Abstracts

Rationale: In Europe and the United States, a natural adrenocorticotropic hormone (ACTH) is available for a treatment of West syndrome (WS). In Japan, however, a natural ACTH was eliminated from the market in 1970 and a synthetic ACTH was replaced. Since the synthetic ACTH was reported to have more adverse effects than the natural ACTH, the dosage for the synthetic ACTH was usually lower than that of the natural ACTH. Recent studies showed a short-term effectiveness of lower dosages of the synthetic ACTH in reducing adverse effects. However long-term effects of the low-dose synthetic ACTH has not been precisely studied. The purpose of this study is to examine a long-term effect of the low-dose ACTH therapy for patients with WS who were treated at a single institution.Methods: Medical record of 118 patients diagnosed as having WS at Tohoku University between 1978 and 2004, were analyzed. Patients who achieved cessation of spasm before the ACTH therapy and second trial of the ACTH therapy were excluded. Remain 55 patients received 4 weeks regimen of synthetic ACTH. Initial and long term outcome were measured by complete cessation of seizures and disappearance of hypsarrhythmia on EEG. Results: Immediately after the ACTH therapy, 49 (89%) patients showed cessation of seizure. There was no severe adverse effect related to ACTH therapy. The onset age (<4 months old vs. ≥ 4 months old), the treatment lag (< 3 months vs. ≥ 3 months), the dosage of ACTH (0.02mg/kg vs. 0.015mg/kg), the etiology (cryptogenic vs. symptomatic) and the length of days needed to achieve the successful short-term outcome had no significant effects on the long-term outcome. The overall probability of the long-term effect was approximately 0.38 after 2000 days (5.5 years). Among patients who achieved the successful short-term outcome, about 45% of them remained seizure free for more than 5.5 years. Conclusions: Low dose synthetic ACTH therapy benefited for seizure control as natural ACTH therapy for the initial outcome. This study indicated that 38% of patients had not experienced any seizure for at least 5.5 years after low dose synthetic ACTH therapy. Onset age, treatment lag, dosage of the ACTH, etiology and the length of days needed to achieve the successful short-term outcome had no significant effect on long-term outcome.