A multicentre randomised study of intrasphincteric botulinum toxin in patients with oesophageal achalasia

Background-Intrasphincteric injection of botulinum toxin (Botx) has been pr oposed as treatment for oesophageal achalasia. However, the predictors of r esponse and optimal dose remain unclear. Aims-To compare the effect of different doses of Botx and to identify predi ctors of response. Patients/methods-A total of 118 achalasic patients were randomised to recei ve one of three doses of Botx in a single injection: 50 U (n=40), 100 U (n= 38), and 200 U (n=40). Of those who received 100 U, responsive patients wer e reinjected with an identical dose after 30 days. Clinical and manometric assessments were performed at baseline, 30 days after the initial injection of botulinum toxin, and at the end of follow up (mean 12 months; range 7-2 4 months). Results-Thirty days after the initial injection, 82% of patients were consi dered responders without a clear dose related effect. At the end of follow up however, relapse of symptoms was evident in 19% of patients who received two injections of 100 U compared with 47% and 43% in the 50 U and 200 U gr oups, respectively. Using Kaplan-Meier analysis, patients in the 100x2 U gr oup were more likely to remain in remission at any time (p<0.04), with 68% (95% CI 59-83) still in remission at 24 months. In a multiple adjusted mode l, response to Botx was independently predicted by the occurrence of vigoro us achalasia (odds ratio 3.3) and the 100x2 U regimen (odds ratio 3.2). Conclusions-Two injections of 100 U of Botx 30 days apart appeared to be th e most effective therapeutic schedule. The presence of vigorous achalasia w as the principal determinant of the response to Botx.