"Over the past 15 years, six RCTs [Randomized Controlled Trials] have been conducted involving more than 1,500 patients, and they provide strong evidence, both individually and collectively, in support of the efficacy of treatment with fully supervised self-administered injectable heroin, when compared with oral MMT, for long-term refractory heroin-dependent individuals. These have been conducted in six countries: Switzerland (Perneger et al., 1998); the Netherlands (van den Brink et al., 2003); Spain (March et al., 2006); Germany (Haasen et al., 2007), Canada (Oviedo-Joekes et al., 2009) and England (Strang et al., 2010).
"Across the trials, major reductions in the continued use of ‘street’ heroin occurred in those receiving SIH [Supervised Injectable Heroin] compared with control groups (most often receiving active MMT). These reductions occasionally included complete cessation of ‘street’ heroin use, although more frequently there was continued but reduced irregular use of ‘street’ heroin, at least through the trial period (ranging from 6 to 12 months). Reductions also occurred, but to a lesser extent, with the use of a range of other drugs, such as cocaine and alcohol. However, the difference between reductions in the SIH group and the various control groups was not as great (compared with major reductions in the use of ‘street’ heroin)."
European Monitoring Centre for Drugs and Drug Addiction, "EMCDDA INSIGHTS No. 11: New heroin-assisted treatment: Recent evidence and current practices of supervised injectable heroin treatment in Europe and beyond" (Luxembourg: Publications Office of the European Union, April 2012), doi: 10.2810/50141, p. 11.