Oral doxycycline reduces pterygium lesions; results from a double blind, randomized, placebo controlled clinical trial

A Phase IIa Multicenter, Randomized, Vehicle-Controlled, Dose Escalating Study to Evaluate the Safety, Efficacy, and Pharmacokinetics of CBT-001 Ophthalmic Solution in Patients With Primary or Recurrent Pterygium

Purpose

To evaluate the safety and efficacy of CBT-001, a multitarget tyrosine kinase inhibitor eyedrop, for pterygia.

Design

Phase II clinical trial. Stage 1 was a single center, open-labeled, vehicle-controlled study. Stage 2 was a multicenter, randomized, double-masked, vehicle-controlled trial.

Participants

Patients with primary or recurrent pterygia.

Main Outcome Measures

The primary efficacy end point was lesion vascularity based on masked grading of photographs by an independent reading center. Other end points included dimensions of pterygia and safety.

Methods

In stage 1, 24 eyes of 24 patients received 1 drop of CBT-001 in a dose escalation fashion (0.02%, 0.05%, and 0.2%) to determine the maximally tolerated dose based on adverse events (AEs) and blood drug levels. In stage 2, subjects were randomly assigned to receive the maximally tolerated dose of CBT-001 or vehicle dosed 3 times a day for 4 weeks with a 20-week follow-up.

Results

In stage 1, the plasma maximum concentration values for all doses of CBT-001 were at or below the limit of detection (0.01 ng/ml). The most commonly reported AEs were mild foreign body sensation and irritation. CBT-001 0.2% was evaluated in stage 2. Baseline demographic characteristics were similar between patients receiving CBT-001 (n = 25) and vehicle (n = 23). After 4 weeks of dosing, the mean change from baseline in pterygium vascularity scores was -0.8 ± 0.7 (mean ± standard deviation) in subjects receiving CBT-001 0.2% and 0.0 ± 0.5 in subjects receiving vehicle (P < 0.001; 95% confidence interval: -1.12, -0.40). Pterygium vascularity scores remained significantly decreased, after the 4-week dosing period, at weeks 8 and 16, but not at week 24. The mean changes from baseline in the length of the pterygia were also significantly lower in subjects receiving CBT-001 compared with vehicle at weeks 2, 4, and 8 (P ≤ 0.014). The most commonly reported AEs were ocular, mild in severity, resolved after therapy, and did not result in discontinuation.

Conclusions

CBT-001 0.2% decreased pterygia vascularity and lesion length after 4 weeks of dosing with a prolonged effect after dosing. The drug was well tolerated with minimal detected systemic drug levels.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Doxycycline Suppresses Vasculogenic Mimicry in Human Pterygium Fibroblasts

PURPOSE

To explore the effect of doxycycline on vasculogenic mimicry (VM) formation and the potential mechanism in human pterygium fibroblasts in order to find novel targets for pterygium therapy.

METHODS

First, we demonstrate the existence of VM in 73 pterygium specimens by CD31 and periodic acid Schiff (PAS) dual staining. Then we used cell counting kit-8, clone formation assay and flow cytometry to prove the inhibitory effect of doxycycline on cell proliferation and apoptosis. The VM formation was evaluated through wound healing assay, cell transwell assay and three-dimensional cell culture combined with PAS staining. Finally, we used Western blot to testify the correlation of the VM and the factors in protein level preliminarily.

RESULTS

Our results showed that VM existed in human pterygium specimens exactly. Otherwise, in human pterygium fibroblasts, doxycycline induced a dose-dependent inhibitory effect on cell proliferation and apoptosis induction. Besides, doxycycline significantly suppressed vasculogenic mimicry tube formation, cell migration and invasion. Furthermore, doxycycline impaired the expression of MMP-9, MMP-2 and VEGF which may related to pterygium VM formation.

CONCLUSIONS

Doxycycline decelerated pterygium progression might be through inhibiting VM formation according to the downregulation of MMP-9, MMP-2 and VEGF, which may provide the basis of further studies involving doxycycline for pterygium treatment.

Predictive Biomarkers of Age-Related Macular Degeneration Response to Anti-VEGF Treatment

Age-related macular degeneration (AMD) is an incurable disease associated with aging that destroys sharp and central vision. Increasing evidence implicates both systemic and local inflammation in the pathogenesis of AMD. Intravitreal injection of anti-vascular endothelial growth factor (VEGF) agents is currently the first-line therapy for choroidal neovascularization in AMD patients. However, a high number of patients do not show satisfactory responses to anti-VEGF treatment after three injections. Predictive treatment response models are one of the most powerful tools for personalized medicine. Therefore, the application of these models is very helpful to predict the optimal treatment for an early application on each patient. We analyzed the transcriptome of peripheral blood mononuclear cells (PBMCs) from AMD patients before treatment to identify biomarkers of response to ranibizumab. A classification model comprised of four mRNAs and one miRNA isolated from PBMCs was able to predict the response to ranibizumab with high accuracy (Area Under the Curve of the Receiver Operating Characteristic curve = 0.968), before treatment. We consider that our classification model, based on mRNA and miRNA from PBMCs allows a robust prediction of patients with insufficient response to anti-VEGF treatment. In addition, it could be used in combination with other methods, such as specific baseline characteristics, to identify patients with poor response to anti-VEGF treatment to establish patient-specific treatment plans at the first visit.

Tetracyclines and photosensitive skin reactions: A narrative review

Tetracyclines are a group of broad‐spectrum antibiotics largely employed in infectious, dermatological and surgical fields. Some adverse events may occur during treatment, including photosensitivity reactions, which are divided in phototoxic or photoallergic. We performed a systematic search on Pubmed, Cochrane and Embase from database inception to August 9, 2020 aim to summarize all available papers on photosensitive reactions related to tetracyclines in all clinical settings where they are used on human being. On the basis of our inclusion criteria, we selected only randomized controlled trials, open comparative trials and prospective cohort studies performed on both volunteers and patients, moreover we included a pharmacovigilance register. Thirty‐eight articles met inclusion criteria, describing photo‐sensitive effects due to doxycycline, minocycline, tetracycline, lymecycline, sarecycline, demethylchlortetracycline, chlortetracycline and metacycline, across six diagnoses (acne, Lyme disease, Gulf Veteran Illness, adbominal aortic aneurysms, traveler's diarrhea and pterygium) and several volunteers who were deliberately exposed to natural or artificial light sources. Not all drugs belonging to tetracyclines class are available to date, moreover the studies included lacked a homogeneous design and most of them involved a scarce number of patients, including reactions induced in volunteers during photo‐testing. Available data on incidence, severity and clinical relevance of tetracyclines‐related photo‐sensitive reactions are scarce, heterogeneous and weak. What we can extrapolate is that some tetracyclines are more often related to phototoxic skin reactions than others and some of those seem to have a very low risk of phototoxicity.

Clinical profile of pterygium in patients seeking eye care in India: electronic medical records-driven big data analytics report III

OBJECTIVE

To describe the clinical profile of pterygium in patients presenting to a multi-tier ophthalmology hospital network in India.

METHODS

This cross-sectional hospital-based study included 1,610,843 new patients presenting between 2010 and 2019. Patients with a clinical diagnosis of pterygium in at least one eye were included as cases. The data were collected using an electronic medical record system. Multiple logistic regression analysis with odds ratios (OR) was performed to identify the associated risk factors.

RESULTS

Overall, 168,807 (10.5%) new patients were diagnosed with pterygium, of which 43,692 (26%) patients complained about the lesion. The prevalence rates were 0.7% in children and 12.6% in adults. Majority of patients were female (54.5%) and had unilateral (57%) affliction. Among the 241,631 affected eyes, the pterygia were primary in 99.6%, nasally located in 94%, and were grade I-II in 84.8%. Four in 5 eyes did not have any cylindrical refractive error, and 44% had coexistent cataract. Pterygium surgery was indicated in 10.3% eyes. Female sex (OR 1.37), increasing age (OR 19.5), rural residence (OR 1.21), agriculture work (OR 2.19), manual labor (OR 2.05), low socioeconomic status (OR 2.14) and geographical location closer to the equator (OR 3.4) were identified as the risk factors for developing pterygium.

CONCLUSION

About one-tenth of individuals seeking eye care in India have pterygium in at least one eye. It rarely impacts vision, is commonly unilateral and nasal and usually does not require surgery. It is associated with increasing age, females, outdoor work, low income and geographical location closer to the equator.

[Pterygium: etiology, pathogenesis, treatment]

Pterygium is a degenerative condition characterized by fibrovascular outgrowth of conjunctiva over the cornea. Many theories exist that try to explain its pathogenesis. The current belief is that this disease is multifactorial with ultraviolet radiation being the most important trigger. Attention is also paid to such factors as tear film changes, cytokines and growth factors disbalance, immunologic disturbances, genetic mutations, and viral infections. Modern classifications consider the rate of fibrovascular growth, its progressive potential, and histological features. In the beginning pterygium is usually asymptomatic, however, dry eye manifestations may be present, such as burning, itching, and/or tearing. As the lesion grows toward the optical zone, visual acuity gets compromised, and thus, surgical treatment is required. Because of recurrences and repeated surgeries, the growth of the lesion may become more aggressive and cause irregular astigmatism. Comprehensive surgery of pterygium is aimed at not only removing the lesion, but also preventing recurrences. Advisable are modified bare sclera techniques with subsequent transposition of the conjunctival flap, conjunctival autotransplantation, amniotic membrane transplantation, and peripheral lamellar keratoplasty (in cases of significant ingrowth). In some cases, antirecurrent adjuvant therapy may be considered that involves the use of mitomycin C, 5-fluoruracil, and VEGF inhibitors. However, the search for the best treatment for pterygium, i.e. an easy to perform, cosmetically-friendly method associated with minimal risk of recurrences and/or complications, remains an interest of modern ophthalmology.

Recurrence After Primary Pterygium Excision: Amniotic Membrane Transplantation with Fibrin Glue Versus Conjunctival Autograft with Fibrin Glue

PURPOSE

The aim of the present study was to compare the surgical results and recurrence rates of primary pterygium excision with conjunctival autografts versus amniotic membrane grafts fixated with fibrin glue.

MATERIALS AND METHODS

In this prospective study, 73 eyes of 65 patients who had undergone conjunctival autograft group (CAG) (n:37) or amniotic membrane group (AMG) (n:36) after pterygium excision were evaluated. Fibrin glue was used for the fixation of grafts in both groups. The patients were followed up for 12 months. Postoperative complications were recorded. The rate of recurrence was defined as the primary outcome measure.

RESULTS

In the CAG, partial dehiscence of the graft was observed on the nasal edge on postoperative day 1 in two (5.4%) eyes that healed with secondary re-epithelialization at week 1. Twelve (32.4%) eyes showed a yellowish-orange or hemorrhagic edema of the graft on postoperative day 7 that spontaneously resolved in 1 to 3 weeks. In the AMG, partial dehiscence and folding of the amniotic membrane occurred in two (5.5%) eyes. Two eyes (5.4 %) in the CAG developed corneal recurrence and five eyes (13.8%) in the amniotic membrane graft group developed recurrence; one limbal (2.7%), four corneal recurrences (11.1%) (p = 0.25).

CONCLUSION

Fibrin glue is a safe and effective method for attaching conjunctival or amniotic membrane grafts for wound closure following pterygium surgery. Although the results were not statistically significant, amniotic membrane grafting using fibrin glue seems to have a higher pterygium recurrence rate compared with conjunctival autografting.

Molecular Basis of Pterygium Development

Pterygium pathogenesis is mainly related to UV light exposure. However, the exact mechanisms by which it is formed have not been elucidated. Clinical advances in surgical treatment use conjunctival autografts and amniotic membranes in combination with adjuvant therapies, including mitomycin C, β-radiation, and 5-fluoroacil, to reduce recurrence. Several studies aim to unveil the molecular mechanisms underlying pterygium growth and proliferation. They demonstrate the role of different factors, such as viruses, oxidative stress, DNA methylation, apoptotic and oncogenic proteins, loss of heterozygosity, microsatellite instability, inflammatory mediators, extracellular matrix modulators, lymphangiogenesis, cell epithelial-mesenchymal transition, and alterations in cholesterol metabolism in pterygium development. Understanding the molecular basis of pterygium provides new potential therapeutic targets for its prevention and elimination. This review focuses on providing a broad overview of what is currently known regarding molecular mechanisms of pterygium pathogenesis.