Glenn C. Pixton

Effects of Tiagabine Monotherapy on Abilities, Adjustment and Mood

Summary: Purpose: We evaluated the dose‐related impacts of tiagabine (TGB) on cognition and mood in a monotherapy study.

A double-blind, randomized, placebo-controlled trial of a diazepam auto-injector administered by caregivers to patients with epilepsy who require intermittent intervention for acute repetitive seizures

A diazepam auto‐injector (AI) has been developed for intramuscular administration to treat acute repetitive seizures (ARS). The objective of this study was to evaluate the efficacy and safety of the diazepam AI when administered by caregivers to control an episode of ARS (ClinicalTrials.gov identifier NCT00319501).

Safety and effectiveness of long-term treatment with diazepam auto-injector administered by caregivers in an outpatient setting for the treatment of acute repetitive seizures

Part 1 of this phase III study was a randomized, double‐blind, parallel‐group, placebo‐controlled, multicenter study of caregiver administered diazepam auto‐injector (AI) in subjects with acute repetitive seizures (ARS) and demonstrated that diazepam AI was well‐tolerated and significantly more effective than placebo AI in delaying the time to next seizure or rescue. Part 2 of this study, presented herein, was an open‐label continuation to assess the long‐term safety and effectiveness of diazepam AI for the treatment of ARS.

A multicenter, primary care-based, open-label study to identify behaviors related to prescription opioid misuse, abuse, and diversion in opioid-experienced patients with chronic moderate-to-severe pain

Objective To compare the investigator assessment of patient risk for prescription opioid misuse, abuse, and diversion with patient self-reports of these activities in a population with chronic pain. Methods As a secondary objective of an open-label, multicenter, primary care-based clinical study to evaluate the success of converting opioid-experienced patients with chronic pain to morphine sulfate with sequestered naltrexone hydrochloride, risk for misuse, abuse, and diversion was assessed using two nonvalidated questionnaires: one was completed by the investigator and another by the patient (Self-Reported Misuse, Abuse, and Diversion [SR-MAD]). In addition, the validated Current Opioid Misuse Measure (COMM) test and urine drug test were used. Results Of the 684 patients assessed by the investigators, 537 returned the self-assessment, SR-MAD. Most patients were assigned by the investigator as low risk for misuse (84.2%), abuse (89.3%), and diversion (94.3%). Of the patients who returned SR-MAD, 60% indicated having taken more opioids than prescribed and 10.9% reported chewing or crushing their opioids in the past. Of the patients who completed COMM, 40.6% were deemed as having aberrant behaviors. COMM results correlated with the risk levels from the investigator assessment. One-third of patients (33.8%) had at least one abnormal urine drug test result. Conclusion More research is needed to better understand the gap between the investigator assessment of potential risk for misuse, abuse, and diversion and the actual extent of these behaviors among patients with chronic pain.

A randomized double-blind, placebo-controlled efficacy and safety study of ALO-02 (extended-release oxycodone surrounding sequestered naltrexone) for moderate-to-severe chronic low back pain treatment.

Abstract The objective of this multicenter, double-blind, placebo-controlled, randomized withdrawal study was to evaluate the efficacy and safety of ALO-02, an abuse-deterrent formulation containing pellets of extended-release oxycodone hydrochloride (HCl) surrounding sequestered naltrexone HCl, compared with placebo in the treatment of moderate-to-severe chronic low back pain. An open-label titration period in which all patients received ALO-02 was followed by a double-blind treatment period where patients meeting treatment response criteria were randomized to either a fixed dose of ALO-02 or placebo. Daily average low back pain was assessed using an 11-point numeric rating scale (NRS)-Pain. Of the 663 patients screened, 410 received ALO-02 during the open-label conversion and titration period and 281 patients were randomized to the double-blind treatment period (n = 134, placebo; n = 147, ALO-02). Change in the mean NRS-Pain score from randomization baseline to the final 2 weeks of the treatment period was significantly different favoring ALO-02 compared with placebo (P = 0.0114). Forty-four percent of patients treated with placebo and 57.5% of patients treated with ALO-02 reported ≥30% improvement in weekly average NRS-Pain scores from screening to the final 2 weeks of the treatment period (P = 0.0248). In the double-blind treatment period, 56.8% of patients in the ALO-02 group and 56.0% of patients in the placebo group experienced a treatment-emergent adverse event (TEAE). The most common treatment-related TEAEs for ALO-02 during the treatment period were nausea, vomiting, and constipation, consistent with opioid therapy. ALO-02 has been demonstrated to provide significant reduction of pain in patients with chronic low back pain and has a safety profile similar to other opioids.

Dose Proportionality and the Effects of Food on Bioavailability of an Immediate-Release Oxycodone Hydrochloride Tablet Designed to Discourage Tampering and Its Relative Bioavailability Compared With a Marketed Oxycodone Tablet Under Fed Conditions: A Single-Dose, Randomized, Open-Label, 5-Way Crossover Study in Healthy Volunteers

BACKGROUND An immediate-release oxycodone hydrochloride formulation (IRO-A) indicated for moderate to severe pain was designed (by adding functional excipients) to discourage tampering associated with intranasal and intravenous abuse of prescription opioids. OBJECTIVES The primary objective of this study was to determine the dose proportionality of oxycodone in IRO-A tablets under fasted conditions. Secondary objectives were to assess food effects on the pharmacokinetics of IRO-A tablets, to compare the relative bioavailability of oxycodone in IRO-A tablets versus marketed oxycodone hydrochloride (IRO) tablets under fed conditions and to evaluate the single-dose safety profile of the IRO-A tablets in healthy volunteers pretreated with naltrexone. METHODS This open-label, single-dose, randomized, 5-way crossover study was conducted in healthy adults who received each of the following treatments, separated by a washout period of ≥7 days: IRO-A 1 × 5 mg, 2 × 5 mg, and 2 × 7.5 mg under fasted conditions, and IRO-A 2 × 7.5 mg and IRO 1 × 15 mg after a high-fat, high-calorie breakfast. Naltrexone was administered to minimize untoward pharmacologic effects of oxycodone. Dose proportionality (IRO-A), food effects (IRO-A), and relative bioavailability in a fed state (IRO-A and IRO) were assessed by using bioequivalence criteria (90% CIs between 80% and 125% for C(max) and AUC). RESULTS Of the 35 adults enrolled in the study, 33 completed at least 1 dosing period. Most participants were male (54%) and white (69%), with a mean (SD) age of 32.6 (11.1) years and mean weight of 75.5 (12.3) kg. Plasma levels of oxycodone in IRO-A suggested dose-proportional pharmacokinetics; 90% CIs for dose-normalized C(max), AUC(0-last), and AUC(0-∞) fell within the 80% to 125% range. Concomitant food intake with IRO-A resulted in an ~14% reduction in oxycodone C(max) and an ~21% increase in AUC(0-last). The bioavailability of oxycodone from IRO-A tablets in the fed state was comparable with IRO tablets based on AUC parameters, although C(max) was ~16.5% lower. Reported or observed treatment-emergent adverse events were monitored throughout the study and were similar for IRO-A and IRO tablets. Nausea, headache, abdominal pain, and dizziness were the most common and are consistent with known effects of oxycodone after naltrexone blockade. CONCLUSIONS Plasma levels of oxycodone in IRO-A tablets were compatible with proportional single-dose pharmacokinetics from 5 to 15 mg under fasted conditions. Administration of IRO-A with food suggested increased overall bioavailability relative to fasting conditions and a reduction in peak systemic exposure of oxycodone that is not expected to be clinically significant. When comparing IRO-A tablets with IRO tablets in the fed state, the overall systemic exposure of oxycodone was comparable, and peak systemic exposure was lower.

A multicenter, 12-month, open-label, single-arm safety study of oxycodone-hydrochloride/naltrexone-hydrochloride extended-release capsules (ALO-02) in patients with moderate-to-severe chronic noncancer pain

OBJECTIVE To evaluate the long-term safety of oxycodone-hydrochloride and sequestered naltrexone-hydrochloride (ALO-02) administered for up to 12 months. DESIGN Open-label, single-arm safety study. SETTING Thirty-two US research centers (ClinicalTrials.gov identifier NCT01428583). PATIENTS Three hundred ninety-five adults (opioid experienced and opioid naïve) with moderate-to-severe chronic noncancer pain (CNCP). INTERVENTIONS Open-label, oral ALO-02 capsules, daily dose ranging from 20 to 160 mg oxycodone for up to 12 months. MAIN OUTCOME MEASURES Number and type of adverse events (AEs) and drugrelated AEs, including assessments of withdrawal (Clinical Opiate Withdrawal Scale; COWS), pharmacokinetics, efficacy, and aberrant behaviors (Current Opioid Misuse Measure). RESULTS A total of 193 (48.9 percent) patients received ALO-02 for ≥181 days and 105 (26.6 percent) patients for ≥361 days. The most common treatment-emergent AEs were nausea (25.3 percent), constipation (21.3 percent), vomiting (13.9 percent), and headache (11.6 percent). The most common drug-related AEs were constipation (18.0 percent), nausea (14.9 percent), somnolence (8.4 percent), fatigue (6.8 percent), dizziness (5.6 percent), and vomiting (5.1 percent). A majority of patients (86.6 percent) had a maximum COWS total score below the level for mild withdrawal symptoms at every visit throughout the study. Pain severity scores as measured by the short Form of the Brief Pain Inventory (BPI-SF) decreased over time. CONCLUSIONS Repeat dosing of ALO-02 for up to 12 months is safe and well tolerated in a CNCP population of both opioid-experienced and opioid-naïve patients. ALO-02 demonstrated a safety profile consistent with extended-release opioids and the expected analgesic efficacy. The addition of sequestered naltrexone had no significant clinical effect on patients when taken as directed.

Immune Responses Associated With Perioperative Exposure and Reexposure to Topical Bovine Thrombin Do Not Impair Hemostasis

Topical bovine thrombin has been associated with immune responses and anecdotal reports of coagulopathy. This open-label study assessed the impact on clinical hemostasis of human antibodies to bovine thrombin (aBT) or factor V/Va (aBV/Va) in response to topical bovine thrombin (THROMBIN-JMI) in patients both with and without preexisting anti-bovine antibodies. Noninferiority analysis assessed primary endpoint for mean shift from baseline activated partial thromboplastin time (aPTT) at 48 hours postsurgery; secondary endpoints included changes from baseline antibodies/titers and coagulation parameters through 8 weeks postsurgery. A total of 550 patients underwent surgery with THROMBIN-JMI utilized at investigator’s discretion. Adjusted mean aPTT change in (+)aBT/(+)THROMBIN-JMI cohort was greater than (-)aBT/(-)THROMBIN-JMI cohort; 4.67-second upper confidence bound exceeded 4.5-second margin (based on assumed mean aPTT of 30 seconds) and noninferiority was not met. Post hoc analysis indicated noninferiority would have been met had noninferiority margin been set prior at relative 15% of actual baseline aPTT. Antibodies/titers were unchanged by THROMBIN-JMI exposure 48 hours postsurgery and unrelated to postsurgical changes in coagulation. Thus, THROMBIN-JMI exposure in patients with/without preexisting aBT or aBV/Va does not alter hemostasis.

Prescription opioid abuse and misuse: gap between primary-care investigator assessment and actual extent of these behaviors among patients with chronic pain

ABSTRACT Objectives: To compare the results of two open-label primary care–based studies that examined investigator assessment of patient risk for prescription opioid misuse, abuse, and diversion relative to patient self-reports and urine drug tests (UDTs). Methods: Risk assessment data from two open-label, multicenter, primary care–based US studies in patients with chronic pain were compared. Results: In one study (n = 1487), 54.4% of patients were at moderate, 24.8% at high, and 20.8% at low risk based on patients’ self-reports at baseline on the Screener and Opioid Assessment for Patients with Pain®-Revised questionnaire. Investigators assigned 1.3% of patients as high risk despite 5.0% self-reporting prior illicit drug use and 15.3% with positive UDT(s) for an illicit drug at baseline. In the second study (n = 684), few patients were considered by investigators to be at high risk for misuse (1.6%), abuse (1.8%), or diversion (1.0%). However, 10.4% of patients reported prior illicit drug use; 23.4% had at least one abnormal baseline UDT; 60% of 537 patients reported on the Self-Reported Misuse, Abuse, and Diversion questionnaire they took more opioids than prescribed; and 10.9% reported chewing/crushing opioids in the past. Of patients completing the Current Opioid Misuse Measure, 40.6% were classified as having aberrant behaviors. Conclusion: A comparison of risk assessment across two studies indicates a tendency for investigators to assess patients as lower risk for opioid-related aberrant behaviors despite a significant proportion self-reporting aberrant behavior and/or presenting with illicit UDTs. These consistent findings underline the importance of appropriate implementation of objective measures and self-reporting tools when evaluating risk in patients. Clinical trial registration: www.clinicaltrials.gov identifiers: NCT00640042 and NCT01179191

Self-reports of prescription opioid abuse and diversion among recreational opioid users in a Canadian and a United States city

OBJECTIVE To explore behaviors related to prescription opioid abuse and diversion in individuals who self-reported past recreational (nonmedical) opioid use. DESIGN A questionnaire was developed and included in two abuse potential clinical studies conducted in Canada (Toronto, ON, August 2010 to January, 2011) and the United States (Salt Lake City, UT, February-May 2011). PARTICIPANTS Recreational opioid users. MAIN OUTCOME MEASURE(S) Self-reported behaviors related to prescription opioid abuse and diversion. RESULTS The questionnaire was completed by 174 participants in the Canadian study and 80 participants in the US study. Most participants reported that they used prescription opioids for nonmedical purposes a few times a month. Most had taken their first prescription opioid between the ages of 12 and 24 years and the two most common reasons were to treat pain or to feel high/stoned. When asked about specific opioids taken for nonmedical purposes in the past year, oxycodone, acetaminophen with codeine, and morphine were commonly used by both cohorts, whereas hydrocodone use was substantially greater in the US cohort versus the Canadian cohort. Participants reported various tampering methods and routes of administration, with swallowed whole, crushed and snorted, and chewed/crushed and swallowed as the most prevalent. Most participants indicated taking other drugs with prescription opioids to get high, most commonly marijuana and alcohol. The most common sources for obtaining prescription opioids were family/friends. CONCLUSIONS Two cohorts of recreational opioid users from Canada and the United States reported similar experiences with various prescription opioids and indicated a predominance of diversion from family/friends.