Morphine Sulfate/Naltrexone Hydrochloride

Clinical trial safety data following chronic administration of extended-release opioids within an older population is limited. Embeda * is an extended-release formulation of morphine sulfate surrounding sequestered naltrexone hydrochloride (MSN) and is designed to deter opioid misuse and abuse. The present analysis compared pooled safety outcomes among patients aged ≥65 years and those aged <65 years from three phase 2/3 studies (ranging from 2 weeks to 12 months) in patients treated with MSN.

Subgroup analysis of patients aged ≥65 years and <65 years was performed on pooled data for adverse events (AEs), potentially clinically significant laboratory values (hematology/chemistry), and signs/symptoms of opioid withdrawal using the Clinical Opiate Withdrawal Scale (COWS) (phase 3 trials only) for patients who received at least one dose (short-term studies, maximum dose was 160 mg/d or 320 mg/d depending on study; long-term study, no maximum dose) of study medication during titration and maintenance phases.

ClinicalTrials.gov: NCT00420992, NCT00415597.

During titration, 173 (17.1%) of 1012 patients treated with MSN were aged ≥65 years, while during maintenance 76/564 (13.5%) patients were aged ≥65 years. Treatment-emergent AEs were similar in frequency and type between the two cohorts, with the most common being constipation, nausea, and somnolence; no consistent patterns relating to age and only one possibly treatment-related serious AE in patients ≥65 years was noted. No clinically significant differences in laboratory values or COWS scores (average maximum score ≤2.5) were observed between age groups.

Safety outcomes following daily administration of MSN (2 weeks-12 months) were similar between patients aged ≥65 years and <65 years. Key limitations include the variable study designs and length of treatment (2 weeks-12 months), small sample size, and the inclusion of only those patients who were otherwise in relatively good health with restrictions on concomitant medications.

Millions of patients are treated with opioid analgesics (OpAs) to relieve pain. Unfortunately, these medications are subject to abuse and/or unintended misuse. Abuse deterrent formulations (ADFs) represent an intervention strategy to decrease abuse/misuse without affecting patient access. The Food and Drug Administration (FDA) has issued Draft Guidance "Abuse deterrent opioids, Evaluation and Labeling" and is currently actively pursuing scientific input on this issue.

The development of ADF technologies was reviewed using peer reviewed journals describing OpA post marketing studies, web sites containing FDA announcements on product approvals and manufacturer product use profiles.

Reviewed is the FDA recent approval of a product label describing the abuse deterrent characteristics of OxyContin(®) (physical barrier formulation), and the FDA determination that studies were insufficient for an Opana(®) (physical barrier) ADF label. Additional reviewed marketed OpAs with ADF technologies include: Suboxone(®) and Embeda(®) (opioid agonist/antagonist combinations), Oxecta(®) (aversion technology), and Nucynta(®) (physical barrier). Reviewed ADF technologies currently in development include: new physical barrier and aversion technologies, an innovative extended release formulation as well as novel polymer-opioid conjugates. As ADF technologies are part of a comprehensive intervention strategy to promote safe OpA use, additional components including governmental, community, and educational initiatives are reviewed.

The outcomes of the recent ADF labeling applications for OxyContin(®) (Tier 3 approval) and Opana(®) (non-approval) suggest that the threshold for ADF labeling will be appropriately high. The presented findings indicate that ADF technologies can be a critical component of a comprehensive strategy to promote the safe and effective use of OpAs.