Tolerability and efficacy of memantine add-on therapy to rivastigmine transdermal patches in mild to moderate Alzheimer's disease: a multicenter, randomized, open-label, parallel-group study

Abstract

Objective:

To compare the tolerability and efficacy of combination therapy of memantine plus rivastigmine patch with rivastigmine patch monotherapy in patients with mild to moderate Alzheimer's disease (AD).

Research design and methods:

In this multicenter, randomized, open-label study, patients entered an 8-week run-in period (a 5 cm rivastigmine patch for 4 weeks, then a 10 cm² patch for 4 weeks) followed by 16 weeks of memantine plus rivastigmine patch or rivastigmine patch monotherapy. The primary outcome measure was the retention rate at the end of the trial.

Clinical trial registration:

clinicaltrials.gov. NCT01025466.

Results:

Overall, 88 and 84 patients received rivastigmine patch with and without memantine, respectively, and of these, 77 (87.5%) and 70 (83.3%) patients completed the study. The difference in retention rate was not significant (95% confidence interval: −6.3–14.7%). The incidence of adverse events (AEs) (53.4 vs. 50.6%) and discontinuation due to AEs (6.8 vs. 4.8%) were not different between patients with and without memantine. The most frequent AEs were skin irritation in patients with and without memantine (42.0 vs. 34.9%, p = 0.71), but discontinuation due to skin irritation was rare (4.5 vs. 2.4%, p = 0.74). The incidence of gastrointestinal AEs was very low in patients with and without memantine (nausea, 2.3 vs. 1.2%; vomiting, 1.1 vs. 1.2%). The Korean Version of the Cohen Mansfield Agitation Inventory scores favored rivastigmine patch monotherapy at the end of treatment (p = 0.01). Changes in other efficacy measures were similar between the groups.

Conclusion:

There were no significant differences in tolerability and safety between the treatment groups. The combination therapy of memantine plus rivastigmine patch did not show an advantage over rivastigmine patch monotherapy on efficacy analyses. The sample size for comparing tolerability may have been too small to detect a difference of efficacy between the two groups.

Key words::

• Alzheimer's disease
• Combination
• Memantine
• Rivastigmine
• Transdermal patch

Transparency

Declaration of funding

This study was supported by Novartis and Korea Healthcare technology R&D Project, Ministry for Health & Welfare (A050079). The financial sponsors played no role in the design, execution, analysis and interpretation of data, or writing of the study.

Declaration of financial/other relationships

S.H.C. has disclosed that she has received research funding from Novartis. D.L.N. has disclosed that he has received research funding from Korea Healthcare technology R&D Project, Ministry for Health & Welfare (A050079). All authors did not have any conflicts of interest associated with this study and did not have any declaration of financial or other relationships. All authors contributed to design of the analysis, interpretation of the data, and collecting the data. S.H.C. and K.W.P. contributed to execution of the statistical analysis, writing of the article, and final approval of the manuscript.

Acknowledgments

The authors would like to acknowledge the commitment and hard work of additional members of the EXelon Patch and combination with mEmantine Comparative Trial (EXPECT) Study Group: Byeong-Chae Kim, Chonnam National University School of Medicine, Gwangju; Hae Ri Na, Bobath Memorial Hospital, Seongnam; Jun-Young Lee, Seoul National University Boramae Hospital, Seoul; So Young Moon, Ajou University School of Medicine, Suwon; Jay C. Kwon, Changwon Fatima Hospital, Changwon; Seung-Ho Ryu, Konkuk University School of Medicine, Konkuk University Medical Center, Seoul; Jung Eun Kim, Ewha Womans University School of Medicine, Seoul; Bon D. Ku, College of Medicine, Kwandong University Myongji Hospital, Goyang; Shin Gyeom Kim, Soonchunhyang University of Bucheon Hospital, Bucheon; Kee Hyung Park, Gachon University Gil Hospital, Incheon; Key-Chung Park, Kyung Hee University School of Medicine, Seoul; Soo Jin Yoon, Eulji University College of Medicine, Daejeon; Jong-Moo Park, Eulji General Hospital, Eulji University School of Medicine, Seoul; Jae-Hyeok Heo, Seoul Medical Center, Seoul; Mun Seong Choi, Maryknoll Hospital, Pusan; Hyon-Ah Yi, Keimyung University College of Medicine, Daegu; Hyun Young Park, Wonkang University College of Medicine, Iksan; Joon-Hyun Shin and Soo Jin Cho, Hallym University College of Medicine, Chuncheon; Kwang K. Kim, Dongguk University College of Medicine, Goyang, South Korea.

The authors also wish to acknowledge the statistical support provided by Prof. Young Ju Suh and Dae Hyung Lee, Inha University Hospital, Incheon, South Korea.

Some of the results in this article were previously presented as an abstract and a poster at the 11th International Geneva/Springfield Alzheimer Symposium, March 24–27, 2010, Geneva, Swiss (Poster No. 14A).