Proof of Concept Trial of Cannabis Derivatives in Neuropathic Pain
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ClinicalTrials.gov Identifier: NCT05351801 |
Recruitment Status :
Not yet recruiting
First Posted : April 28, 2022
Last Update Posted : December 27, 2022
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Veterans with diabetes are more likely than diabetic civilians to develop disabling chronic diabetic neuropathic pain (CDNP). Research on frontline treatments for CDNP (enhanced glycemic control, exercise, pharmacological agents), shows inconsistent outcomes and dissatisfaction among Veterans. Veterans and clinicians have shown significant interest in cannabis derivatives (THC, CBD) for neuropathic pain control, but there are no well-controlled trials guiding expectations for benefit and adverse outcomes associated with cannabis for CDNP. Because Veterans are likely to present with pain and pain-related polymorbidity significantly differing from that of civilians, a well-structured clinical trial of cannabinoids for Veterans with CDNP is vital.
The present phase II study will offer the first evidence describing the potential benefits and adverse effects of cannabinoids for CDNP in Veterans using a four-arm, double-blind, multisite randomized trial comparing THC, CBD, THC+CBD and placebo on neuropathic pain outcomes.
Condition or disease | Intervention/treatment | Phase |
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Diabetic Neuropathic Pain | Drug: THC (Dronabinol) Drug: CBD (Epidolex) Drug: THC + CBD (Nabiximols) Drug: Placebo | Phase 2 |
Study Type : | Interventional (Clinical Trial) |
Estimated Enrollment : | 320 participants |
Allocation: | Randomized |
Intervention Model: | Parallel Assignment |
Intervention Model Description: | Double-blind, randomized, placebo-controlled, parallel group Phase II study with randomization to one of the four treatment arms: 1) 10 mg mg THC , 2) 800 mg CBD , 3) 10.8 mg THC + 10 mg CBD , and 4) placebo. The 8-week treatment phase comprises a 2-week up-titration, 4 weeks maintenance on the target dose followed by 2 weeks down-titration, to minimize cannabis withdrawal syndrome. The two-weeks up titration phase is to minimize side effects and improve tolerability. Efficacy will be assessed by responses during the 4-week target dose phase. |
Masking: | Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor) |
Primary Purpose: | Treatment |
Official Title: | Proof of Concept Trial of Cannabis Derivatives in Neuropathic Pain. |
Estimated Study Start Date : | February 1, 2023 |
Estimated Primary Completion Date : | June 30, 2027 |
Estimated Study Completion Date : | June 30, 2027 |
Arm | Intervention/treatment |
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Active Comparator: THC (Dronabinol)
Target dose of 10mg per day.
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Drug: THC (Dronabinol)
Participants will receive a target dose of 10mg per day of THC (Dronabinol). Drug: Placebo Placebo |
Active Comparator: CBD (Epidolex)
Target dose of 800 mg per day.
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Drug: CBD (Epidolex)
Participants will receive a target dose of 800 mg per day of CBD (Epidolex). Drug: Placebo Placebo |
Active Comparator: THC + CBD (Nabiximols)
Target dose of 10.8 mg / 10 mg per day.
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Drug: THC + CBD (Nabiximols)
Participants will receive a target dose of 10.8 mg / 10 mg per day of THC + CBD (Nabiximols). Drug: Placebo Placebo |
Placebo Comparator: Placebo
Identical in appearance to the three active comparators.
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Drug: Placebo
Placebo |
- To compare the short-term efficacy of THC, CBD, or THC+CBD vs Placebo on Neuropathic Pain as measured by the Numeric Rating Scale of Pain [ Time Frame: Baseline, Week 6 ]The mean change in the weekly average of daily Numeric Rating Scale (NRS) pain score (0-10 scale; 0=no pain, 10=worst possible pain) from baseline to week 6.
- To assess the efficacy of THC, CBD, or THC+CBD vs Placebo in pain quality (allodynia) as measured by the Quantitative Sensory Testing. [ Time Frame: Baseline, Week 2, Week 4, Week 6, Week 8 ]Allodynia measured by Quantitative Sensory Testing (QST) (0-10 scale; 0=no pain, 10=worst possible pain)
- To assess the efficacy of THC, CBD, or THC+CBD vs Placebo in disability and function as measured by the Neuropathic Pain Scale. [ Time Frame: Baseline, Week 1, Week 2, Week 3, Week 4, Week 5, Week 6, Week 7, Week 8 ]Neuropathic Pain Scale (NPS) total score; 7 different questions/sensations (for each individual item 0-10 scale; 0= not present/no pain, 10= most sensation). Individual scores analyzed separately for pain quality and mean score analyzed for overall neuropathic pain).
- To assess the efficacy of THC, CBD, or THC+CBD vs Placebo in disability and function as measured by the Gait Speed Test [ Time Frame: Baseline, Week 4, Week 8 ]Distance walked (meters)/time (seconds) measured by Gait Speed Test (lower score = worse, higher score =better)
- To assess the efficacy of THC, CBD, or THC+CBD vs Placebo in mean changes in perceived improvement as measured by the Patient Global Impression of Change [ Time Frame: Baseline, Week 2, Week 4, Week 6, Week 8 ]Patient Global Impression of Change (PGIC) 1-7 point ordinal scale assessed (1 = worse, 7 = better)
- To assess the efficacy of THC, CBD, or THC+CBD vs Placebo in mean changes in perceived improvement as measured by the patient satisfaction visual analog scale. [ Time Frame: Baseline, Week 1, Week 2, Week 3, Week 4, Week 5, Week 6, Week 7, Week 8 ]Patient satisfaction with intervention on visual analog scale (VAS, 0-100, 0=no satisfaction, 100 = complete satisfaction).
- To assess the efficacy of THC, CBD, or THC+CBD vs Placebo in mean changes in quality of life measured by the Veterans RAND 12 Item Health Survey [ Time Frame: Baseline, Week 4, Week 8 ]Mental Component Score (MCS) and Physical Component Score (PCS) measured by Veterans RAND 12 Item Health Survey (VR-12). VR-12 is an algorithmic score with ranges from 0-100 (0 indicates worse health-related quality of life and 100 represents better health-related quality of life).
- To assess the efficacy of THC, CBD, or THC+CBD vs Placebo in anxiety measured by the Generalized Anxiety Disorder-7. [ Time Frame: Baseline, Week 1, Week 2, Week 3, Week 4, Week 5, Week 6, Week 7, Week 8 ]Generalized anxiety symptomology is measured by Generalized Anxiety Disorder-7 (GAD-7) total score. (total score ranges from 0-21; Score 0-4 = minimal anxiety, Score 5-9 = mild anxiety, Score 10-14 = moderate anxiety, Score 15-21 = severe anxiety)
- To assess the efficacy of THC, CBD, or THC+CBD vs Placebo in pain quality as measured by the Short Form McGill Pain Questionnaire (SF-MPQ-2). [ Time Frame: Baseline, Week 2, Week 4, Week 6, Week 8 ]Short Form McGill Pain Questionnaire (SF-MPQ-2) total score and four subscales (continuous pain, intermittent pain, predominantly neuropathic pain, affective). (0= no pain to 5= excruciating pain)
- To assess the efficacy of THC, CBD, or THC+CBD vs Placebo in mean changes in disability and function as measured by the Brief Pain Inventory-Diabetic Peripheral Neuropathy. [ Time Frame: Baseline, Week 1, Week 2, Week 3, Week 4, Week 5, Week 6, Week 7, Week 8 ]Brief Pain Inventory-Diabetic Peripheral Neuropathy (BPI-DPN) pain intensity score (first four items 0-10; 10= pain as bad as can imagine) (remaining items 0% (no relief)-100% (complete relief)) and pain interference score (0-10, 10= completely intense).
- To assess the efficacy of THC, CBD, or THC+CBD vs Placebo in emotional functioning (severity of depression) as measured by the Patient Health Questionnaire-9. [ Time Frame: Baseline, Week 1, Week 2, Week 3, Week 4, Week 5, Week 6, Week 7, Week 8 ]Severity of depression is measured by Patient Health Questionnaire-9 (PHQ-9) total score (0-27; 0=none, 27=worst).
- To assess the efficacy of THC, CBD, or THC+CBD vs Placebo in emotional functioning (PTSD symptoms) as measured by the PTSD Checklist-DSM-5 (PCL-5). [ Time Frame: Baseline, Week 1, Week 2, Week 3, Week 4, Week 5, Week 6, Week 7, Week 8 ]PTSD symptoms are assessed by PTSD Checklist-DSM-5 (PCL-5) total score symptom severity score (0-80; 0= not at all to 80= worst).

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Ages Eligible for Study: | 21 Years and older (Adult, Older Adult) |
Sexes Eligible for Study: | All |
Accepts Healthy Volunteers: | No |
Inclusion Criteria:
- Able to provide written consent
- Veterans 21 years and older at the date of screening
- Meet NEURODIAB criteria for painful diabetic peripheral neuropathy
- Meet criteria for persistent, high-impact pain criteria.
- Presence of allodynia confirmed by one of the screening dynamic brush tests
Exclusion Criteria:
- Primary source of pain not related to diabetic neuropathy
- Hypersensitivity to THC, CBD, or THC/CBD
- Positive urine toxicology for THC-COOH on 2 consecutive visits before and including baseline assessment
- Unwilling to refrain from using cannabis or cannabis-based products through the entire duration of the study
- Diagnosis of DSM-5 Cannabis Use Disorder in the past 6 months
- Current DSM-5 diagnosis of cannabis use disorder, substance use disorder or serious psychiatric disorders
- Actual change or intent to change is greater than a 20% change (increase or decrease) in any other medication for pain or non-pharmacological treatment from 4 weeks before the screening appointment until completion of study (i.e., visit 13)
- Opioid doses > 400 mg MME (morphine milligram equivalent)
- Women who are pregnant or breastfeeding, or who intend to become pregnant in the 12 weeks from enrollment
- Any current unstable or concerning medical condition that would place the patient at increased risk, including hepatic, respiratory, immunological, cardiovascular, endocrine, or renal disease
- Need for immediate psychiatric hospitalization
- Enrolled in a medical marijuana program
- Federal employee

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT05351801
Contact: Christina L Luddy, BS | (203) 932-5711 ext 4549 | christina.luddy@va.gov | |
Contact: Mohini Ranganathan, MD | (203) 932-5711 | Mohini.Ranganathan@va.gov |
United States, California | |
VA San Diego Healthcare System, San Diego, CA | |
San Diego, California, United States, 92161 | |
Contact: Albert Leung, MD 858-642-3029 albert.leung@va.gov | |
United States, Connecticut | |
VA Connecticut Healthcare System West Haven Campus, West Haven, CT | |
West Haven, Connecticut, United States, 06516 | |
Contact: Deepak D'Souza, MD MBBS 203-932-5711 ext 2594 Deepak.DSouza@va.gov | |
Principal Investigator: Deepak D'Souza, MD MBBS | |
United States, Rhode Island | |
Providence VA Medical Center, Providence, RI | |
Providence, Rhode Island, United States, 02908 | |
Contact: Jane Metrik, PhD 401-273-7100 ext 3400 jane.metrik@va.gov | |
United States, Texas | |
South Texas Health Care System, San Antonio, TX | |
San Antonio, Texas, United States, 78229 | |
Contact: Muhammad Baig, MD 210-617-5300 ext 18244 muhammad.baig@va.gov | |
United States, Washington | |
VA Puget Sound Health Care System Seattle Division, Seattle, WA | |
Seattle, Washington, United States, 98108 | |
Contact: Elaine Peskind, PhD 206-277-3965 elaine.peskind@va.gov |
Principal Investigator: | Deepak D'Souza, MD MBBS | VA Connecticut Healthcare System West Haven Campus, West Haven, CT | |
Principal Investigator: | Donald McGeary, PhD | South Texas Health Care System, San Antonio, TX |
Responsible Party: | VA Office of Research and Development |
ClinicalTrials.gov Identifier: | NCT05351801 |
Other Study ID Numbers: |
NURP-002-20F |
First Posted: | April 28, 2022 Key Record Dates |
Last Update Posted: | December 27, 2022 |
Last Verified: | December 2022 |
Individual Participant Data (IPD) Sharing Statement: | |
Plan to Share IPD: | No |
Studies a U.S. FDA-regulated Drug Product: | Yes |
Studies a U.S. FDA-regulated Device Product: | No |
Product Manufactured in and Exported from the U.S.: | No |
Neuralgia Peripheral Nervous System Diseases Neuromuscular Diseases Nervous System Diseases Pain Neurologic Manifestations Dronabinol Nabiximols Hallucinogens Physiological Effects of Drugs Psychotropic Drugs |
Analgesics, Non-Narcotic Analgesics Sensory System Agents Peripheral Nervous System Agents Cannabinoid Receptor Agonists Cannabinoid Receptor Modulators Neurotransmitter Agents Molecular Mechanisms of Pharmacological Action Hormones Hormones, Hormone Substitutes, and Hormone Antagonists |