Pregabalin in CIPN

Investigation of Somatosensory Predictors of Response to Pregabalin in Painful Chemotherapy-induced Peripheral Neuropathy (CIPN)

The investigators seek to investigate certain patient characteristics that would predict the response to a currently approved analgesic, pregabalin, in patients with chronic pain due to nerve damage caused by chemotherapy. Patients with this painful condition, called chemotherapy-induced peripheral neuropathy (CIPN) have a current or recent history of chemotherapy with particular chemotherapy agents called taxanes or oxaliplatin. The investigators will recruit potential subjects from both the Siteman Cancer Center and the Washington University Pain Management Center. Those patients who meet the inclusion and satisfy the exclusion criteria will be enrolled. Subjects will undergo mechanical and thermal sensitivity testing on their extremities, will provide quality of life information by completing questionnaires and will receive pregabalin followed by placebo, or placebo followed by pregabalin [crossover design] in order to assess how well the sensory tests predict the analgesic effect of pregabalin (compared to placebo).

Inclusion Criteria:

1. Age >18
2. Distal symmetric pain distribution (both feet, with or without pain in hands).
3. The pain appeared during or up to 12 weeks after treatment with oxaliplatin, paclitaxel, docetaxel or any combination of these.
4. Score of 4 or more on DN4 (Douleur Neuropathique 4) neuropathic pain questionnaire
5. Pain duration > 2 months.
6. Patient report of average daily pain intensity in the last week >3 on 0-10 Numerical Rating Scale (NRS).
7. Women of childbearing potential and men must agree to use adequate contraception (hormonal or barrier method of birth control, abstinence) prior to study entry and for the duration of study participation.
8. Able and willing to sign an IRB-approved written informed consent.

Exclusion Criteria:

1. Hypersensitivity to pregabalin.

2. Current treatment with pregabalin.

3. Current treatment with a vinca alkaloid (e.g. vincristine, vinblastine), or CIPN that may be associated with previous treatment with a vinca alkaloid.

4. History of diabetes mellitus or a neurological disorder with any previous signs of distal symmetric polyneuropathy.

5. Moderate to severe renal failure (Creatinine clearance < 30mL/min, by Cockcroft-Gault formula).

6. ALT (alanine aminotransferase) or AST (aspartate aminotransferase ) > 3 times the upper limit of normal.

7. Planned surgeries or radiation treatment within 10 weeks following study inclusion.

8. Inability to complete pain self-report.

9. Pregnancy or lactation

10. Patients with seizure disorders treated with anticonvulsants

11. Current participation in a trial with another investigational agent.

12. Concomitant medication as follows:

    • Subjects treated with gabapentin or other anticonvulsant for neuropathic pain will be required to taper the medication and discontinue for at least 2 weeks prior to study initiation.
    • Patients on antidepressant treatment for pain or depression (TCAs, SSRI, SNRIs etc. will be allowed to continue their medications provided they have been on a stable dose for at least 4 weeks before study initiation. No dose regimen changes of antidepressants will be allowed during the study period.
    • Patients on around-the clock opioid treatment (including tramadol) will be allowed to continue their medication provided they have been on a stable dose for at least 4 weeks before study initiation. The maximum allowed dose of opioid will be equivalent to 60mg oral morphine sulphate. Patients with higher doses will be required to taper down their opioid dose to maximum 60mg oral morphine equivalent, and continue on stable dose for 4 weeks before enrollment in the study. Short-acting opioids for painful CIPN treatment will not be allowed.
    • Treatment with non-steroidal anti-inflammatory drugs (NSAIDs) will be discontinued at least 2 weeks before study initiation. However, low-dose aspirin (≤325mg/day) will be allowed.