Background:Intra-articular corticosteroids are commonly used for pain relief in patients
with knee osteoarthritis. Simultaneous intra-articular corticosteroid (CS)
knee injections may be beneficial for the ~80–90% of patients who present
with, or develop, bilateral knee osteoarthritis, but concurrent injections
may increase systemic CS exposure and data on safety/tolerability are
lacking. Triamcinolone acetonide extended release (TA-ER) has shown
decreased systemic triamcinolone acetonide exposure compared with
traditional triamcinolone acetonide crystalline suspension (TAcs) after a
single knee injection in patients with knee osteoarthritis. This phase IIa
study was designed to assess the safety and systemic triamcinolone acetonide
exposure following injections of TA-ER or TAcs into each knee of patients
with bilateral knee osteoarthritis.Methods:Patients (⩾40 years) meeting American College of Rheumatology criteria for
knee osteoarthritis in both knees received concurrent single intra-articular
injections of TA-ER 32 mg or TAcs 40 mg into each knee (total: 64 mg and
80 mg, respectively) and were followed for 6 weeks. Safety was evaluated
based on treatment-emergent adverse events (TEAEs). Blood samples for
pharmacokinetic analysis were collected pre-injection, and at the following
postinjection time points: 1, 2, 3, 4, 5, 6, 8, 10, 12, and 24 h, and days
8, 15, 29, and 43.Results:Baseline characteristics were balanced between patients randomly assigned to
TA-ER (n = 12) or TAcs (n = 12). Both
treatments were well tolerated with comparable TEAE profiles. Peak plasma
triamcinolone acetonide concentrations (Cmax) were lower
following bilateral TA-ER injections [geometric mean, 2277.7 pg/ml (95% CI,
1602.13–3238.04)] compared with bilateral TAcs injections [7394.7 pg/ml
(2201.06–24,843.43)], with median times to Cmax (Tmax)
of 4.5 and 6.5 h, respectively.Conclusions:In patients with bilateral knee osteoarthritis, intra-articular injection of
TA-ER into both knees was well tolerated. Consistent with pharmacokinetic
profiles observed after a single knee injection, plasma triamcinolone
acetonide concentrations were lower after bilateral TA-ER injections
compared with the higher and more variable concentrations observed after
bilateral TAcs injections.ClinicalTrials.gov identifier:NCT03378076