ORLANDO, Florida—Extended release (ER) drugs that help patients cope with chronic back pain or osteoarthritis (OA) pain attracted considerable attention at this year's American Academy of Pain Medicine meeting. An ER formulation of tapentadol (Johnson & Johnson), a centrally-acting analgesic with a unique dual mode of action as an agonist at the μ-opioid receptor and as a norepinephrine reuptake inhibitor, was as effective as oxycodone for relieving moderate-to-severe knee OA pain.¹

Hydrocodone/acetaminophen controlled release (HC/APAP CR, Vicoden CR®, Abbott Laboratories) worked significantly better among patients with chronic OA or low back pain (LBP), saving about $8,000 per year per patient to otherwise lost productivity.² And oxymorphone ER might be a useful alternative for back pain patients who need to avoid the dosing due to acetaminophen in HC/APAP combinations.³

Tapentadol ER 200 mg effective in knee OA pain

Christine Rauschkolb-Loeffler, MD, of Johnson & Johnson pharmaceutical research and development in Titusville, New Jersey, led the randomized, placebo- and active-comparator controlled trial of tapentadol ER in 670 patients with moderate-to-severe chronic pain from knee OA. Patients in the Johnson & Johnson-funded study were randomly assigned to 28 days of tapentadol ER 100 mg or 200 mg, oxycodone CR 20 mg, or placebo twice daily. The primary endpoint was average pain intensity over the preceding 24 hours, based on a 100 mm visual analogue scale (VAS). Subjects also assessed pain relief as excellent, very good, good, fair, or poor.

Tapentadol ER 200 mg was significantly more effective than placebo (P = .021), unlike lower dose tapentadol. Interestingly, oxycodone CR was no better than placebo (P = .091) and caused more side effects. "Tapentadol patients experienced less gastrointestinal and central nervous system disorders compared with patients receiving oxycodone," Dr. Rauschkolb-Loeffler said.

As might be expected, considerably more patients rated pain relief with tapentadol ER 200 mg "very good" or "excellent" compared with placebo (48.8% vs 29.2%). The potency of tapentadol, also known as CG5503, is thought to be between morphine and tramadol. A new drug approval (NDA) application for tapentadol was filed with the US Food and Drug Administration on January 23, 2008.

12-hour HC/APAP CR might shave $8,000/year off lost productivity

Dave Webster, DO, and colleagues estimated that 12-hour HC/APAP CR might have dramatic effects on workplace productivity for workers with chronic pain conditions such as OA or mechanical chronic LBP.² Using subjects from a larger 56-week open-label trial, Dr. Webster, of team research of central Texas in Killeen, analyzed lost productivity time to calculate the potential economic effects to employers of treatment with HC/APAP CR in workers.

Patients completed the Work Productivity and Activity Impairment (WPAI) instrument at baseline and at weeks 24 and 56 to measure reduced productivity and overall work impairment due to health. Using the 2006 US average weekly wage of $861, the investigators calculated that impairment while at work decreased from baseline by 17.4% at week 24 and by 16.6% at week 56, and that this translated into a cost-savings to employers of $3527 per employee at week 24, and $8019 at week 56.

Overall work impairment decreased from baseline by 17.5% at week 24 and 15.8% at week 56, for an average potential savings to employers of $3614 at week 24 and $7596 at week 56. "As assessed by WPAI instrument, this subanalysis demonstrated 12-hour, HC/APAP CR improved work productivity after 24 and 56 weeks of treatment in patients with OA and [chronic] LBP," Dr. Webster said. The study was funded by Abbott Laboratories, Inc.

Oxymorphone ER in chronic LBP

Dose-limiting, acetaminophen-induced liver enzyme elevations can limit dosing of acetaminophen-containing combinations, however. Martin E. Hale, MD, reported a subgroup analysis of a randomized, double-blind, placebo-control trial that showed that oxymorphone ER might be a better choice for some patients with chronic LBP.³

In work supported by Endo Pharmaceuticals, Dr. Hale, of Gold Coast Clinical Research in Weston, Florida, analyzed a subset of patients with suboptimal responses to hydrocodone-containing combination therapy who were in a clinical trial testing oxymorphone ER (Opana® ER). All had moderate to severe chronic LBP at baseline. Patients were titrated to a stabilized oxymorphone ER dose (every 12 hours) that reduced pain to <e;40 mm on 100-mm VAS, such that they needed no more than 2 doses/day of rescue medication. They were then randomized to double-blind placebo or oxymorphone ER for 12 weeks.

"The majority of hydrocodone-experienced patients with poorly controlled pain obtained an effective and generally well-tolerated oxymorphone ER dose. Switching from an opioid combination product to the single-agent opioid oxymorphone ER gives patients the ability to achieve adequate pain relief without the dosing limitations imposed by the nonopioid component of a combination product," Dr. Hale said.

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