USL255 extended-release topiramate: dose-proportional pharmacokinetics and tolerability in healthy volunteers

Safety, pharmacokinetics and pharmacodynamics of SHR-1703, an innovative long-acting anti-interleukin-5 monoclonal antibody, in healthy subjects: a randomized, double-blind, dose-escalation, placebo-controlled phase I study

OBJECTIVE

SHR-1703 is a novel humanized IgG1 monoclonal antibody with high IL-5 affinity and prolonged half-life, aiming to control eosinophil-related diseases. The study intended to evaluate pharmacokinetics, pharmacodynamics, immunogenicity, safety, and tolerability of SHR-1703 in healthy subjects.

METHODS

A single-center, randomized, double-blind, placebo-controlled, single-dose escalation phase I study was conducted. 42 subjects were allocated to sequentially receive single subcutaneous injection of 20, 75, 150, 300, and 400 mg SHR-1703 or placebo.

RESULTS

After administration, SHR-1703 was slowly absorbed with median Tmax ranging from 8.5 to 24.5 days. Mean t1/2 in 150 to 400 mg doses was 86 to 100 days. Cmax and AUC increased in nearly dose-proportional pattern over range of 75 to 400 mg SHR-1703. After receiving SHR-1703, peripheral blood eosinophils (EOS) greatly decreased from baseline, which showed no significant change from baseline in placebo group. Magnitude and duration of reduction of EOS rose with increased dosing of SHR-1703. In 400 mg dose, remarkable efficacy of reducing EOS maintained up to approximately 6 months post single administration. Moreover, SHR-1703 exhibited low immunogenicity (2.9%), favorable safety, and tolerability in healthy subjects.

CONCLUSION

Pharmacokinetics, pharmacodynamics, immunogenicity, safety, and tolerability of SHR-1703 support further clinical development of SHR-1703 in eosinophil-associated diseases.

CLINICAL TRIAL REGISTRATION

The study was registered on the ClinicalTrials.gov (identifier: NCT04480762).

Pharmacokinetics, pharmacodynamics, safety and tolerability of FTP-198, a novel, selective Autotaxin inhibitor, in healthy subjects: A phase I randomized placebo-controlled trial

BACKGROUND

Autotaxin (ATX) and lysophosphatidic acid (LPA) play an important role in pathogenesis of idiopathic pulmonary fibrosis (IPF). FTP-198 is an oral, novel and selective ATX inhibitor indicated for treating IPF. The study aimed to investigate the pharmacokinetics, pharmacodynamics, safety and tolerability of FTP-198 in healthy subjects.

METHODS

A single-center, randomized, double-blind, placebo-controlled, single ascending-dose Phase I study was performed. Pharmacokinetics, pharmacodynamics, food effect on pharmacokinetics, elimination, safety and tolerability of FTP-198 were evaluated.

RESULTS

A total of 30 subjects were enrolled and completed the study. After oral administration of single ascending-dose of 100 mg, 300 mg and 400 mg FTP-198 under fasted condition, FTP-198 was absorbed with median time to reach peak concentration (Tmax) of 1.75, 2.75 and 3.5 h, respectively and eliminated with mean elimination half-life (t1/2) of 8.77, 10.58 and 10.57 h, respectively. Peak concentration (Cmax), plasma area under concentration-time curve from time 0 to the last measurable concentration (AUC0-t) and to infinity (AUC0-∞) increased in dose-proportional manner for 100 mg to 400 mg FTP-198. Food intake slightly increased the Cmax, AUC0-t and AUC0-∞ and prolonged Tmax, but not affecting t1/2 of FTP-198 compared with fasted state. The pharmacodynamic biomarker plasma lysophosphatidic acid (LPA) 18:2 decreased significantly for 100 mg to 400 mg FTP-198, with inhibition rate from baseline reaching approximately 80% at 24 h post dosing, and higher dose of FTP-198 increased the time to maintain inhibitory plateau. FTP-198 was eliminated from the body almost with no unchanged drug excreted in urine and a small amount of unchanged drug detected in feces of human. Moreover, FTP-198 exhibited favorable safety and tolerability in healthy subjects.

CONCLUSION

Pharmacokinetics, pharmacodynamics, safety and tolerability of FTP-198 support further subsequent clinical development of FTP -198 in IPF patients.

The pharmacokinetics of single oral dose extended-release topiramate and adverse effects after multi-dose administration in healthy cats

Current treatment options for feline epilepsy are limited to medications that require administration of multiple doses per day or administration of a capsule or large tablet. Expanding the current treatment options could improve patient and owner compliance and optimize seizure control. Topiramate has been used sparingly in veterinary medicine, and limited pharmacokinetic studies have focused on immediate release formulations in dogs. If effective and safe, topiramate extended-release (XR) could broaden the current treatment options for feline epilepsy. The aims of this two-phase study were to establish single-dose pharmacokinetics for topiramate XR in cats, identify a dosing regimen that maintains steady-state plasma drug concentrations within a reference range extrapolated from human medicine (5-20 μg/mL), and evaluate the safety of topiramate XR in cats following multidose administration. Topiramate XR administered orally at 10 mg/kg once daily for 30 days was sufficient to achieve the desired concentrations in all cats. While no clinically apparent adverse effects were observed, four out of eight cats developed subclinical anemia, calling into question the safety of topiramate XR with chronic administration. Further studies are necessary to better understand the potential adverse effects and overall efficacy of topiramate XR for the treatment of feline epilepsy.

Use of extended-release and immediate-release anti-seizure medications with a long half-life to improve adherence in epilepsy: A guide for clinicians

Poor adherence to anti-seizure medications (ASMs) is associated with breakthrough seizures and potentially increased toxicity in patients with epilepsy. Extended-release (ER) drugs and immediate-release (IR) drugs with a long half-life (t_1/2) that permit once-daily dosing (such as, perampanel, zonisamide, lamotrigine [IR, ER] and topiramate [ER]) have a number of advantages over short t_1/2 ASMs that require multiple daily dosing. These advantages include simplification of dosing regimens, reduction in pill burden, and a decrease in the peak-to-trough fluctuations in serum drug concentration that may be associated with a decreased risk of adverse effects and seizures. Such properties have wider implications in improving patient adherence to treatment. This article is intended as a practical guide for clinicians that provides an overview of the features of ER ASMs and long t_1/2 IR ASMs that are advantageous in the context of patient adherence and pharmacokinetic "forgiveness" (after missing a dose). In addition, we note that efforts to improve adherence should not depend solely on drug dosing regimens and drug pharmacokinetics, but should be part of a wider strategy that includes therapeutic drug monitoring, improved healthcare provider-patient dialogue, patient education, and the use of "reminder" technology.

Usefulness of extended-release topiramate in patients with epilepsy: A two-year retention study

WHAT IS KNOWN AND OBJECTIVE

Extended-release topiramate (TPM-XR) was recently approved for the treatment of epilepsy, but there is only limited real-world information on the clinical usefulness of TPM-XR in epilepsy patients. We investigated the usefulness of TPM-XR in clinical practice by analysing the retention of TPM-XR in adult epilepsy patients.

METHODS

We performed a single-centre retrospective study covering two years. Epilepsy patients taking TPM-XR were included in the study and classified into one of three groups: the monotherapy group, in which patients took only TPM-XR; the adjunctive therapy group, in which patients took TPM-XR concomitant with other AEDs; and the switching AED regimen group, in which patient's AED was switched from immediate-release TPM (TPM-IR) to TPM-XR. We evaluated the retention rates of TPM-XR and analysed the differences in retention rate among the three patient groups.

RESULTS AND DISCUSSION

We included 164 epilepsy patients who received TPM-XR for the treatment of epilepsy. The overall retention rate of TPM-XR was generally favourable: 79.1% after one year and 77.7% after two years. The switching AED regimen group had a better retention rate than the other two groups (p = 0.04), with a one-year retention rate of 90.6% and a two-year retention rate of 88.1%.

WHAT IS NEW AND CONCLUSION

The favourable retention rate of TPM-XR shows that TPM-XR can be an effective treatment option for epilepsy patients, as either a monotherapy or as an adjunctive therapy. Additionally, switching AED regimen to TPM-XR from TPM-IR can be considered in selected epilepsy patients with poor adherence to TPM-IR.

Extended-release drug formulations for the treatment of epilepsy

INTRODUCTION

Extended-release (ER) preparations are either available or have been tested for several antiepileptic drugs (AEDs). Indeed, they may be helpful in improving efficacy, tolerability, adherence, compared to the corresponding immediate release (IR) preparations available. The use of ER preparations has been advocated in women of childbearing age and is - depending on the drug - especially helpful in patients who are treated in combination with enzyme inducing AEDs as well as in children.

AREAS COVERED

Clinical and pharmacokinetic studies on ER formulations of AEDs were identified by a PubMed literature research. Further references were added from the authors' personal knowledge and from the reference lists of the identified studies. Reviews and expert commentaries were included, where necessary.

EXPERT OPINION

Unfortunately, studies providing direct comparisons of ER and IR formulations of a given drug are only available for a handful of drugs. ER preparations are especially helpful in drugs with a short elimination half-life and concentration-depending efficacy and tolerability.

Pharmacokinetic Variability of Drugs Used for Prophylactic Treatment of Migraine

In this review, we evaluate the variability in the pharmacokinetics of 11 drugs with established prophylactic effects in migraine to facilitate 'personalized medicine' with these drugs. PubMed was searched for 'single-dose' and 'steady-state' pharmacokinetic studies of these 11 drugs. The maximum plasma concentration was reported in 248 single-dose and 115 steady-state pharmacokinetic studies, and the area under the plasma concentration-time curve was reported in 299 single-dose studies and 112 steady-state pharmacokinetic studies. For each study, the coefficient of variation was calculated for maximum plasma concentration and area under the plasma concentration-time curve, and we divided the drug variability into two categories; high variability, coefficient of variation >40%, or low or moderate variability, coefficient of variation <40%. Based on the area under the plasma concentration-time curve in steady-state studies, the following drugs have high pharmacokinetic variability: propranolol in 92% (33/36), metoprolol in 85% (33/39), and amitriptyline in 60% (3/5) of studies. The following drugs have low or moderate variability: atenolol in 100% (2/2), valproate in 100% (15/15), topiramate in 88% (7/8), and naproxen and candesartan in 100% (2/2) of studies. For drugs with low or moderate pharmacokinetic variability, treatment can start without initial titration of doses, whereas titration is used to possibly enhance tolerability of topiramate and amitriptyline. The very high pharmacokinetic variability of metoprolol and propranolol can result in very high plasma concentrations in a small minority of patients, and those drugs should therefore be titrated up from a low initial dose, depending mainly on the occurrence of adverse events.

Antiepileptic drugs in development pipeline: A recent update

Epilepsy is the most common neurological disorder which significantly affects the quality of life and poses a health as well as economic burden on society. Epilepsy affects approximately 70 million people in the world. The present article reviews the scientific rationale, brief pathophysiology of epilepsy and newer antiepileptic drugs which are presently under clinical development. We have searched the investigational drugs using the key words ‘antiepileptic drugs,’ ‘epilepsy,’ ‘Phase I,’ ‘Phase II’ and ‘Phase III’ in American clinical trial registers (clinicaltrials.gov), the relevant published articles using National Library of Medicine's PubMed database, company websites and supplemented results with a manual search of cross-references and conference abstracts. This review provides a brief description about the antiepileptic drugs which are targeting different mechanisms and the clinical development status of these drugs. Besides the presence of old as well as new AEDs, still there is a need of new drugs or the modified version of old drugs in order to make affected people free of seizures. An optimistic approach should be used to translate the success of preclinical testing to clinical practice. There is an urgent need to improve animal models and to explore new targets with better understanding in order to develop the novel drugs with more efficacy and safety.

•

This review primarily focused on antiepileptic drugs under clinical development.

•

The more realistic approach is needed to discover and develop the novel antiepileptic drugs.

•

Modification of conventional drugs or search of newer targets can lead to development of promising antiepileptic drugs.

•

To develop more efficacious and safe drugs for treatment of epilepsy and refractory seizures

•

There are a number of novel antiepileptic compounds which are under various stages of drug development.

Topiramate Extended Release: A Review in Epilepsy

Once-daily oral topiramate extended release (USL255; hereafter referred to as topiramate XR) [QUDEXY(®) XR] is approved in the USA for use as initial monotherapy and adjunctive therapy in patients aged ≥2 years with partial-onset seizures (POS) or primary generalized tonic-clonic seizures and as adjunctive therapy in patients aged ≥2 years with seizures associated with Lennox-Gastaut syndrome. Compared with twice-daily topiramate immediate release at the same total daily dose, topiramate XR provided bioequivalent exposure, an extended absorption rate (permitting convenient once-daily dosing) and more constant therapeutic plasma concentrations (potentially minimizing topiramate-associated adverse events). Switching between the two formulations did not affect the maintenance of topiramate concentrations. Moreover, the contents of a topiramate XR capsule may be sprinkled on to soft food for patients who have difficulty swallowing. In a multinational phase III study in adults with refractory POS, adjunctive topiramate XR was associated with significantly greater improvements from baseline in weekly median seizure frequency and the proportion of patients achieving a ≥50 % reduction in seizure frequency compared with placebo. These benefits were sustained during a 55-week open-label extension study. Adjunctive topiramate XR was generally well tolerated in these studies, with the majority of treatment-emergent adverse events being mild or moderate in intensity. In conclusion, current evidence suggests once-daily topiramate XR extends the treatment options currently available for patients aged ≥2 years with epilepsy, with its dosing regimen potentially delivering tolerability and adherence advantages over AEDs that require more frequent administration.

Clinical utility of topiramate extended-release capsules (USL255): Bioequivalence of USL255 sprinkled and intact capsule in healthy adults and an in vitro evaluation of sprinkle delivery via enteral feeding tubes

OBJECTIVE

The objectives of these two studies were to determine if beads from extended-release topiramate capsules sprinkled onto soft food are bioequivalent to the intact capsule and if beads from the capsule can be passed through enteral gastrostomy (G-) and jejunostomy (J-) feeding tubes.

METHODS

Bioequivalence of 200-mg USL255 (Qudexy XR [topiramate] extended-release capsules) sprinkled onto soft food (applesauce) versus the intact capsule was evaluated in a phase 1, randomized, single-dose, crossover study (N=36). Pharmacokinetic evaluations included area under the curve (AUC), maximum plasma concentration (Cmax), time to Cmax (Tmax), and terminal elimination half-life (t1/2). If 90% confidence intervals (CI) of the ratio of geometric least-squares means were between 0.80 and 1.25, AUC and Cmax were considered bioequivalent. In separate in vitro experiments, 100-mg USL255 beads were passed through feeding tubes using gentle syringe pressure to develop a clog-free bead-delivery method. Multiple tube sizes (14- to 18-French [Fr] tubes), dilutions (5 mg/15 mL-25 mg/15 mL), and diluents (deionized water, apple juice, Ketocal, sparkling water) were tested.

RESULTS

Area under the curve and Cmax for USL255 beads sprinkled onto applesauce were bioequivalent to the intact capsule (GLSM [90% CI]: AUC0-t 1.01 [0.97-1.04], AUC0-∞ 1.02 [0.98-1.05]; Cmax 1.09 [1.03-1.14]). Median Tmax was 4h earlier for USL255 sprinkled versus the intact capsule (10 vs 14 h; p=0.0018), and t1/2 was similar (84 vs 82 h, respectively). In 14-Fr G-tubes, USL255 beads diluted in Ketocal minimized bead clogging versus deionized water. Recovery of USL255 beads diluted in deionized water was nearly 100% in 16-Fr G-, 18-Fr G-, and 18-Fr J-tubes.

SIGNIFICANCE

For patients with difficulty swallowing pills, USL255 sprinkled onto applesauce offers a useful once-daily option for taking topiramate. USL255 beads were also successfully delivered in vitro through ≥14-Fr G- or J-tubes, with tube clogging minimized by portioning the dose and using glidant diluents for smaller tubes.

Modified-Release Formulations of Second-Generation Antiepileptic Drugs: Pharmacokinetic and Clinical Aspects

Modified-release or extended-release (XR) formulations are used to decrease the frequency of dosing for drugs with rapid elimination, to improve convenience and adherence. Use of a modified-release formulation can decrease the peak to trough fluctuations in serum concentrations and theoretically improve the therapeutic benefit of the drug, by decreasing adverse events associated with the higher peak concentrations. Once-daily formulations of lamotrigine (Lamictal XR(®)), levetiracetam (Keppra XR(®)), oxcarbazepine (Oxtellar XR(®), Apydan(®) extent) and topiramate (Qudexy XR™, Trokendi XR™) are approved for the treatment of focal and/or generalized onset seizures. Other seizure medications have been approved for non-epileptic symptoms. Gabapentin XR (Gralise(®)) is approved for the treatment of post-herpetic neuralgias. Gabapentin enacarbil XR (Horizant(®)) is a prodrug of gabapentin and is indicated for treatment of post-herpetic neuralgia and restless leg syndrome, a novel indication. For all but Qudexy XR™, the tablets/capsules must be swallowed whole, without cutting, crushing or chewing, in order to maintain the XR properties of the formulation. Qudexy XR™ can be swallowed intact or the capsules can be opened and sprinkled onto soft food for those with swallowing difficulties, for example, children and the elderly. The bioavailability of Gralise(®) and Horizant(®) is significantly affected by food, specifically fat content, and should be taken with a meal to maximize absorption. Overall, the primary advantage of the newly released XR formulations is the once-daily dosing to improve convenience and adherence, with very limited data suggesting improved tolerability.

A review of the efficacy and safety of extended-release topiramate in the adjunctive treatment for refractory partial-onset seizures

Topiramate has been widely utilized worldwide as an effective medication against partial- and generalized-onset seizures. Extended-release topiramate was developed to provide patients with the convenience of once-daily dosing and potentially improved tolerability by reducing serum concentration fluctuation. USL255 is a once-daily, extended-release formulation of topiramate, which was recently approved in the USA. Compared with immediate-release topiramate taken twice daily, once-daily USL255 provides equivalent topiramate exposure with a 26% reduction in plasma fluctuations. A multinational, phase III, randomized, double-blind, placebo-controlled clinical trial in patients with refractory partial-onset seizures demonstrated that USL255 (200 mg/day) significantly improved seizure control and was well tolerated with low overall neuropsychiatric and neurocognitive adverse events.

USL255 extended-release topiramate for the treatment of epilepsy

USL255 is a once-daily, extended-release formulation of the well-established antiepileptic drug topiramate that was recently approved by the US FDA. As a capsule formulation, USL255 can be swallowed intact or opened and sprinkled onto soft food for patients with swallowing difficulties, including children (≥2 years old) and older patients. USL255 has been evaluated in seven key Phase I and III studies. Compared with immediate-release topiramate taken twice daily, once-daily USL255 provides equivalent topiramate exposure with a 26% reduction in plasma fluctuations. A multinational, Phase III, randomized, double-blind, placebo-controlled clinical trial in patients with refractory partial-onset seizures (PREVAIL) demonstrated that USL255 (200 mg/day) significantly improved seizure control and clinical outcomes versus placebo. USL255 is generally safe and well-tolerated, with a low incidence of neuropsychiatric and neurocognitive adverse events. These data suggest that USL255 may provide a useful treatment option for seizure control with convenient once-daily dosing.