Tetrodotoxin Open-label Efficacy and Safety Continuation Study

Inclusion Criteria: All patients who participated in the TEC-006 study (tetrodotoxin and placebo-treated) willbe eligible for inclusion in this study provided they wish to continue to receive treatmentand meet the inclusion and exclusion criteria. NOTE: The blinded treatment assignment of patients in the TEC-006 will not be revealed toeither the investigator or the patient. Patients will not be aware which treatment theyreceived in the TEC-006 study. All patients will receive tetrodotoxin treatment in theTEC-006OL study. A patient will be eligible or continue to be eligible for inclusion in this study (FirstTreatment Cycle and subsequent Treatment Cycles) only if all of the following criteriaapply:

1. Male or female 18 years of age and over

2. In-patients or out-patients with a diagnosis of cancer

3. Patients must be experiencing somatic, visceral and/or neuropathic pain related tocancer.

4. Compliant to the requirements of the TEC-006 Protocol.

5. Inadequately controlled pain: Pain intensity described as 'moderate', 'severe' or 'excruciating', as assessed by the VRS during the screening/baseline period of theFirst Treatment Cycle, and a baseline pain intensity score of ≥4 as assessed by NRS (worst, average, or component-specific pain).

6. Meet the Responder or Clinical Responder definition for repeat cycle treatment (cycle

#2 to cycle #4)

7. Life expectancy of > 3 months.

8. Ability to communicate well with the Investigator and to comply with the requirementsof the entire study.

9. Willingness to give written informed consent (prior to any study-related proceduresbeing performed) and to be able to adhere to the study restrictions, appointments andexamination schedule.

Exclusion Criteria: A patient will not be eligible for inclusion in this study if any of the following criteriaapply:

1. Planned initiation of chemotherapy, radiotherapy or bisphosphonates within 30 daysprior to enrolment.

2. Known renal disease.

3. If it has been more than 14 days since their TEC_006 End of Study Visit or their painreturned to baseline since their last tetrodotoxin treatment cycle (for repeat cycle).

4. Patient has previously completed 4 cycles of tetrodotoxin

5. If it has been more than 6 months since patient signed consent to participate in theTEC-006 OL study.

6. Use of anaesthetics.

7. Use of lidocaine, and other types of antiarrhythmic drugs.

8. Use of scopolamine and acetylcholinesterase-inhibiting drugs such as physostigmine.

9. History of CO2 retention, or SaO2 <80% either on room air or O2 of not greater than 2-4 L/min by nasal cannula.

10. Second or third degree heart block or prolonged QTc interval (corrected for rate) onscreening ECG (confirmed > 450 msec on repeated occasion) or any other active cardiacarrhythmia or abnormality that would constitute a clinical risk.

11. Coagulation or bleeding defects if in the opinion of the Investigator this representsa risk to the subject considering the subcutaneous (s.c.) route of administration.

12. Known hypersensitivity to puffer fish, tetrodotoxin and/or its derivatives.

13. Received an investigational agent other than tetrodotoxin within 30 days prior toscreening or who is scheduled to receive an investigational drug other thantetrodotoxin during the course of the study.

14. Females who are lactating or at risk of pregnancy (i.e., sexually active with fertilemales and not using an adequate form of birth control).

15. Females with a positive pregnancy test at screening or on admission to study site.

16. Any other condition that, in the opinion of the investigators, is likely to interferewith the successful collection of the measures required for the study or poses a riskto the patient.