medwireNews: Findings from an open-label phase IIIb trial suggest that repeat administration of extended-release triamcinolone acetonide (TA) is well tolerated and may result in symptomatic relief for patients with knee osteoarthritis (OA).
The study included 208 participants who were given an intra-articular injection of the microsphere-based formulation of TA at a dose of 32 mg, followed by a second injection 12, 16, 20, or 24 weeks later.
This “flexible repeat-dosing schedule [was] tailored to patient response,” say the researchers, noting that criteria for administration of the second dose included patient- and physician-reported benefit from the first injection, favorable safety profile, and a WOMAC pain score of at least 6 points.
In all, 179 participants (86.1%) received both injections and the median duration between doses was 16.6 weeks.
Andrew Spitzer (Cedars-Sinai Orthopedic Center, Los Angeles, California, USA) and co-investigators report in Rheumatology and Therapy that both injections were well tolerated, with “no substantial difference” in rates of treatment-emergent adverse events (TEAEs) associated with the first and second injections.
TEAEs were experienced by 41.9% of patients between the time of the first and second injections, and by 35.2% in the period following the second dose (12–24 weeks after the second injection, depending on the interval between administrations). Arthralgia was the most commonly reported TEAE, affecting 10.6% of patients in the first period and 19.0% during the second, followed by upper respiratory tract infection, experienced by 3.9% and 2.2%, respectively.
Over a total follow-up period of 1 year, the researchers say that no unexpected adverse events occurred, and there were no cases of chondrolysis, insufficiency fractures, osteonecrosis, or clinically significant subchondral bone changes.
“Taken together, the safety data from the current study are reassuring, particularly in light of the prolonged joint residence time associated with [extended-release] TA,” and “suggest that patients can receive a second [extended-release] TA injection without experiencing an increase in the incidence of TEAEs,” write Spitzer and team.
In exploratory efficacy analyses, the study authors demonstrated “marked improvements” in WOMAC pain scores from the time of both injections to 4 weeks later, which “then faded during each injection period.”
Participants also experienced improvements in stiffness, physical function, and quality of life scores following both injections, and the team says that the duration of clinical benefit “appeared to be similar” after each one.
These results suggest that repeat injections with extended release TA may offer “a nonopioid option for achieving clinically meaningful control of knee OA symptoms,” conclude the investigators.
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