Improved Treatment Effect of Triamcinolone Acetonide Extended-Release in Patients with Concordant Baseline Pain Scores on the Average Daily Pain and Western Ontario and McMaster Universities Osteoarthritis Index Pain Scales

Abstract

Introduction: A phase 3 randomized controlled study comparing triamcinolone acetonide extended-release (TA-ER) to conventional TA crystalline suspension (TAcs) reported variable efficacy results. Enrollment criteria may have contributed to this discrepancy, as moderate-to-severe average daily pain (ADP) was required at baseline, whereas no limitations were placed on Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC-A) pain severity. We conducted a post hoc sensitivity analysis to compare treatment effects in patients reporting moderate-to-severe osteoarthritis (OA) pain on both scales.

Methods: Participants > 40 years old with symptomatic knee OA were randomly assigned to a single intra-articular injection of TA-ER 32 mg, TAcs 40 mg, or saline-placebo and followed for 24 weeks. Patient-reported ADP, WOMAC-A, rescue medication usage, and adverse events (AEs) were assessed. Participants who reported moderate-to-severe OA pain at baseline using both instruments (ADP ≥ 5 to ≤ 9, maximum 10 and WOMAC-A ≥ 2, maximum 4) were categorized as "concordant" pain reporters; patients with baseline moderate-to-severe OA on ADP only were termed "discordant" pain reporters.

Results: Two-hundred-ninety-two concordant pain reporters of 484 total subjects received TA-ER 32 mg (n = 95), TAcs 40 mg (n = 100), or saline-placebo (n = 97). Baseline characteristics and AE profiles of the concordant and discordant pain responders were consistent with the full analysis population. Among concordant pain reporters, TA-ER significantly (p < 0.05) improved ADP scores vs. TAcs (weeks 5-19; area-under-the-effect [AUE]weeks1-12; AUEweeks1-24) and saline-placebo (weeks 1-20; AUEweeks1-12; AUEweeks1-24). At week 12, a higher proportion reported no knee pain (ADP = 0) with TA-ER (~ 28%) vs. TAcs (~ 8%). TA-ER significantly improved WOMAC-A vs. TAcs at weeks 4, 8, and 12, with significant reduction in rescue medication usage observed with TA-ER from weeks 2 to 20 vs. TAcs.

Conclusions: In patients reporting moderate-to-severe knee OA pain at baseline based on concordant ADP and WOMAC-A scores, TA-ER provided statistically significant pain relief for ≥ 12 weeks compared with conventional TAcs.

Trial registration: ClinicalTrials.gov Identifier: NCT02357459.

Keywords: Corticosteroid; Intra-articular; Knee osteoarthritis; Pain; Triamcinolone acetonide extended-release.

© 2021. The Author(s).

Figures

Fig. 1

Correlation between ADP and normalized WOMAC-A-derived baseline pain assessments in the phase 3 full analysis set. NRS numeric rating scale, TAcs triamcinolone acetonide crystalline suspension, TA-ER triamcinolone acetonide extended-release, WOMAC Western Ontario and McMaster Universities Osteoarthritis Index. Data from the phase 3 FAS population: TA-ER (n = 161), saline-placebo (n = 162), TAcs (n = 161) [14]

Fig. 2

Mean changes from baseline in ADP scores over time among concordant pain reporters. ap < 0.05 vs. saline-placebo; bp < 0.05 vs. TAcs. ADP average daily pain, LSM least-squares mean, TAcs triamcinolone acetonide crystalline suspension, TA-ER triamcinolone acetonide extended-release

Fig. 3

Frequency distribution of ADP scores at baseline, week 1, and week 12 among concordant pain reporters. ADP scores rated on a 0–10 NRS, with 0 indicating “no pain” and 10 indicating “pain as bad as you can imagine.” ADP average daily pain, NRS numeric rating scale, TAcs triamcinolone acetonide crystalline suspension, TA-ER triamcinolone acetonide extended-release

Fig. 4

Mean change from baseline in WOMAC-A (pain) score among concordant pain reporters. ap < 0.05 vs. saline-placebo; bp < 0.05 vs. TAcs. LSM least-squares mean, TAcs triamcinolone acetonide crystalline suspension, TA-ER triamcinolone acetonide extended-release, WOMAC Western Ontario and McMaster Universities Osteoarthritis Index

Fig. 5

Mean rescue medication usage among concordant pain reporters. ap < 0.05 vs. saline-placebo; bp < 0.05 vs. TAcs. LSM least-squares mean, TAcs triamcinolone acetonide crystalline suspension, TA-ER triamcinolone acetonide extended-release