"In this trial, both diacetylmorphine treatment and optimized methadone maintenance treatment resulted in high retention and response rates. Methadone, provided according to best-practice guidelines, should remain the treatment of choice for the majority of patients. However, there will continue to be a subgroup of patients who will not benefit even from optimized methadone maintenance. Prescribed, supervised use of diacetylmorphine appears to be a safe and effective adjunctive treatment for this severely affected population of patients who would otherwise remain outside the health care system."

Source

Oviedo-Joekes, E., Brissette, S., Marsh, D. C., Lauzon, P., Guh, D., Anis, A., & Schechter, M. T. (2009). Diacetylmorphine versus methadone for the treatment of opioid addiction. The New England journal of medicine, 361(8), 777–786. doi.org/10.1056/NEJMoa0810635