Rescue Analgesic Medication Use by Patients Treated with Triamcinolone Acetonide Extended-Release for Knee Osteoarthritis Pain: Pooled Analysis of Three Phase 2/3 Randomized Clinical Trials

Introduction In clinical trials for knee osteoarthritis (OAK), rescue medication is commonly provided to manage uncontrolled index-knee pain. The impact of treatment on rescue medication utilization provides important information on the robustness of analgesic effect. In randomized controlled OAK trials (NCT01487161, NCT02116972, NCT02357459), intra-articular (IA) triamcinolone acetonide extended-release (TA-ER) demonstrated substantial, prolonged analgesia versus saline-placebo and TA crystalline solution (TAcs) as assessed by patient-reported pain scales. This pooled analysis assessed the impact of TA-ER on rescue medication use. Methods Patients ( N = 798) with OAK (American College of Rheumatology criteria; Kellgren–Lawrence grade 2/3) and baseline average daily pain intensity score ≥ 5 to ≤ 9 (0–10 numeric rating scale) received a single IA injection of TA-ER ( N = 324), saline-placebo ( N = 262), or TAcs ( N = 212). Acetaminophen/paracetamol tablets were provided to treat uncontrolled pain (knee or otherwise). Rescue medication consumption was monitored through a daily diary; pill counts were confirmed at the clinical site. Differences in rescue medication use were measured by least-squares mean (LSM) differences, number of rescue medication tablets used per day, and in area under the effect (AUE) curves of rescue medication tablets used per week. Results The overall number of rescue medication tablets used per day through week 24 was significantly less ( p ≤ 0.05) for TA-ER versus saline-placebo (LSM difference, − 0.43) and TAcs (− 0.24). Rescue medication use was significantly ( p ≤ 0.05) lower following TA-ER versus saline-placebo across weeks 1–12 (AUE weeks1–12 ; LSM difference, − 24.5) and weeks 1–24 (AUE weeks1–24 ; − 51.6) and versus TAcs across weeks 1–12 (AUE weeks1–12 ; − 21.1). Conclusions In patients with painful OAK, reduced rescue medication use may be a potential benefit of TA-ER and further supports its analgesic efficacy. Additional research is needed to assess whether TA-ER impacts the use of other common oral analgesics (nonsteroidal anti-inflammatory drugs, opioids) for patients with OAK. Funding Flexion Therapeutics, Inc., Burlington, MA, USA. Plain Language Summary Plain language summary available for this article.