Lofexidine increased completion of withdrawal treatment compared to placebo. Patients in the first study had a 5-day completion rate of 53%, compared to 35% for the placebo group. Researchers observed similar results in the 7-day completion rates the second study, with low and high dose completion rates of 42% and 40%, respectively, both of which were much higher than placebo (28%).
Lofexidine also reduced patient withdrawal symptoms, according to SOWS-Gossop scores during peak withdrawal. In the first study, SOWS-Gossop scores were 2-4 points lower in the lofexidine group compared to placebo. Similarly, the scores were significantly better in both lofexidine groups in the second study, compared to placebo, particularly on days 1 to 4. Decreasing withdrawal symptoms during this period is particularly important because this is the most vulnerable window for patient dropout, briefing documents from US WorldMeds.
Several notable adverse events occurred during the study, particularly at higher doses of lofexidine. The risk of bradycardia and hypotension are prominent in patients taking lofexidine, but these are risks associated with this class of drug, according to Mark Pirner, MD, senior medical director at US WorldMeds, who noted that “the lower dose, if that’s what ultimately gets approved [by the FDA], is safe and effective too.”
Development of lofexidine was conducted in collaboration with the National Institute on Drug Abuse and the FDA, according to briefing documents from US WorldMeds.