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

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. T1-MRI, resting state fMRI DTI-MRI, and ASL will be
performed at baseline and at the end of 12 weeks for individuals completing MRI.

Inclusion Criteria:

- 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 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

- 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 OTC medications

- NSAIDS including OTC medications

- Coxibs

- Opioids

- Muscle relaxants

- Gabapentinoids 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.

Exclusion Criteria:

- 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 psychiatric disorder during the past 6 months

- 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

- Significant other medical disease such as 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