A Multicentre , Randomized, Double-blind, Placebo-controlled, Parallel-design Trial of the Efficacy and Safety of Subcutaneous Tetrodotoxin (TTX) for Moderate to Severe Inadequately Controlled Cancer-related Pain

Different pathophysiologic mechanisms are responsible for the development of chronic pain disorders. Pain pathways are triggered in part by ectopic discharges of voltage-sensitive sodium channels, which are in abundance in both the peripheral and the central nervous systems. Tetrodotoxin (TTX) is a selective blocker of Na+ channels and causes analgesia either by decreasing the propagation of action potentials by Na+ channels and/or by blocking of ectopic discharges associated with chronic pain. TTX is extracted from the puffer fish (fugu). Results from animal pharmacology studies revealed that TTX is a more potent analgesic than standard analgesic agents such as aspirin, morphine or meperidine.

At present, the management of severe cancer pain generally includes the use of opiates. This can often result in undesirable side effects, and treatment with this type of medication is not always effective. Because currently available pain-relieving therapy is unsatisfactory for many patients, there is a need for new therapeutic approaches for the management of moderate or severe cancer pain.

Recent studies indicate that intramuscular (into a muscle) or subcutaneous (under the skin) injections of tetrodotoxin (TTX) may reduce pain in cancer patients who did not respond to standard therapies.

The current proposed study (TEC-006) is designed to 1) demonstrate in a double-blind, placebo-controlled trial that the subcutaneous 30 μg b.i.d. dose of TTX for 4 days is effective in reducing pain outcome and improving quality of life; 2) characterize the onset and duration of analgesia, and 3) demonstrate that TTX is well tolerated in patients with inadequately controlled cancer-related pain.