Silexan in the Treatment Of Posttraumatic Stress Disorder Trial

ConditionPost Traumatic Stress Disorder

Trial statusRecruiting

Trial phasePhase 3

Trial typeInterventional

Biological sexAll

Age18+

SponsorDeakin University

About this trial

Posttraumatic stress disorder (PTSD) is a common and debilitating mental illness. Current treatments for PTSD include psychotherapy and antidepressant medications. Many patients are unable to tolerate psychotherapy for PTSD and drop out of it. In addition, its effectiveness is limited. Up to 50 percent of patients who receive psychotherapy do not benefit from it. Antidepressant medications have only small benefits in PTSD. They also have unpleasant side effects that can make patients unwilling to take them. There is an urgent need to develop new treatments for PTSD that work and are well-tolerated. Silexan has the potential to provide an important alternative treatment for PTSD.

Silexan is derived from lavender oil. It is taken orally in the form of capsules. It is currently available over-the-counter in 14 countries, including Australia and the United States. Previous research has shown that it is an effective treatment for anxiety disorders, including Generalized Anxiety Disorder. It is also well-tolerated by patients. The only side effects that have been identified so far are mild gastrointestinal symptoms (including burping and breath odour) and these are uncommon. The results of a small pilot study suggest that Silexan may also be effective and well-tolerated in PTSD.

The STOP trial is a clinical trial that aims to investigate whether adding Silexan to treatment-as-usual improves PTSD symptoms in adults with PTSD. The trial will recruit 278 participants. Participants will be randomly assigned to take Silexan or a placebo (look-alike dummy pills) daily in addition to their usual medications for 12 weeks. The severity of their PTSD symptoms will be assessed prior to and at the end of this 12-week period.

The STOP trial has the potential to obtain definitive evidence regarding whether Silexan helps treat symptoms of PTSD. If Silexan is found to be an effective treatment for PTSD, the pool of patients who could potentially benefit from this treatment includes any adults with PTSD. Silexan is already available over-the-counter at a relatively low cost so there will be few barriers to accessing this treatment.

Eligibility criteria

This trial does not accept healthy volunteers

Qualifiers

Aged 18 years or over.

Fluent in English.

Meet DSM-5 criteria for PTSD, irrespective of occupation (e.g. first responder, police officer, ex-military or civilian), determined using the Mini International Neuropsychiatric Interview 7.0.2.

Have a score on the PTSD Checklist for DSM-5 (PCL-5) equal to or over 33.

Disqualifiers

Are currently serving in the Australian Defence Force

Lifetime history of a psychotic or bipolar disorder, or dissociative identity disorder.

Moderate or severe alcohol or other substance use disorder within 3 months of screening.

Active suicidal or homicidal ideation.

Trial design

Design model

Parallel

Treatments tested in this trial

Silexan
Drug
Participants in the Silexan arm will take two over-encapsulated capsules, each containing 80 mg Silexan, daily orally in the morning in addition to their usual medications. No modifications of allocated interventions will be made for any trial participants; if appropriate (i.e following the emergence of adverse events) participants will be withdrawn from the intervention.
Placebo
Other intervention
Participants in the placebo arm will take two capsules containing an inert placebo daily orally in the morning in addition to their usual medications. The placebo capsules will contain a sub-therapeutic amount of lavender oil to mimic the odor of the experimental drug (Silexan).

Treatment groups

278 Participants

are divided into 2 treatment groups

Group A: Silexan 160 mgExperimental treatment 1 intervention

Group B: PlaceboPlacebo comparator 1 intervention

Trial outcomes

Primary outcomes

Clinician-Administered PTSD Scale for DSM-5 (CAPS-5)

The Primary Outcome Measure will be the between-group difference in the change from baseline to week 12 in the total symptom severity score on the CAPS-5. The CAPS-5 has good internal consistency, inter-rater reliability, test-retest reliability and convergent validity in measuring PTSD symptom severity, and is regarded as the gold-standard for measuring PTSD symptoms in research settings. The CAPS-5 will be used to query the presence of PTSD symptoms across the two weeks prior to each CAPS-5 assessment. We will also compare between-group differences in remission rates of PTSD, as determined by the CAPS-5.

Time frame

At baseline and at week 12 of the study period

Secondary outcomes

Hamilton Anxiety Rating Scale (HAM-A)

One of the Secondary Outcome Measures will be the between-group difference in the change from baseline to week 12, and baseline to week 16 (while including all available time-points including the off-treatment period) in measures of anxiety symptoms on the HAM-A. Additional comparisons for between-group differences from week 12 to week 16 will also be performed. The Hamilton Anxiety Rating Scale consists of 14 items and is the most widely used interview instrument for measurement of anxiety in adults and children.

Time frame

At baseline, at week 12 and at week 16 of the study period

Generalized Anxiety Disorder-7 (GAD-7)

One of the Secondary Outcome Measures will be the between-group difference in the change from baseline to week 12, and baseline to week 16 (while including all available time-points including the off-treatment period) in measures of anxiety symptoms on the GAD-7. Additional comparisons for between-group differences from week 12 to week 16 will also be performed. The Generalized Anxiety Disorder-7 is a 7-item scale with each item scores on a scale of 0 ("not at all") to 3 ("nearly every day") based on symptom presentation in the past two weeks.

Time frame

At baseline, at week 12 and at week 16 of the study period

Generalized Anxiety Disorder-7 (GAD-7)

One of the Secondary Outcome Measures will be the longitudinal trajectory analysis of anxiety symptoms on the GAD-7, measured at baseline, week 4, week 8 and week 12 of treatment. The Generalized Anxiety Disorder-7 is a 7-item scale with each item scores on a scale of 0 ("not at all") to 3 ("nearly every day") based on symptom presentation in the past two weeks.

Time frame

At baseline, week 4, week 8 and week 12 of the study period

Beck Depression Inventory-II (BDI-II)

One of the Secondary Outcome Measures will be the between-group difference in the change from baseline to week 12, and baseline to week 16 (while including all available time-points including the off-treatment period) in measures of depressive symptoms on the BDI-II. Additional comparisons for between-group differences from week 12 to week 16 will also be performed. The BDI-II comprises of 21 questions rated on 4-point scales of severity (0-3), with a total score that reflects the level or degree of depression. The BDI-II has high internal consistency.

Time frame

At baseline, at week 12 and at week 16 of the study period

Other outcomes

Mediators of response to Silexan

We will assess whether additional pre-existing factors, including social support (measured via the Social Support Survey (SSS)), past military deployment (measured via the Deployment Risk \& Resilience Inventory-2 (DRRI-2)), or developmental trauma (measured via the BRFSS Adverse Childhood Experience (ACE) Module) affect response to Silexan.

Time frame

Baseline

Sponsors and contacts

Click on the lead sponsor to view all of their trials.

Deakin University

Lead sponsor

University of Melbourne

Collaborator

Ramsay Clinic Albert Road

Collaborator

Source ClinicalTrials.gov

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