Reducing extramedical use and harms of pharmaceutical opioids: the potential role of abuse-deterrent formulations

Post-marketing studies of pharmaceutical opioid abuse-deterrent formulations: a framework for research design and reporting

BACKGROUND AND AIMS

Opioid formulations with properties to deter abuse (abuse-deterrent formulations; ADFs) have been developed as one response to the prescription opioid 'epidemic'. As for all medicines, ADFs undergo evaluation of safety and efficacy prior to registration for marketing. However, reduced extra-medical use (the primary intended outcome of ADFs and reason for their introduction) can only be established in post-marketing observational studies, comparing them to opioid formulations without abuse-deterrent properties. This has implications for various features of study design and analysis. We discuss proposals for the design, conduct, governance and reporting of post-marketing studies on the effectiveness of pharmaceutical and opioid ADFs.

METHODS

A review of current guidance documents, public work-shops and forums and our own experience with post-marketing studies of ADFs.

RESULTS AND CONCLUSIONS

Research questions for post-marketing studies on ADFs of opioids should reasonably be framed around detecting any probable intended or unintended clinical and/or meaningful changes in specific aspects of extra-medical use (e.g. injection use) and harms. Outcomes reported by prevalence and frequency of occurrence and disaggregated by specific product and route of administration can illustrate the magnitude of ADF impact. We argue that a multi-faceted approach is required, using data from both general population and sentinel high-risk cohorts and from primary and secondary data sources. The comparator (historical non-ADF formulation of that opioid, equivalent current generic or similar opioid product), duration of monitoring and analytical approach require justification and should be sufficient to add weight to conclusions of causality. To maximize transparency, we recommend explicit declarations of funding and conflict of interest, establishment of an advisory committee, publication of study protocol and access to study results.

Combating escalating harms associated with pharmaceutical opioid use in Australia: the POPPY II study protocol

INTRODUCTION

Opioid prescribing has increased 15-fold in Australia in the past two decades, alongside increases in a range of opioid-related harms such as opioid dependence and overdose. However, despite concerns about increasing opioid use, extramedical use and harms, there is a lack of population-level evidence about the drivers of long-term prescribed opioid use, dependence, overdose and other harms.

METHODS AND ANALYSIS

We will form a cohort of all adult residents in New South Wales (NSW), Australia, who initiated prescribed opioids from 2002 using Pharmaceutical Benefits Scheme dispensing records. This cohort will be linked to a wide range of other datasets containing information on sociodemographic and clinical characteristics, health service use and adverse outcomes (eg, opioid dependence and non-fatal and fatal overdose). Analyses will initially examine patterns and predictors of prescribed opioid use and then apply regression and survival analysis to quantify the risks and risk factors of adverse outcomes associated with prescribed opioid use.

ETHICS AND DISSEMINATION

This study has received full ethical approval from the Australian Institute of Health and Welfare Ethics Committee, the NSW Population and Health Services Research Committee and the ACT Health Human Research Ethics Committee. This will be the largest postmarketing surveillance study of prescribed opioids undertaken in Australia, linking exposure and outcomes and examining risk factors for adverse outcomes of prescribed opioids. As such, this work has important translational promise, with direct relevance to regulatory authorities and agencies worldwide. Project findings will be disseminated at scientific conferences and in peer-reviewed journals. We will also conduct targeted dissemination with policy makers, professional bodies and peak bodies in the pain, medicine and addiction fields through stakeholder workshops and advisory groups. Results will be reported in accordance with the REporting of studies Conducted using Observational Routinely collected Data (RECORD) Statement.

The effect of a potentially tamper-resistant oxycodone formulation on opioid use and harm: main findings of the National Opioid Medications Abuse Deterrence (NOMAD) study

BACKGROUND

Escalation of pharmaceutical opioid use and harm in North America is well-documented, with similar issues emerging in Australia. One response is the development of tamper-resistant formulations of opioids. A potentially tamper-resistant formulation of controlled-release oxycodone was introduced in Australia in April, 2014, rapidly replacing the non-tamper-resistant formulation. Our study is the most systematic and comprehensive examination of the impact of a new opioid formulation to date, assessing the effect of tamper-resistant formulation of controlled-release oxycodone on population-level opioid use and opioid-related harm (ie, overdose, help-seeking, and treatment-seeking); and opioid use, tampering, and preference for the tamper-resistant formulation of controlled-release oxycodone compared with other drugs or formulations among sentinel populations likely to tamper with pharmaceutical opioids.

METHODS

We conducted interrupted time-series analyses of opioid sales data and multiple routinely collected health datasets, followed up a cohort of people who tamper with pharmaceutical opioids before and after the introduction of the tamper-resistant formulation of controlled-release oxycodone, and analysed annual surveys of people who inject drugs. Data were collected from several Australian states: New South Wales, South Australia, and Tasmania. Meta-analyses (weighted Z tests) were conducted to synthesise across data sources providing evidence for a given indicator.

FINDINGS

At the population level, we found reduced sales of higher strengths of controlled-release oxycodone and increased sales of other oxycodone formulations. No significant effect was observed among population-level indicators of opioid overdose, or help or treatment-seeking. Mortality data were not available for inclusion at the time of our study. Meta-analyses across sentinel populations (ie, prospective cohort, surveys of people who inject drugs, and clients of supervised injecting facilities or needle and syringe programmes) indicated reduced controlled-release oxycodone use via tampering (mainly injection), with no evidence of switching to heroin or other drug use.

INTERPRETATION

This formulation of controlled-release oxycodone reduced tampering with pharmaceutical opioids among people who inject drugs, but did not affect population-level opioid use or harm.

FUNDING

Mundipharma Australia, the Australian Government, and the National Health and Medical Research Council.