medwireNews: Treatment with teriparatide, a recombinant form of parathyroid hormone, does not reduce joint erosion among patients with rheumatoid arthritis (RA) undergoing treatment with tumor necrosis factor (TNF) inhibitors, researchers report.
In the TERA (Teriparatide to treat Erosions in Rheumatoid Arthritis) trial, 24 RA patients with a median disease duration of 18 years were randomly assigned to receive treatment with teriparatide 20 µg once daily or to a wait-list control arm.
The researchers found that total joint erosion volume per hand/wrist decreased from a median 369.8 mm3 at baseline to 369.4 mm3 at the 1-year follow-up among patients undergoing teriparatide treatment, compared with an increase from 571.4 mm3 to 580.5 mm3 among those in the wait-list control group.
There was no significant difference in erosion volume change over the year between the two groups, at –0.4 mm3 and 9.1mm3, respectively, report Daniel Solomon (Brigham and Women’s Hospital, Boston, Massachusetts, USA) and colleagues in Arthritis & Rheumatology.
Furthermore, the team found no significant difference in erosion volume between the two treatment arms in any of the subregions of the hand/wrist analyzed, including the radius, ulna, metacarpophalangeal joints, and proximal interphalangeal joints.
However, there was a “clear improvement” in bone mineral density at the lumbar spine and femoral neck among patients receiving teriparatide compared with those in the control group, with significant increases of 0.07 and 0.05 g/cm2, respectively.
Solomon and colleagues caution that their study was limited by its small sample size, and that participants in the control group did not receive placebo treatment, meaning that “subjects and their physicians were not blinded to treatment assignment.”
They note that in previous studies conducted in animal models, treatment with intermittent parathyroid hormone and TNF inhibitors resulted in significant repair of joint erosions, suggesting that the “limited inflammation in the bone microenvironment” in animal models “may be different from that which occurs in RA patients with a mean disease duration of 18 years.”
The team speculates: “It is possible that if teriparatide had been used in patients with RA of recent onset and/or in younger patients, greater preservation of the bone marrow niche might have yielded a different result.”
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