P-015 - (Poster #15) Treatment Characteristics of Chronic Low Back Pain Patients Transitioned from Oral Schedule II Short-Acting Opioids to Belbuca or Oral Schedule II Long-Acting Opioids: A Retrospective US Commercial Claims Analysis

Chronic low back pain (cLBP) is a common diagnosis in the US population and represents a major cause of disability. It requires long-term around-the-clock analgesia with concomitant use of multiple pain medications and with invasive procedures for more severe cases. The main treatment options are over-the-counter non-opioid analgesics and opioid medications.  The main goal of cLBP management is to find an effective treatment combination to achieve pain relief and improve quality of life. However, prolonged opioid exposure is often associated with a high incidence of treatment-related adverse events. Optimizing opioid treatment is essential to ensure the safe management of cLBP. Buprenorphine is an atypical opioid which has been demonstrated to exhibit a more favorable safety profile relative to full agonist opioids. Based upon RWE studies, buprenorphine has a lower risk of occurrence of opioid-related adverse events and abuse/dependence potential.

Purpose/Objectives:

The main hypothesis of this study is that transitioning from short-acting opioids (SAO) to Belbuca® (buprenorphine buccal film) instead of long-acting opioids (LAO) would significantly decrease concomitant SAO and overall opioid utilization. Previously published analyses among commercial and Medicare patients with cLBP in the US focused on the comparison between Belbuca® and the buprenorphine transdermal patch. Both studies reported decreasing Schedule II opioid utilization trends after starting Belbuca® or buprenorphine patch treatments, regardless of previous opioid exposure. A Buprenorphine Consensus Expert Panel has proposed use of buprenorphine in chronic pain over Schedule II opioids whenever possible to optimize opioid utilization in the US, though direct comparisons between these medications in real-world settings are missing. Therefore, this study aims to explore treatment characteristics of US patients with a cLBP diagnosis who are treated with oral Schedule II SAO and initiated Belbuca® or oral Schedule II LAO medications.

Methods:

This retrospective study was performed in the Merative MarketScan® insurance claims database of commercially insured US patients from January 2019 to December 2023. The date of the first Belbuca® or oral Schedule II LAO in the database was set to be the index date. The observational period included 6-month pre-index and 12-month follow-up periods. Adult patients with at least two low back pain diagnoses and at least one SAO prescription in the pre-index period were included in the analysis. Patients with a gap in healthcare/pharmaceutical coverage and with cancer or HIV diagnoses during the observational period were excluded. Switching between Belbuca® and LAO medications was not allowed.

Study outcomes were index medication treatment characteristics and rescue medication utilization measures during the 12-month follow-up. Prescription counts, treatment duration, daily doses, and adherence were estimated for Belbuca® and LAO treatments. Rescue medication categories included oral Schedule II SAO, all oral Schedule II opioids (SAO/LAO), buprenorphine patch, and non-opioid rescue medications (NORMs). In addition, rescue medication utilization trends were explored separately within cohorts by comparing differences between periods of equal duration (6-month pre-index vs. 6-month follow-up). Propensity-score matching (PSM) was employed to minimize the impact of covariates on study outcomes.

Results:

There were 3,350 patients identified in the database (1,331 Belbuca® and 2,019 oral Schedule II LAO opioids). PSM yielded 964 patients in each cohort in the final study sample.

During the 12-month follow-up, mean treatment durations were 156.0 days with Belbuca® and 164.2 days with LAO opioids (p=0.180). Average daily doses were 598.1 mcg for Belbuca® and 47.4 morphine milligram equivalents (MME) for LAO opioids. There were fewer Belbuca® than LAO opioid prescriptions in respective cohorts (5.8 vs. 6.5 prescriptions, p=0.003). Adherence measures, estimated during the index treatment duration, were high in both cohorts without between-cohort differences (medication possession ratio 0.91-0.92; proportion of days covered 0.88-0.89).

The rate of patients concomitantly using SAO was lower in the Belbuca® cohort over the 12-month follow-up period (86.1% vs. 92.1%, p< 0.001). Belbuca® patients also had fewer SAO prescriptions per patient (8.9 prescriptions vs. 9.9 prescriptions, p< 0.001), shorter mean SAO treatment duration (208.3 days vs. 226.4 days, p=0.004), and lower average daily SAO MME (38.2 MME vs. 50.9 MME, p< 0.001). On the other hand, higher rates of patients with buprenorphine patch prescriptions were observed in the Belbuca® cohort (8.2% vs. 3.3%, p< 0.001). Belbuca® patients also had more patch prescriptions on average (0.3 vs. 0.1 prescriptions, p< 0.001) and longer mean patch treatment duration (8.9 days vs. 2.6 days, p< 0.001). Regarding NORMs, the only observed difference was in mean duloxetine prescription counts (1.3 prescriptions in Belbuca® vs. 1.0 prescription in LAO, p=0.042).

Rescue medication utilization trends showed significantly greater decreases after Belbuca® initiation in mean SAO treatment duration (-15.4 days vs. -2.2 days, p< 0.001), SAO prescription counts per patient (-0.9 prescriptions vs. -0.3 prescriptions, p< 0.001), and average SAO daily MME (-9.7 MME vs. -6.1 MME, p=0.015). Regarding all oral schedule II opioids (SAO and LAO), more favourable trends were also observed after starting Belbuca® treatment for mean opioid treatment duration (-15.4 days vs. +28.7 days, p< 0.001), opioid prescription counts per patient (-0.9 prescriptions vs. +3.7 prescriptions, p< 0.001), and average opioid daily MME (-9.7 MME vs. +19.0 MME, p< 0.001).

Conclusions/Implications for future research and/or clinical care:

This real-world study showed that transitioning from SAO to Belbuca® instead of LAO substantially decreased further SAO utilization. Number of SAO prescriptions per patient, rates of patients with at least one SAO prescription, mean SAO treatment duration, and average SAO daily dose were significantly lower in the Belbuca® cohort than the LAO cohort during the 12-month follow-up.

Trend analysis (6-month pre-index vs. 6-month follow-up outcome) showed that patients who initiated Belbuca® had greater decreases in SAO utilization measures than those who started LAO. The overall opioid use also significantly decreased after introducing Belbuca® treatment, while an increasing trend was observed in the LAO cohort.

The main study limitations are related to the nature and characteristics of real-world data and coding system restrictions, as the claims are primarily collected for billing purposes. This has been minimized by employing data cleaning, performing a careful patient selection process, and using complex methods to minimize selection bias. There is a lack of data related to low back pain chronicity and severity. Chronicity was assumed by having at least two low back pain claims prior to the index treatment initiation.