A randomized, double-blind, placebo-controlled study to evaluate the efficacy and safety of a bupivacaine hydrochloride implant in patients undergoing abdominoplasty

INTRODUCTION: Surgical site infiltration with bupivacaine hydrochloride (HCl) is a standard element of postoperative analgesia for soft tissue surgeries, but results in short-lived analgesia. A novel bupivacaine implant, XARACOLL (bupivacaine HCl), is Food and Drug Administration approved for treatment of acute postsurgical pain following adult inguinal herniorrhaphy. This study examined the efficacy and safety of the bupivacaine implant (300 mg) compared with placebo for postsurgical pain after abdominoplasty. METHODS: In this double-blind, placebo-controlled study, patients undergoing abdominoplasty were randomized to three 100 mg bupivacaine implants or three placebo collagen implants, in a 1:1 ratio, implanted intraoperatively. No other analgesics were administered into the surgical site. Patients were allowed opioids and acetaminophen for postoperative pain. Patients were followed for up to 30 days after treatment. Primary outcome: the analgesic effect of the bupivacaine implants through 24 hours postsurgery, measured by the sum of time-weighted pain intensity (SPI24). Prespecified key secondary outcomes included SPI48 and SPI72, percentage of opioid-free patients through 24, 48, and 72 hours, and adverse events, which were tested sequentially to control for multiplicity (ie, if the first variable failed to reach significance, no subsequent variables were declared statistically significant). RESULTS: The bupivacaine implant patients (n=181) reported statistically significant lower SPI24 (mean (SD) SPI24=102 (43), 95% CI 95 to 109) compared with placebo patients (n=184; SPI24=117 (45), 95% CI 111 to 123, p=0.002). SPI48 was 190 (88, 95% CI 177 to 204) for INL-001 and 206 (96, 95% CI 192 to 219) for placebo, and not significantly different between groups. The subsequent secondary variables were therefore declared not statistically significant. SPI72 was 265 (131, 95% CI 244 to 285) for INL-001 and 281 (146, 95% CI 261 to 301) for placebo. The opioid-free percentage of patients at 24, 48, and 72 hours was 19%, 17%, and 17% for INL-001 and 6.5% for placebo patients (at all timepoints). The only adverse event occurring in ≥5% of patients and for which proportion INL-001 >placebo was back pain (7.7% vs 7.6%). CONCLUSION: The study design was limited by not containing an active comparator. Compared with placebo, INL-001 provides postoperative analgesia that is temporally aligned with the period of maximal postsurgical pain in abdominoplasty and offers a favorable safety profile. TRIAL REGISTRATION NUMBER: NCT04785625.