Presentation: One-Year Durability of Response to Milnacipran Treatment for Fibromyalgia (2007)

1526 One-Year Durability of Response to Milnacipran Treatment for Fibromyalgia

Purpose: This was a Phase III, multicenter, randomized, blinded extension study to assess the long-term safety and efficacy of milnacipran for the treatment of fibromyalgia. Patients who successfully completed 6 months of treatment in the lead-in pivotal efficacy study of milnacipran were eligible for enrollment. The objectives were to evaluate durability of response in patients who achieved therapeutic improvement during the first study, assess efficacy in patients crossing over from placebo to active treatment during the transition from the lead-in study, and collect additional information on the safety and efficacy of long-term exposure to milnacipran.

Methods: A total of 449 patients enrolled. Patients were either maintained at 200 mg daily (n=209) or re-randomized (from placebo or 100 mg daily) at a 1:4 ratio to either 100 mg (n=48) or 200 mg (n=192) daily for an additional 6 months of treatment. Efficacy assessments included change from original baseline on 24-hour and weekly recall of pain measured on a 10 cm VAS scale, change in Fibromyalgia Impact Questionnaire (FIQ) total score, and Patient Global Impression of Change (PGIC).

Results: The continuing 12-month treatment cohort demonstrated persistent drug efficacy over the entire period (Table 1). Patients initially assigned to placebo and re-randomized to milnacipran 200 mg daily experienced a 47% mean pain total improvement on drug (pain scores 53.9 to 39.4). Similar significant improvements in patients newly exposed to drug, and durability of response in those continuing milnacipran, were also reflected in the PGIC and the FIQ.
Table 1 Pain Scores by Visit (Continuing Patients)
Table 1 Pain Scores by Visit (Continuing Patients)
Study Visit
Pain Score
*Study Baseline
A total of 67% of patients completed this extension study. Primary reasons for discontinuation were AEs common to this drug class, therapeutic failure, and withdrawal of consent. Milnacipran treatment was generally well-tolerated. The most commonly reported treatment-emergent AE (TEAE) was nausea, occurring in 22.9% of patients treated with 100 mg, and 23.9% of patients treated with 200 mg. Other TEAEs reported in >5% of patients were sinusitis, headache, hypertension, constipation, hyperhidrosis and dizziness.

Conclusions: These data provide further support that milnacipran is safe and effective in fibromyalgia patients, that multidimensional symptom improvement can be achieved in this condition, and that durable efficacy was maintained in patients who continued treatment for one year. To our knowledge, this is the first demonstration of one year sustained efficacy in drug trials for this common, chronic disorder.

  D. Goldenberg, Wyeth Pharmaceuticals, 2; Forest Laboratories, Inc., 2; Forest Laboratories, Inc., 5; Eli Lilly and Company, 5; Merck and Company, Inc., 5; D.J. Clauw, Cypress Bioscience, Inc., 1; Cypress Bioscience, Inc., 5; Pfizer Inc, 5; Wyeth Pharmaceuticals, 5; Eli Lilly and Company, 5; R.H. Palmer, Forest Laboratories, Inc., 1; Forest Research Institute, 3; P. Mease, Cypress Bioscience, Inc., 2; Forest Laboratories, Inc., 2; Cypress Bioscience, Inc., 5; Forest Laboratories, Inc., 5; R. Gendreau, Cypress Bioscience, Inc., 3.