Session Type: Poster Session (Monday)
Session Time: 9:00AM-11:00AM
Background/Purpose: In a Phase 3 randomized controlled study, differing efficacy results were observed when triamcinolone acetonide extended-release (TA-ER) was compared to conventional TA crystalline suspension (TAcs) with two different pain measures, average daily pain (ADP) using a 0-10 numeric rating scale (NRS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC-A subscale). Trial enrollment criteria may have contributed to this discrepancy, as a moderate-to-severe ADP score of ≥5 to ≤9 was required at baseline whereas no limitations were placed on baseline WOMAC-A score (0-4 Likert). This allowed for randomization of patients who reported their knee pain as mild via WOMAC-A criteria. This post hoc analysis assessed treatment effects in those patients who reported moderate-to-severe OA pain prior to treatment on both ADP and WOMAC-A scales.
Methods: This post hoc analysis included adults (≥40 years) with knee OA (Kellgren-Lawrence Grade 2-3) who reported moderate-to-severe knee OA pain at baseline using both instruments (ADP ≥5 to ≤9 and WOMAC-A ≥2) from a Phase 3 randomized controlled study (concordant pain reporters; n=292). Patients received a single intra-articular injection of TA-ER 32 mg (n=95), TAcs 40 mg (n=100), or Saline-placebo (n=97). Patient-reported ADP‐intensity (including area under the effect [AUE] curves), WOMAC-A (pain), WOMAC-B (stiffness), WOMAC-C (function), Knee Injury and Osteoarthritis Outcome Score Quality of Life (KOOS-QoL), rescue medication use, Patient Global Impression of Change (PGIC), and adverse events (AEs) were assessed throughout the study.
Results: Baseline characteristics (Table 1) and AE profiles were consistent with the full analysis population. TA-ER significantly (P < 0.05) improved ADP scores compared with TAcs (Weeks 5-19) and Saline-placebo (Weeks 1-20) (Figure 1). AUEWeeks1–12 and AUEWeeks1–24 were statistically significantly greater for TA-ER compared with TAcs (-47.7 [-94.4, -1.0] and -98.4 [-194.5, -2.3], respectively; P < 0.05 for both) and Saline-placebo (-136.1 [-184.2, -88.0] and -212.1 [-311.1, -113.1], respectively; P < 0.0001 for both). At Week 12, the proportion of patients who reported they had no knee pain (ADP score=0) was greater with TA-ER (~28%) compared with TAcs (~8%) (Figure 2); ~20% of patients who received TA-ER still reported no knee pain at Week 16. TA-ER significantly (P < 0.05) improved WOMAC-A, -B, -C, KOOS-QoL, rescue medication use, and PGIC compared with TAcs and Saline-placebo through at least Weeks 4-12.
Conclusion: In patients with knee OA who reported concordant moderate-to-severe pain at baseline across two different reporting instruments, TA-ER provided statistically significant and clinically meaningful pain relief for ≥16 weeks compared with conventional TAcs and Saline-placebo, and also improved stiffness, function, and QoL. Concordant pain reporters were better able to discern treatment effect; results of this post hoc analysis have implications for study design and patient recruitment of future trials evaluating efficacy of analgesics.
To cite this abstract in AMA style:Conaghan P, Ross E, Kivitz A, Turk D, Spitzer A, Jones D, Lanier R, Cinar A, Lufkin J, Kelley S. Concordance of Baseline Pain Measures (Across Two Reporting Instruments) Influences Treatment Effect: Post Hoc Analysis of a Phase 3 Randomized Controlled Trial of Triamcinolone Acetonide Extended-Release in Patients with Knee Osteoarthritis [abstract]. Arthritis Rheumatol. 2019; 71 (suppl 10). https://acrabstracts.org/abstract/concordance-of-baseline-pain-measures-across-two-reporting-instruments-influences-treatment-effect-post-hoc-analysis-of-a-phase-3-randomized-controlled-trial-of-triamcinolone-acetonide-extended-rel/. Accessed April 12, 2021.
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