A randomized, vehicle-controlled, Phase 2b study of two concentrations of the TRPM8 receptor agonist AR-15512 in the treatment of dry eye disease (COMET-1)

The ion channel TRPM8 is a direct target of the immunosuppressant rapamycin in primary sensory neurons

BACKGROUND AND PURPOSE

The mechanistic target of rapamycin (mTOR) signalling pathway is a key regulator of cell growth and metabolism. Its deregulation is implicated in several diseases. The macrolide rapamycin, a specific inhibitor of mTOR, has immunosuppressive, anti-inflammatory and antiproliferative properties. Recently, we identified tacrolimus, another macrolide immunosuppressant, as a novel activator of TRPM8 ion channels, involved in cold temperature sensing, thermoregulation, tearing and cold pain. We hypothesized that rapamycin may also have agonist activity on TRPM8 channels.

EXPERIMENTAL APPROACH

Using calcium imaging and electrophysiology in transfected HEK293 cells and wildtype or Trpm8 KO mouse DRG neurons, we characterized rapamycin's effects on TRPM8 channels. We also examined the effects of rapamycin on tearing in mice.

KEY RESULTS

Micromolar concentrations of rapamycin activated rat and mouse TRPM8 channels directly and potentiated cold-evoked responses, effects also observed in human TRPM8 channels. In cultured mouse DRG neurons, rapamycin increased intracellular calcium levels almost exclusively in cold-sensitive neurons. Responses were markedly decreased in Trpm8 KO mice or by TRPM8 channel antagonists. Cutaneous cold thermoreceptor endings were also activated by rapamycin. Topical application of rapamycin to the eye surface evokes tearing in mice by a TRPM8-dependent mechanism.

CONCLUSION AND IMPLICATIONS

These results identify TRPM8 cationic channels in sensory neurons as novel molecular targets of the immunosuppressant rapamycin. These findings may help explain some of its therapeutic effects after topical application to the skin and the eye surface. Moreover, rapamycin could be used as an experimental tool in the clinic to explore cold thermoreceptors.

Quintessence of currently approved and upcoming treatments for dry eye disease

Dry eye disease (DED), also known as dry eye syndrome, is a multifactorial ocular surface disease. The aim of this review is to present the details of currently approved and upcoming treatment options for DED in a nutshell. We conducted a thorough literature search using PubMed and searched US FDA website, clinicaltrials.gov, and data available in public domain for currently approved and upcoming treatment options for DED. Currently, the US Food and Drug Administration (FDA)-approved medical treatments for treatment of DED include cyclosporine formulations (RESTASIS® [cyclosporine 0.05% ophthalmic emulsion], VEVYE® [cyclosporine 0.1% ophthalmic solution], and CEQUA™ [cyclosporine 0.09% ophthalmic solution]), XIIDRA® (lifitegrast), a leukocyte function-associated antigen-1 (LFA-1)/intracellular adhesion molecule-1(ICAM-1) inhibitor, EYSUVIS™ (loteprednol etabonate ophthalmic suspension 0.25%), a corticosteroid, and MIEBO™ (perfluorohexyloctane ophthalmic solution), a semifluorinated alkane. TYRVAYA™ (varenicline solution nasal spray), a cholinergic agonist, is another formulation approved for the treatment of the signs and symptoms of DED. The medical devices approved for treating DED due to meibomian glands dysfunction (MGD) include Lumenis OptiLight™ (intense pulsed light [IPL] device), TearCare® system, and TearScience™ LipiFlow™ thermal pulsation system. Punctal plugs are another treatment option approved for management of DED. There are hundreds of clinical studies evaluating newer treatments for managing the signs and symptoms. Cyclosporine formulations TJO-087 (cyclosporine A nanoemulsion 0.08%), SCAI-001 eye drops (cyclosporine 0.01%, 0.02%) are being evaluated against RESTASIS® and other approved treatments. The potential treatments being assessed include IC 265, OK-101, PL9643, SYL1001 (tivanisiran), SHJ002, OXERVATE® (cenegermin-bkbj ophthalmic solution 0.002%), HBM9036 (tanfanercept ophthalmic solution), OCS-02 (licaminlimab), MIM-D3 (tavilermide ophthalmic solution 5%), AR-15,512, BRM421, reproxalap, and AZR-MD-001 (selenium sulphide ointment 0.5%). The pathophysiology of DED is complex and multifactorial; there is a need to understand it even deeper. The new treatments and different delivery systems seem promising and provide a hope of effective treatment for DED.

Tolerability of Current Treatments for Dry Eye Disease: A Review of Approved and Investigational Therapies

Dry eye disease (DED) is a common, multifactorial ocular disease impacting 5% to 20% of people in Western countries and 45% to 70% in Asian countries. Despite the prevalence of DED and the number of treatment approaches available, signs and symptoms of the disease continue to limit the quality of life for many patients. Standard over-the-counter treatment approaches and behavior/environmental modifications may help some cases but more persistent forms often require pharmacological interventions. Approved and investigational pharmaceutical approaches attempt to treat the signs and symptoms of DED in different ways and tend to have varying tolerability among patients. While several pharmacological approaches are the standard for persistent and severe disease, mechanical options provide alternate treatment modalities that attempt to balance efficacy and comfort. Newer approaches target the causes of DED, utilizing novel delivery methods to minimize irritation and adverse events. Here, we review approved and investigational approaches to treating DED and compare patient tolerability.

Recent United States Developments in the Pharmacological Treatment of Dry Eye Disease

Dry eye disease (DED) can arise from a variety of factors, including inflammation, meibomian gland dysfunction (MGD), and neurosensory abnormalities. Individuals with DED may exhibit a range of clinical signs, including tear instability, reduced tear production, and epithelial disruption, that are driven by different pathophysiological contributors. Those affected often report a spectrum of pain and visual symptoms that can impact physical and mental aspects of health, placing an overall burden on an individual's well-being. This cumulative impact of DED on an individual's activities and on society underscores the importance of finding diverse and effective management strategies. Such management strategies necessitate an understanding of the underlying pathophysiological mechanisms that contribute to DED in the individual patient. Presently, the majority of approved therapies for DED address T cell-mediated inflammation, with their tolerability and effectiveness varying across different studies. However, there is an emergence of treatments that target additional aspects of the disease, including novel inflammatory pathways, abnormalities of the eyelid margin, and neuronal function. These developments may allow for a more nuanced and precise management strategy for DED. This review highlights the recent pharmacological advancements in DED therapy in the United States. It discusses the mechanisms of action of these new treatments, presents key findings from clinical trials, discusses their current stage of development, and explores their potential applicability to different sub-types of DED. By providing a comprehensive overview of products in development, this review aims to contribute valuable insights to the ongoing efforts in enhancing the therapeutic options available to individuals suffering from DED.

Thermosensitive TRP Channels Are Functionally Expressed and Influence the Lipogenesis in Human Meibomian Gland Cells

While the involvement of thermosensitive transient receptor potential channels (TRPs) in dry eye disease (DED) has been known for years, their expression in the meibomian gland (MG) has never been investigated. This study aims to show their expression and involvement in the lipogenesis of the MG, providing a possible new drug target in the treatment of DED. Our RT-PCR, Western blot and immunofluorescence analysis showed the expression of TRPV1, TRPV3, TRPV4 and TRPM8 in the MG at the gene and the protein level. RT-PCR also showed gene expression of TRPV2 but not TRPA1. Calcium imaging and planar patch-clamping performed on an immortalized human meibomian gland epithelial cell line (hMGECs) demonstrated increasing whole-cell currents after the application of capsaicin (TRPV1) or icilin (TRPM8). Decreasing whole-cell currents could be registered after the application of AMG9810 (TRPV1) or AMTB (TRPM8). Oil red O staining on hMGECs showed an increase in lipid expression after TRPV1 activation and a decrease after TRPM8 activation. We conclude that thermo-TRPs are expressed at the gene and the protein level in MGs. Moreover, TRPV1 and TRPM8's functional expression and their contribution to their lipid expression could be demonstrated. Therefore, TRPs are potential drug targets and their clinical relevance in the therapy of meibomian gland dysfunction requires further investigation.

Novel treatments for dry eye syndrome

Dry eye syndrome (DES) is a prevalent and multifactorial disease that leads to a self-perpetuating cycle of inflammation and damage to the ocular surface. This results in symptoms such as redness, burning, and blurred vision, which can negatively affect a patient's quality of life. While treatments are available to manage DES, they only temporarily relieve symptoms. Furthermore, long-term use of certain medications can cause harm to the ocular surface. Therefore, there is a need for safer and effective treatments for DES. This review highlights the latest advancements in DES therapy, providing valuable insights into ongoing efforts to improve patient outcomes.

Update on pharmacotherapy for dry eye

PURPOSE OF REVIEW

This review provides an overview of pharmacologic treatments for dry eye disease (DED), with a focus on newer developments.

RECENT FINDINGS

Along with the existing treatments, there are several new pharmacologic treatments available and being developed for DED.

SUMMARY

There are many currently available options for treatment of DED, and ongoing research and development to expand potential treatments for patients with DED.

Recent advances in drug treatments for dry eye disease

INTRODUCTION

Dry eye disease (DED) is a common ocular condition with a significant impact on patients' quality of life. Conventional treatments include behavioral changes, tear substitutes, and anti-inflammatory agents; however, recent advances in the understanding of DED pathogenesis have opened the way to the development of novel treatment strategies able to target several pathways involved in the onset and persistence of DED.

AREAS COVERED

Literature search was conducted on PubMed and Scopus around the term 'dry eye disease' and others involving its pathophysiology and therapeutic strategy. The primary focus was on recent drugs approved by FDA or under investigation in phase 3 clinical trials. Google and ClinicalTrials.gov were used for obtaining information about the status of FDA approval and ongoing clinical trials.

EXPERT OPINION

Due to its multifaced pathogenesis, DED management is often challenging, and patients' needs are frequently unmet. Recently, several novel treatments have been either FDA-approved or studied in late-phase trials. These novel drugs target-specific biological components of the ocular surface and reduce inflammation and ocular pain. Additionally, new drug delivery systems allow for increased bioavailability, improve effective dosing, and minimize ocular side effects. These advances in drug therapies show real promise for better management of DED patients.

A phase 2a, double-masked, randomized, vehicle-controlled trial of VVN001 in subjects with dry eye disease

PURPOSE

Evaluate the initial ocular safety and tolerability and efficacy of VVN001 Ophthalmic Solution (VVN001), a small-molecule antagonist of lymphocyte function-associated antigen-1 (LFA-1), in subjects with dry eye disease (DED).

METHODS

This was a multi-center, double-masked, randomized, dose-response, vehicle-controlled, parallel-group study conducted in 170 subjects with DED. Subjects were randomized to receive VVN001 (1% or 5%) or its vehicle, twice-daily in both eyes for 84 days. The primary outcome measure was inferior region corneal fluorescein staining (iCFS, 0-4 scale) at Day 84. Visual Analogue Scale eye dryness (VAS, 0-100 scale) was a secondary outcome.

RESULTS

The primary and first secondary outcomes were not met. At Day 84 treatment effects in favor of VVN001 5% relative to its vehicle for iCFS were 0.29 units (p = 0.054), and for VAS were 3.18 units (p = 0.533). In other secondary outcomes, treatment effects in favor of VVN001 5% relative to its vehicle were seen in total CFS (1.61 units, 0-20 scale, p = 0.004) and Schirmer score (1.77 and 2.32 mm, p = 0.049 and p = 0.17 at Days 14 and 28 respectively). Adverse events of incidence 5% or greater in either active treatment group were instillation site pain (3/57, 5.3%), dysgeusia (3/56, 5.4%) and urinary tract infection (3/57, 5.3%).

CONCLUSIONS

There were no major safety issues of note. Appropriately powered studies will be required with a priori selection of the efficacy endpoints to evaluate VVN001's therapeutic potential.