The Pharmacokinetics and Local Tolerability of a Novel Sublingual Formulation of Buprenorphine

Aim

The principal study objective was to investigate the pharmacokinetic characteristics and determine the absolute bioavailability and tolerability of a new sublingual (SL) buprenorphine wafer.

Methods

The study was of open label, two-way randomized crossover design in 14 fasted healthy male and female volunteers. Each participant, under naltrexone block, received either a single intravenous dose of 300 mcg of buprenorphine as a constant infusion over five minutes or a sublingual dose of 800 mcg of buprenorphine in two treatment periods separated by a seven-day washout period. Blood sampling for plasma drug assay was taken on 16 occasions throughout a 48-hour period (predose and at 10, 20, 30, and 45 minutes, 1, 1.5, 2, 2.5, 3, 4, 6, 8, 12, 24 and 48 hours postdose). The pharmacokinetic parameters were determined by noncompartmental analyses of the buprenorphine plasma concentration-time profiles. Local tolerability was assessed using modified Likert scales.

Results

The absolute bioavailability of SL buprenorphine was 45.4% (95% confidence interval = 37.8-54.3%). The median times to peak plasma concentration were 10 minutes and 60 minutes after IV and SL administration, respectively. The peak plasma concentration was 2.65 ng/mL and 0.74 ng/mL after IV and SL administration, respectively. The half-lives were 9.1 hours and 11.2 hours after IV and SL administration, respectively. The wafer had very good local tolerability.

Conclusions

This novel sublingual buprenorphine wafer has high bioavailability and reduced Tmax compared with other SL tablet formulations of buprenorphine. The wafer displayed very good local tolerability. The results suggest that this novel buprenorphine wafer may provide enhanced clinical utility in the management of both acute and chronic pain.

Background

Buprenorphine is approved for use in pain management and opioid addiction. Sublingual administration of buprenorphine is a simple and noninvasive route of administration and has been available for many years. Improved sublingual formulations may lead to increased utilization of this useful drug for acute and chronic pain management.

Immunogenicity and safety of an investigational tetravalent recombinant subunit vaccine for dengue: results of a Phase I randomized clinical trial in flavivirus-naïve adults

There is an unmet medical need for vaccines to prevent dengue. V180 is an investigational recombinant subunit vaccine that consists of truncated dengue envelope proteins (DEN-80E) for all 4 serotypes. Three dosage levels of the tetravalent DEN-80E antigens were assessed in a randomized, placebo-controlled, Phase I dose-escalation, first-in-human proof-of-principle trial in healthy, flavivirus-naïve adults in Australia (NCT01477580). The 9 V180 formulations that were assessed included either ISCOMATRIX™ adjuvant (2 dosage levels), aluminum-hydroxide adjuvant, or were unadjuvanted, and were compared to phosphate-buffered saline placebo. Volunteers received 3 injections of assigned product on a 0, 1, 2 month schedule, and were followed for safety through 1 year after the last injection. Antibody levels were assessed at 6 time-points: enrollment, 28 days after each injection, and 6 and 12 months Postdose 3 (PD3). Of the 98 randomized participants, 90 (92%) received all 3 injections; 83 (85%) completed 1-year follow-up. Immunogenicity was measured by a qualified Focus Reduction Neutralization Test with a 50% neutralization cutoff (FRNT₅₀). All 6 V180 formulations with ISCOMATRIX™ adjuvant showed robust immunogenicity, while the 1 aluminum-adjuvanted and 2 unadjuvanted formulations were poorly immunogenic. Geometric mean antibody titers generally declined at 6 months and 1 year PD3. All 9 V180 formulations were generally well tolerated. Formulations with ISCOMATRIX™ adjuvant were associated with more adverse events than aluminum-adjuvanted or unadjuvanted formulations.

A Phase I study of the pharmacokinetics, safety and tolerability of a novel tocopheryl phosphate mixture/oxymorphone transdermal patch system

AIM

Characterize the pharmacokinetic profile and tolerability of two tocopheryl phosphate mixture/oxymorphone patch formulations in healthy subjects, and the active metabolite (6-OH-oxymorphone).

MATERIALS & METHODS

Fifteen participants received a single application of oxymorphone patches +/- capsaicin for 72 h and were crossed-over for another 72 h.

RESULTS

Plasma oxymorphone was detected approximately 7 h and 6-OH-oxymorphone after approximately 18-19 h postapplication of both formulations, respectively. For oxymorphone, median t_max was 24 h, and C_max/C_min ratio was approximately 2.4. The most frequently reported treatment-related adverse event was application site reaction, mainly with capsaicin formulation.

CONCLUSION

Tocopheryl phosphate mixture/oxymorphone transdermal patches can successfully deliver therapeutic amounts of oxymorphone in a sustained manner over 72 h and are well tolerated. ANZCTR registration number: ACTRN12614000613606.

A phase I trial of PRN1008, a novel reversible covalent inhibitor of Bruton's tyrosine kinase, in healthy volunteers

AIM

To evaluate the safety, tolerability, and pharmacokinetics/pharmacodynamics of PRN1008, a novel Bruton's tyrosine kinase (BTK) inhibitor, in healthy volunteers, and thus determine the dose range for future clinical studies.

METHODS

This was a two-part randomized, placebo controlled study in healthy volunteers using a liquid formulation. Part I was a single ascending dose design with dose levels of 50-1200 mg (n = 6 active, two placebos per cohort); Part II was a multiple ascending dose design, with dose regimens ranging from 300 to 900 mg daily, either four times or twice daily for 10 days. Plasma pharmacokinetics, adverse events, vital signs, electrocardiograms and laboratory parameters were assessed. BTK occupancy in peripheral blood mononuclear cells was evaluated as a marker of target engagement.

RESULTS

PRN1008 was rapidly absorbed following oral administration, and was safe and well tolerated in all dose regimens evaluated in both single and multiple doses. PRN1008 demonstrated a large volume of distribution, and a half-life of approximately 3-4 h. BTK occupancy of >90% was observed within 4 h after dosing in both single and multiple dose regimens, and was closely linked to maximum plasma concentration. BTK occupancy decay was slow (-1.6% h^-1 ), and occupancy was sustained despite drug concentrations being undetectable. No severe or serious adverse events occurred, and the most common adverse events were gastrointestinal in nature.

CONCLUSIONS

PRN1008 was safe and well-tolerated following oral administration, and achieved high, sustained levels of BTK occupancy in peripheral blood mononuclear cells.

Epitope-specific immunotherapy targeting CD4-positive T cells in coeliac disease: two randomised, double-blind, placebo-controlled phase 1 studies

BACKGROUND

A gluten-free diet is the only means to manage coeliac disease, a permanent immune intolerance to gluten. We developed a therapeutic vaccine, Nexvax2, designed to treat coeliac disease. Nexvax2 is an adjuvant-free mix of three peptides that include immunodominant epitopes for gluten-specific CD4-positive T cells. The vaccine is intended to engage and render gluten-specific CD4-positive T cells unresponsive to further antigenic stimulation. We assessed the safety and pharmacodynamics of the vaccine in patients with coeliac disease on a gluten-free diet.

METHODS

We did two randomised, double-blind, placebo-controlled, phase 1 studies at 12 community sites in Australia, New Zealand, and the USA, in HLA-DQ2·5-positive patients aged 18-70 years who had coeliac disease and were on a gluten-free diet. In the screening period for ascending dose cohorts, participants were randomly assigned (1:1) by central randomisation with a simple block method to a double-blind crossover, placebo-controlled oral gluten challenge. Participants with a negative interferon γ release assay to Nexvax2 peptides after the screening oral gluten challenge were discontinued before dosing. For the biopsy cohorts, the screening period included an endoscopy, and participants with duodenal histology who had a Marsh score of greater than 1 were discontinued before dosing. Participants were subsequently randomly assigned to either Nexvax2 or placebo in ascending dose cohorts (2:1) and in biopsy cohorts (1:1) by central randomisation with a simple block method. In the three-dose study, participants received either Nexvax2 60 μg, 90 μg, or 150 μg weekly, or placebo over 15 days; in a fourth biopsy cohort, patients received either Nexvax2 at the maximum tolerated dose (MTD) or placebo. In the 16-dose study, participants received Nexvax2 150 μg or 300 μg or placebo twice weekly over 53 days; in a third biopsy cohort, patients also received either Nexvax2 at the MTD or placebo. In the 4-week post-treatment period, ascending dose cohorts underwent a further double-blind crossover, placebo-controlled oral gluten challenge, which had a fixed sequence, and biopsy cohorts had a gastroscopy with duodenal biopsies and quantitative histology within 2 weeks without oral gluten challenge. Participants, investigators, and study staff were masked to the treatment assignment, except for the study pharmacist. The primary endpoint was the number and percentage of adverse events in the treatment period in an intention-to-treat analysis. Both trials were completed and closed before data analysis. Trials were registered with the Australian New Zealand Clinical Trials Registry, numbers ACTRN12612000355875 and ACTRN12613001331729.

FINDINGS

Participants were enrolled from Nov 28, 2012, to Aug 14, 2014, in the three-dose study, and from Aug 3, 2012, to Sept 10, 2013, in the 16-dose study. Overall, 62 (57%) of 108 participants were randomly assigned after oral gluten challenge and 20 (71%) of 28 participants were randomly assigned after endoscopy. In the three-dose study, nine participants were randomly allocated to Nexvax2 60 μg and three to placebo (first cohort), nine were allocated to Nexvax2 90 μg and four to placebo (second cohort), eight were allocated to Nexvax2 150 μg and four to placebo (third cohort), and three were allocated to Nexvax2 150 μg and three to placebo (biopsy cohort). In the 16-dose study, eight participants were randomly allocated to Nexvax2 150 μg and four to placebo (first cohort), ten were allocated to Nexvax2 300 μg and three to placebo (second cohort), and seven were allocated to Nexvax2 150 μg and seven to placebo (biopsy cohort). The MTD for Nexvax2 was 150 μg because of transient, acute gastrointestinal adverse events with onset 2-5 h after initial doses of the vaccine, similar to those caused by gluten ingestion. In the ascending dose cohorts in the three-dose study, six (55%) of 11 placebo recipients, five (56%) of nine who received Nexvax2 60 μg, seven (78%) of nine who received Nexvax2 90 μg, and five (63%) of eight who received Nexvax2 150 μg had at least one treatment-emergent adverse event, as did all three (100%) placebo recipients and one (33%) of three Nexvax2 150 μg recipients in the biopsy cohort. In the ascending dose cohorts of the 16-dose study, five (71%) of seven placebo-treated participants, six (75%) of eight who received Nexvax2 150 μg, and all ten (100%) who received Nexvax2 300 μg had at least one treatment-emergent adverse event, as did six (86%) of seven placebo recipients and five (71%) of seven Nexvax2 150 μg recipients in the biopsy cohort. Vomiting, nausea, and headache were the only treatment-emergent adverse events that occurred in at least 5% of participants in either study. Among participants given the MTD, eight gastrointestinal treatment-emergent adverse events occurred in four (50%) of eight participants in the third cohort and none (0%) of three participants in the biopsy cohort in the three-dose study, and five events occurred in five (63%) of eight participants in the first cohort and three events in two (29%) of seven participants in the biopsy cohort of the 16-dose study. Median villous height to crypt depth ratio in distal duodenal biopsies was not significantly different between those who received the vaccine at the MTD on either schedule and those who received placebo. Of the participants who completed the post-treatment oral gluten challenge per protocol, interferon γ release assay to Nexvax2 peptides was negative (responders to treatment) in two (22%) of nine placebo-treated participants in the three-dose study versus two (33%) of six who received Nexvax2 60 μg, five (63%) of eight who received Nexvax2 90 μg, and six (100%) of six who received Nexvax2 150 μg (p=0·007); in the 16-dose study, none (0%) of five placebo-treated participants had a negative assay versus six (75%) of eight who received Nexvax2 150 μg (p=0·021).

INTERPRETATION

The MTD of Nexvax2 was 150 μg for twice weekly intradermal administration over 8 weeks, which modified immune responsiveness to Nexvax2 peptides without deterioration in duodenal histology. The gastrointestinal symptoms that followed the first intradermal administration of the vaccine resembled those associated with oral gluten challenge. These findings support continued clinical development of this potential therapeutic vaccine for coeliac disease.

FUNDING

ImmusanT.

Efficacy and safety of beloranib for weight loss in obese adults: a randomized controlled trial

AIM

To assess the efficacy, safety and tolerability of beloranib treatment for obesity.

METHODS

This phase II, double-blind, randomized study investigated the effects of beloranib suspension (0.6, 1.2 and 2.4 mg) or placebo, administered subcutaneously, for 12 weeks in 147 participants (primarily white women) with obesity. No diet or exercise advice was administered.

RESULTS

At week 12, beloranib resulted in dose-dependent progressive weight loss of -5.5 ± 0.5, -6.9 ± 0.6 and -10.9 ± 1.1 kg for the 0.6, 1.2 and 2.4 mg beloranib doses, respectively, compared with -0.4 ± 0.4 kg with placebo (all p < 0.0001 vs placebo). Weight loss with beloranib was associated with corresponding reductions in waist circumference and body fat mass, as well as improvements in lipids, high-sensitivity C-reactive protein and blood pressure. Sleep disturbance and gastrointestinal adverse events were more common with beloranib than with placebo; these were generally mild to moderate, transient and dose-related, and led to more early study withdrawals in participants in the group with the highest dose of beloranib.

CONCLUSIONS

In this 12-week phase II study, beloranib produced clinically and statistically significant weight loss and corresponding improvements in cardiometabolic risk factors. Beloranib appeared safe, and the 0.6 and 1.2 mg doses were generally well tolerated. The 2.4 mg dose was associated with increased sleep latency and mild to moderate gastrointestinal adverse events over the first month of treatment. These findings represent a novel mechanism for producing clinically meaningful weight loss.

Refined localisation of the genes for nebulin and titin on chromosome 2q allows the assignment of nebulin as a candidate gene for autosomal recessive nemaline myopathy

A locus for autosomal recessive nemaline myopathy (NEM2) has been assigned by linkage analysis to a 13-cM region between the markers D2S150 and D2S142 on 2q21.2-q22. The genes for the giant muscle proteins nebulin and titin have previously been assigned by FISH to 2q24.1-q24.2 and 2q31, respectively. By using radiation hybrid mapping, we have reassigned the nebulin gene close to the microsatellite marker D2S2236 on 2q22 and the titin gene to the vicinity of the markers D2S384 and D2S364 on 2q24.3. The genomic orientation of the nebulin gene was determined as 5'-3' and of TTN as 3'-5' from the centromere. We conclude that the nebulin gene resides within the candidate region for NEM2 on the long arm of chromosome 2, while the titin gene is located outside this region.