Session Type: ACR Poster Session C
Session Time: 9:00AM-11:00AM
Fibromyalgia (FM) is a chronic, widespread pain disorder for which Lyrica is an approved treatment. Antidepressants, gabapentin, muscle relaxants, and opioids are frequently used to treat FM. The impact of prior use of these treatments on the response to pregabalin treatment in FM has not been assessed. Previous work showed that FM patients respond to treatment with pregabalin with significant improvements in pain scores irrespective of prior opioid use (Argoff et al. Clin J Pain. 2015).
A pooled analysis of 4 Phase 3 placebo-controlled clinical trials of pregabalin (300-600 mg/day) of 13-15 week duration in FM patients was conducted to assess the effect of prior treatment with antidepressants (including SSRIs, SNRIs, and TCAs), gabapentin, or muscle relaxants on the response to treatment with pregabalin. Patients were divided into those who had used one of these treatments prior to the trial and those who had not. Patients could have taken prior FM treatments in more than 1 category. Changes in least squares (LS) mean pain scores (assessed by NRS-Pain, a 0-10 numeric rating scale administered daily, controlled for baseline pain score) in the pregabalin and placebo groups were assessed. Last observation carried forward (LOCF) methodology was used to impute missing data.
There were 2668 patients in the analysis set, including 717 patients with prior antidepressant use, 380 with prior muscle relaxant use, and 113 with prior gabapentin use. Pregabalin improved the LS mean difference in pain score compared with placebo in patients both with and without prior use of these medications. Treatment differences (placebo adjusted) for subjects with prior use of these medications were as follows: gabapentin: -0.78 (95% confidence interval -1.56, 0.01), p=0.0522; antidepressants: -1.00 (CI -1.33, -0.67), p<.0001; and muscle relaxants: -0.96 (CI -1.46, -0.46), p=0.0002. Treatment differences (placebo adjusted) for subjects who did not previously use these medications were as follows: no prior gabapentin: -0.54 (CI -0.71, -0.37), p<.0001; no prior antidepressant: -0.40 (CI -0.59, -0.21), p<.0001; and no prior muscle relaxant: -0.49 (CI -0.67, -0.31), p<.0001. These results were statistically significant in each case apart from prior gabapentin (treatment difference -0.78, p=0.0522), likely due to the smaller size (N=113; pregabalin N=74, placebo N=39) of this cohort. Similar results compared with the overall antidepressant result were observed for SSRIs, SNRIs, and TCAs separately, based on summary statistics. In general, patients with prior FM treatment had slightly higher baseline pain scores.
FM patients responded to treatment with pregabalin with improvements in pain scores relative to placebo, irrespective of prior treatment with gabapentin, muscle relaxants, or antidepressants. These results were statistically significant apart from the smallest population studied (gabapentin, N=113), which had a similar magnitude of effect. Similar conclusions were reached in previous work regarding opioids (Argoff et al). These data could inform treatment decisions for FM patients currently taking these medications.
To cite this abstract in AMA style:Pauer L, Clair A, Bhadra Brown P, Ortiz M, Scavone J. The Impact of Prior Fibromyalgia Treatment on the Response to Pregabalin in Fibromyalgia Clinical Trials [abstract]. Arthritis Rheumatol. 2015; 67 (suppl 10). https://acrabstracts.org/abstract/the-impact-of-prior-fibromyalgia-treatment-on-the-response-to-pregabalin-in-fibromyalgia-clinical-trials/. Accessed September 21, 2019.
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ACR Meeting Abstracts - https://acrabstracts.org/abstract/the-impact-of-prior-fibromyalgia-treatment-on-the-response-to-pregabalin-in-fibromyalgia-clinical-trials/