Clauw DJ, Mease PJ, Palmer, RH, et al., Continuing efficacy of milnacipran following long-term treatment in fibromyalgia: a randomized trial, Arthritis Research & Therapy (2013) 15:R88 doi:10.1186/ar4268 [Epub 16 August 2013]
Continuing milnaciprain (Savella) for years to maintain pain relief in fibromyalgia is definitely the right strategy, to judge from a randomized, placebo-controlled extension to an open-label multicenter trial of the drug. Among patients randomized to continue the drug, not only did pain relief persist for significantly longer among those not switched to placebo; many who continued on the drug never lost their pain response during the 12-week randomized extension.
The 12-week double-blind trial measured loss of treatment response (LTR) among patients (almost all white females, mean age 54) switching to placebo after using milnacipran during the prior long-term, open-label (OL) lead-in studies (mean exposure 3 years).
Among the OL group of 357 patients, those reporting a ≥50% improvement in visual analog scale (VAS) pain over a 4-week period after the prior studies were randomized 2:1 to continue on ≥100 mg a day of milnacipran (n=100) or to take a placebo (n=51).
At the end of the clinical trial, 64% of those on placebo experienced LTR, defined as a specified increase in VAS pain or a worsening of fibromyalgia to the point that it required alternative treatment. The median time to LTR in the placebo group was 56 days.
In contrast, LTR could not be calculated for the milnacipran patients because half of the group did not report any increase in pain by end of study.
Among patients continuing on milnacipran, 81% maintained a clinically meaningful pain response (≥30% improvement from previous exposure), compared to only 58% of those switched to placebo.
Adverse events (AE) with milnacipran included nausea, vomiting, increased heart rate, hypertension and non-cardiac chest pain. The most common AE among the placebo group was irritability (potentially consistent with withdrawal from serotonin–norepinephrine reuptake inhibitors).