An estimated 20 to 35% of chronic low back pain (cLBP) cases involve a neuropathic component (NC), and these patients have been found to have greater pain intensity and disability and worse quality of life (QoL) compared with patients with nociceptive pain.1,2 A non-interventional cohort study published in the Journal of Pain Research aimed to compare the benefit–risk profile (BRP) of oxycodone/naloxone (OXN) and tapentadol (TAP) for such patients in daily clinical practice.3
For patients who experience intolerable side effects or inadequate treatment response to first-line therapies, according to the World Health Organization’s (WHO) Step III, opioid analgesics are recommended as second- or third-line treatments. The current study evaluated the BRPs of 2 such agents, OXN and TAP, which were approved for use in the US in 2014 and 2011, respectively. Though results of a recent randomized open-label trial suggest that TAP may have superior efficacy to OXN, high attrition rates and gaps in data hamper the generalizability of the findings.4
In the present investigation, researchers used the German Pain Registry to analyze data of 261 randomly selected adult patients with moderate-to-severe nonmalignant cLBP-NC receiving TAP or OXN after non-response or adverse events due to WHO Step I or II treatments. The data covered results of various patient questionnaires assessing pain intensity and related disability, as well as other parameters such as QoL, adverse events , and bowel function. Various comorbidities were cause for exclusion from the study, including pulmonary hypertension, renal impairment, and irritable bowel syndrome.
The authors defined the primary endpoint as a “composite of 3 efficacy components (≥30% improvement of pain, pain-related disability, and quality of life, each at the end of observation vs baseline) and 3 tolerability components (normal bowel function, absence of either central nervous system side effects, and treatment-emergent adverse event [TEAE]-related treatment discontinuation during the observation period) adopted to reflect BRP assessments under real-life conditions.”
The findings show a noninferior BRP for OXN compared to TAP, and a higher primary endpoint response due to superior analgesic effects (39.8% vs 25.6%, odds ratio: 1.93; P =.014). Additionally, differences between OXN and TAP increased in favor of OXN when stricter response definitions were used for 1 or all 3 efficacy components as follows:
Response rates of ≥30%/≥50%/≥70% for OXN vs TAP were observed for:
- pain intensity in 85.2%/67.2%/39.1% vs 83.5%/54.1%/15.8% of patients (P =ns/0.031/<0.001)
- pain-related disability in 78.1%/64.8%/43.8% vs 66.9%/50.4%/24.8% of patients (P =0.043/0.018/0.001)
- quality of life in 76.6%/68.0%/50.0% vs 63.9%/54.1%/34.6% of patients (P =0.026/0.022/0.017)
Both treatments were well-tolerated, and similar proportions of patients in both groups maintained normal bowel function (68.0% vs 72.2%), reported no side effects related to the central nervous system (91.4% vs 89.5%), and completed the 12-week study period without discontinuing treatment due to treatment-emergent adverse events (93.0% vs 92.5%) (P =ns for each comparison).
Summary and Clinical Applicability
In a study designed to reflect outcomes of patients with cLBP-NP in routine clinical practice, the benefit-risk profile of OXN was found to be noninferior compared to TAP, and OXN demonstrated superior analgesic efficacy when stricter response definitions were applied.
Limitations and Disclosures
Limitations: One limitation is presented by the fact that patient selection and treatment choice were at the discretion of the treating physician, and the lack of a placebo group presents an additional limitation.
Disclosures: Both authors report reimbursements from various pharmaceutical companies.
- Freynhagen R, Baron R. The evaluation of neuropathic components in low back pain. Curr Pain Headache Rep. 2009; 13:185–190.
- Smart KM, Blake C, Staines A, Doody C. Self-reported pain severity, quality of life, disability, anxiety and depression in patients classified with ‘nociceptive’, ‘peripheral neuropathic’ and ‘central sensitisation’ pain. The discriminant validity of mechanisms-based classifications of low back (±leg) pain. Man Ther. 2012; 17:119–125.
- Ueberall MA, Mueller-Schwefe. Efficacy and tolerability balance of oxycodone/naloxone and tapentadol in chronic low back pain with a neuropathic component: a blinded end point analysis of randomly selected routine data from 12-week prospective open-label observations. J Pain Res. 2016; 9: 1001–1020.
- Baron R, Likar R, Martin-Mola E, et al. Effectiveness of tapentadol prolonged release (PR) compared with oxycodon/naloxone PR for the management of severe chronic low back pain with a neuropathic component: a randomized, controlled, open-label, phase 3b/4 study. Pain Pract. 2016; 16(5):580–599.10.1111/papr.12308.