RESEARCH - Lidocaine patch may equal coxibs for knee OA pain relief

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Lidocaine patch may equal coxibs for knee OA pain relief

Apr 6, 2005

Rheumawire

Janis

Boston, MA - One of the studies cut off short when safety concerns arose

about COX-2 inhibitors was a head-to-head comparison of a 5% lidocaine patch

(Lidoderm, Endo Pharmaceuticals, Altoona, PA) against celecoxib (Celebrex,

Pfizer) for relief of knee osteoarthritis (OA) pain. Endo researchers, led

by senior medical officer Dr Bradley S Galer, salvaged something from the

study by analyzing data for 143 (of a planned 200) patients who were

enrolled when the company stopped the trial. They reported in March 2005 at

the American Pain Society annual meeting that these data strongly suggest

that the patch (currently approved in the US for treating postherpetic

neuralgia) was as effective as celecoxib for reducing daily pain intensity

in knee OA.

" Because the study was discontinued before full enrollment, we did not reach

our n size to meet the needed power calculations to perform a true

statistical noninferiority test. Thus, we presented the data descriptively.

Indeed, though, the actual raw data regarding changes in pain and

improvements in function are comparable, " Galer tells rheumawire.

A patch for the arthritic knee?

" The results of this exploratory study suggest that Lidoderm can alleviate

the pain associated with OA of the knee. I am encouraged by these findings,

since there is a critical need for new approaches to managing this type of

pain, " Dr Alan Kivitz (Altoona Center for Clinical Research, Duncansville,

PA) said at the meeting. " For me, the most important thing is to have

[treatment] options available. "

Kivitz said that the investigators were not seeking an alternative to coxibs

when they began the study but were just curious about whether the pain

relief seen with the lidocaine patch in postherpetic neuralgia would also

occur if the patch were applied over arthritic joints.

The main objective of this randomized, open-label, active-control, parallel

group study was to compare the efficacy of the patch with celecoxib 200 mg.

The protocol called for 200 patients with unilateral or bilateral OA of the

knee with an average daily pain intensity score >5 on a scale of 0 to 10 for

3 of 5 consecutive days and an OA severity score of >7 on a scale of 2 to

24.

Patients went through a 14-day washout during which all analgesic

medications, glucosamine, and chondroitin were discontinued and then were

randomized to treatment with the 5% lidocaine patch or with celecoxib 200

mg/day. Patients in the patch group applied 1 patch to the front and one

third of a patch to the back of each affected knee every 24 hours. The main

outcome measures were the Western Ontario and McMaster Universities (WOMAC)

OA Index, the Brief Pain Index, the Pain Quality Assessment Scale, and

global assessments of OA pain.

The protocol had been designed for 12 weeks of treatment but was stopped

after 6 weeks due to coxib safety concerns. Kivitz reported that after 6

weeks of treatment, 54% of patients in the lidocaine patch group (n=56) and

62% in the celecoxib group (n=63) had achieved at least a 30% reduction in

average daily pain intensity. This degree of pain reduction is generally

thought to be clinically meaningful and was sustained to week 12 in the

patients who continued for that period.

Lidocaine acts in postherpetic neuralgia by blocking abnormally functioning

sodium channels and decreasing ectopic nociceptive transmission. The

researchers assume that this might also be the mechanism behind the effect

in OA pain.

Both the patch and celecoxib were well tolerated, with adverse events

reported in 8 patients in each group. The most common adverse events were

itchiness or redness at the patch site. Three patients in the lidocaine

group discontinued the study due to adverse events. None of the celecoxib

patients discontinued due to adverse events.

Both Galer and Kivitz stress that these preliminary findings require

confirmation in randomized, placebo-controlled trials.

" We realize that many physicians and patients are in desperate need for new,

effective, and safe alternatives to treat OA pain, which has a drastic

negative effect on the quality of life of many patients, " Galer says. He

tells rheumawire that Endo is currently considering similar head-to-head

trials testing the lidocaine patch against other arthritis drugs.

Source

Galer B, Kivitz A, Fairfax E, et al. A randomized,

open-label study comparing the efficacy and safety of lidocaine patch 5%

with celecoxib 200mg in patients with pain from osteoarthritis of the knee.

24th Annual Scientific Meeting of the American Pain Society; March 30-April

2, 2005; Boston, MA; abstract 771.

Not an MD

I'll tell you where to go!

Mayo Clinic in Rochester

http://www.mayoclinic.org/rochester

s Hopkins Medicine

http://www.hopkinsmedicine.org