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Low Back PainPhase 2NCT03535688

D-cycloserine for the Treatment of Chronic, Refractory Low Back Pain

A Phase 2 study testing D-cycloserine in people with Low Back Pain and Pain, run by Northwestern University at 1 site in United States.

Terminated

Stopped early. The study ended before it was planned to and will not resume.

Official record
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Trial summary

The purpose of this study is to evaluate the efficacy and safety of D-cycloserine versus placebo in relieving the signs and symptoms of patients with chronic lower back pain. Read more about this study

Who is it for?
Ages 18 years and older
Conditions the study is for
Low Back Pain, Pain
What is being tested?
D-cycloserine
Could I receive a placebo?
Yes, some participants may receive a placebo
How many people
203 participants
Where
1 siteUnited States
Study dates
30 Mar 2018to 7 Feb 2024
Phase
Phase 2
Are there results?
Yes, posted in the registrySummary in the doctors' view

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 years and older
  • All sexes
  • No healthy volunteers
  • Adult, Older adult

Who may be able to join

  • Must have a history of low back pain for a minimum of 6 months with or without signs and symptoms of radiculopathy
  • Male or female, age 18 years or older, (no racial/ethnic restrictions)
  • Must have an average pain score of ≥ 4 (on a 0-10 NRS) over a 5-7 day period (minimum of daily eDiary entries for at least 5 of 7 days) immediately preceding the baseline visit (visit 2)
  • Must be willing to read and able to understand instructions as well as patient reported outcomes (PROs)
  • Must be in generally stable health
  • Must sign an informed consent document after complete explanation of the study documenting that they understand the purpose of the study, procedures to be undertaken, possible benefits, potential risks, and are willing to participate
Show all 16Show fewer
  • Must be willing to discontinue all pain medications for chronic back pain (listed below) except the study medication and rescue medication provided and not use the following prohibited pain medications throughout the duration of the treatment period
  • analgesics including over the counter (OTC) medications
  • NSAIDS including OTC medications
  • Coxibs
  • Opioids
  • Muscle relaxants
  • Gabapentins including pregabalin and gabapentin
  • Must be willing to comply with recording pain, mood, and study treatment adherence twice daily using study eDiary
  • Must be willing to abstain from drinking alcohol during the course of the study.
  • If female, must be post-menopausal for at least one year or practicing an accepted, highly effective method of contraception or abstinence and plan to continue during the course of the study.

Who cannot join

  • Low back pain associated with any systemic signs or symptoms, e.g., fever, chills
  • Evidence of rheumatoid arthritis, ankylosing spondylitis, acute vertebral fractures, fibromyalgia, or history of surgery or tumor in the back within the past 6 months
  • Involvement in litigation regarding their back pain or has a disability claim or is receiving workman's compensation or is seeking either as a result of their low back pain
  • Epidural steroid injection within the past 3 months
  • History of seizures
  • Major new or untreated psychiatric disorder during the past 6 months and/or ongoing treatment with buproprion or fluphenazine
Show all 27Show fewer
  • Beck Depression Inventory II score of >28
  • Significant renal disease or severe renal insufficiency
  • Substance abuse/dependence including alcohol within the past 6 months
  • Significantly abnormal laboratory values
  • Pregnant or lactating at the time of randomization
  • Known sensitivity to D-cycloserine
  • Currently taking any of the following medications: ethionamide, dilantin, isoniazid (INH)
  • In the judgment of the investigator, unable or unwilling to follow the protocol and instructions
  • Any change in medication or physical therapy regime for back pain in the last 30 days.
  • Chronic progressive neurologic conditions, including Parkinson's disease, Alzheimer's disease, and other conditions associated with dementia
  • Other medical disease such as clinically significant congestive heart failure, coronary or peripheral vascular disease, chronic obstructive lung disease, or malignancy
  • Presence of undiagnosed skin lesions or history of melanoma
  • Current use of recreational drugs
  • Current use of medical marijuana
  • High dose opioid prophylaxis, defined as > 50mg morphine equivalent/day
  • Intra-axial implants (e.g. spinal cord stimulators or pumps)
  • Pregnancy or inability to use an effective method of birth control in sexually active men and women while taking the study drug and for one week thereafter. Barrier contraceptives (condoms or diaphragm) with spermicide, intrauterine devices (IUD's), hormonal contraceptives, oral contraceptive pills, surgical sterilization, and complete abstinence are examples of effective methods of contraception.
  • Following laboratory abnormalities: liver function tests (SGOT/SGPT) greater than 2.5 times the upper limit of normal; unexplained anemia; evidence of renal insufficiency (creatinine > upper limit of normal) or any other abnormality that the principal investigator feels puts the participant at risk during the study.
  • Any medical condition that in the investigator's judgment may prevent the individual from completing the study or put the individual at undue risk
  • Lactose allergy
  • Ongoing participation in another clinical research study involving an investigational product or having received another investigational product within the last 90 days

Trial locations and contacts

1 site in 1 country.

United States1 site

  • Northwestern University Feinberg School of Medicine

    Chicago, Illinois, 60611

Other trials in United States

About this study

The purpose of this study is to evaluate the efficacy and safety of D-cycloserine versus placebo in relieving the signs and symptoms of patients with chronic lower back pain.

Read the detailed description

This is a 26-week, double-blind, randomized, placebo-controlled two-arm parallel-group trial of d-cycloserine, a pharmacological treatment selected based on positive results from previous preclinical and clinical studies, for the treatment of chronic, refractory low back pain (CBP). After a 2-week screening period, individuals will be randomized to receive either 12 weeks of d-cycloserine or placebo and then followed for an additional 12 weeks to evaluate persistence of benefit at study endpoint, 24 weeks after randomization. During the 12-week treatment period, participants will undergo evaluation at baseline and at clinic visits on weeks 2, 6 and 12 after randomization to assess pain, proper treatment use and side effects. During the subsequent 12-week follow-up period, pain and safety will continue to be assessed monthly by phone calls. All patients will also be assessed daily using an electronic diary (eDiary) to record pain and mood. Magnetic resonance imaging (MRI), anatomical MRI, resting state functional MRI (fMRI), diffusion-tensor imaging (DTI) MRI, and arterial spin labeling (ASL) will be performed at baseline and at the end of 12 weeks for individuals completing MRI.

Conditions
Low Back Pain, Pain
Being tested
D-cycloserine, Placebo
Keywords
Chronic Pain, Low Back Pain, D-cycloserine
Medical subject headings
Low Back Pain, Pain, Chronic Pain

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • D-cycloserineDrug

    200 mg twice daily

  • PlaceboDrug

    twice daily

Study groups in NCT03535688
Study groupRoleWhat they receive
D-cycloserineExperimentalD-cycloserine 200 mg twice daily
Receives: Drug: D-cycloserine
PlaceboPlacebo comparatorPlacebo twice daily
Receives: Drug: Placebo

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Change in Numeric Rating Scale (NRS) Pain Score 0-10; Higher Worse

    Mean pain levels will be assessed at study baseline and compared to mean pain levels at Week 12 (study efficacy endpoint). Pain will be assessed using an 11-point NRS scale.

    Measured: 12 weeks

Secondary outcomes (14)

  1. Effect of Gender on Magnitude of Pain Response.

    Assess the effect of gender on the on the pain rating response in each group (pain rating scale: 0 (no pain) to 10 (highest pain)).

    Measured: 12 weeks

  2. Brain Biomarkers (MRI)

    Evaluate interaction between the primary endpoint and specified brain biomarkers, with particular attention to corticostriatal connectivity. Whole-brain exploratory analyses will also be used to identify both brain predictors or treatment response and brain reorganization in response to treatment.

    Measured: 12 weeks

  3. Patient Global Assessment

    A 5-point scale used to reflect the global impact of pain from the patient's perspective. Scale range 0-10; higher = worse.

    Measured: 12 weeks

  4. Patient Global Impression of Change

    A 7-point self-report measure that reflects a patient's belief about the efficacy of treatment; by depicting a patient's rating of overall improvement. Scale range 1-7, higher = worse.

    Measured: 12 weeks

  5. McGill Pain Questionnaire (MPQ)

    A 17-item self-reported measure assessing both the quality and intensity of subjective pain. Score 0-45, higher worse

    Measured: 12 weeks

  6. PainDETECT Questionnaire (PDQ)

    A 14-item self-reported measure assessing qualities for pain of neuropathic origin to distinguish pain severity. Score 0-38; higher more neuropathic

    Measured: 12 weeks

  7. Beck Depression Inventory (BDI)

    A 21-item self-report rating inventory that measures characteristic attitudes and symptoms of depression. Score 0-63, higher worse

    Measured: 12 week

  8. Positive and Negative Affect Schedule (PANAS) - Positive

    A self-report questionnaire consisting of two 10-item (5-point) scales to measure both positive and negative affects of pain. Score 10-50; higher more positive

    Measured: 12 weeks

  9. Pain Catastrophizing Scale (PCS)

    A 13-item scale assessing the degree of catastrophic cognitions in the sensation of pain.

    The scale ranges from 1 (not at all) to 4 (always). Score 0-52, higher worse

    Measured: 12 weeks

  10. Multidimensional Assessment of Interoceptive Awareness (MAIA)

    A 32-item self-reported measure delineating between beneficial versus maladaptive interoceptive attention. Score 0-160, higher more awareness.

    Measured: 12 weeks

  11. Oswestry Disability Index (ODI)

    A 10-item self-reported measure quantifying a subjective percentage score of level of function (disability) in activities of daily living in those with chronic low back pain. Score 0-50; higher is greater disability

    Measured: 12 weeks

  12. 12-Item Short Form Survey (SF-12) - Mental

    A 12-item self-report questionnaire measuring functional health and well-being from the patient's point of view. The SF-12 measures patient reported, health related quality of life from 0 to 100, with higher scores indicating better physical and mental health functioning.

    Measured: 12 weeks

  13. Positive and Negative Affect Schedule (PANAS) - Negative

    A self-report questionnaire consisting of two 10-item (5-point) scales to measure both positive and negative affects of pain. Score 10-50; higher more positive

    Measured: 12 weeks

  14. 12-Item Short Form Survey (SF-12) - Physical

    A 12-item self-report questionnaire measuring functional health and well-being from the patient's point of view. The SF-12 measures patient reported, health related quality of life from 0 to 100, with higher scores indicating better physical and mental health functioning.

    Measured: 12 weeks

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted24 May 2018
  2. Study start30 Mar 2018
  3. Primary completion7 Feb 2024
  4. Study completion7 Feb 2024

Why it stopped: Insufficient funding to complete the study

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase 2
Primary purpose
Treatment
Allocation
Randomised
Intervention model
Parallel groups
Masking
Triple blind
Who is masked
Participant, Investigator, Outcomes assessor
Enrolment
203 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT03535688
Sponsor's protocol ID
STU00205398
Other IDs
A-20364
Status last verified
Apr 2026
First submitted
3 Apr 2018
Last updated
4 May 2026
Data monitoring committee
Yes
FDA-regulated drug
Yes
FDA-regulated device
No

Publications

  • Pinto CB, Bielefeld J, Barroso J, Yip B, Huang L, Schnitzer T, Apkarian AV. Chronic pain domains and their relationship to personality, abilities, and brain networks. Pain. 2023 Jan 1;164(1):59-71. doi: 10.1097/j.pain.0000000000002657. Epub 2022 Apr 20. No abstract available.

    PubMed 35612403

Questions about this trial

What is this clinical trial studying?

A Phase 2 study testing D-cycloserine in people with Low Back Pain and Pain, run by Northwestern University at 1 site in United States.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 16 inclusion and 27 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: stopped early, as of the sponsor's last update on 4 May 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

Yes. Results are posted in the registry (first posted 4 May 2026). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Change in Numeric Rating Scale (NRS) Pain Score 0-10; Higher Worse (time frame: 12 weeks). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT03535688, which also lists 1 linked publication.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 4 May 2026.

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