GRASSP: Gralise® for Spine Surgery Pain

Inclusion Criteria.

• Male and female subjects age 18 to 80 years.
• Primary diagnosis of post-laminectomy pain syndrome (PLPS), defined as having their most severe pain related to a prior history of lumbar surgery including decompressive (e.g. laminectomy) or fusion (e.g. posterior lumbar interbody fusion) procedures performed from the L1-S1 level at least 6 months prior to enrollment.
• Pain Detect score ≥12, denoting neuropathic pain is probable.
• At least 50% of present pain intensity is attributed to the lower extremity (Quebec Task Force Grade 3 or 4) on most days.
• All subjects must be decisionally capable and must give their own consent to be enrolled.

Exclusion Criteria.

• Lumbar surgery <6 months prior to enrollment
• Subjects with PLPS and pain free interval (defined as chronic low back pain and radicular symptoms <=3/10) related the indication for their PLPS defining event and a new, acute or subacute symptom pattern (e.g. new disc herniation at an adjacent level as documented by imaging).
• Subjects regularly taking gabapentin or pregabalin for their chronic pain after spine surgery who do not endorse relief (defined as either minimally, much or very much improved on a 7 point likert scale when asked about these medications' effects).
• Having another type of pain that is as or more severe than pain associated with PLPS.
• An average daily pain score of 10 on the NRS scale during either the screening or initial washout period.
• Concurrent medication that includes antiepileptic drugs (AEDs) (exceptions: pregabalin or gabapentin).
• Subjects taking concomitant neuropathic pain medication (stable dose for at least 4 weeks) may reduce the number and/or dose of their current pain medications: If the number and/or dose exceed the limits of allowed neuropathic pain medications (refer to Use of Allowed Pain Medication), then the number and/or dose must be reduced to fall within acceptable limits. Concomitant neuropathic pain medication needs to be kept stable during the study.
• Subjects who have previously not responded to treatment with gabapentin at doses of ≥900 mg/day or pregabalin at doses ≥300 mg/day.
• Known hypersensitivity to Gralise, or gabapentin, or its ingredients.
• Dose limiting adverse events to gabapentin; subjects who previously experienced dose-limiting adverse effects that prevented titration of gabapentin to an effective dose.
• History of alcohol and/or drug abuse in the investigator's judgment, based on subject history and physical examination.
• Subject who consumes excessive amounts of alcohol, defined as greater than 3 glasses of alcoholic beverages (1 glass is approximately equivalent to: beer [10 ounces], wine [4 ounces], or distilled spirits [1 ounce]) per day on a regular basis.
• Participation in a clinical trial of an investigational drug or device within 30 days of the screening visit.
• Gastric reduction surgery.
• Acute gastrointestinal symptoms such as diarrhea, dyspepsia, or gastric or duodenal ulcers.
• Malignancy within past 2 years other than basal cell carcinoma.
• Women who are pregnant or breastfeeding.
• History of seizure or is at risk of seizure due to head trauma.
• History of significant cardiovascular, respiratory, endocrine, liver or kidney disease (subjects with renal impairment or creatine clearance <30 ml/min).
• Any significant medical condition, laboratory abnormality, or psychiatric illness (e.g. depression, mood problems, suicidal thoughts) that would prevent the subject from participating in the study.