A Multicenter, Randomized, Double-Blind, Placebo-Controlled, Phase IIb Clinical Study to Evaluate the Safety and Efficacy of DHP1401 in Patients with Mild to Moderate Alzheimer's Disease Treated with Donepezil: DHP1401 Randomized Trial in Mild to Moderate Alzheimer's Disease (DRAMA)

Background: Preclinical studies in transgenic models of Alzheimer's disease (AD) suggest that DHP1401 has neuroprotective and memory-enhancing effects. Objective: To evaluate the efficacy and safety of DHP1401 in AD patients treated with donepezil. Methods: In a double-blind study, patients with mild-to-moderate AD were randomized (1:1:1) to receive a twice daily total dose of 500 mg or 1000 mg DHP1401 or placebo for 24 weeks. Tolerability and safety were monitored at baseline and weeks 12 and 24. Results: A total of 180 patients were randomized to Active 1 (500 mg: n= 62), Active 2 (1000 mg: n=53), and control groups (n = 65) in 16 sites in Korea. There was no significant difference in the Alzheimer's Disease Assessment Scale (ADAS-cog) score, the primary efficacy endpoint, from baseline. However, in the subgroup with mild AD patients (MMSE, 20-26) who received the high dose of DHP1401 and the group that received donepezil 5 mg, the ADAS-cog scores improved. MMSE and K-TMT-e type B were significant in both active groups at week 24. The most frequently observed symptom was dizziness (2.78%), and the most commonly observed reactions were related to metabolism and nutrition disorders (5.00%). No remarkable adverse events were observed for 24 weeks. Conclusion: Although the effectiveness of DHP1401 was not proved to be superior as the primary efficacy endpoint, the secondary endpoints, MMSE and K-TMT-e type B, showed significant beneficial effects. Also, the subgroups showed that ADAS-cog scores significantly were improved. DHP1401 could be proven beneficial for the AD treatment by further clinical trials.