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Aldeyra Therapeutics Announces Positive Top-Line Symptom and Sign Results from Run-In Cohort of Phase 3 TRANQUILITY Trial in Dry Eye Disease

Posted on January 24, 2021 at 6:55 AM

LEXINGTON, Mass.--(BUSINESS WIRE)--Aldeyra Therapeutics, Inc. (Nasdaq: ALDX) (Aldeyra) today announced positive top-line symptom, redness, and Schirmer’s test results from the run-in cohort of the Phase 3 TRANQUILITY clinical trial in patients with dry eye disease.


The double-masked, single-center, parallel-group run-in cohort enrolled 23 patients: 12 patients were randomized to receive 0.25% reproxalap ophthalmic solution and 11 patients were randomized to receive vehicle ophthalmic solution. Patients received four doses one day prior to and two doses on the day of exposure to a 90-minute dry eye chamber with minimal humidity, high airflow, and forced visual tasking.


Over all time points in aggregate in the dry eye chamber, reproxalap was observed to be statistically superior to vehicle for the two assessed symptoms, visual analog scale (VAS) ocular dryness score (p = 0.001) and ocular discomfort score (p < 0.0001) in the run-in cohort of TRANQUILITY. Consistent with previously announced allergen chamber Phase 2 clinical trial results, reproxalap demonstrated statistically significant improvement over vehicle (p = 0.03) in ocular redness, an objective sign of dry eye disease. Improvement in ocular symptoms and redness occurred within minutes after reproxalap dosing. Following acute dosing on the day prior to the dry eye chamber, Schirmer test scores were directionally in favor of reproxalap over vehicle, and reproxalap was statistically superior to vehicle in improvement in VAS dryness score (p = 0.003), ocular discomfort 4-symptom questionnaire (OD4SQ) dryness score (p = 0.006), OD4SQ grittiness score (p = 0.006), and OD4SQ discomfort score (p = 0.003). Consistent with clinical experience in over 1,100 patients, no adverse findings on safety assessments were observed, and reproxalap was well-tolerated. 


“The symptom improvement observed in the run-in cohort of TRANQUILITY announced today support the first-line potential use of reproxalap in dry eye disease, and represent the first results from an ophthalmic solution for chronic use that demonstrate activity acutely following drug administration,” stated Todd C. Brady, M.D., Ph.D., President and Chief Executive Officer of Aldeyra. “The activity of reproxalap in reducing ocular redness, initially demonstrated in the allergen chamber Phase 2 clinical trial, was also observed in the dry eye chamber run-in results of TRANQUILITY, and we look forward to initiating enrollment of the main cohort.”


Among many patients and physicians, current dry eye disease therapies are considered inadequate. Discontinuation rates for lifitegrast and cyclosporine, which currently comprise standard of care, exceed 60% within 12 months of initiation of therapy, in part due to delayed onset of effect.


“The potential for patients to experience acute symptomatic relief and observe rapid improvement in ocular redness after the initiation of therapy represents a new possible paradigm in dry eye disease treatment and could offer significant clinical advantage over existing therapies, which often require weeks of drug administration before patients experience even moderate improvement,” stated Victor Perez, M.D., Professor of Ophthalmology at Duke University School of Medicine and a member of Aldeyra’s Anterior Segment Scientific Advisory Board.


The main cohort of TRANQUILITY is expected to begin enrollment in February 2021, following completion of tear RASP analysis from the run-in cohort and confirmation of endpoints and number of subjects. Results from TRANQUILITY are expected in the second half of 2021. A second Phase 3 clinical trial, TRANQUILITY-2, is expected to initiate in the first quarter of 2021.


Reference


https://www.businesswire.com/news/home/20210107005235/en/Aldeyra-Therapeutics-Announces-Positive-Top-Line-Symptom-and-Sign-Results-from-Run-In-Cohort-of-Phase-3-TRANQUILITY-Trial-in-Dry-Eye-Disease

IACTA Pharmaceuticals and Pharmaleads to Develop the World's First Epithelial Protective Drug Harnessing Endogenous Analgesia for the Topical Treatment of Acute and Chronic Ocular Pain

Posted on January 10, 2021 at 7:55 AM

 

  • Ocular Pain, a $10+ billion global market, with significant unmet medical need
  • License agreement aims to accelerate global development of DENKIs, leveraging expertise and resources of both companies

 


Irvine, Calif., Paris, Hong Kong, Jan. 7, 2021 /PRNewswire/ — IACTA Pharmaceuticals, Inc. (“IACTA" and Pharmaleads, with Pharmaleads Greater China, today announced they have entered into licensing agreements, with IACTA acquiring global rights to Pharmaleads’ Dual Enkephalinase Inhibitors (DENKI®, a novel class of non-opioid compounds for the treatment of acute and chronic ocular pain.

 

“With this agreement, IACTA and Pharmaleads will collaborate to develop next-generation pain treatments to help the millions of people across the globe living with the debilitating effects of ocular pain,” said Damon Burrows, CEO of IACTA. “We believe that the epithelial protective properties of DENKI observed in preclinical studies, combined with its pain-relieving properties will revolutionize eye care.”

 

The epithelial protective promise of DENKI, combined with its pain-relieving properties will revolutionize eye care.


“Today’s announcement further exemplifies IACTA’s business momentum, as we continue to foster research and development initiatives to address unmet medical needs in the global eye care market,” continued Damon Burrows.

 

Under the terms of these agreements, Pharmaleads and Pharmaleads Greater China have granted IACTA an exclusive, worldwide, royalty-bearing license to lead the clinical and commercial development of IC800 (acute) and IC805 (chronic) and other DENKI drugs from Pharmaleads’ portfolio. Pharmaleads and Pharmaleads Greater China will together be eligible to receive up to $100M in total deal value including upfront, development, regulatory, and commercial milestone payments. Based on the ocular preclinical package already available and human systemic safety data, IACTA expects to start human proof of concept trials in ocular pain in 2021. IACTA’s ophthalmic drug development expertise combined with Pharmaleads breakthrough discoveries will work to bring to market the world’s first non-opioid, epithelial protective drug harnessing endogenous analgesia for the treatment of chronic (i.e., neuropathic pain and dry eye) and acute (e.g., post-surgical) ocular pain, which is estimated to affect more than 175 million people globally.

 

“We are thrilled to be partnering with IACTA, as we remain focused on advancing our pipeline of candidates targeting pain management, including a program for acute migraine headache. This partnership will give us the opportunity to accelerate the development of our drugs and to bring alternative non-addictive pain treatments to address the opiate crisis,” said Tanja Ouimet, PhD, COO of Pharmaleads. “IACTA’s expertise in the development of ocular drugs will reveal the full potential of DENKI-based treatments to protect and extend the life of enkephalins expressed locally on the eye surface and work to bring the first dedicated ocular pain treatments to the market and to many suffering patients who currently have no treatment for their pain besides NSAIDs or opiates.”


“This partnership stands for a pivotal move towards our organization’s overall strategic direction to foster opportunities for delivering transformative treatments which at the same time puts the human aspect of medicine in focus,” said Tian Ye, CEO of Pharmaleads Greater China. “We believe that as a first-of-its-kind treatment in non-addictive pain management, this breakthrough alternative has unprecedented potential in addressing unmet medical needs in eye care.”


“DENKI has the potential to transform the treatment of ocular pain, advance patient care, and become one of the most significant scientific innovations for the eye care industry.” said Taryn Conway, former Associate Vice President of Marketing, for Allergan, Inc., and Strategic Advisor to IACTA Pharmaceuticals.


“Ocular pain management, whether as a disease or a symptom, has been hampered by the lack of local, non-epithelial-toxic analgesics,” said Dr. Marjan Farid Director of the Cornea, Cataract, and Refractive Surgery and Vice Chair of Ophthalmic Faculty at the Gavin Herbert Eye Institute. “DENKIs could provide the first chronic pain management option for the millions of patients suffering from ocular pain and be a true game-changer in the field of ophthalmic therapeutics.”


Reference


http://iactapharma.com/2021/01/07/iacta-and-pharmaleads-to-develop-the-worlds-first-epithelial-protective-drug-harnessing-endogenous-analgesia-for-the-topical-treatment-of-ocular-pain/


About DENKIs

DENKIs (Dual ENKephalinase inhibitors) aim to protect enkephalins from degradation, hence increasing their local concentrations and thereby inducing a physiological analgesia, which improves pain management.

 

About IACTA Pharmaceuticals, Inc.

IACTA is an ophthalmic focused pharmaceutical company led by former top executives from one of the leading eye care companies in the world, Allergan. The company currently has six products in development for major market opportunities. The Company’s lead product, IC 265, is ready to enter a Phase 2 clinical study with data outcomes expected in 2022. For more information on IACTA Pharmaceuticals, Inc., visit www.iactapharma.com

 

In addition, this announcement comes on the heels of the recent agreement between IACTA Pharmaceuticals, Inc. and Zhaoke (Hong Kong) Ophthalmology Pharmaceutical Limited (“ZKO”;), on the licensing of two of the Company’s products, IC 265 for dry eye and IC 270 for allergic conjunctivitis.

 

About Pharmaleads

Headquartered in Paris, Pharmaleads, with its sister company Pharmaleads Greater China, is a clinical stage private biotech company creating and developing innovative non-opiate, non-addictive products for the management of acute and chronic moderate to severe pain, a growing market with significant unmet medical need. Pharmaleads’ drugs are based on its deep knowledge and understanding of the metabolism of enkephalins, a key element of the body’s natural pain management system.

 

Pharmaleads has two products in clinical development, targeting multi-billion-dollar markets: chronic neuropathic pain (oral), post-surgical/breakthrough cancer pain as a substitute for injectable opiates (intravenous.), and acute migraine headache (oral). Pharmaleads is also collaborating with academic partners to explore the potential therapeutic actions of IC800 in opiate use and withdrawal disorders.

 

For more information about Pharmaleads please visit www.Pharmaleads.com

 

Forward-Looking Statements

Any statements in this press release that are not historical facts are forward-looking statements made under the provisions of the Private Securities Litigation Reform Act of 1995. Any forward-looking statements involve risks and uncertainties that could cause actual results to be materially different from historical results or any future results expressed or implied by such forward-looking statements. Such statements include the potential for IC800 and IC805 and the development of IC 265 and IC 270. Any forward-looking statements in this press release represent the Company’s views only as of the date of this release and should not be relied upon as representing its views as of any subsequent date. The Company specifically disclaims any obligation to update this information as a result of future events or otherwise, except as required by applicable law.

SilkTech completes enrollment in trial of biological dry eye treatment candidate

Posted on November 28, 2020 at 7:00 AM

SilkTech Biopharmaceuticals has completed enrollment in a phase 2b clinical trial of SDP-4, its eye drop formulation for the treatment of the signs and symptoms of dry eye disease, according to a press release.


 

The randomized, double-masked, vehicle-controlled, multicenter trial is evaluating the safety and efficacy of SDP-4 at 0.1%, 1% and 3% concentrations in 305 patients at 25 U.S. sites.


 

SDP-4, a biotherapeutic naturally derived from silk protein, is designed to utilize a dual mechanism of action to physically improve tear film stability and reduce inflammation to treat dry eye. It also inhibits kinase activation of the NF-kB gene transcription pathway.


 

“Our team has accomplished a significant milestone in reaching full enrollment of our first-in-human ophthalmic study for a silk protein-derived biotherapeutic,” Brian Lawrence, PhD, SilkTech CEO, said in the release. “The trial enrolled 6 weeks ahead of projected schedule indicating the significant and growing need for new therapeutic approaches to this debilitating disease.”


 

Topline data are expected to be reported by the end of this year’s fourth quarter.


Reference


https://www.healio.com/news/ophthalmology/20190807/silktech-completes-enrollment-in-trial-of-biological-dry-eye-treatment-candidate

Azura Ophthalmics Raises US$20 Million for Registration Studies for Treatment of Leading Cause of Dry Eye Disease

Posted on November 7, 2020 at 5:55 PM

Azura Ophthalmics Ltd., a clinical-stage company developing innovative therapies for Meibomian gland dysfunction (MGD) and related eye diseases, today announced a US$20 million financing. The round was led by a syndicate of existing investors including OrbiMed, TPG Biotech, Brandon Capital’s Medical Research Commercialization Fund (MRCF) and Ganot Capital.

 

On the back of encouraging Phase 2 data to date proceeds from the funding round will be used to advance Azura’s lead product candidate AZR-MD-001 through a registration study for the treatment of MGD – an eye condition where the Meibomian glands become dysfunctional, resulting in rapid evaporation of the tear film.

 

Azura’s novel medicines in development are designed to address abnormal hyperkeratinization – the build-up and shedding of the proteins at the opening of the Meibomian gland or within the gland itself – known to be the root cause of obstructive MGD. This approach has been used safely and effectively for decades in dermatology and is based on the understanding that Meibomian glands share strong similarities with sebaceous glands, skin glands responsible for conditions like acne, including the ability to undergo keratinization.

 

Meibomian gland dysfunction is the leading cause of evaporative Dry Eye Disease, a condition known to affect more than 30 million adults in the United States alone presenting a huge unmet need globally.1,2

 

“The current options we have to treat patients with Meibomian gland dysfunction focus primarily on relieving obstruction and have not focused on the role of keratin within meibum. There are millions of patients with ocular surface disease and MGD worldwide; we need better treatments to help our symptomatic patients,” said Dr. Preeya K. Gupta, clinical medical director of Duke Eye Center at Page Road and associate professor of ophthalmology at Duke University Eye Center. “The promise of Azura’s dermatological approach lies in its ability to open the glands, increase lipid production and restore tear-layer health, as well as preventing disease progression in patients with Meibomian gland dysfunction.”

 

Azura’s lead compound AZR-MD-001 is a topical ointment applied to the lower lid that has shown a positive safety and efficacy profile in several studies in MGD. Based on these data and interactions with the U.S. Food and Drug Administration (FDA), the company plans to proceed to registration studies in 2021.

 

“We are thrilled to enter 2021 with the additional funding that will allow us to conduct the studies needed to build a strong body of clinical evidence for our approach, so we can seek FDA approval for the first ophthalmic keratolytics for the treatment of Meibomian gland dysfunction,” said Marc Gleeson, CEO of Azura. “We are grateful for the support of our investors who share our conviction that Azura’s medicines in development have the potential to transform treatment and provide hope to millions of patients suffering from unresolved eye conditions.”

 

“The investor syndicate believes in Azura and in its team’s ability to bring promising ocular products through approval and ultimately commercialization. The company is led by strong repeat entrepreneurs and industry veterans who have proven astute and resourceful in constructing an elegant pipeline and executing on efficient yet robust trials that have enabled swift progress,” said Dr. Chris Nave, managing director at Brandon Capital. “The investor syndicate is committed to continuing to support the advancement of Azura’s innovative pipeline as they create medicines to target Meibomian gland dysfunction and related conditions that impact the ocular health of millions of people around the world.”

 

 

About Meibomian Gland Dysfunction

 

Meibomian gland dysfunction (MGD) is the leading cause of Dry Eye Disease (DED), a condition known to affect more than 30 million adults in the United States alone.2 MGD is a chronic, diffuse abnormality of the Meibomian glands, commonly characterized by terminal duct obstruction and/or qualitative/quantitative changes in the glandular secretion.3 There are no approved prescription pharmaceutical agents that specifically treat these glandular changes. If left untreated, MGD will alter the tear film, resulting in damage to the front of the eye and severe discomfort from associated ocular surface diseases. Though there are treatments on the market for ocular surface diseases, many patients still suffer from dry eye, and research shows that hyperkeratinization of the Meibomian glands is the underlying cause of the disease.4 There are currently no approved medicines for MGD.

 

 

About AZR-MD-001

 

Azura Ophthalmics has a robust clinical development pipeline investigating the reformulated, prescription-strength SeS2 (Selenium Disulfide). The company has a pipeline of new chemical entities in pre-clinical through Phase 2 development for a number of ocular and lid margin diseases, including Meibomian gland dysfunction, acute use for Meibomian gland dysfunction, Inflammatory/Aqueous Deficient Dry Eye, Blepharitis, contact lens discomfort and ocular manifestations of Graft versus Host Disease (GvHD).

 

Azura’s lead product candidate, AZR-MD-001, is a topical ointment that has been developed to yield properties ideal for ophthalmic use. The formulation would be applied to the lower lid margin before bedtime. Azura is currently evaluating the safety, tolerability and effectiveness of AZR-MD-001, developed for ophthalmic use, in a Phase 2 study in patients with MGD and evaporative DED.

 

AZR-MD-001 leverages SeS2 as the active ingredient. SeS2 has a triple mechanism of action: it slows down keratin production; breaks down the bonds between abnormal keratin proteins; and increases the quantity of lipid produced by the Meibomian glands. If approved, AZR-MD-001 will be a first-in-class ophthalmic keratolytic for the treatment of lid margin diseases, starting with Meibomian gland dysfunction and contact lens discomfort.

 

Paulsen AJ, Cruickshanks KJ, Fischer ME, et al. Dry eye in the beaver dam offspring study: prevalence, risk factors, and health-related quality of life. Am J Ophthalmol. 2014;157(4):799–806.

U.S. Census

Nichols et al. The International Workshop on Meibomian Gland Dysfunction: Executive Summary IOVS, Special Issue 2011, Vol. 52, No. 4

Knop E, Knop N, Millar T, Obata H, Sullivan DA. The international workshop on meibomian gland dysfunction: report of the subcommittee on anatomy, physiology, and pathophysiology of the meibomian gland. Invest Ophthalmol Vis Sci. 2011 Mar 30;52(4):1938-78.

 

 

Media Contact:

Health+Commerce

Sierra Smith

sierra@healthandcommerce.com

408.540.4296


References


https://azuraophthalmics.com/press-releases

Can cannabis succeed where other compounds have failed

Posted on November 20, 2017 at 8:15 PM

Cannabinoids could have potential in a novel topical drug delivery vehicle to treat neuropathic dry eye pain.


The disconnect between signs and symptoms in dry eye disease is an intriguing clinical problem. Although we know quite a lot about the etiology of dry eye, the ideal structure of the tear film and how to diagnose and treat dry eye disease, there are still some patients who do not respond to treatment or who present complaining of severe symptoms that seem to be poorly correlated with clinical signs. Complaints may include a burning or stabbing sensation or a feeling of pressure in the eyes.


Many clinicians find these patients—and the chair time they consume—frustrating. But before dismissing them as “crazy,” it may help to consider whether they could be suffering from a different form of dry eye that is difficult to detect by traditional methods.


In 2009, Perry Rosenthal and colleagues observed what they presumed to be corneal neuralgia, which they termed “pain without stain” because of the paucity of corneal staining or other clinical signs.1 They speculated that the pain symptoms could be related to a neuropathic disorder, rather than to qualitative or quantitative tear film factors.


Later work by Rosenthal further elucidated how the nociceptive system—critical to vision when functioning properly, because it monitors and restores the optical tear film—could become dysfunctional.2 When this happens, the corneal nerves, the central trigeminal sensory network, and/or the pain organising centres in the brain escalate the eye’s natural ‘alarm system’, sending pain signals that are out of proportion to the physical insult (if indeed there is any injury at all).


Neuropathic dry eye pain may be triggered or exacerbated by ocular surgery, systemic conditions or even psychological distress.


The dry eye community has been increasingly interested in neuropathic dry eye. In fact, the new DEWS II definition of dry eye explicitly includes “neurosensory abnormalities” in the list of etiological factors in dry eye.3


A DEWS II subcommittee report on pain and sensation notes that long-term inflammation can alter neuron excitability, connectivity and impulse firing and that disturbances in ocular sensory pathways may ultimately lead to neuropathic pain.4 However, as yet, there are no dry eye therapies that specifically target neuropathic pain.

The role of cannabis


Cannabinoids and, in particular, tetrahydrocannabinol (THC, the main active ingredient in recreational marijuana) is of great interest in the treatment of neuropathic pain. Cannabinoid receptors are known to modulate pain and inflammation and are located throughout the eye, including the corneal epithelium and the retina; they are present on immune cells and may be involved in wound healing, as well.5 So, from a theoretical perspective there are a number of reasons to pursue the use of cannabinoids to treat dry eye.


And the time may be right to conduct such research now. Regulatory restrictions around the use of cannabinoids are being loosened, with more than half of U.S. states and several European countries now permitting the use of THC for medical purposes.


In Germany, where I practice, a special permit is required and the drug must be used in a controlled research setting as part of a clinical trial, which seems to be a reasonable way to open the doors to research on cannabinoid compounds while still limiting the potential for abuse.


In my laboratory, we have been actively investigating what the best targets for treating neuropathic pain might be and how THC could be safely and effectively delivered to those targets. 

There are a number of challenges in using THC therapeutically. Smoking marijuana or consuming THC in edible form is impractical for the treatment of ocular disease; these systemic applications deliver an unpredictable dose with unwanted systemic side effects.


Sublingual and dermal administration have similar effects and are probably not appropriate for ocular conditions. For these reasons, and due to a lack of evidence of predictable, long-lasting therapeutic effect, a number of professional organisations, including the Canadian Ophthalmological Society and the American Academy of Ophthalmology, have taken positions against the use of systemic THC treatment for ocular conditions.


Local application of THC is considerably more compelling. Cannabinoid eye drops have been investigated and are available for glaucoma from at least one small manufacturer. But noone yet has been particularly successful with this approach due to the challenges of formulating the drops appropriately.


THC and most other pain-relieving or anaesthetic compounds are quite lipophilic. Like oil with water, they do not mix well with the aqueous solutions in most eye drops, making it difficult to get THC into the target ocular tissues.

Enhanced topical drug delivery


Recently, we have been investigating the use of a novel semi-fluorinated alkane (SFA) drug delivery technology (EyeSol, Novaliq) as a vehicle to deliver cannabinoids to the ocular surface. This class of molecules has a number of advantages as an eye drop.


EyeSol-based drops contain no water, so they mix well with lipophilic substances, including cyclosporine and THC, and allow them to remain solubilised instead of separating out in the bottle. They have a very low surface tension so a drop on the eye rapidly forms a very thin layer, giving it spreading properties that are far superior to an aqueous eye drop (Figure 1).


These properties should help to distribute a drug across the uneven ocular surface without the drug being immediately drained or spilling out of the eye as excess aqueous. SFA molecules are metabolically inert and do not interact with the immune system. Finally, they have a refractive index similar to water, so they do not disturb vision the way oil emulsions of lipophilic ingredients can.


In several observational trials we conducted, q.i.d. treatment with an EyeSol delivery vehicle alone resulted in a highly significant reduction in corneal staining and a 20-point improvement in OSDI scores after just six weeks.6 We thought that if this vehicle could be combined with a compound like THC for pain and inflammation, it could be very beneficial in dry eye treatment.


We began to conduct experiments using an established mouse model for dry eye disease that relies on behavioural testing methods to determine pain levels, as well as other testing methods (Figure 2). We compared a group treated with EyeSol THC eye drops to a control group treated with topical cyclosporine.


One-year results of these preclinical studies suggest that the drop is at least as effective as cyclosporine and may have dual or even triple mechanisms of action, including lubrication, anti-inflammation and pain reduction. Although we continue to evaluate various parameters, the pharmacodynamics thus far are very promising.


We are fairly confident that topical application of THC dissolved in EyeSol will not result in any measurable systemic effects. The first human clinical trials in dry eye disorder are expected to begin in the second half of 2018.

Understanding neuropathic pain


Even as research into THC delivery to the ocular surface continues, we have also been seeking to gain a better understanding of neuropathic pain and the characteristics of patients who may suffer from this form of dry eye. To do this, we in the dry eye clinic have been working closely with experts from the University of Cologne’s pain clinic.


We retrospectively evaluated 52 patients seen in our dry eye clinic who fell into the ‘pain without stain’ category. These subjects had normal Schirmer’s, no corneal staining and no signs of blepharitis, but they had OSDI scores >40, in the ‘severe’ symptom range (median score 77).


In addition to a very thorough history and examination in our clinic, many of the patients also underwent a full pain inventory and Hospital Anxiety and Depression Score (HADS) questionnaire. Comorbidities included depression (n=9), chronic pain syndrome (9), anxiety disorders (4), and prior eye surgery (17).7 Other researchers have also recently shown that severe dry eye pain is correlated with antidepressant use but not with corneal staining.8


For ophthalmologists, these are exactly the sort of patients who are mystifying at best, and often get dismissed as people whose symptoms are “just” psychological. To the pain experts we consulted, however, it was very clear that these were typical pain patients, with the same types of concomitant psychosomatic conditions they often see among patients who suffer from chronic headache or back pain.


A typical patient in our study, for example, might have fibromyalgia and rheumatoid arthritis, with an OSDI score of 65 but no clinical signs of dry eye. Upon questioning, she might have first noticed the dry eye pain following LASIK or around the time of a particularly stressful life event, such as the death of a close family member.


In some cases, the patients had no response to topical anaesthesia or to systemic pain medications, which was quite interesting, since it indicates there is something very unusual going on with regards to their pain response. It seems that these individuals may be predisposed to systemic neuropathic pain, of which ocular pain is but one manifestation.


These insights have changed the way I practice in a number of ways. For example, I have started using the HADS questionnaire more frequently for patients with severe symptoms. I ask broader questions about fatigue, anxiety and depression as part of my history taking.


Recognising that ocular surgery can trigger an underlying pain syndrome, I am more thoughtful about evaluating postoperative patients with unexplained symptoms to determine whether they might be most appropriately managed as a pain patient. As medical doctors, it is our responsibility to see the whole patient and, when appropriate, help them to seek treatment for systemic autoimmune disorders, psychosomatic illnesses and other pain syndromes.

Research implications


‘Pain without stain’ patients provide us with a model to understand the process of neuropathic dry eye. Because they do not have significant meibomian gland dysfunction or aqueous deficiency, we are able to isolate the neuropathic disease and hopefully identify new therapies to relieve their symptoms.


While these patients represent what is probably a very rare subtype of dry eye, it is likely that many more dry eye patients who do have clinical signs also have neuropathic pain as a component of their dry eye. In fact, I believe that most of the patients who fail, even partially, to respond to stepwise, appropriate dry eye therapy or for whom resolution of signs does not lead to significant improvement in symptoms, might also have an additional neuropathic disorder.


What we learn from treating the extreme form, therefore, has the potential to benefit a much broader range of patients whose pain is inadequately addressed with current therapy.


It has become clear to me that there is a strong unmet need for treatments that specifically address ocular surface pain. Although much research remains to be undertaken, I am optimistic about the potential for cannabinoid therapies, particularly if we are able to confirm that use of an SFA drug delivery technology is effective in reaching the target tissues without systemic side effects.

References


Rosenthal P, Baran I, Jacobs DS. Corneal pain without stain: Is it real? Ocul Surf. 2009;7(1):28-40.


Rosenthal P, Borsook D. Ocular neuropathic pain. Br J Ophthalmol. 2016;100(1):128-134.


Nelson JD, Craig JP, Akpek EK, et al. TFOS DEWS II introduction. Ocul Surf. 2017;15:269-275.


Belmonte C, Nichols JJ, Cox SM, et al. TFOS DEWS II pain and sensation report. Ocul Surf. 2017;15(3):404-437.


Toguri JT, Caldwell M, Kelly MEM. Turning down the thermostat: modulating the endocannabinoid system in ocular inflammation and pain. Front Pharmacol. 2016;7:304.


Steven P, Scherer D, Krösser S, et al. Semifluorinated alkane eye drops for treatment of dry eye disease—a prospective, multicenter noninterventional study. J Ocul Pharmacol. Ther 2015;31(8):498-503.


Steven P, Schneider T, Ramesh I, et al. Pain in dry eye patients without corresponding clinical signs—a retrospective analysis. Association for Research in Vision and Ophthalmology. 2016, Abstract 2848-A0057.


Satitpitakul V, Kheirkhah A, Cmej A, et al. Determinants of ocular pain severity in patients with dry eye disease. Am J Ophthalmol. 2017;179:198-204.



Professor Philipp Steven, MD


E: philipp.steven@uk-koeln.de


Prof. Steven is principle investigator for the Ocular Surface Group in the Department of Ophthalmology at the University of Cologne, in Germany. He consults for and receives research funding from Novaliq and has a patent pending related to the work described within this article.