Interim analysis completed and decided to terminate and proceed to Phase 3 trial.

Chemotherapy-induced peripheral neuropathy (CIPN) is a major dose-limiting side effect of many chemotherapeutic agents including vincristine, paclitaxel, cisplatin, oxaliplatin, bortezomib and ixabepilone. Chemotherapy-induced peripheral neuropathy commonly occurs in greater than 40% of patients. To improve the peripheral neuropathy, the chemotherapy dosing is often either decreased or discontinued potentially affecting tumor responsiveness, prognosis, and survival.

There is an unmet medical need for treatment of cancer patients with chemotherapy induced neuropathic pain (CINP) and the proposed study will investigate the efficacy and safety of multiple dose levels of tetrodotoxin (TTX) versus placebo in moderate to severe neuropathic pain caused by chemotherapy.

Inclusion Criteria:

• If female, not of childbearing potential.
• Patients with documented neuropathic pain
• Cancer Patients who have completed a chemotherapy regimen which included taxanes or platinums (or both) and have no evidence actively progressive disease. Concurrent hormonal therapies are allowed
• Patients with stable moderate to severe neuropathic pain
• Patients with an Eastern Cooperative Oncology Group (ECOG) Performance Status score of 0 or 1.
• Patients who are able to complete the study-related questionnaires independently in either English or Spanish.

Exclusion Criteria:

• History of peripheral neuropathy attributed to any cause other than chemotherapy.
• Patients receiving any concurrent agents known to cause peripheral neuropathy within 30 days of Randomization.
• Current use of other therapy (ies), including "alternative" therapies, for treatment of peripheral neuropathy within 30 days of Randomization (with the exception of protocol allowed concurrent medications).
• Patients who used controlled release opioids within seven days of baseline period or who expect to use controlled release opioids at any time from baseline to end of study.
• Patients with abnormal kidney function.
• Patients with bone metastases.
• Patients scheduled for treatment for their cancer with chemotherapy or radiotherapy between screening and the end of study visit.
• Current use of lidocaine and other types of antiarrhythmic drugs within 30 days of Randomization.
• Current use of scopolamine and acetylcholinesterase-inhibiting drugs such as physostigmine within 30 days of Randomization.
• Current cause of Chemotherapy Induced Neuropathic Pain attributed to Velcade (Bortezomib) or vinca alkaloids or analogues such as vincristine, vinblasine, vinorelbine and vindesine.
• Current use of tricyclic antidepressant medication, anticonvulsants and monoamine oxidase inhibitors.
• Patients with current uncontrolled asthma or lung disease.
• Patients with significant heart disease.
• Use of an investigational agent within 30 days prior to screening or is scheduled to receive an investigational drug other than TTX during the course of the study.
• Females who are pregnant or nursing