Comparing Oxycodone/Naloxone to Tapentadol for Chronic Low Back Pain

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. 

 

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References

1. Freynhagen R, Baron R. The evaluation of neuropathic components in low back pain. Curr Pain Headache Rep. 2009; 13:185–190.
2. 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.
3. 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.
4. 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.