Abstract | BACKGROUND:
Cancer pain is highly prevalent, and existing treatments are often insufficient to provide adequate relief. OBJECTIVES: METHODS: In this multicentre open-label longitudinal trial, 30 μg tetrodotoxin was administered subcutaneously twice daily for 4 days in a heterogeneous cohort of patients with persistent pain despite opioids and other analgesics. "Responder" was defined as a mean reduction of 30% or more in pain intensity from baseline; and "clinical responder" as some pain reduction, but less than 30%, plus agreement on the part of both the patient and the physician that a meaningful analgesic response to treatment had occurred. RESULTS: Of 45 patients who entered the longitudinal trial, 41 had sufficient data for analysis. Of all 45 patients, 21 (47%) met the criteria for "responder" [16 patients (36%)] or "clinical responder" [5 patients (11%)]. Onset of pain relief was typically cumulative over days, and after administration ended, the analgesic effect subsided over the course of a few weeks. No evidence of loss of analgesic effect was observed during subsequent treatments (2526 patient-days in total and a maximum of 400 days in 1 patient). One patient withdrew from the study because of adverse events. Toxicity was usually mild (82%) or moderate (13%), and remained so through subsequent treatment cycles, with no evidence of cumulative toxicity or tolerance. CONCLUSIONS: Long-term treatment with tetrodotoxin is associated with acceptable toxicity and, in a substantial minority of patients, resulted in a sustained analgesic effect. Further study of tetrodotoxin for moderate-to-severe cancer pain is warranted.
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Authors | N A Hagen, B Lapointe, M Ong-Lam, B Dubuc, D Walde, B Gagnon, R Love, R Goel, P Hawley, A Ho Ngoc, P du Souich |
Journal | Current oncology (Toronto, Ont.)
(Curr Oncol)
Vol. 18
Issue 3
Pg. e109-16
(Jun 2011)
ISSN: 1718-7729 [Electronic] Switzerland |
PMID | 21655148
(Publication Type: Journal Article)
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