RESEARCH - Anti-TNF may be effective for rheumatoid cachexia (muscle wasting/loss of cell mass)

[Guest guest]

Anti-TNF May Be Effective for Rheumatoid Cachexia

Rizzo

NEW YORK (Reuters Health) Jan 03 - Although a clinical response was

observed, anti-tumor necrosis factor (TNF) therapy with etanercept did not

appear to be superior to methotrexate for the treatment of rheumatoid

cachexia, according to findings published in the December issue of the

American Journal of Clinical Nutrition. However, in a subgroup of rheumatoid

arthritis (RA) patients, etanercept normalizes an anabolic response to

overfeeding.

Blockade of tumor necrosis factor has been shown to prevent catabolism in

animal models. Little evidence exists showing that anti-TNF therapy

effectively treats cachexia in humans.

In the current study, Dr. e M. Marcora, of the University of Wales,

Bangor, and colleagues examined the effect of etanercept, a synthetic

soluble TNF receptor, on body composition in patients with early RA. They

compared etanercept with methotrexate, the most common anti-rheumatic drug.

Twenty-six patients were randomized to 24 weeks of etanercept or

methotrexate. The team measured body composition, physical function, disease

activity, systemic inflammation, and the circulating insulin-like growth

factor (IGF) system at baseline and at 12 and 24 weeks. Twelve patients in

each treatment group completed the study.

No significant changes in body composition were observed, according to the

investigators. There was a transient increase in IGF-I at week 12 (p <

0.01), which returned to baseline values by week 24.

The secondary analysis of the six patients in each treatment group who

gained weight during follow-up demonstrated a significant effect of

etanercept on the composition of the weight gained. In the etanercept group,

44% of weight gained was fat-free mass, compared with 14% in the

methotrexate group (p = 0.04). Both treatments were equally effective in

controlling the disease and improving physical function.

" Anti-TNF therapy seems to have a specific effect on skeletal muscles only

in those RA patients who are on positive energy balance, not on the overall

RA population, " Dr. Marcora said in an interview with Reuters Health. " The

results of our subgroup analysis of RA patients on positive energy balance

suggest the possibility of using anti-TNF therapy in conjunction with

hypercaloric feeding when the aim is to increase body weight in catabolic

patients, " he said. However, muscle wasting in RA is " usually accompanied by

a concomitant increase in body fat, the so-called 'cachetic obesity.' "

The author noted that the problem of cachexia is seriously overlooked in

rheumatology. " What is clear from this and other studies is that RA patients

have significant muscle atrophy, " Dr. Marcora said. " Although effective

anti-rheumatic treatment reduces further muscle wasting, it is necessary to

include an adjunct anabolic treatment such as intense resistance training to

recover the muscle tissue lost even before starting medical therapy, " he

added. " Anti-rheumatic drugs are not enough. " ]

Am J Clin Nutr 2006;84:1463-1472.

http://www.medscape.com/viewarticle/550227

Not an MD