label, 4-week drug-free follow-up). Safety assessments included adverse events (AEs), laboratory tests, vital signs, electrocardiograms (ECGs), and extrapyramidal symptom (EPS) scales. Psychiatric stability was monitored using the Positive and Negative Syndrome Scale (PANSS) and Calgary Depression Scale for Schizophrenia (CDSS) (SCHZ subgroup), as well as the Montgomery-Åsberg Depression Rating Scale (MADRS) and Young Mania Rating Scale (YMRS) (mood subgroup). All data were analyzed descriptively.

RESULTS

The LTE population included 430 subjects (KINECT, n = 46; KINECT 3, n = 220; KINECT 4, n = 164), 71.7% with SCHZ and 28.3% with a mood disorder; 85.5% were taking an antipsychotic (atypical only, 69.8%; typical only or typical + atypical, 15.7%). In the LTE population, treatment-emergent AEs (TEAEs) and discontinuations due to AEs were reported in 66.5% and 14.7% of subjects, respectively. The TEAE incidence was lower in the SCHZ subgroup (64.4%) than in the mood subgroup (71.9%). The 3 most common TEAEs in the SCHZ subgroup were urinary tract infection (UTI, 6.1%), headache (5.8%), and somnolence (5.2%). The 3 most common TEAEs in the mood subgroup were headache (12.4%), UTI (10.7%), and somnolence (9.1%). Mean score changes from baseline to end of treatment (Week 48) indicated that psychiatric stability was maintained in the SCHZ subgroup (PANSS Total, -3.4; PANSS Positive, -1.1; PANSS Negative, -0.1; PANSS General Psychopathology, -2.2; CDSS total, -0.4) and the mood subgroup (MADRS Total, 0.0; YMRS Total, -1.2). These scores remained generally stable during the 4-week drug-free follow-up periods. In the LTE population, mean changes in laboratory parameters, vital signs, ECG, and EPS scales were generally minimal and not clinically significant.

CONCLUSION

Valbenazine appeared to be well tolerated in adults with TD who received up to 48 weeks of treatment. In addition to long-term efficacy results (presented separately), these results suggest that valbenazine may be appropriate for the long-term management of TD regardless of underlying psychiatric diagnosis (SCHZ disorder or mood disorder).

Efficacy of Valbenazine (NBI-98854) in Treating Subjects with Tardive Dyskinesia and Mood Disorder

BACKGROUND

Valbenazine (VBZ, NBI-98854) is a novel vesicular monoamine transporter 2 (VMAT2) inhibitor approved for the treatment of tardive dyskinesia (TD). The KINECT 3 study (NCT02274558) evaluated the effects of VBZ on TD in subjects with mood disorder or schizophrenia/schizoaffective disorder (SCHZ, presented separately) who received up to 48 weeks of treatment.

METHODS

KINECT 3 included: 6-week, double-blind, placebo (PBO)-controlled (DBPC) period (205 completers); 42-week VBZ extension (VE) period (124 completers); 4-week washout period (121 completers). Subjects entering the DBPC were randomized 1:1:1 to once-daily VBZ 80 mg, VBZ 40 mg, or PBO; stable concomitant antipsychotic medication regimens were allowed. Subjects completing the DBPC and entering the VE period were re-randomized (blinded) from PBO to VBZ (80 or 40 mg) or continued VBZ treatment at the same dose. Efficacy assessments included: mean changes from baseline in Abnormal Involuntary Movement Scale (AIMS) total score (items 1-7); mean Clinical Global Impression of Change (CGI-TD) scores; AIMS responders (subjects with ≥50% score reduction from baseline); and CGI-TD responders (subjects with score ≤2 ["much improved" or "very much improved"]). Treatment effect sizes (Cohen's d) and numbers needed to treat (NNTs) were analyzed for DBPC outcomes.

RESULTS

Efficacy analyses were conducted in 77 subjects (DBPC) and 73 subjects (VE) with a mood disorder. At Week 6 (end of DBPC), AIMS mean score improvements were greater in the VBZ groups (in a dose-related pattern) than in the PBO group (80 mg, -3.6, d = 0.94; 40 mg, -2.4, d = 0.55; PBO, -0.7). AIMS mean score changes at Week 48 (end of VE) showed continued TD improvement during long-term VBZ treatment (80 mg, -5.8; 40 mg, -4.2). By Week 52 (end of washout), AIMS mean scores in both dose groups were returning toward baseline levels, indicating re-emergence of TD. CGI-TD scores showed a similar pattern: Week 6 (80 mg, 2.7, d = 0.64; 40 mg, 2.9, d = 0.39; PBO, 3.2), Week 48 (80 mg, 2.0; 40 mg, 2.2), Week 52 (80 mg, 3.6; 40 mg, 2.8). AIMS responder rates (≥50% score reduction) were greater with VBZ vs PBO at Week 6 (80 mg, 38.5%, NNT = 4; 40 mg, 19.0%, NNT = 9; PBO, 7.7%), were increased at Week 48 (80 mg, 56.0%; 40 mg, 33.3%), and lower after VBZ washout (Week 52 80 mg, 16.7%; 40 mg, 27.8%). CGI-TD responder rates followed a similar pattern: Week 6 (80 mg, 34.6%, NNT = 6; 40 mg, 28.6%, NNT = 8; PBO, 15.4%), Week 48 (80 mg, 80.0%; 40 mg, 61.1%), Week 52 (80 mg, 25.0%; 40 mg, 44.4%).

CONCLUSION

Sustained TD improvements were found in subjects with a mood disorder who received up to 48 weeks of VBZ, with TD reverting toward baseline severity when assessed 4 weeks after treatment withdrawal. Together with results from SCHZ subjects and the long-term safety profile (presented separately), these results indicate that long-term VBZ can be beneficial for managing TD regardless of psychiatric diagnosis.

Efficacy of Valbenazine (NBI-98854) in Treating Subjects with Tardive Dyskinesia and Schizophrenia or Schizoaffective Disorder

BACKGROUND

Valbenazine (VBZ, NBI-98854) is a novel vesicular monoamine transporter 2 (VMAT2) inhibitor approved for the treatment of tardive dyskinesia (TD). The KINECT 3 study (NCT02274558) evaluated the effects of VBZ on TD in subjects with schizophrenia/schizoaffective disorder (SCHZ) or mood disorder (mood disorder presented separately) who received up to 48 weeks of treatment.

METHODS

KINECT 3 included: 6-week, double-blind, placebo (PBO)-controlled (DBPC) period (205 completers); 42-week VBZ extension (VE) period (124 completers): 4-week washout period (121 completers). Subjects entering the DBPC were randomized 1:1:1 to once-daily VBZ 80 mg, VBZ 40 mg, or PBO; stable concomitant antipsychotic medication regimens were allowed. Subjects completing the DBPC and entering the VE period were re-randomized (blinded) 1:1 from PBO to VBZ (80 or 40 mg) or continued VBZ treatment at the same dose. Efficacy assessments included: mean changes from baseline in Abnormal Involuntary Movement Scale (AIMS) total score (items 1-7); mean Clinical Global Impression of Change (CGI-TD) scores; AIMS responders (subjects with ≥50% score reduction from baseline): and CGI-TD responders (subjects with score ≤2 ["much improved" or "very much improved"]). Treatment effect sizes (Cohen's d) and numbers needed to treat (NNTs) were analyzed for DBPC outcomes.

RESULTS

Efficacy analyses were conducted in 148 subjects (DBPC) and 125 subjects (VE) with SCHZ. At Week 6 (end of DBPC), AIMS mean score improvements were greater in the VBZ groups (in a dose-related pattern) than in the PBO group (80 mg, -2.9, d = 0.88; 40 mg, -1.6, d = 0.52; PBO, +0.3). AIMS score changes at Week 48 (end of VE) showed continued TD improvement during long-term VBZ treatment (80 mg, -4.2; 40 mg, -2.5). By Week 52 (end of washout), AIMS scores were returning toward baseline levels, indicating re-emergence of TD. CGI-TD mean scores were as follows: Week 6 (80 mg, 3.0, d = 0.11; 40 mg, 2.9, d = 0.23; PBO, 3.2), Week 48 (80 mg, 2.2; 40 mg, 2.4), Week 52 (80 mg, 3.4; 40 mg, 3.3). AIMS responder rates (≥50% score reduction) were greater with VBZ than with PBO at Week 6 (80 mg, 40.9%, NNT = 4; 40 mg, 26.2%, NNT = 6; PBO, 9.3%), were increased at Week 48 (80 mg, 50.0%; 40 mg, 26.2%), and decreased after VBZ washout (80 mg, 21.6%; 40 mg, 9.5%). CGI-TD responder rates followed a similar pattern: Week 6 (80 mg, 29.5%, NNT = 17; 40 mg, 33.3%, NNT = 10; PBO, 23.3%), Week 48 (80 mg, 73.7%; 40 mg, 58.1%), Week 52 (80 mg, 29.7%; 40 mg, 33.3%).

CONCLUSION

Sustained TD improvements were found in subjects with SCHZ who received up to 48 weeks of VBZ, with TD reverting toward baseline when assessed 4 weeks after treatment withdrawal. Together with results from mood disorder subjects and the long-term safety profile (presented separately), these results indicate that long-term VBZ can be beneficial for managing TD regardless of psychiatric diagnosis category.

Pharmacotherapy for the treatment of tardive dyskinesia in schizophrenia patients

INTRODUCTION

Tardive dyskinesia (TD) is an iatrogenic movement disorder most commonly observed in patients with psychotic disorders who are treated with dopamine blocking antipsychotic medications. Treatment options are limited, and recommendations for treatment are based on a relative scarcity of evidence. Areas covered: After briefly highlighting current mechanistic theories of TD, this review will discuss the evidence for a number of medications of several different classes that have been studied for the treatment of TD since the 1970s with an emphasis on placebo controlled trials when possible. We used a Pubmed search of primary studies, reviews, and metaanalyses on the topic of TD treatment in order to cover this topic. Expert opinion: Treatment of TD is difficult given limited data and incomplete understanding of the mechanism. Treatment of TD must be evaluated on an individual basis with careful weight given to severity of symptoms. We suggest the use of atypical versus conventional antipsychotics whenever possible and would recommend trials with one or more of a number of additional agents starting with valbenazine.

Dopamine depleters in the treatment of hyperkinetic movement disorders

INTRODUCTION

Abnormal involuntary movements often improve in response to anti-dopaminergic drugs. In contrast to classic neuroleptics that block dopamine receptors, drugs that deplete presynaptic dopamine by blocking vesicular monoamine transporter type 2 (VMAT2) seem to be safer and have little or no risk of tardive dyskinesia. This is one reason why there has been a recent emergence of novel VMAT2 inhibitors. Areas covered: Since the approval of tetrabenazine, the classic VMAT2 inhibitor, in the treatment of chorea associated with Huntington disease (HD), other VMAT2 inhibitors (e.g. deutetrabenazine and valbenazine) have been studied in the treatment of HD-related chorea, tardive dyskinesia and tics associated with Tourette syndrome. This review, based largely on a detailed search of PubMed, will summarize the pharmacology and clinical experience with the various VMAT2 inhibitors. Expert commentary: Because of differences in pharmacology and pharmacokinetics these new VMAT2 inhibitors promise to be at least as effective as tetrabenazine but with a lower risk of adverse effects, such as sedation, insomnia, depression, parkinsonism, and akathisia.

Emerging pharmacological therapies in schizophrenia: what's new, what's different, what's next?

There are several new and emerging medication interventions for both the acute and maintenance treatment phases of schizophrenia. Recently approved are 2 new dopamine receptor partial agonists, brexpiprazole and cariprazine, as well as 2 new long-acting injectable antipsychotic formulations, aripiprazole lauroxil and 3-month paliperidone palmitate. Although differences in efficacy compared to other available choices are not expected, the new oral options offer different tolerability profiles that may be attractive for individual patients who have had difficulties with older medications. The new long-acting injectable options provide additional flexibility in terms of increasing the time interval between injections. In Phase III of clinical development is a novel antipsychotic, lumateperone (ITI-007), that appears to have little in the way of significant adverse effects. Deutetrabenazine and valbenazine are agents in Phase III for the treatment of tardive dyskinesia, a condition that can be found among persons receiving chronic antipsychotic therapy. On the horizon are additional injectable formulations of familiar antipsychotics, aripiprazole and risperidone, that may be more convenient than what is presently available.