Maximizing retention in long‐term clinical trials of a weight loss agent: use of a dietitian support team

OBJECTIVE: High‐attrition rates have been observed in long‐term clinical trials of weight loss agents. We evaluated the impact of an innovative retention programme on 1‐year retention. METHODS: Three Phase 3 global multicentre clinical trials evaluated the efficacy and safety of a CB1 receptor antagonist in subjects with BMI ≥ or = 27 kg/m(2). The impact of a multifaceted retention programme including a dietitian screening interview, a comprehensive culturally adapted lifestyle modification programme, and a dietitian support system to maximize lifestyle adherence, was evaluated in 4,410 subjects from four subpopulations (non‐US English‐speaking, non‐English‐speaking, US‐without dietitian screening and US‐with dietitian screening) comprising 208 centres from 15 countries. RESULTS: The median proportion retained over the first year among subjects in three protocols was 82%. Non‐English‐speaking countries showed higher retention rates (89%) compared with the USA (73%) and non‐US English‐speaking (81%) countries. Within the USA, behavioural screening was associated with 29% reduction in dropout rate; for every five monthly teleconferences attended above 11, there was a 32% decrease in dropout rate. CONCLUSIONS: This novel retention programme greatly improved upon reported retention rates of studies conducted with other weight loss agents in long‐term clinical trials. Its effectiveness should be confirmed in future trials.