[Chances and risks of anti-VEGF therapy]

Effects of ranibizumab (Lucentis®) and bevacizumab (Avastin®) on human corneal endothelial cells

Background

Ingrowth of newly formed blood and lymph vessels (angiogenesis) from the limbus region into the cornea can be treated successfully by subconjunctival application of antiangiogenic agents. Currently, there are several angiogenesis inhibitors from various manufacturers available, such as vascular endothelial growth factor (VEGF) antibodies. The aim of the study was to investigate potential cytotoxic effects of two anti-VEGF agents, ranibizumab (Lucentis®) and bevacizumab (Avastin®) on the human corneal endothelium.

Methods

Human donor corneas, not suitable for corneal transplantation, were organ-cultured in the presence of either ranibizumab (Lucentis®) or bevacizumab (Avastin®) at different concentrations (group 1: 250 μg / ml, group 2: 25 μg / ml, group 3: 2.5 μg / ml) for a period of up to 4 weeks. Microscopic imaging for endothelial cell counting, detection of morphologic alterations of the endothelium, and molecular biology testing (Enzyme-linked Immunosorbent Assay [ELISA]) for metabolic changes was performed.

Results

Background-corrected results showed neither a significant lactate dehydrogenase (LDH) change with increasing culturing time nor a significant difference between ranibizumab (Lucentis®) and bevacizumab (Avastin®) treatment. The endothelial cell density revealed also no statistically significant difference between the two treatment groups with ranibizumab (Lucentis®) and bevacizumab (Avastin®) at all concentrations tested in this study.

Conclusions

In this study, the anti-angiogenic agents ranibizumab (Lucentis®) and bevacizumab (Avastin®) demonstrated no cytotoxic effects on the corneal endothelium of human organ-cultured donor corneas over the limited study time period of 4 weeks. However, based on the study design (in-vitro) and the limited follow-up period, no conclusions on potential long-term effects can be drawn.

Course of Intraocular Pressure after Intravitreal Injection of 0.05 mL Ranibizumab (Lucentis®)

Purpose

This prospective study examines the changes in short-term intraocular pressure (IOP) in patients with wet age-related macular degeneration (AMD) receiving intravitreal injections of 0.05 mL ranibizumab (Lucentis®) in a supine position.

Methods

A total of 45 eyes (45 patients, 16 M, 29 F, mean age: 78 y) received intravitreal ranibizumab injections for treatment of wet AMD (0.05 mL = 0.5 mg). The IOP was measured by Schiötz tonometry immediately preoperatively and postoperatively, and also after 3 and 10 minutes in a supine position. No history of glaucoma was present.

Results

The mean preoperative IOP was 22.4±5.5 mmHg in supine position. Immediately after the injection, IOP increased to 47.9±15.1 (range 23–82, p<0.001), with 32 eyes (71.1%) >40 and 19 eyes (42.2%) >50 mmHg. The mean difference between preoperative IOP and immediately after the injection was +25.5±13.6 mmHg. IOP decreased spontaneously by the first 3 minutes after operation by 12.6±6.0 mmHg and after 10 minutes by 21±9.4 mmHg. The mean difference between preoperative IOP and 10 minutes postoperatively was +4.6±7.0 mmHg (range: −9.3 to +25.9 mmHg, p<0.001). Eyes without a subconjunctival reflux had a higher increase in IOP than eyes with any reflux (p<0.001).

Conclusions

IOP increased significantly in a considerable number of patients after intravitreal ranibizumab injections. A rapid and spontaneous decline was observed in the majority of cases. If there is no subconjunctival reflux after the injection, the increase in IOP is higher than in eyes with any back-flow under the conjunctiva.

Effect of the Honan intraocular pressure reducer to prevent vitreous reflux after intravitreal bevacizumab injection

PURPOSE

To evaluate the effect of the Honan intraocular pressure reducer (HIPR) on vitreous reflux during intravitreal (IVT) injection.

METHODS

Prospective, comparative, controlled, investigator-blinded, randomized clinical study. Sixty eyes of 60 patients who underwent IVT injection were allocated into 2 groups with or without using the HIPR. Vitreous reflux was estimated by measuring largest diameter of the conjunctival bleb formed after IVT injection. Preoperative intraocular pressure (IOP) before and after application of the HIPR and IOP immediately postoperatively and 3 and 10 minutes postoperatively were evaluated.

RESULTS

The mean amount of vitreous reflux was significantly less with the HIPR than without the HIPR (1.46±1.04 mm vs 2.61±1.37 mm; p<0.001). The preoperative IOP was significantly lower with the HIPR than without the HIPR (11.62±4.04 mmHg vs 16.26±3.86 mmHg; p=0.026). The 3-minute postoperative IOP was 31.34±3.16 mmHg with the HIPR and 32.61±5.62 mmHg without the HIPR (no statistical significance; p=0.345).

CONCLUSIONS

The HIPR prevents vitreous reflux after IVT through a reduction in the preoperative IOP. However, the HIPR appears not to affect the postoperative course of transient IOP elevation.

Subretinal recombinant tissue plasminogen activator and pneumatic displacement for the management of subretinal hemorrhage occurring after anti-VEGF injections for wet AMD

We describe three cases of submacular hemorrhage that occurred two to four days after anti-VEGF intravitreal injection for occult choroidal neovascularisation in age-related macular degeneration and their management with 25 gauge pars plana vitrectomy with injection of subretinal recombinant tissue plasminogen activator (rTPA) followed by fluid-air exchange and postoperative prone position. Vitrectomy, subretinal rTPA injection and fluid-gas exchange apply as a safe and effective treatment in these cases. Functional results seem to be positive especially if surgical treatment is promptly performed.

Subconjunctival reflux and need for paracentesis after intravitreal injection of 0.1 ml bevacizumab: comparison between 27-gauge and 30-gauge needle

PURPOSE

Intravitreal injections may lead to a significant elevation of the intraocular pressure (IOP). A paracentesis may become necessary for acute reduction of the IOP in certain cases. The purpose of this study was to determine the frequency of paracentesis performed and the grade of reflux under the conjunctiva after injection of 0.1 ml bevacizumab (1.25 mg), depending on the thickness of the needles used.

METHODS

A retrospective review was undertaken of the surgery reports of 234 consecutive intravitreal bevacizumab injections in 145 eyes of 144 patients within 14 months. In particular, the frequency of paracentesis, the thickness of the needles used (27-gauge versus 30-gauge), the lens status, and a semi-quantitative reflux grade were analysed.

RESULTS

A paracentesis was performed in 78 cases (33%) for acute reduction of the IOP. In the 27-gauge group the frequency was 26% (25 of 96), and in the 30-gauge group 38% (53 of 138) (p = 0.05, independent estimating equation (IEE)). The medians of the semi-quantitative assessment of the reflux grade under the conjunctiva were 2.0 in the 27-gauge group (corresponding to a mild reflux) and 1.0 in the 30-gauge group (corresponding to a minimal reflux, p < 0.001, IEE).

CONCLUSIONS

When using a 30-gauge needle for intravitreal injections, the reflux under the conjunctiva was less than with a 27-gauge needle. However, the use of a 30-gauge needle appeared to be associated with a higher frequency of paracentesis.

Off-label use of bevacizumab for the treatment of age-related macular degeneration: what is the evidence?

There is an active and controversial debate about the role of intravitreal bevacizumab versus approved drugs in the treatment of neovascular age-related macular degeneration (AMD). Because bevacizumab was available prior to the launch of ranibizumab, off-label use of the former became widespread and the cancer drug bevacizumab is the most commonly used medication in ophthalmology nowadays. This review considers every publication identified in MEDLINE using the keywords 'bevacizumab' and 'Avastin' between 1 June 2005 and 31 July 2008. The search identified 511 papers that were evaluated. In 33 studies, there was consistent and clear evidence for the efficacy of bevacizumab in neovascular AMD. However, the highest grade studies (three prospective, randomized, controlled trials) did not attain better than grade 2b level of evidence, and objective evaluation of the benefit of bevacizumab relative to representative controls was therefore not possible. Certainly, the available evidence is inferior to that obtained from the approval studies of ranibizumab and this should influence treatment selection and guidance of patients. These considerations indicate that important quality criteria need to be included in future studies to ensure more meaningful conclusions can be drawn. These include clearly defined inclusion criteria, information about the recruitment procedure (including data on withdrawals, excluded patients, concealed treatment allocation, use of intention-to-treat analyses and blinded assessment procedures). Although preclinical studies have almost exclusively found bevacizumab to be safe, the design utilized in clinical case series cannot rule out a possible increase in adverse events, which already show a high spontaneous incidence in elderly AMD patients. The superior evidence level for ranibizumab and the limited safety data for bevacizumab must be taken into consideration when evaluating the costs that a healthcare system is willing to spend. However, the superior grade of evidence for ranibizumab should not be confused with the (still missing) evidence for superior efficacy. The results of ongoing randomized, controlled, comparative trials will provide further data on the efficacy and cost effectiveness of bevacizumab and ranibizumab in the treatment of AMD. In the meantime, patients should be informed about the alternatives, the price differences and the restricted liability issue when off-label use of bevacizumab is offered.