An open-label, long-term, phase III extension trial of duloxetine in Japanese patients with fibromyalgia

Abstract

Objectives: We aimed to evaluate the long-term safety and efficacy of duloxetine 60 mg in Japanese patients with fibromyalgia enrolled from a preceding randomized, placebo-controlled, phase III duloxetine trial.

Methods: This was a long-term, open-label extension study. Patients received oral duloxetine once daily at a dose of 20 mg for 1 week, followed by 40 mg for 1 week, and then 60 mg for 48 weeks. The primary outcome was the frequency of adverse events (AEs) and adverse drug reactions (ADRs) of duloxetine. Efficacy and health outcomes were assessed.

Results: In total, 149 patients were enrolled from the preceding study. The median length of treatment was 364.0 days. The incidence of AEs and ADRs was 92.6 and 63.8%, respectively. ADRs occurring at an incidence of ≥5% were somnolence, constipation, nausea, weight increase, thirst, and malaise. The proportion of patients with mild, moderate, and severe AEs was 80.5, 10.1, and 2.0%. There were no serious treatment-related AEs in this study. The Brief Pain Inventory average pain score improved at all time-points compared with baseline (mean change ± standard deviation at Week 50 was −1.31 ± 1.70).

Conclusions: Duloxetine was safe and effective in the long-term treatment of Japanese patients with fibromyalgia.

Keywords:

• Duloxetine
• Fibromyalgia
• Japan
• Long-term safety
• Open-label

Acknowledgments

We thank the following investigators for their cooperation in this research: Kazutoshi Seto (Shinsapporo Seiryou Hospital), Eishi Shirasawa (Shirasawa Orthopedic Clinic), Yukio Sato (Sendai Taihaku Hospital), Sadahiko Kameda (Kameda Clinic), Ryoichi Yamazaki (Yamazaki Orthopaedics Clinic), Kimihiro Suzuki (Suzuhiro Clinic), Hiroshi Oka (Tokyo Medical University Hachioji Medical Center), Masanari Omata (Oimachi Orthopaedic Clinic), Akiko Miyazawa (Miyazawa Clinic), Yasuyuki Watanabe (Shinkoiwa Watanabe Clinic), Satoe Shimoda (Ginza Internal Medicine Clinic), Kenya Nishioka (Kasumigaseki Urban Clinic), Hidehiko Honda (Honda Hidehiko Clinic), Mikichika Inoue (Ikebukuro Internal Medicine), Shohei Nagaoka (Yokohama Minami Kyousai Hospital), Kenichi Osada (St. Marianna University School of Medicine Hospital), Hyeteok Kim (Yokohama Minoru Clinic), Yuki Sekiguchi (Yokohama Motomachi Women’s Clinic LUNA), Shinichi Aoki (Aoki Orthopedic), Fusazo Urano (Shinonoi General Hospital), Akihito Mizutani (Mizutani Pain Clinic), Tomomasa Kimura (Kimura Clinic), Kojiro Kumagai (Pain Ikeshita Clinic), Mami Morimoto (Morimoto Clinic), Kenji Miki (Amagasaki Chuo Hospital), Shiro Nakayama (Nakayama Rheumatism and Allergy Clinic), Keizo Kobayashi (Kobayashi Orthopedics Clinic), Kanzo Amano (Hiroshima Clinic), Nobuo Takubo (Takubo Rheumatism and Orthopedics Clinic), Kenmei Sakata (Kumamoto Rheumatology Clinic), Toru Fujigaki (Fujigaki Clinic) and Motohiro Oribe (Oribe Rheumachika-Naika Clinic).

The authors would also like to thank Dr Keyra Martinez Dunn and Dr Michelle Belanger, of Edanz Group Ltd., for providing medical writing support, which was funded by Shionogi & Co. Ltd.

Conflict of interest

H.I., H.M., T.O. and M.I. are employees of Shionogi & Co. Ltd. L.A. is an employee of Eli Lilly Japan K.K. M.M., K.O. and K.N. have provided consultancy services, and M.M. and K.O. received compensation from Shionogi & Co. Ltd. for their participation in this study. M.M., K.O. and K.N. did not receive any compensation for their input into this article.

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.

This study was sponsored by Shionogi & Co. Ltd., Eli Lilly Japan K.K., and Eli Lilly and Company.

Supplementary material available online