Capsaicin NGX-1998 for Postherpetic Neuralgia

IRB #: 101441

Study Title: “C204: A Multicenter Randomized, Double-Blind, Controlled Study to Evaluate Safety, Tolerability and Preliminary Efficacy of Two Capsaicin Concentration Variations of NGX-1998 (10% or 20% w/w) in Subjects with Postherpetic Neuralgia (PHN)”

Dr. Mark Wallace and his associates are conducting an Investigational research study for NeurogesX, Inc. The goal of this 14 week clinical research study is to assess the effectiveness of NGX-1998 in the treatment of Postherpetic Neuralgia (PHN) by selecting the duration of a procedure that may include pre-procedure with a topical numbing cream [lidocaine (2.5%)/prilocaine (2.5%)] and a five minute application of an investigational capsaicin liquid (NGX-1998).  The study will also evaluate how safe, tolerable and effective different strengths of the investigational capsaicin liquid are as potential treatments for people with PHN. An investigational drug is one that has not received approval by the U.S. Food and Drug Administration (FDA) or Non-U.S. Regulatory Authorities. The investigational liquids contain a synthetic version of capsaicin which is the peppery substance found in chili peppers.  The experimental capsaicin liquid will be applied directly to the skin by study personal using a foam-tipped applicator.  

Subjects will be eligible to participate in the clinical trial if they meet the following Inclusion Criteria:

  1. Between 18 and 90 years of age
  2. Diagnosis of PHN made by the primary treating physician or Investigator, with at least six (6) months of pain since shingles vesicle crusting.
  3. Intact, unbroken skin over the painful area(s) to be treated.
  4. If taking chronic pain medications, be on a stable (not as needed) regimen for at least 21 days prior to Test Article Application Visit and willing to maintain medications at same stable dose(s) and schedule throughout the study.
  5. Must be willing to use effective methods of birth control and/or refrain from participating in a conception processd during the study (or in the event of early termination from the study for 30 days following experimental drug exposure).

Subjects will not be eligible to participate in the clinical trial if they meet any of the following Exclusion Criteria:

  1. Concomitant opioid medication, unless orally or transdermally administered and not exceeding a total daily dose of morphine 60 mg/day, or equivalent.
  2. Recent use (within 21 days preceding the Test Article Application Visit) of any topically applied pain medication(s)
  3. Receipt of Qutenza® within 12 months of the Test Article Application Visit. Subjects who have received Qutenza® 12 months or more before Test Article Application Visit, and who did not respond should also be excluded.
  4. Current use of any Class I or III anti-arrhythmic drugs (for abnormal heart rhythms)
  5. Diabetes mellitus, unless well-controlled as evidenced by an HbA1c level less than or equal to nine percent (9%).
  6. Painful PHN areas located on the face, above the hairline of the scalp, and/or in proximity to mucous membranes.
  7. Any implanted medical device (spinal cord stimulator, intrathecal pump or peripheral nerve stimulator) for the treatment of neuropathic pain.

For more information, please contact:

Katie Lam, Clinical Research Coordinator
Staff Research Associate III
University of California, San Diego Medical Center
Center for Pain Medicine
Tel.  858-657-6125 ext. 76125