Learning Curve and One-Year Outcome of XEN 45 Gel Stent Implantation in a Swedish Population

Minimally invasive micro sclerostomy (MIMS) procedure in the treatment of open-angle glaucoma

BACKGROUND

To evaluate the safety and efficacy of the Minimally Invasive Micro Sclerotomy (MIMS) procedure in the management of uncontrolled open-angle glaucoma.

METHODS

A prospective, open-label, single-arm clinical evaluation with intra-subject comparisons performed at the Ophthalmologic Center after S.V. Malayan, Yerevan, Armenia. Included were adults with primary open-angle glaucoma (OAG) (N = 114) or exfoliative glaucoma (N = 6) who were uncontrolled (IOP > 21) on tolerated topical medication. Mild (N = 7), moderate (N = 66) and severe (n = 47) cases were prospectively included without preselection. Following subconjunctival Mitomycin C, an ab-interno MIMS procedure was performed alone (N = 100) or combined with phacoemulsification (N = 20). Patients were followed for 52 weeks. Procedure-related complications and adverse events were recorded. Success criteria were defined as -5 < IOP ≤ 21mmHg OR a reduction in IOP of ≥ 20% from baseline with (qualified success) or without (complete success) hypotensive medications.

RESULTS

Mean patient age was 69 ± 10.1 years. The mean duration of the procedure was 2:01 ± 0:41 min:sec. Scleral drainage channels were achieved in all cases. No device malfunctions, intraoperative complications, or serious adverse events were reported. Iris plugging of the sclerostomy site and early spikes in IOP were the most common adverse events. The only reason for failure was final IOP > 21 mmHg on tolerated medication. At 52 weeks (n = 93), mean IOP decreased by 38% from baseline (P < 0.001), from 27.9 ± 3.7 to 17.5 ± 5.3 mmHg, a difference of 10.5 mmHg (95% CI: -11.7, -9.3). One-year qualified success was documented in 82.1% (95% CI: 72.9%,89.2%) of the patients and complete success, in 70.5% (60.3-79.4%). 60% (95 CI:49.4%,69.9%) of the patients achieved maximum IOP level of 14 mmHg or at least 30% reduction in IOP.

CONCLUSIONS

MIMS procedure is a relatively simple, short and safe minimally invasive bleb-forming procedure. Its efficacy, as found in this short-term evaluation, lends it suitable for mild and moderate uncontrolled open-angle glaucoma patients.

TRIAL REGISTRATION

ClinicalTrials.gov ID: NCT04503590 2019-05-29.

Effectiveness and Safety of Xen Gel Stent in Glaucoma Surgery: A Systematic Review of the Literature

Although topical medical therapy and selective-laser-trabeculoplasty represent the treatments of choice to reduce intraocular pressure, many patients do not achieve adequate glaucoma control; therefore, they require further options and eventually surgery. Trabeculectomy is still considered the gold standard, but the surgical management of glaucoma has undergone continuous advances in recent years, XEN-gel-stent has been introduced as a safer and less traumatic means of lowering intraocular pressure (IOP) in patients with open-angle glaucoma (OAG). This study aimed to review the effectiveness and safety of clinical data on XEN-stent in OAG patients with a Synthesis-Without-Meta-analysis (SWiM) methodology. A total of 339 studies were identified following a literature search adhering to PRISMA guidelines and, after evaluation, 96 studies are discussed. XEN63 and XEN45 device data were collected both short and long term. In addition, this document has evaluated different aspects related to the XEN implant, including: its role compared to trabeculectomy; the impact of mitomycin-C dose on clinical outcomes; postoperative management of the device; and the identification of potential factors that might predict its clinical outcomes. Finally, current challenges and future perspectives of XEN stent, such as its use in fragile or high myopia patients, were discussed.

Four-Year Outcome of XEN 45 Gel Stent Implantation in a Swedish Population

Purpose

To report the long-time success rate of XEN 45 gel stent implantation in a Scandinavian population.

Patients and Methods

This was a retrospective single-center analysis of all patients undergoing XEN 45 stent surgery between December 2015 and May 2017. The main outcome was success rate according to several definitions of success. Subgroup analysis was performed. Secondary outcomes were change in intraocular pressure (IOP) and number of IOP-lowering agents. Need for secondary glaucoma surgery, needling rate and complications were recorded.

Results

A total of 103 eyes could be evaluated after four years. Mean age was 70.6 years. Primary open-angle glaucoma (POAG) accounted for 46.6% and exfoliative glaucoma (PEXG) for 39.8%. Mean IOP dropped from 24.0 to 15.9 mmHg (p<0.001) and IOP-lowering agents from 3.5 to 1.5 (p<0.001). The success rate with individual target pressures after four years was 43.7%. Secondary glaucoma surgery was performed in 45 (43.7%) of cases. Combined cases (n=12) were not statistically different to stand-alone procedures (p=0.28). No difference between PEXG and POAG could be detected (p=0.44). During the learning curve, stent misplacement was common and resulted in worse outcome for less experienced surgeons.

Conclusion

The overall success rate of XEN 45 gel stent surgery in the present cohort is relatively low in a long-time follow-up under the given circumstances if all initial patients are included to follow-up. The influence of the surgeon's learning curve is obvious, and improvement in success can be expected when used by experienced and high-volume surgeons. No significant differences were found in PEXG compared to POAG or in XEN surgery combined with cataract surgery compared to stand-alone.

Archway Phase 3 Trial of the Port Delivery System with Ranibizumab for Neovascular Age-Related Macular Degeneration 2-Year Results

PURPOSE

To report 2-year results from the Archway clinical trial of the Port Delivery System with ranibizumab (PDS) for treatment of neovascular age-related macular degeneration (nAMD).

DESIGN

Phase 3, randomized, multicenter, open-label, active-comparator trial.

PARTICIPANTS

Patients with previously treated nAMD diagnosed within 9 months of screening and responsive to anti-vascular endothelial growth factor therapy.

METHODS

Patients were randomized 3:2 to PDS with ranibizumab 100 mg/ml with fixed refill-exchanges every 24 weeks (PDS Q24W) or intravitreal ranibizumab 0.5 mg injections every 4 weeks (monthly ranibizumab). Patients were followed through 4 complete refill-exchange intervals (∼2 years).

MAIN OUTCOME MEASURES

Change in best-corrected visual acuity (BCVA) Early Treatment Diabetic Retinopathy Study (ETDRS) letter score from baseline averaged over weeks 60 and 64, and weeks 88 and 92 (noninferiority margin, -3.9 ETDRS letters).

RESULTS

PDS Q24W was noninferior to monthly ranibizumab, with differences in adjusted mean change in BCVA score from baseline averaged over weeks 60/64 and 88/92 of +0.4 (95% confidence interval [CI], -1.4 to +2.1) and -0.6 ETDRS letters (95% CI, -2.5 to +1.3). Anatomic outcomes were generally comparable between arms through week 96. Through each of 4 PDS refill-exchange intervals, 98.4%, 94.6%, 94.8%, and 94.7% of PDS Q24W patients assessed did not receive supplemental ranibizumab treatment. PDS ocular safety profile was generally unchanged from primary analysis. Prespecified ocular adverse events (AEs) of special interest were reported in 59 (23.8%) PDS and 17 (10.2%) monthly ranibizumab patients. Most common AE of special interest reported in both arms was cataract (PDS Q24W, 22 [8.9%]; monthly ranibizumab, 10 [6.0%]). Events in the PDS Q24W arm included (patient incidence) 10 (4.0%) conjunctival erosions, 6 (2.4%) conjunctival retractions, 4 (1.6%) endophthalmitis cases, and 4 (1.6%) implant dislocations. Serum ranibizumab sampling showed that the PDS continuously released ranibizumab over the 24-week refill-exchange interval and ranibizumab serum concentrations were within the range experienced with monthly ranibizumab.

CONCLUSIONS

PDS Q24W showed noninferior efficacy to monthly ranibizumab through approximately 2 years, with approximately 95% of PDS Q24W patients not receiving supplemental ranibizumab treatment in each refill-exchange interval. AEs were generally manageable, with learnings continually implemented to minimize PDS-related AEs.

Intraocular Pressure and Medication Changes Associated with Xen Gel Stent: A Systematic Review of the Literature

The Xen gel stent (Allergan Inc, an AbbVie company; Dublin, Ireland) was conceived as an option for patients requiring modest IOP reduction but for whom trabeculectomy was not yet indicated. As with any glaucoma surgery, establishing criteria for patient selection and identifying factors that contribute to a high likelihood of success are important. To help guide clinical decision-making, a systematic review of published studies on the gel stent was performed, with the goal of understanding postoperative outcomes based on clinical and patient factors. Results were organized around a series of pertinent clinical questions based on scenarios encountered in clinical practice. Criteria for including studies were intentionally broad, with the objective of simulating the diverse population of glaucoma patients encountered in real-world practice. Outcomes for IOP and medication reduction postoperatively were assessed in various analyses, including in eyes with various glaucoma types and severity; in eyes naïve to surgery as well as those with a history of prior incisional glaucoma surgery; and when surgery was performed as a standalone procedure or at the time of cataract surgery. The results of each of the various analyses were consistent in demonstrating that successful gel stent surgery achieved a postoperative IOP of approximately 14.0 mm Hg and reduction to fewer than 1 glaucoma medication. Additional data are shown on outcomes by method of implant (ab interno vs ab externo); intraoperative use of antifibrotics; and rates of needling in published studies.

One-Year Outcomes of Standalone XEN Gel Stent Versus Nonpenetrating Deep Sclerectomy

PRCIS

The nonpenetrating deep sclerectomy (NPDS) procedure resulted in significantly more surgical success than the standalone XEN gel stent procedure without differences in safety profile.

PURPOSE

The purpose of this study was to compare surgical success and safety profile of NPDS and XEN gel stent.

METHODS

A retrospective chart review of 328 eyes of 282 patients who were scheduled for standalone XEN gel stent surgery (n=140) or NPDS (n=188) at Groupe Hospitalier Paris Saint-Joseph between January 2017 and December 2018 was conducted. Primary outcome measure was the proportion of surgical success 12 months after surgery. Complete and qualified surgical successes were defined by intraocular pressure (IOP)≤18 mm Hg and a reduction of IOP≥20% without or with hypotensive medication, respectively.

RESULTS

In total, 82 eyes were included in the XEN group and 124 eyes in the NPDS group. In the 1-eye analysis, rates of "complete success" and "qualified success" were, respectively, at the end of follow-up, 28.57% and 20.00% in the XEN group, and 42.72% and 16.50% in the NPDS group ( P =0.17). Success probability plots based on the Kaplan-Meier estimate for overall surgical success demonstrated a median success probability time of 3.73 years for the NPDS group and 2.38 years for the XEN group ( P <0.0001). After adjustment for confounding variables using Cox regression, the NPDS procedure was significantly more associated with surgical success than the XEN gel stent implantation ( P <0.001). No difference was demonstrated in terms of reduction of antiglaucoma medications, needling procedures, or reoperations.

CONCLUSIONS

The NPDS procedure may be more effective than the XEN gel stent in reducing IOP in patients with open angle glaucoma and may result in longer surgical success. However, a well-conducted prospective randomized study is required to confirm these results.

Minimally Invasive Glaucoma Surgery: Safety of Individual Devices

Primary open-angle glaucoma progression in those already on maximal medical therapy has traditionally been treated with trabeculectomy, a surgical procedure that carries a high degree of morbidity. In the last few decades, significant advances have been made in the field of minimally invasive glaucoma surgery (MIGS) devices, which aim to defer or prevent trabeculectomy via less arduous surgical techniques in certain types of glaucoma. Although reviews have been published examining the efficacy of various MIGS techniques, no article synthesises the comparative safety of all available devices. We performed a literature review examining the safety of MIGS devices. Fifteen devices were included, variously attempting to increase aqueous outflow through the trabecular meshwork or the suprachoroidal space, shunting into the subconjunctival space, or reducing aqueous production through ciliary body ablation. Notably, the earliest product attempting to increase outflow to the suprachoroidal space, Alcon's CyPass Micro-Stent, was withdrawn from the market due to concerns regarding increased corneal endothelial cell loss at five years post-implantation. All other devices were described as well-tolerated, with the most common adverse effects including hyphaema, intraocular pressure spikes, and device migration or obstruction. MIGS devices are purported to be uniformly safe, and many studies report no statistically significant increased complications beyond those associated with cataract surgery alone. It is important to note, however, the generally poor quality of current studies, with a dearth of randomised, or even prospective, data, and a large proportion of studies funded by device producers.

Management of Key Ocular Adverse Events in Patients Implanted with the Port Delivery System with Ranibizumab

PURPOSE

To provide strategies for the management of key ocular adverse events (AEs) that may be encountered with the Port Delivery System with ranibizumab (PDS) in practice and provide recommendations that may mitigate such AEs based on clinical trial experiences and considerations from experts in the field.

DESIGN

Safety evaluation based on the phase 2 Ladder (NCT02510794) and phase 3 Archway (NCT03677934) trials of the PDS.

METHODS

The PDS implant is a permanent, indwelling, and refillable ocular drug delivery system that requires standardized procedural steps for its insertion and refill-exchange procedures, which evolved during the PDS clinical program. We described identified AEs that may arise after implant insertion or refill-exchange procedures, including conjunctival retraction, conjunctival erosion, endophthalmitis, implant dislocation, conjunctival blebs or conjunctival filtering bleb leaks, wound leaks, hypotony, choroidal detachment, vitreous hemorrhage, rhegmatogenous retinal detachment, cataract, and septum dislodgement.

RESULTS

Adverse events related to the PDS were well understood, were manageable by trial investigators, and did not prevent patients from achieving optimal outcomes in most cases.

CONCLUSIONS

Surgeons using the PDS should be aware of potential ocular AEs and identify them early for optimal management. As with any new surgical procedure, it is important to provide surgeons with appropriate training, ensure adherence to optimal surgical techniques, and continually refine the procedure to mitigate complications and improve outcomes.

XEN45 Gelstent Implantation in the Treatment of Glaucoma Secondary to Fuchs Uveitis Syndrome

PURPOSE

Evaluation of treatment efficacy of XEN45 gelstent for glaucoma secondary to Fuchs uveitis syndrome (FUS).

METHODS

This retrospective case series evaluated patients with glaucoma secondary to FUS, who underwent XEN45 implantation. Complete success was defined as IOP lowering of ≥ 20% and cutoff IOP at ≤18 mmHg. Success was qualified if additional glaucoma medication was necessary. Additional glaucoma surgery except for needling and open bleb revision was regarded as failure.

RESULTS

Twelve eyes of 12 patients were included. Qualified and complete success rates were 50% after one year (n = 10). Qualified success was achieved in 66.6% of patients with 33.3% of patients achieving complete success after two years (n = 6).

CONCLUSIONS

XEN45 implantation had some success in the treatment of glaucoma secondary to FUS, but needling was frequently necessary to improve outcome.

Two-year Outcomes of XEN Implantation with Minimal Bleb Needling

Aim

Our study aims to report the 2 years outcomes of the XEN implant in a single unit, single surgeon setting with minimal bleb needling.

Methods

A retrospective cohort study was conducted. Inclusion criteria were patients who underwent implantation with a XEN device between May 2016 and December 2017. This included patients who underwent both combined phacoemulsification and intraocular lens implantation alongside XEN implantation and those who underwent XEN implantation alone. Data gathered included basic demographic data, best-corrected visual acuity (LogMAR), intraocular pressure (IOP) in mm Hg, mean deviation from their visual field test, and the number of IOP-lowering medications they were on. This information was recorded for their preoperative visit, and then at 6, 12, 18 and 24 months postoperatively. The primary outcome assessed was a complete success when the patient was without glaucoma medications and had an IOP of 18 mm Hg or less, but more importantly, this also had to equate to a 20% reduction in IOP compared to baseline. Qualified success was defined as the same change in IOP but with medications. Surgical failure is defined as those who required additional glaucoma surgery or those who did not obtain an IOP of 18 mm Hg alongside a 20% reduction in IOP compared to baseline.

Results

At 24 months follow-up 82.5% of patients were surgical successes. Complete surgical success was achieved in 27% of patients. Qualified surgical success was achieved in 55.6% of patients. Subgroup analysis of those undergoing XEN implantation on its own and those combined with phacoemulsification + IOL were similar. The rate of bleb needling was low at 4.5%. Complication rates were acceptable at 9.5%.

Conclusion

It is possible to get good IOP control with minimal postoperative bleb needling in patients who have undergone XEN implantation. Similar success rates are found in those undergoing combined procedures.

Clinical Significance

Bleb needling carries its own risks. Minimizing the number of bleb needling allows procedures to be reserved at a later date. Furthermore, our study shows that success rates are not affected by doing a combined procedure with phacoemulsification.

How to cite this article

Ali ZC, Moshin N, Hakim MT, et al. Two-year Outcomes of XEN Implantation with Minimal Bleb Needling. J Curr Glaucoma Pract 2022;16(2):79-83.

The efficacy of XEN gel stent implantation in glaucoma: a systematic review and meta-analysis

Background

Xen is a device for minimally invasive glaucoma surgery, and is used to treat POAG, pseudoexfoliative or pigmentary glaucoma, as well as refractory glaucoma. The efficacy of XEN in treating glaucoma remains to be confirmed and clarified. Hence, we conducted a systematic review and meta-analysis to examine the efficacy and associated complication of XEN implantations.

Methods

We conducted a literature search in PubMed, EMBASE, the Cochrane Library of Systematic Reviews, Web of Science, China National Knowledge Infrastructure, WanFang and SinoMed databases to identify studies, published before May 15, 2021, which evaluated XEN in glaucoma, and parameters for measurements included intra-ocular pressure (IOP), number of anti-glaucoma medications (NOAM), and bleb needling rate. We compared the measurements of XEN-only procedure between phaco-XEN and trabeculectomy, and we also did sub-analysis based on time points, glaucoma types, ethnics, etc. Sensitivity analyses and publication bias were conducted for evaluating bias.This study followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA 2020) reporting guideline.

Results

We identified 78 eligible studies, analysis revealed obvious IOP reduction after XEN stent implantation (SMD: 1.69, 95% CI 1.52 to 1.86, p value < 0.001) and NOAM reduction (SMD: 2.11, 95% CI 1.84 to 2.38, p value < 0.001). Sub-analysis showed no significant difference with respect to time points, ethnicities, and economic status. No significant difference was found between XEN treatment effect on POAG and PEXG eyes and between pseudo-phakic and phakic eyes. Also no significant difference was found between XEN and phaco-XEN surgery in terms of IOP after surgery (SMD: -0.01, 95% CI -0.09 to 0.08, p value 0.894). However, NOAM (after publication bias correction) and bleb needling rate (RR: 1.45, 95% CI 1.06to 1.99, p value 0.019) were lower in phaco-XEN group compared to XEN only group. Compared to trabeculectomy, XEN implantation had similar after-surgery IOP, however bleb needling rate (RR: 2.42, 95% CI 1.33 to 4.43, p value 0.004) was higher.

Conclusion

Our results confirmed that XEN is effective in lowering both IOP and NOAM till 48 months after surgery. It is noteworthy that XEN implantation leads to higher needling rate, compared to phaco-XEN or trabeculectomy. Further research, studying complications of XEN on non-European ethnicities, especially on Asian, are in urgent need before XEN is widely applied.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12886-022-02502-y.

Retrospective Analysis of 12 Months Glaucoma Implant Efficacy: XEN45 and PreserFlo Microshunt

PURPOSE

Several new implant devices have recently been introduced to glaucoma surgery using various techniques for reducing intraocular pressure (IOP). Two implants introduced during the past couple of years, XEN45 and PreserFlo Microshunt, are both designed to control subconjunctival filtration. There are two Swiss multicenter studies that collected the data retrospectively to analyze the efficacy and safety of these two devices separately. In this study, we report the analysis of the combined data subset from the University Hospital of Basel.

SUBJECTS AND METHODS

The XEN45 implantation technique was introduced to Basel University Hospital in 2016 and PreserFlo Microshunt in 2018. Sixty operated patients, thirty in each group, were operated on by one surgeon, clinically followed up, and their data retrospectively analyzed from medical records. Only standalone procedures, without combined phacoemulsification, were considered in this analysis; the lens status, however, was neither an inclusion nor an exclusion criterion. Further inclusion criteria were the diagnosis of open-angle glaucoma, no previous glaucoma surgery, other than laser trabeculoplasty, and complete medical records during the 12 months of follow-up. IOP reduction during a 12-month postoperative period was the primary outcome measure as well as the number of IOP reducing drugs. The number of subsequent surgical interventions and complications/adverse events are descriptively reported.

RESULTS

Patient age, gender, ophthalmological diagnosis, and initial preoperative IOP were well balanced between the two groups. Postoperative IOP course was comparable between the two methods for the first 12 months. IOP measurements were taken preoperatively and then on the first postop day, week 1, month 1, and months 3, 6, and 12 for the PreserFlo Microshunt vs. XEN45 (mmHg): 23.6 vs. 24.9, 9.0 vs. 8.9, 11.4 vs. 10.6, 13.0 vs.18.3, 16.8 vs.15.1, 15.9 vs.15.0, and 15.4 vs.14.5, respectively. IOP reducing medications were also comparable between the two groups. The study showed that subsequent interventions were more frequent in the XEN45 (13) than in the PreserFlo Microshunt group (7).

CONCLUSION

Both methods demonstrate satisfactory IOP control within a 12-month postoperative period with practically no serious adverse events/complications, but with relatively high numbers of subsequent interventions (needlings), particularly in the XEN45 group.

Appositional Choroidal Detachment Following XEN45 Gel Stent Requiring Surgical Drainage

An 82-year-old man with severe primary open-angle glaucoma on maximal medical therapy underwent an ab externo closed conjunctival Xen45 device insertion with mitomycin C. The surgery was uncomplicated, with a first postoperative day intraocular pressure of 4 mm Hg and visual acuity of 20/40 OD. Ten days later, the patient presented with an intraocular pressure of 5 mm Hg and a visual acuity of counting fingers at 5 feet. Examination showed Seidel negative bleb, shallow anterior chamber, and large nonappositional choroidal detachments. Medical therapy with steroids and cycloplegia was initiated. One week later, the serous choroidal detachments became appositional, and Xen explantation and surgical drainage of the choroidal detachment was performed. Postoperatively, the vision improved to 20/60. Significant choroidal detachments can occur after XEN45 implantation requiring surgical intervention.

The Outcomes of XEN Gel Stent Implantation: A Systematic Review and Meta-Analysis

Purpose

XEN gel stents are used for the treatment of open-angle glaucoma (OAG), including primary and secondary glaucoma that are uncontrolled by previous medical therapy and cases with previous failed surgery. Our aim was to systematically review of the clinical data of currently published ab-interno XEN gel stents with an emphasis on intraocular pressure (IOP), antiglaucoma medication outcomes, and safety profiles.

Methods

We analyzed all of the publications (MEDLINE, EMBASE, Cochrane Library) on the ab-interno XEN gel stent to evaluate the reduction in IOP and antiglaucoma medications following the procedure. The primary outcomes measured for the meta-analysis were reduction in IOP and anti-glaucoma medications. The secondary outcome were adverse events. For each study, we used a random effects analysis model to calculate the mean difference and 95% confidence intervals for the continuous results (reduction in IOP and antiglaucoma medications) using the inverse variance statistical method.

Results

Five hundred twenty-seven articles were checked and 56 studies were found to be relevant with a total of 4,410 eyes. There was a significant reduction in IOP as well as in the number of medications required in patients treated with ab-interno XEN implant either alone or combined with cataract surgery. This new treatment for various types of glaucoma reduced the IOP by 35% to a final average close to 15 mmHg. This reduction was accompanied by a decrease in the number of antiglaucoma medications in all the studies, approximately 2 classes of medication at the price of more needlings. The overall complete success rate was 21.0–70.8% after 2 years using strict criteria originally designed to record success rate in filtration surgery. The incidence of complications vision-threatening was low at <1%.

Conclusions

XEN gel stent was effective and safe for primary and secondary OAG. Further studies should be performed to investigate the impact of ethnicity on the success and failure rate after XEN implantation.

Animal models and drug candidates for use in glaucoma filtration surgery: A systematic review

Glaucoma, a degenerative disease of the optic nerve, is the leading cause of irreversible blindness worldwide. Currently, there is no curative treatment. The only proven treatment is lowering intraocular pressure (IOP), the most important risk factor. Glaucoma filtration surgery (GFS) can effectively lower IOP. However, approximately 10% of all surgeries fail yearly due to excessive wound healing, leading to fibrosis. GFS animal models are commonly used for the development of novel treatment modalities. The aim of the present review was to provide an overview of available animal models and anti-fibrotic drug candidates. MEDLINE and Embase were systematically searched. Manuscripts until September 1st^, 2021 were included. Studies that used animal models of GFS were included in this review. Additionally, the snowball method was used to identify other publications which had not been identified through the systematic search. Two hundred articles were included in this manuscript. Small rodents (e.g. mice and rats) are often used to study the fibrotic response after GFS and to test drug candidates. Due to their larger eyes, rabbits are better suited to develop medical devices. Novel drugs aim to inhibit specific pathways, e.g. through the use of modulators, monoclonal antibodies, aqueous suppressants or gene therapy. Although most newly studied drugs offer a higher safety profile compared to antimetabolites, their efficacy is in most cases lower when compared to MMC. Current literature on animal models and potential drug candidates for GFS were summarized in this review. Future research should focus on refining current animal models (for example through the induction of glaucoma prior to undertaking GFS) and standardizing animal research to ensure a higher reproducibility and reliability across different research groups. Lastly, novel therapies need to be further optimized, e.g. by conducting more research on the dosage, administration route, application frequency, the option of creating combination therapies, or the development of drug delivery systems for sustained release of anti-fibrotic medication.

Influence of Mitomycin C on the Therapeutic Success of Stand-Alone Xen45 Gel Stents and Its Combination with Cataract Surgery in Open-Angle Glaucoma Patients

PURPOSE

Minimally invasive glaucoma surgery (MIGS), like Xen45 gel stents, is known as effective therapy in lowering intraocular pressure (IOP); however, fibrotic reactions are a common problem in postoperative management. It was the aim of this study to investigate the therapeutic success of Xen45 gel stents as a stand-alone technique (Xen) and combined with cataract surgery (XenPhaco), and with antimetabolites (mitomycin C, MMC) in open-angle glaucoma patients.

METHODS

Retrospective analysis was performed of 199 eyes of 177 glaucoma patients of the Department of Ophthalmology, University of Erlangen Nürnberg, and from the Erlangen Glaucoma Registry (NCT00494923; ISSN 2191-5008, CS-2011) who underwent implantation of a Xen45 gel stent. Therapeutic success was defined as IOP reduction of ≥ 20% on the same or less anti-glaucomatous medication after 12 months compared to preoperative and without any additional glaucoma-related surgery (except bleb needling). IOP reduction, reduction in local anti-glaucomatous eye drops, and intra- and postoperative complications were monitored.

RESULTS

Stand-alone Xen45 gel stent: therapeutic success was reached in 39% (-MMC) and 55% (+MMC). Failure rate was 61% (-MMC) and 45% (+MMC). XenPhaco: therapeutic success was achieved in 57% (-MMC) and 46% (+MMC). Failure rate was 43% (-MMC) and 54% (+MMC). Data were not different for group and subgroup analyses (p > 0.05).

CONCLUSIONS

The use of MMC seemed to increase the therapeutic success rate after stand-alone Xen45 gel stent implantation and combined with cataract surgery, yet statistical significant was not reached.