Pharmacokinetics and Dose Proportionality of Fentanyl Effervescent Buccal Tablets in Healthy Volunteers

Transmucosal drug administration as an alternative route in palliative and end-of-life care during the COVID-19 pandemic

The Coronavirus disease 2019 (COVID-19) pandemic has led to a surge in need for alternative routes of administration of drugs for end of life and palliative care, particularly in community settings. Transmucosal routes include intranasal, buccal, sublingual and rectal. They are non-invasive routes for systemic drug delivery with the possibility of self-administration, or administration by family caregivers. In addition, their ability to offer rapid onset of action with reduced first-pass metabolism make them suitable for use in palliative and end-of-life care to provide fast relief of symptoms. This is particularly important in COVID-19, as patients can deteriorate rapidly. Despite the advantages, these routes of administration face challenges including a relatively small surface area for effective drug absorption, small volume of fluid for drug dissolution and the presence of a mucus barrier, thereby limiting the number of drugs that are suitable to be delivered through the transmucosal route. In this review, the merits, challenges and limitations of each of these transmucosal routes are discussed. The goals are to provide insights into using transmucosal drug delivery to bring about the best possible symptom management for patients at the end of life, and to inspire scientists to develop new delivery systems to provide effective symptom management for this group of patients.

Safety, Tolerability, and Dose Proportionality of a Novel Transdermal Fentanyl Matrix Patch and Bioequivalence With a Matrix Fentanyl Patch: Two Phase 1 Single-Center Open-Label, Randomized Crossover Studies in Healthy Japanese Volunteers

Two open‐label, single‐dose, randomized crossover studies were conducted in healthy Japanesemen to (1) assess dose proportionality of 5 doses (1.38, 2.75, 5.5, 8.25, and 11.0 mg) of Lafenta, a novel matrix‐type transdermal fentanyl patch with a rate‐controlling membrane; and (2) compare patch bioequivalence (11.0 mg) with a commercially available reference patch (Durotep MT Patch [16.8 mg]). Pharmacokinetics, adhesion performance, residual fentanyl, and safety parameters were assessed. Increases in mean AUC_0‐t and C_max after application of the test patch were dose proportional. The test patch (11.0 mg) was bioequivalent to the 16.8‐mg reference patch in terms of mean AUC_0‐inf, AUC_0‐t, and C_max. Residual fentanyl levels 72 hours postapplication were lower in the test than in the reference patch. Differences in adhesion performance between the test and the reference patch did not affect delivery efficacy and reliability of the novel matrix patch. Safety findings were in line with previous experiences with fentanyl. Both studies showed low variation in fentanyl exposure and delivery via the test patch. The test patch provided equivalent fentanyl exposure at a lower dose than the reference patch formulation with lower variability and the potential to lower medicinal waste.

Initial titration with 200 μg fentanyl buccal tablets: a retrospective safety analysis in Korean cancer patients

BACKGROUND/AIMS

Managing breakthrough pain (BTP) is important for many cancer patients because of the rapid onset and unpredictable nature of the pain episodes. Fentanyl buccal tablets (FBTs) are a rapid-onset opioid indicated for BTP management. However, FBT titration is needed to optimize BTP management. In this study, we aimed to evaluate the safety and efficacy of initiating 200 μg FBTs in Korean cancer patients.

METHODS

A retrospective analysis of medical records was performed on all advanced cancer patients treated with FBTs for BTP between October 2014 and July 2015. Patients who received initial doses of 200 μg FBTs for at least 3 days and cases in which FBT was available at doses of 200, 400, and 800 μg were included.

RESULTS

A total of 56 patients with a median age of 62 years (range, 32 to 80) were analyzed, 61% of whom were male. The median and mean values of morphine equivalent daily doses were 60 mg/day (range, 15 to 540) and 114.8 ± 124.8 mg/day, respectively. The most frequent effective doses of FBT were 200 μg (41 patients, 74%) and 400 μg (12 patients, 21%). Three patients (5%) could not tolerate 200 μg of FBT and discontinued treatment. Nausea, vomiting, somnolence, and dizziness were the most frequent treatment-related adverse events (AEs), and all AEs were grade 1 (mild) or 2 (moderate).

CONCLUSIONS

FBT at the initial 200 μg dosage was well-tolerated and effective as a BTP management strategy in Korean cancer patients. Further prospective studies are needed to determine appropriate initiating doses of FBT in Korean patients with opioid tolerance.

Challenges of post-authorization safety studies: Lessons learned and results of a French study of fentanyl buccal tablet

PURPOSE

Recruiting and retaining participants in real-world studies that collect primary data are challenging. This article illustrates these challenges using a post-authorization safety study (PASS) to assess adverse events (AEs) experienced with fentanyl buccal tablet (FBT) over 3 months of treatment.

METHODS

This was an observational, prospective, multicenter study in France conducted over 1 year. The study employed primary data collection in FBT-treated patients and their treating physicians via a site qualification questionnaire and patient log completed by physicians and a questionnaire and pain diary completed by patients. Strategies to increase participation included reminders, newsletters, frequent follow-up telephone calls, and reducing the extent of data collected.

RESULTS

Of the 1118 physicians contacted who returned the participation form or responded to a telephone call, only 128 expressed willingness to participate. Key reasons for non-participation were lack of interest (69.7%) and FBT not being used in practice by the contacted physician (25.1%). Overall, 224 patients were screened by 31 physicians, and 97 were enrolled. Key reasons for patient non-inclusion were unwillingness or inability to complete the patient AE diary or questionnaire (40.9% [52/127]) and patients' decision (33.9% [43/127]).

CONCLUSIONS

Despite efforts to increase participation, enrollment in this study was low. Recruitment and retention methods are limited in their capacity to optimally execute a primary data collection in a PASS. For a PASS to provide reliable and valid information on medication use, involvement from health care agencies, regulators, and pharmaceutical companies is needed to establish their importance, drive study participation, and reduce patient withdrawal.

Rapid acting fentanyl formulations in breakthrough pain in cancer. Drug selection by means of the System of Objectified Judgement Analysis

Drug selection of rapid acting fentanyl formulations in the treatment of breakthrough pain in patients with cancer is performed by the System of Objectified Judgement Analysis method. All seven available formulations were included in the analysis. The following selection criteria were used: number of available strengths, variability in the rate of absorption, interactions, clinical efficacy, side effects, ease of administration and documentation. No direct double-blind comparative studies between two or more formulations were identified and the clinical documentation of all formulations is limited. The most distinguishing criterion was ease of use. This led to slightly higher scores for Abstral, Instanyl and PecFent than for the other formulations. The pros and cons of each formulation should be discussed with the patient, and the most suitable formulation selected for each individual patient.

Management of the acute painful crisis in sickle cell disease- a re-evaluation of the use of opioids in adult patients

Management of the acute painful crisis (APC) of sickle cell disease (SCD) remains unsatisfactory despite advances in the understanding and management of acute pain in other clinical settings. One reason for this is an unsophisticated approach to the use of opioid analgesics for pain management. This applies to haematologists who are responsible for developing acute sickle pain management protocols for their patients, and to health care staff in the acute care setting. The objective of this article is to evaluate the evidence for use of opioids in APC management. We have highlighted the possibilities for improving management by using alternatives to morphine, and intranasal (IN) or transmucosal routes of administration for rapid onset of analgesia in the emergency department (ED). We suggest how experience gained in managing acute sickle pain in children could be extrapolated to adolescents and young adults. We have also questioned whether patients given strong opioids in the acute setting are being safely monitored and what resources are required to ensure efficacy, safety and patient satisfaction. We also identify aspects of care where there are significant differences of opinion, which require further study by randomized controlled trial.

Clinical pharmacology of fentanyl buccal tablet for the treatment of breakthrough pain

Fentanyl buccal tablet (FBT) is a new formulation of fentanyl providing rapid-onset analgesia for the treatment of breakthrough pain. FBT has been approved for the management of breakthrough pain in patients with cancer who are already receiving and who are tolerant to opioid therapy for underlying persistent pain. FBT has demonstrated a favorable pharmacokinetic profile, which is closely aligned to the rapid onset and duration of an episode of breakthrough pain, and is generally safe and well tolerated.

Pharmacokinetics and dose proportionality of fentanyl sublingual spray: a single-dose 5-way crossover study

BACKGROUND

Fentanyl sublingual spray is a novel formulation of fentanyl for sublingual delivery that was designed to enhance the rate and extent of absorption of fentanyl for management of breakthrough cancer pain (BTCP).

OBJECTIVES

The primary objective of this study was to determine the pharmacokinetics and dose proportionality of 5 different doses (100, 200, 400, 600, and 800 μg) of fentanyl sublingual spray in healthy subjects under fasted conditions (part A); the secondary objective was to assess the effects of temperature and pH in the oral cavity on relative bioavailability of fentanyl (part B).

METHODS

Analyses were performed on venous blood samples drawn 5 min to 36 h after administration of fentanyl sublingual spray (Subsys(®), Insys Therapeutics, Inc., Chandler, AZ, USA). Part A of this phase I study was a 5-treatment, 5-sequence, 5-period crossover study in which subjects received a single treatment of each of the 5 fentanyl sublingual spray doses. Dose proportionality was assessed using analysis of variance and linear regression techniques. Part B was a 5-treatment, 2-sequence, 5-period crossover study in which subjects received a single assigned dose of fentanyl sublingual spray 200 μg under the following 5 conditions: no pretreatment, pretreatment with cold or hot beverage, and pretreatment with low- or high-pH beverage. Naltrexone was administered to block potential opioid effects associated with fentanyl. Adverse events (AEs) were monitored and recorded throughout the study.

RESULTS

Fifty-three subjects (15 men, 38 women; mean age, 31 years) were enrolled in part A. Fourteen subjects (11 men, 3 women; mean age, 32 years) were enrolled in part B. The first quantifiable mean plasma concentrations of fentanyl were observed at the first sample time (5 min) for all doses. Mean maximum plasma concentration (C(max)) increased with increases in dose, whereas median time to reach C max (t max) tended to decrease with increases in dose. The dose-normalized C(max), area under the plasma concentration-time curve from time zero to infinity (AUC∞), and AUC from time zero to time of last measurable concentration (AUClast) values were linear and consistent with dose proportionality across the 100-800 μg dose range. Pretreatment of the oral cavity with a cold or hot beverage, or low- or high-pH beverage, did not appreciably alter fentanyl absorption (C(max) and AUC∞ values). The most commonly reported AEs were nausea and vomiting.

CONCLUSIONS

In healthy subjects, administration of fentanyl sublingual spray produced a rapid rise in fentanyl plasma concentrations. Dose-dependent parameters (C max and AUC) showed dose proportionality across the range of 100-800 μg. Altering the local environment of the oral cavity (temperature and pH) showed no effects on the bioavailability of fentanyl. The rapid and predictable rise in plasma fentanyl concentrations following administration of fentanyl sublingual spray corresponds with the rapid onset and duration of many BTCP episodes.

A review of the pharmacokinetic profile of transmucosal fentanyl formulations

BACKGROUND AND OBJECTIVES

Breakthrough pain (BTP) is a transitory flare of moderate-to-severe pain that occurs in patients with stable, controlled persistent pain. Management of BTP episodes is difficult because frequency, time-to-peak intensity, and duration of episodes vary both within and between individuals. Formulations of fentanyl that use a buccal, sublingual, or nasal transmucosal route of administration have been developed for the treatment of BTP in opioid-tolerant patients with cancer. These formulations allow rapid passage into the bloodstream and avoid first-pass metabolism and, therefore, are more likely to match the time-course of BTP episodes than are oral formulations. The purposes of this analysis were to identify and review published data describing the pharmacokinetic properties of rapid-onset fentanyl formulations and to evaluate these properties in view of the temporal dynamic characteristics of BTP in order to help guide medical practice.

METHODS

Relevant publications were searched in the PubMed database from 1998. The plasma drug concentration-time profile of each formulation obtained from the identified studies was adjusted to a consistent scale for comparison.

RESULTS

The data revealed that the various transmucosal formulations resulted in three typical plasma fentanyl concentration profiles: (1) type 1: a very rapid rise and short duration; (2) type 2: a rapid increase and sustained intensity; and (3) type 3: a slower onset and longer duration.

CONCLUSIONS

Given the substantial variability of BTP episodes experienced by patients, these pharmacokinetic differences may provide useful information for a physician who is selecting a rapid-onset opioid medication for a patient.

Intranasal drug delivery: an efficient and non-invasive route for systemic administration: focus on opioids

Intranasal administration is a non-invasive route for drug delivery, which is widely used for the local treatment of rhinitis or nasal polyposis. Since drugs can be absorbed into the systemic circulation through the nasal mucosa, this route may also be used in a range of acute or chronic conditions requiring considerable systemic exposure. Indeed, it offers advantages such as ease of administration, rapid onset of action, and avoidance of first-pass metabolism, which consequently offers for example an interesting alternative to intravenous, subcutaneous, oral transmucosal, oral or rectal administration in the management of pain with opioids. Given these indisputable interests, fentanyl-containing formulations have been recently approved and marketed for the treatment of breakthrough cancer pain. This review will outline the relevant aspects of the therapeutic interest and limits of intranasal delivery of drugs, with a special focus on opioids, together with an in-depth discussion of the physiological characteristics of the nasal cavity as well as physicochemical properties (lipophilicity, molecular weight, ionisation) and pharmaceutical factors (absorption enhancers, devices for application) that should be considered for the development of nasal drugs.

Fentanyl for breakthrough pain: a systematic review

The purpose of this article is to systematically review the use of fentanyl as an analgesic for breakthrough pain. This article found that the oral transmucosal fentanyl (OTFC) had a quicker onset to analgesia than oral immediate-release opioids. Intranasal fentanyl (INFS) had a quicker onset to analgesia than buccal tablets, which in turn had a quicker onset to analgesia than OTFC. Patient acceptance and global rating of efficacy were greater for INFS than for buccal fentanyl. OTFC and INFS have been used effectively to reduce acute pain in children who are opioid-naive. Abuse and addiction to OTFC, fentanyl buccal tablets and INFS was low, owing to patient selection.

Fentanyl buccal tablets for the treatment of breakthrough pain

SUMMARY Fentanyl buccal tablets (FBT) have been designed to treat breakthrough pain (BTP) in patients who are already receiving, and who are tolerant to, opioid therapy for their underlying persistent pain. FBT are a formulation that uses an effervescent drug delivery system to enhance penetration across the buccal mucosa. OraVescent technology provides an effervescent reaction that liberates carbon dioxide in the buccal cavity. This reaction causes an initial decrease in pH, which facilitates solubilization, thus driving fentanyl into solution. Subsequently, carbon dioxide increases the local pH, which facilitates permeation of unionised fentanyl across the buccal mucosa. In clinical studies of opioid-tolerant patients with cancer and noncancer-related BTP, FBT have provided consistent and clinically relevant improvements in pain intensity and pain relief relative to placebo and oral opioids like oxycodone. The safety and tolerability profile is generally typical of that observed with other opioids. The pharmacokinetic properties of FBT allow for a meaningful clinical efficacy, with an onset of action that closely matches the onset of BTP. FBT, as with any other transmucosal preparations of fentanyl, should not be used in patients who are not opioid-tolerant.

Pharmacokinetics of fentanyl buccal tablet: a pooled analysis and review

Fentanyl buccal tablet (FBT) is indicated for the treatment of breakthrough pain in patients who are already receiving and are tolerant to opioid therapy for underlying, persistent cancer pain. FBT is designed to enhance the rate and efficiency of absorption of fentanyl through the buccal mucosa. FBT was shown to be dose proportional from 100 to 1,300 μg. This analysis provides an overview of the pharmacokinetic profile of FBT based on pooled data from nine pharmacokinetic studies. In all, 365 healthy non-opioid-tolerant adults receiving naltrexone were included in the analysis. Single-dose (100 to 1,300 μg) pharmacokinetic parameters were dose normalized to 100 μg. Pharmacokinetic measures included maximum observed plasma drug concentration (C(max)), plasma drug concentration versus time curve from time zero to infinity (AUC(0-∞)), time to reach C(max) (T(max)), apparent plasma terminal elimination rate constant, and elimination half-life. After FBT administration, fentanyl was rapidly absorbed, with T(max) ranging from 20 minutes to 4 hours postdose. Mean AUC(0-∞) was 1.49 ng•hour/mL, and mean C(max) was 0.237 ng/mL. However, plasma fentanyl concentration reached 80% of C(max) within 25 minutes and was maintained through 2 hours after administration. Based on the individual studies, bioequivalence was shown for sublingual and buccal tablet placement, and no significant effect of dwell time (duration of FBT presence in the oral cavity) was observed. The pharmacokinetic profile of FBT was characterized by rapid absorption, which is consistent with the rapid-onset efficacy profile of FBT observed in clinical studies.

Pharmacokinetics, safety, and tolerability of ascending doses of sublingual fentanyl, with and without naltrexone, in Japanese subjects

This open-label, nonrandomized study assessed single and repeat ascending doses of a new sublingual fentanyl (SLF) formulation in 48 healthy Japanese opiate-naïve subjects (47 completed). Subjects received single-dose SLF 100, 200, 400, or 800 µg followed by 13 doses 6 hourly, at their dose level. Subjects taking repeat-dose 400 and 800 µg were pretreated with naltrexone in order to block opiate-receptor-mediated effects on respiration, monitored by pulse oximetry and transcutaneous pco(2). Sublingual fentanyl was rapidly and consistently absorbed. After single doses, median t(first) was 0.08 to 0.25 hours and t(max) 0.50 to 1.00 hours. After repeat dosing, median t(max) (t(max,ss)) was 0.50 to 2.00 hours. Plasma concentrations were dose proportional both after single and repeat dosing, and naltrexone appeared to have no effect on SLF pharmacokinetics. Plasma fentanyl reached steady state within the 72-hour dosing period and accumulation was approximately 2-fold. After single doses, effects on respiratory variables were evident after the 400-µg and 800-µg doses. Transcutaneous pco(2) was not helpful in detecting respiratory depression. Thus, SLF yielded rapid absorption of fentanyl and dose-proportional plasma concentrations that, for 400 µg and 800 µg, were within the typical analgesic range. Respiratory depression in these opioid-naïve volunteers was manageable with simple clinical measures.

Dose proportionality of fentanyl buccal tablet in doses ranging from 600 to 1300 microg in healthy adult subjects: a randomized, open-label, four-period, crossover, single-centre study

Fentanyl buccal tablet (FBT) is indicated for the treatment of breakthrough pain in patients who are already receiving, and who are tolerant to, opioid therapy for underlying, persistent cancer pain. Breakthrough pain may be severe or excruciating, and some patients may require high doses of rapid-onset opioids to obtain adequate analgesia. The objective of this study was to assess the dose proportionality of FBT over a range of 600-1300 microg in healthy subjects. This was a randomized, open-label, four-period, crossover, single-centre study of FBT (Fentora) conducted in healthy adult subjects who were not tolerant to opioids. The study included 120 men and women aged 18-45 years with a body mass index of 20-30 kg/m2 who had no clinically significant findings on medical and psychiatric histories, physical examination, ECG or standard clinical laboratory tests, and who had a negative urine screen for drugs and alcohol. Eligible subjects were randomized to one of four dose sequences: ABDC, BCAD, CDBA and DACB, where A, B, C and D were FBT doses from lowest to highest (600, 1000, 1200 and 1300 microg). Each dose of FBT was separated by a minimum of 7 days. Naltrexone 50 mg was administered to block the opioid receptor-mediated effects of fentanyl. Plasma fentanyl concentration was measured through 72 hours after placement of FBT. The main outcome measures, maximum plasma fentanyl concentration (C(max)) and area under the plasma drug concentration versus time curve from time zero to infinity (AUC(infinity)), were analysed to determine dose proportionality. Other pharmacokinetic parameters were also evaluated. Dose proportionality was concluded if the two-sided 90% confidence intervals (CIs) for the slopes of the C(max) versus dose and AUC(infinity) versus dose curves were completely contained within the range of 0.711-1.289. The safety and tolerability of FBT were assessed throughout the study. The slope for C(max) versus dose was 0.8627 (90% CI 0.7730, 0.9525), and the slope for AUC(infinity) versus dose was 0.9330 (90% CI 0.8738, 0.9922). Given that the CIs for C(max) and AUC(infinity) were within the predefined range of 0.711-1.289, dose proportionality was concluded over the 600-1300 microg range. The mean dose-normalized plasma fentanyl concentration reached 80% of C(max) within 25 minutes; plasma fentanyl concentration was maintained at this level for 3 hours after dose. No unexpected safety or tolerability concerns were noted in the naltrexone-blocked healthy subjects. Seventy-four subjects (68%) experienced adverse events (AEs); all were mild (56 [51%]) or moderate (18 [17%]). The most common AEs were nausea, dizziness and headache. No serious AEs were reported. The dose proportionality of FBT from 600-1300 microg was shown in healthy subjects. Based on the data, when FBT is titrated up to 1300 microg, a predictable and linear increase in systemic exposure can be expected. Currently, FBT is approved up to 800 microg. This study provides pharmacokinetic data to support a potential, expanded therapeutic dose range of FBT.

Fentanyl buccal tablet for the treatment of breakthrough pain: pharmacokinetics of buccal mucosa delivery and clinical efficacy

The treatment of breakthrough pain (BTP), a transitory exacerbation of pain that occurs on a background of otherwise-controlled, persistent pain, requires an opioid formulation and/or method of administration that can provide rapid and extensive systemic exposure. Fentanyl buccal tablet (FBT; FENTORA^®, Cephalon, Inc.) employs OraVescent^® drug delivery technology, which enhances the rate and extent of fentanyl absorption. OraVescent technology enhances the oral dissolution and buccal absorption of fentanyl, which facilitates rapid uptake of fentanyl into the bloodstream, reducing gastrointestinal absorption and minimizing extensive first-pass metabolism. The resulting pharmacokinetic profile of FBT is characterized by greater bioavailability and a higher early systemic exposure compared with the earlier oral transmucosal fentanyl citrate formulation. In clinical studies of opioid-tolerant patients with cancer-related and noncancer-related BTP, FBT has provided consistent and clinically relevant improvements in pain intensity and pain relief relative to placebo, with a safety and tolerability profile that is generally typical of that observed with other potent opioids. The pharmacokinetic properties of FBT allow for meaningful clinical efficacy, with an onset of action that closely matches the onset of BTP.

Single-dose pharmacokinetics of fentanyl buccal soluble film

Objective

The objectives of the study were to determine the absolute bioavailability of fentanyl from fentanyl buccal soluble film, estimate the percentage of a fentanyl dose absorbed through the buccal mucosa, and compare the bioavailability of equivalent doses administered either as single or multiple dose units.

Design

Open-label, randomized, four-period, Latin-square crossover pharmacokinetic study.

Setting

Inpatient phase 1 unit.

Patients

Twelve healthy volunteers.

Interventions

Injectable fentanyl citrate (200 µg) administered by intravenous infusion, injectable fentanyl citrate (800 µg/16 mL) administered orally, and fentanyl buccal soluble film (800 µg) administered as a single film and as four separate 200 µg films simultaneously.

Outcome Measures

Plasma concentrations after fentanyl dosing; pharmacokinetic parameters.

Results

The two buccal film treatments were bioequivalent and both had an absolute bioavailability of 71%. The percentage of an administered dose absorbed through the buccal mucosa was calculated to be 51%.

Conclusions

Fentanyl buccal soluble film effectively delivers a high percentage of the administered fentanyl dose and nearly identical plasma profiles are obtained when equivalent doses are delivered by single or multiple dosage units.

Formulations of fentanyl for the management of pain

Fentanyl is an opioid initially developed for parenteral administration. While oral administration is not an option due to a high first-pass metabolism, its high potency and lipophilicity have made a number of new routes of administration feasible. The transdermal therapeutic system offers an excellent option for long-term treatment of cancer and chronic pain, achieving stable plasma concentrations over the treatment period. The recent change from reservoir to matrix systems has made these systems more convenient to wear and safer to use, while being bioequivalent. In contrast, the patient-controlled iontophoretic transdermal system has been developed to enable on-demand delivery of transdermal bolus doses of fentanyl to treat postoperative pain. It offers a needle-free system to provide patient-controlled analgesia otherwise offered by intravenous pumps. However, due to technical difficulties the system is currently not clinically available. Oral transmucosal fentanyl utilizes the rapid uptake through the buccal mucosa to achieve high plasma concentrations rapidly and is indicated to treat breakthrough pain in patients who are not opioid-naive. The recently introduced fentanyl buccal tablets offer slightly better pharmacokinetics for the same indication. The intranasal route is another option to achieve rapid uptake of fentanyl, and is currently being investigated to provide acute and breakthrough pain relief. Transpulmonary administration of fentanyl remains experimental and this route of administration is not yet in clinical use. Overall, the specific pharmacological and physicochemical properties of fentanyl have made this compound highly suitable for novel routes of administration in a range of clinical indications.

Exploratory assessment of dose proportionality: review of current approaches and proposal for a practical criterion

This article reviews currently used approaches for establishing dose proportionality in Phase I dose escalation studies. A review of relevant literature between 2002 and 2006 found that the power model was the preferred choice for assessing dose proportionality in about one-third of the articles. This article promotes the use of the power model and a conceptually appealing extension, i.e. a criterion based on comparing the 90% confidence interval for the ratio of predicted mean values from the extremes of the dose range (R(dnm)) to pre-defined equivalence criterion (theta(L),theta(U)). The choice of bioequivalence default values of theta(L)=0.8 and theta(U)=1.25 seems reasonable for dose levels only a doubling apart but are impractically strict when applied over the complete dose range. Power calculations are used to show that this prescribed criterion lacks power to conclude dose proportionality in typical Phase I dose-escalation studies. A more lenient criterion with values theta(L)=0.5 and theta(U)=2 is proposed for exploratory dose proportionality assessments across the complete dose range.

A new transmucosal drug delivery system for patients with breakthrough cancer pain: the fentanyl effervescent buccal tablet

Breakthrough pain, a transitory severe pain with the background of otherwise controlled persistent pain has a prevalence between 52% and 67% in outpatients with cancer. Medications for such sudden-onset pain require non-invasive delivery of a potent and short-acting opioid for rapid pain relief. Although oral transmucosal delivery of fentanyl citrate (OTFC) has been shown to provide better pain relief than a typical oral opioid administration such as morphine sulfate immediate release (MSIR) in the management of breakthrough pain in patients with cancer-related pain, newer delivery systems offer a potential for further enhancement of pain relief. The fentanyl effervescent buccal tablet (FBT) formulation employs a novel drug delivery system that relies on an effervescence reaction to improve buccal fentanyl absorption. Using the effervescence reaction results in the production and dissipation of carbon dioxide with a dynamic shift in pH as the tablet dissolves. The induced low pH favors dissolution of fentanyl citrate in saliva (higher water solubility). The subsequent increase in pH thereafter favors the buccal absorption of non-ionized fentanyl across the buccal mucosa. Such a pH “pumping” mechanism increases the permeation of fentanyl into and through the buccal to the vascular system from where the agent is transported to the specific opioid receptor sites in the CNS. Compared with OTFC, data in healthy volunteers show that the effervescence reaction employed in FBT increases the total amount and the speed of absorption of fentanyl being absorbed. Compared with OTFC there is an increase in peak fentanyl blood concentrations, and an enhancement of the amount of buccal delivery of fentanyl. Such favorable data are underlined by the results of clinical studies where the FBT technology was studied in patients with breakthrough pain in chronic malignant pathologies.

Extent of Fentanyl Accumulation Following Multiple Doses of Fentanyl Buccal Tablet 400 microg in Healthy Japanese Volunteers

Objective

This study was conducted to characterize the pharmacokinetics, including extent of accumulation, and safety and tolerability of fentanyl following multiple doses of fentanyl buccal tablet (FBT) in healthy Japanese volunteers.

Methods

Healthy Japanese adults received 10 successive doses of open-label FBT 400 µg at 6-hour intervals. Naltrexone was given to minimize the opioid effects of fentanyl. FBT was placed above a molar tooth between the gum and cheek. Peak serum fentanyl concentration (C_max), time to C_max (t_max), and area under the serum fentanyl concentration-time curve from 0 to 6 hours (AUC_0–6) were summarized using descriptive statistics. Accumulation ratio was calculated as C_max for dose 10/C_max for dose 1, and was calculated similarly for AUC_0–6.

Results

Fourteen volunteers (mean age 33 years) were enrolled, and 13 completed the study. After doses 1 and 10, respectively, mean (SD) C_max was 1.70 (0.49) ng/mL and 1.97 (0.42) ng/mL, AUC_0–6 was 4.46 (1.14) ng·h/mL and 6.81 (0.90) ng·h/mL, and median (range) t_max was 50 (30–110) minutes and 30 (15–120) minutes. Following 10 successive doses, systemic exposure (AUC_0–6) was 55% higher than after dose 1, and C_max was 23% higher. Steady state was achieved within 3 days of dosing at 6-hour intervals, i.e., prior to dose 10. The most frequent adverse events (AEs) were somnolence (N = 9), decreased oxygen saturation (N = 4), headache (N = 3), application-site pain (N = 8), application-site erythema (N = 6), and application-site reaction (N = 5). All AEs were mild or moderate.

Conclusions

Following administration of FBT at 6-hour intervals to healthy Japanese volunteers, at steady state, fentanyl exposure was higher by 55% (AUC_0–6) and 23% (C_max) than after a single dose of FBT. Adverse events were mild or moderate.

Current developments in opioid therapy for management of cancer pain

Pain remains a highly prevalent problem for patients with cancer and typically falls into one of 3 types: visceral, somatic, and neuropathic. A mechanistic, pathophysiologic approach to pain management involves a good assessment of the type of pain, followed by tailoring of the treatment based on the diagnosis. This pain management strategy can provide rapid pain control with a lower incidence of complications and side effects than other methods. Furthermore, pharmacogenetics may play an important role in individualizing therapies in the future, but for now this type of data offers explanations for phenomena commonly observed in clinical practice, such as (1) differences in individual analgesic and side-effect responses to various opioid agents, (2) incomplete cross-tolerance seen when switching between mu opioid analgesics, and (3) why opioid rotation can be beneficial for patients after an opioid therapy loses efficacy or becomes associated with intolerable side effects. Especially for difficult-to-manage pain patients, additions to the opioid analgesic armamentarium can potentially better individualize pain management, and provide another option to be used for opioid rotation. Among the most recent Food and Drug Administration-approved opioid analgesics for acute pain and persistent pain are oral immediate-release and extended-release formulations of oxymorphone, whereas for breakthrough pain, the ultrarapid-acting opioid, fentanyl effervescent buccal tablets, has newly been developed and indicated within the United States.

Management of breakthrough pain in patients with cancer

Breakthrough pain (BTP) in patients with cancer lacks a consensus definition and is subsequently inadequately diagnosed and assessed, therefore making it more challenging to manage. Cancer pain is generally moderate to severe in intensity and persistent in nature. Despite the problematic definition of BTP, it is generally described as having similar intensity, but may also be transitory and variable in predictability. Most breakthrough analgesia fails to be effective in the time required for BTP. No useful analgesia is therefore provided but drug adverse effects escalate. Cancer pain management relies on the WHO analgesic ladder. The frequency of BTP and its inadequate management means that it has significant adverse effects on patients, their families and those involved in their care. This article outlines a systematic, clinical and evidence-based approach to managing BTP in patients with cancer that emphasizes a holistic approach and an understanding of multidimensional 'total pain'. Guidelines for managing BTP are presented and areas of developing research are identified.

Effect of buccal dwell time on the pharmacokinetic profile of fentanyl buccal tablet

BACKGROUND

The time fentanyl buccal tablet (FBT) takes to completely dissolve after placement on the buccal mucosa (i.e., 'dwell time') could exceed the time to onset of analgesia.

OBJECTIVE

To examine the relationship between FBT dwell time and fentanyl pharmacokinetic parameters.

RESEARCH DESIGN AND METHODS

This was a post hoc exploratory analysis of data from two randomized, open-label, crossover, pharmaco-kinetic studies that were designed to assess dose proportionality within the anticipated therapeutic dose range. Healthy adults received single FBT doses of 200-1080 microg in Study 1 (n = 28) and 270-1300 microg in Study 2 (n = 42).

MAIN OUTCOME MEASURES

Assessments included buccal dwell time, defined as the duration of FBT presence in the oral cavity, and the following pharmacokinetic measures: maximum serum concentration (C(max)), time to C(max) (T(max)) and area under the concentration-time curve (AUC; exposure) from 0 minutes to median T(max) adjusted for the dose (T(max')) (AUC(0 T(max'))). Spontaneously reported adverse events were recorded.

RESULTS

Mean buccal dwell time for FBT across the dose range varied from 14 to 25 minutes (range 3 - 62 minutes). There was no evidence of an association between FBT dwell time and values for T(max) (medians 45 - 60 minutes), dose-normalized C(max) (means 0.42-0.66 pg/ml/200 microg) or dose-normalized AUC(0 T(max')) (means 0.24-0.38 pg x h/ml/200 microg) over the range of FBT doses delivered. All adverse events reported were mild to moderate; none were unexpected or serious.

CONCLUSION

The pharmacokinetic parameters of FBT did not appear to be related to its buccal dwell time.

Absolute and relative bioavailability of fentanyl buccal tablet and oral transmucosal fentanyl citrate

This study assessed the absolute and relative bioavailabilities and transmucosal and gastrointestinal absorbency of fentanyl buccal tablet (FBT) and oral transmucosal fentanyl citrate (OTFC). In a randomized crossover design, 26 healthy subjects received FBT 400 microg (transmucosal), FBT 800 microg (oral), OTFC 800 microg (transmucosal), and fentanyl 400 microg (intravenous). The transmucosal FBT had the highest absolute bioavailability (0.65) compared with the oral FBT (0.31) or transmucosal OTFC (0.47). More fentanyl was absorbed transmucosally from FBT than OTFC (48% vs 22%). Median t(max) values were shorter following the transmucosal FBT (47 minutes) than the oral FBT (90 minutes) or the transmucosal OTFC (91 minutes). Transmucosal administration of FBT compared with dose-normalized OTFC resulted in higher total systemic fentanyl exposure, higher early systemic exposure, and higher C(max). The rate and extent of fentanyl absorption were greater following administration of FBT compared to OTFC. An approximately 30% smaller dose of FBT achieved systemic exposures comparable to OTFC.

Fentanyl buccal tablet for the relief of breakthrough pain in opioid-tolerant adult patients with chronic neuropathic pain: a multicenter, randomized, double-blind, placebo-controlled study

BACKGROUND

Patients with chronic noncancer pain, including neuropathic pain, may have transitory exacerbations of pain (median duration, 60 minutes), termed breakthrough pain (BTP), that may reach peak intensity within minutes. Typical short-acting oral opioids may not provide sufficiently rapid relief (30- to 60-minute onset of analgesia). The fentanyl buccal tablet (FBT) provides a rapid onset of analgesia (10-15 minutes) by enhancing fentanyl absorption across the buccal mucosa.

OBJECTIVE

This study evaluated the efficacy and tolerability of FBT in opioid-tolerant patients with BTP associated with chronic noncancer neuropathic pain.

METHODS

This was a multicenter, randomized, double-blind, placebo-controlled study in men and women aged 18 to 80 years who were opioid tolerant; had a >/= 3-month history of chronic persistent neuropathic pain associated with diabetic peripheral neuropathy, postherpetic neuralgia, traumatic injury, or complex regional pain syndrome; and reported having episodes of BTP. After an open-label titration period to identify an effective FBT dose (the dose at which the patient reported receiving adequate pain relief within 30 minutes after administration of a single tablet of that dose during at least 2 of 3 BTP episodes), patients were randomly assigned to treat 9 consecutive episodes of BTP over the next 21 days with 1 of 3 double-blind dose sequences of FBT and placebo tablets. Pain intensity (PI) (rated on an 11-point pain scale, from 0 = no pain to 10 = worst pain) and other outcomes were assessed before dosing and for 2 hours after dosing. The primary efficacy measure was the sum of PI differences (PIDs) for the first 60 minutes (SPID(60)). Secondary efficacy measures included the proportion of BTP episodes with >/= 33% and >/= 50% improvement in PI from baseline; PID at other time points (5, 10, 15, 30, 45, 60, 90, and 120 minutes after dosing); pain relief (PR) at the same time points (rated on a 5-point Likert scale from 0 = none to 4 = complete); proportion of BTP episodes with meaningful PR; time to meaningful PR; and proportion of BTP episodes in which supplemental medication was required after administration of study drug. Adverse events (AEs) spontaneously reported by the patient or elicited by the investigator were recorded throughout the study.

RESULTS

Of 102 patients in the open-label titration period, 80 identified an effective dose of FBT and 79 entered the double-blind phase. Of these 79 patients, 77 (97%) completed the study and 75 (95%) were evaluable for efficacy. Of the 79 patients who entered the double-blind phase, 63% were women and 92% were white; their mean (SD) age was 48.3 (10.42) years, and their mean weight was 96.8 (33.42) kg. Baseline demographic and pain characteristics were similar between the overall population and the double-blind population. SPID(60) was significantly greater for BTP episodes treated with FBT compared with those in which placebo was administered (mean [SE], 9.63 [0.75] vs 5.73 [0.72], respectively; P < 0.001). Significant differences between FBT and placebo were seen beginning at 10 minutes for PID (mean, 0.740 [0.149] vs 0.427 [0.081]; P < 0.047) and PR (mean, 0.561 [0.087] vs 0.324 [0.056]; P < 0.001). A >/= 33% improvement in PI from baseline was seen in a greater proportion of BTP episodes treated with FBT compared with placebo from 10 minutes (9% vs 3%; P = 0.008) through 2 hours (66% vs 37%; P < 0.001). Patients were almost 4 times less likely to require supplemental opioids when BTP episodes were treated with FBT compared with placebo (odds ratio = 0.28; 95% Cl, 0.18-0.42). AEs were reported by 64 (63%) of 102 patients. The most commonly reported AEs were those typical of opioids (nausea [13%], dizziness [13%], somnolence [10%], and vomiting [5%]) and occurred more often during the dose-titration phase (55/102 [54%]) than during the double-blind phase (22/79 [28%]).

CONCLUSION

In these opioid-tolerant patients with chronic neuropathic pain who identified an effective FBT dose, FBT had a rapid onset of action and was effective and well tolerated in the treatment of BTP.

Fentanyl buccal tablet: faster rescue analgesia for breakthrough pain?

Breakthrough pain (BTP) is an unmet clinical need that is still poorly diagnosed, evaluated and inadequately treated. The prevalence of BTP has been estimated to affect at least 64% of cancer patients. Two pain-relief strategies were proposed: preventive and active ('rescue'). Oral short-acting opioid seems to be the most popular approach for BTP treatment, however, it is likely to be inadequate for a substantial proportion of patients as a result of the slow-onset of most available opioid preparations. Fentanyl buccal tablet (FBT) is a novel delivery system for fentanyl citrate. FBT utilizes OraVescent technology to improve bioavailability and speed of drug delivery. Recent studies have demonstrated superior pharmacokinetic profiles when compared with other available transmucosal opioids (OTFC), however, pharmacodynamic data are still somewhat limited.

Rational Use of Sublingual Opioids in Palliative Medicine

The sublingual administration of opioid analgesics has been a mainstay in the pain management of homebound dying hospice patients who are no longer able to swallow. It is also a potentially useful route of administration in other situations in which the oral route is not available and other routes are impractical or inappropriate. Potential advantages of the sublingual route include rapid analgesic onset and avoidance of hepatic first-pass metabolism. Pharmacokinetic and pharmacodynamic studies have yielded widely disparate data on sublingual morphine. Other opioids have been less studied. Available data suggests limited sublingual availability of hydrophilic opioids (e.g., morphine, oxycodone, and hydromorphone) and superior absorption of the lipophilic opioids (e.g., methadone and the fentanils). Buprenorphine, a potent, lipophilic, partial mu-opioid receptor agonist, appears promising but awaits further study.

Fentanyl Effervescent Buccal Tablet

Each month, subscribers to The Formulary Monograph Service receive five to six well-documented monographs on drugs that are newly released or are in late phase 3 trials. The monographs are targeted to your Pharmacy and Therapeutics Committee. Subscribers also receive monthly one-page summary monographs on the agents that are useful for agendas and pharmacy/nursing in-services. A comprehensive target drug utilization evaluation (DUE) is also provided each month. With a subscription, the monographs are sent to you in print and CD-ROM forms and are available online. Monographs can be customized to meet the needs of your facility. Subscribers to the The Formulary Monograph Service also receive access to a pharmacy bulletin board, The Formulary Information Exchange (The F.I.X.). All topics pertinent to clinical and hospital pharmacy are discussed on The FIX.

Through the cooperation of The Formulary, Hospital Pharmacy publishes selected reviews in this column. If you would like information about The Formulary Monograph Service or The F.I.X., call The Formulary at 800-322-4349. The March 2007 monograph topics are paliperidone extended-release tablets, retapamulin ointment 1%, estradiol gel, diclofenac sodium solution 1.5%, and oral beclomethasone dipropionate. The DUE is on paliperidone extended-release tablets.

Single-dose and steady-state pharmacokinetics of fentanyl buccal tablet in healthy volunteers

This study evaluated the single-dose and steady-state pharmacokinetics of fentanyl buccal tablet 400 microg in healthy adult volunteers. After receiving naltrexone 50 mg to block opioid receptor-mediated effects of fentanyl, subjects received fentanyl buccal tablet 400 microg on day 1, then every 6 hours from day 4 to day 9 (21 doses). Naltrexone 50 mg was administered every 12 hours throughout the study. Plasma fentanyl concentrations were determined for 72 hours after administration of fentanyl buccal tablet 400 microg on day 1 and the last dose of fentanyl buccal tablet 400 microg on day 9. Following single- and multiple-dose administration of fentanyl buccal tablet, the median time to maximum concentration (tmax) was 52.2 and 49.8 minutes, respectively. Peak plasma concentration of fentanyl (Cmax) was 0.88 ng/mL for the single-dose regimen and 1.77 ng/mL for the multiple-dose regimen. Steady state was reached within 5 days, consistent with the observed median half-life of approximately 22 hours following multiple doses. Observed accumulation of fentanyl after multiple doses of fentanyl buccal tablet was slightly greater than would be expected based on the single-dose data. This was attributed to the redistribution of fentanyl from a deep tissue compartment into the plasma. This study indicates that fentanyl buccal tablet has predictable pharmacokinetics following multiple-dose administration.

Fentanyl buccal tablet (FBT) for relief of breakthrough pain in opioid-treated patients with chronic low back pain: a randomized, placebo-controlled study

BACKGROUND

Short-acting opioids are commonly used to treat breakthrough pain (BTP) and rapid-onset formulations are being developed to improve the effectiveness of this approach. Fentanyl buccal tablet (FBT) is a new formulation of fentanyl that enhances transbuccal drug delivery via an effervescent reaction and may provide relatively rapid-onset analgesia. FBT was evaluated for BTP in opioid-treated patients with chronic low back pain--the first such study in a population with chronic non-cancer pain.

DESIGN

Randomized, double-blind, placebo-controlled.

PATIENTS AND SETTING

Patients with chronic low back pain receiving long-term opioid therapy at 16 pain treatment centers in the United States.

PROCEDURES

Following open-label titration to identify an effective FBT dose, patients were randomly assigned to one of three double-blind dose sequences (six doses of FBT, three placebo) to treat nine BTP episodes. Pain intensity (PI), measured on an 11-point scale (0 = no pain; 10 = worst pain), and other outcomes were assessed for 2 h after dosing.

DATA ANALYSIS

The primary efficacy measure was the sum of pain intensity differences (PIDs) for the first 60 min (SPID60); secondary efficacy measures included PIDs at other time points, pain relief (PR), meaningful PR, time to meaningful PR, use of supplementary BTP medication, and self/investigator-reported adverse events.

RESULTS

Of the 124 patients screened, 105 patients were enrolled, 84 identified an effective FBT dose, and 77 entered the double-blind phase. SPID60 significantly favored FBT (p < 0.0001). All secondary measures also favored FBT, with PIDs and PR showing significant differences versus placebo as early as 10 and 15 min, respectively. An improvement in PI score of > or = 33% occurred in a significantly larger proportion of FBT-treated episodes versus placebo from 15 min (20% vs. 11%, p < 0.01) through 2 h (65% vs. 28%, p < 0.0001). Patients were approximately four times more likely to require supplemental opioids for BTP episodes following administration of placebo compared with episodes treated with FBT. AEs were typical for opioids, and were mostly reported during dose titration. Limitations of this study may be related to its open-label dose-titration phase (which has the potential to compromise blinding) and the recruitment of patients from pain clinics, which could potentially yield a study population that is not representative of the general population with BTP.

CONCLUSIONS

FBT was efficacious and well tolerated in the treatment of BTP in opioid-treated patients with chronic low back pain.

Absorption of Fentanyl from Fentanyl Buccal Tablet in Cancer Patients With or Without Oral Mucositis

BACKGROUND AND OBJECTIVES

Patients with cancer, particularly those undergoing chemotherapy or radiotherapy, may develop oral mucositis. This is the first study to investigate the absorption profile of fentanyl buccal tablet (FBT) - an effervescent formulation of fentanyl indicated for the management of breakthrough pain in opioid-tolerant cancer patients - in patients with or without oral mucositis.

METHODS

In this open-label study, patients with or without oral mucositis self-administered a single 200 microg dose of FBT by placing the tablet between the upper gum and cheek above a molar tooth. Venous blood samples for measurement of plasma fentanyl concentrations were collected at regular intervals up to 8 hours following FBT administration. Parameters of interest included maximum plasma concentration (C(max)), time to reach C(max) (t(max)), area under the plasma concentration-time curve from time zero to 8 hours (AUC(8)), and AUC from time zero to the median t(max) (AUC(tmax)(')). Adverse events were monitored throughout the study. Oral mucosal examinations and measurements of vital signs were performed at intervals up to 8 hours following FBT administration.

RESULTS

Sixteen patients, 8 with and 8 without oral mucositis, received FBT and completed the study. The severity of oral mucositis was mild in the patients exhibiting this condition. Median C(max) values were comparable: 1.14 ng/mL (range 0.26-2.69 ng/mL) in patients with mucositis, and 1.21 ng/mL (range 0.21-2.34 ng/mL) in patients without mucositis. The t(max) was not significantly different in the two groups: median t(max) was 25.0 min (range 15-45 min) in patients with mucositis and 22.5 min (range 10-121 min) in patients without mucositis. Median AUC(tmax') values were 0.17 ng . h/mL (range 0.04-0.52 ng . h/mL) in patients with mucositis, and 0.20 ng . h/mL (range 0.00-0.65 ng . h/mL) in patients without mucositis. The corresponding AUC(8) values were 2.05 ng . h/mL (range 1.16-3.83 ng . h/mL) and 1.55 ng . h/mL (range 0.74-3.07 ng . h/mL), respectively. FBT was generally well tolerated in this small group. No application site adverse events or changes in oral mucosal assessments were reported.

CONCLUSION

The absorption profile of a single dose of FBT 200 microg was similar in patients with or without mild oral mucositis. The compound was generally well tolerated.

Pharmacokinetic properties of fentanyl effervescent buccal tablets: A phase I, open-label, crossover study of single-dose 100, 200, 400, and 800 μg in healthy adult volunteers

BACKGROUND

The fentanyl effervescent buccal tablet (FEBT) is designed to enhance the rate and extent of the absorption of fentanyl, an opioid, through the buccal mucosa.

OBJECTIVES

The purposes of this study were to assess the dose proportionality of FEBT in healthy volunteers over the potential therapeutic dose range (100-800 microg) and characterize the pharmacokinetic (PK) profile of 4 doses (100, 200, 400, and 800 microg) of FEBT.

METHODS

This Phase I, randomized, open-label, 4-period crossover study was conducted at Radiant Research, Honolulu, Hawaii. Healthy adult volunteers with intolerance to opioids were randomly assigned to receive 1 of 4 single-dose sequences of FEBT: 100, 200, 400, and 800 microg (selected to encompass the anticipated therapeutic dose range), with each successive administration separated by a washout period of >or=7 days. Naltrexone hydrochloride (50-mg tablet) was administered-15 and 3 hours before and 9 hours after FEBT administration to block opioid receptor-mediated effects of fentanyl. Plasma fentanyl concentrations were measured from venous samples obtained over 72 hours after FEBT administration. Early fentanyl exposure was assessed using AUC from time 0 to 0.75 hour (the median T(max) of the reference dose [100 microg]) (AUC(0-Tmax')). Adverse events (AEs) were monitored and recorded throughout the study by medically qualified personnel.

RESULTS

Thirty-two subjects (26 men, 6 women; mean [SD] age, 29.3 [7.2] years [range, 19-44 years]; mean [SD] weight, 74.7 [10.7] kg) were enrolled. Median T was between 35 and 45 minutes after FEBT administration. AUC(0-infinity) and C(max) increased approximately linearly with increasing doses of FEBT. Mean plasma fentanyl concentrations decreased from C(max) in a biexponential manner at the 100- and 200-microg doses and decreased in a triexponential manner at the 800-mug dose. Despite the triexponential decrease in the mean profile observed with the 400-microg dose, a biexponential decrease was observed in approximately half of the individual profiles. AUC(0-Tmax') ranged from 0.09 ng x h/mL with the 100-microg dose to 0.52 ng x h/mL with the 800-microg dose. The most commonly reported AEs in the 100-, 200-, 400-, and 800-microg dose groups were as follows: application-site erythema, 3, 3, 4, and 3 subjects, respectively; nausea, 3, 2, 5, and 4 subjects; somnolence, 3, 2, 3, and 2 subjects; and headache, 3, 2, 1, and 4 subjects. None of the AEs were serious.

CONCLUSIONS

In this study of the dose proportionality of FEBT in healthy volunteers, the PK profile of FEBT was characterized by a high early systemic exposure of fentanyl (0.09-0.52 ng x h/mL). Dose-dependent parameters (C(max) and AUC) increased in an approximately dose-proportional manner from 100 to 800 microg FEBT.

Relative bioavailability of the fentanyl effervescent buccal tablet (FEBT) 1080 pg versus Oral transmucosal fentanyl citrate 1600 pg and dose proportionality of FEBT 270 to 1300 μg: A single-dose, randomized, open-label, three-period study in healthy adult volunteers

BACKGROUND

The fentanyl effervescent buccal tablet (FEBT) was designed to enhance the rate and extent of absorption of fentanyl through the buccal mucosa. FEBT is being investigated for the management of breakthrough pain.

OBJECTIVES

The primary objective of this study was to compare the relative bioavailability of FEBT 1,080 microg with that of oral transmucosal fentanyl citrate (OTFC) 1,600 microg, and the secondary objective was to assess the dose proportionality of FEBT 270 to 1,300 microg in healthy adult volunteers.

METHODS

This single-dose, randomized, open-label, 3-period study was conducted by MDS Pharma Services, Lincoln, Nebraska. Non-opioid-tolerant healthy adult volunteers were included. In periods 1 and 2 (relative-bioavailability analysis), subjects were randomly assigned to 1 of 2 administration sequences: single-dose FEBT 1,080 microg followed by single-dose OTFC 1,600 microg, or vice versa; in period 3 (dose-proportionality analysis), they were randomly assigned to receive a single dose of FEBT 270, 810, or 1,300 microg. Subjects were instructed to place FEBT between the gum and cheek above an upper molar tooth and allow it to disintegrate for 10 minutes. Subjects were instructed to place the OTFC lozenge between the cheek and lower gum and move the unit from side to side using the handle and allow the unit to dissolve for 15 minutes. All subjects received naltrexone 50 mg PO at 15 and 3 hours before and 12 hours after fentanyl administration, except those receiving FEBT 270 microg, who were not given naltrexone at 12 hours. For the measurement of serum concentrations of fentanyl, venous blood samples were collected before and up to 36 hours after study drug administration. For tolerability analysis, continuous pulse oximetry, 12-lead electrocardiography, clinical laboratory analysis, and physical examination, including vital-sign measurements, were performed; the oral mucosa was inspected; and spontaneous reporting was employed.

RESULTS

A total of 42 subjects were enrolled (25 women, 17 men; mean [SD] age, 27 [11] years; mean [SD] weight, 68.4 [8.7] kg); 39 completed the study. Total systemic exposure (as measured using AUC(0-infinity))) was statistically similar between FEBT 1,080 microg and OTFC 1,600 microg (mean [SD], 18.0 [5.4] vs 18.0 [7.1] ng x h/mL). However, the mean (SD) C(max) with FEBT 1,080 microg was 2.7 (0.9) ng/mL compared with 2.2 (0.7) ng/mL with OTFC 1,600 microg (P = NS), and the T(max) of 1.0 hour with FEBT was significantly less compared with OTFC (2.0 hours; P < 0.001). Similarly, mean (SD) early systemic exposure (AUC(0-Tmax'); ie, AUC from time 0 to 1 hour the median T(max) of the reference dose of FEBT [810 microg]) was significantly greater with FEBT compared with OTFC (1.5 [0.5] vs 0.8 [0.4] ng x h/mL; P < 0.001). Exploratory analyses suggested dose proportionality as assessed using AUC(0-infinity) and AUC(0-Tmax') over the range of FEBT 270 to 1,300 microg. Increases in C(max) were less than dose proportional at FEBT doses >810 microg. Definitive attribution of adverse events (AEs) to FEBT or OTFC was generally not possible because these medications were coadministered with naltrexone. With naltrexone alone, there were reports of headache (3 [7%] subjects), nausea (1 [2%]), upset stomach (1 [2%]), and low systolic blood pressure (1 [2%]) after naltrexone administration, but before FEBT or OTFC administration. The AEs were typical of opioids (ie, headache, nausea, lightheadedness), and most (89.6%) were mild. One case each of mild oral irritation and redness were reported after the administration of FEBT Both occurrences resolved within 4.5 hours after study drug administration. No irritation or redness was reported after the administration of OTFC.

CONCLUSIONS

In this pharmacokinetic study in healthy volunteers, total systemic exposure increased in a dose-proportional manner up to FEBT 1,300 microg, whereas doses above 810 microg showed a less-than-dose-proportional increase in C(max). The results suggest that fentanyl enters the systemic circulation to a significantly greater extent (C(max) and AUC(0-Tmax')) and significantly more rapidly (T(max)) with FEBT compared with OTFC.