10 actual role of aptamer pegaptanib in treatment of wet amd, our experience of four year1

University “Sapienza�of Rome Italy ASL Latina: Ospedale A.Fiorini Terracina, U.O.C. Oftalmologia Universitaria Head: Prof Enzo M. Vingolo M.D., Ph.D.

Actual Role of aptamer (pegaptanib) in treatment of wet AMD, our experience of four year.

Vingolo E.M., Fragiotta S., Grenga P., Domanico D.

_____________________ Corresponding Author: Enzo M. Vingolo M.D., Ph.D. Email: evingolo@libero.it Tel.: +393486500312

Introduction: Age-related macular degeneration (AMD) is the main 10 cause of visual impairment in the developed world . The onset of the disease is characterized by damage to the outer retinal cells and retinal pigment epithelium. These processes can elicit a cascade of inflammatory and angiogenic responses leading to the growth of abnormal new blood vessels (neovascularisation) underlying the retina which can cause severe and rapid vision loss due to 1,2 hemorrhage and exudation . This form of AMD is called wet AMD. Exudative or wet AMD is a late form of AMD (as distinguished from atrophic, so-called dry, AMD) and is responsible for 60–80% of all cases of blindness due to AMD. As soon as neo- vascularisation becomes established, several pro-angiogenic mediators begin to play a pivotal role. Vascular endothelial growth factors (VEGFs) are the most specific and potent regulators of 2 angiogenesis . The introduction of anti-VEGF therapy caused a ‘Copernican revolution’ in ophthalmology.

Intravitreal administration of these agents, which consists of injecting anti-angiogenic agents directly into the vitreous humor, has been used since 2005 worldwide for the treatment of neovascular AMD (n-AMD) and currently 1,3 represents the primary therapy for this condition . Three anti-VEGFs (pegaptanib, ranibizumab and bevacizumab) are currently used for the treatment of patients with nAMD. Pegaptanib (PB) was the first anti-VEGF to be investigated in one of the largest clinical trials reported in the medical literature in terms of the number of patients enrolled the VEGF Inhibition Study In Ocular Neovascularisation 4 (VISION) study . VISION, actually two randomized controlled trials (RCTs) involving 117 centers and a total of 1208 patients, investigated the safety and efficacy of PB in patients with n-AMD. Patients who received PB (0.3mg) had significantly better outcomes compared to the sham arm. Furthermore, patients who continued long-term

treatment had a more favorable outcome than those who discontinued therapy early. PB, a selective RNA-aptamer, which targets VEGF165, an isoform, has been shown to play an important role in the pathophysiology of neovascular process and it is known that PB spares other isoforms of VEGFs such as VEGF120. Preclinical studies in animal models suggest that the selective inhibition by intravitreal PB can minimize some of the safety issues associated with the use of non-selective anti-VEGF 5 agents .

Starting 2008 some inhibitors based on antibody structure reacting against VEGF were introduced in wet AMD treatment. These monoclonal antibodies called bevacizumab (BB) and its a derivative from BB called ranimizumab (RB)modified natural history of the disease and were more effective inhibiting all isoforms of VEGF (pan-VEGF inhibitors).

Since the introduction of the pan-VEGF inhibitors, the use of PB has decreased as it was considered to have reduced bioactivity compared with BB and RB. Although there is a lack of randomized controlled trials comparing PB with the pan-VEGF inhibitors it is generally accepted that BB and PB are superior in controlling the acute occurrence of the neovascular process. Nevertheless, while the panVEGF inhibitors have greater activity against VEGF, there are some concerns regarding their long-term use in relationship to their systemic effects in terms of cardiovascular stroke and ischemic or thromboembolic accidents, as VEGF is also considered an important factor 8 in retinal physiology . For these reasons, new therapeutic strategies have been investigated to maximize efficacy and minimize possible risks. The aim of this paper is to present our experience and our current therapeutic strategies for the management of n-AMD reducing systemic risks on wet-AMD. Materials:

All patients were selected following guidelines of Vision Study; Inclusion criteria: age higher than 50 years with subfoveal choroidal neovascularization secondary to AMD and best-corrected visual acuities (VAs) of 20/40 to 20/320 in the study eye. Patients with all angiographic subtypes of AMD were enrolled. Total lesion size could not exceed 12 total disc areas, in which at least 50% of the lesion was active choroidal neovascularization and no greater than 50% of the lesion was comprised of subretinal hemorrhage. Eligible patients also were required to have an intraocular pressure (IOP) lower than 23 mmHg. Patients with a history of no more than 1 prior administration of photodynamic therapy with verteporfin were also eligible for enrollment.

At baseline, patients were selected to receive 0.5 mg, of ranimizumab by intravitreous injection every 4 weeks for 12 weeks for a total of 3 treatments. After that for the first year (54 weeks), subjects were treated with pegaptanib sodium every 6-8 weeks (some patients depending from clinical conditions were treated with PB every every 6-8 weeks for two years104 week, after that the treatment was discontinued). For ethical reasons, subjects who were selected to stop treatment were permitted to resume therapy (compassionate rescue therapy) if they had benefited from treatment in the first year, and subsequently lost at least 2 lines (10 letters) of vision after discontinuation.

In our opinion combining nonselective and selective VEGF blockade may provide clinical benefit with minimal risks in the treatment of neovascular age-related macular degeneration (AMD). Our study design: Pilot retrospective observational study, one eye only was studied for each

patient, 147 patients (69 male and 78 female) age range 58-91 years (SD17,54); patients were treated from May 2006 to June 2011 in our Department in “A. Fiorini” Hospital Terracina (Italy). Patients were divided in two groups: (A) All subtypes of neovascular AMD 135 patients

and (M) myopic CNV 12 patients. were included in the study. Broad range of baseline vision Follow-up: 60 months, At Baseline all patients were completely examinated with Best Corrected Visual Acuity measurements (BCVA), reading speed, OCT scans, Fluorescein Angiography,(FA) Microperimetric examination. All examinations except FA were repeated every two months for 104 weeks and every six months after as presented in our previous study11. Moreover every systemic ischemic condition and adverse event occurred after the injections was registered on file were registered for each patient.

Parameter Macular thickness, BCVA

All patients gave their informed consent to the treatment and to the study according the Italian Society of Ophthalmology rules and the study followed the Helsinki declaration guidelines.

Tab. I shows the grading scheme of each studied parameter, considering that all values were reported at the end of the study in percentage on the baseline value according our previous study on the follow up of Retinitis pigmentosa patients12.

Improved

Unchanged

Worsen

<80%

80-120%

>120%

>3 letters gain

Same value

>3 letters loss

Fixation (BCEA)

<80%

80-120%

>120%

Reading Speed

<80%

80-120%

>120%

Tab. I: Clinical evaluation parameters

Results: Group Age-Related Macular Degeneration (A): from baseline 107 (78,1%) presented after two year a reduction of macular thickness in studied eye, 18 (13,14%) were unchanged and 12 (8,76%) worsened. Best corrected visual acuity was improved in 88 (64,23%) after two year in studied eye, 25 (18,25%) were unchanged and 14 (10,22%)

worsened. Microperimetry results in BCEA were as follows: improved in 114 (83,21%) after two year in studied eye, 19 (13,87%) were unchanged and 4 (2,92%) worsened. Regarding reading speed 112 eyes (81,75%) presented improvements in understood words while 19 (13,87%) were unchanged and 6 (4,38%) were worsened (fig. 1).

100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% spessore

BCVA

MP

RS

In this group were performed 1327 Intravitreal injections with different drugs and we observed side effects as reported in Tab. Tab II Intravitreal air bubble

435/1327

31,75%

Subconjuntival hemorrhage

377/1327

28,41%

Vitreal Hemorrhage

1/1327

0,08%

Retinal tear

3/1327

0,23%

Retinal detachment

0/1327

0%

Anterior Segment R Reaction

2/1327

0,15%

Cheratoipopion

1/1327

0.08%

Ischemic systemic episode

0/1327

0%

Tab. II: Group A side effects Group Myopic CNV (B): from baseline 7 patients (58,33%) %) presented after two year a reduction of macular thickness in studied eye, 4 (33,33%) were unchanged and 1 (8,34%) worsened. Best corrected visual acuity was improved in 8 (66,66%) after two year in studied eye, 4 (33,34%) were unchanged and 0 (0%) %) worse worsened.

Microperimetry results in BCEA were as follows: improved in 10 (83,33%) %) after two year in studied eye, 2 (16,67%) 7%) were unchanged and 0 (%) worsened. Regarding reading speed 10 eyes (83,33 3,33%) presented improvements in understood words while 2 (16,67%) were unchanged and 0 (0%) %) were worsened (fig. 2).

100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Thickness

BCVA

Microperimetry

R. S.

In this group were performed 159 Intravitreal injections with different drugs and we observed side effects as reported in Tab. Tab III. Intravitreal air bubble

25/159

15,72%

Subconjuntival hemorrhage

42/159

26,42%

Vitreal Hemorrhage

0/159

0%

Retinal tear

2/159

1,26%

Retinal detachment

0/159

0%

Anterior Segment Reaction

3/159

1,89%

Cheratoipopion

0/159

0%

Ischemic systemic episode

0/159

0%

Tab. III: Group B side effects Discussion: Advances in understanding the pathophysiology of n-AMD AMD led to the introduction of new anti-angiogenic agents targeting VEGF. These drugs either inhibit a selected VEGF isoform or inhibit all the VEGF isoforms. w suggested that pan pan-VEGF A recent literature review inhibitors itors offer improved treatment outcomes in wet-AMD and as a result, these drugss that inhibit all VEGF isoforms are now considered the gold standard as first first-line therapy.

Although pan-VEGF inhibitors nhibitors currently represent the mainstay of treatment for wet AMD, there is concern regarding their long-term tolerability. VEGF plays aan important role in neovascularisation isation and increasing increasingly evidence suggests that VEGF plays a key role various physiological pathways,, mainly in recovery from ischemic episodes8.

While local toxicity is the major concern with the use of VEGF inhibitors, the risk of systemic thromboembolic events with their long-term term use still needs to be adequately addressed as it is recognized that VEGF maintains the integrity of the cardiovascular system. In addition, VEGF also plays a neuroprotective role in non-vascular non cells in various animal models by reducing oxidative stress.

The neuroprotective effect of VEGF on retinal ganglion gangl cells (RGC) has been recently confirmed13, showing that VEGF protects differentiated RGC-5 RGC against H2O2mediated oxidative stress. Selective elective VEGF inhibition may reduce at least theoretically the risk associated with non selective-VEGF blocking â&#x20AC;&#x201C; indicating that their present limited use needs to be re-evaluated. evaluated. Selective anti-VEGF anti drugs have therefore been suggested for the long-term long treatment of wet-AMD.

Results of our retrospective study seems to be overlapping the considerations done by Hughes and Sang in a study on 20 patients published in 2006 by suggested that nonselective VEGF blockade with BB induction and selective VEGF165 blockade with PB as maintenance therapy in patients with wet-AMD may provide clinically meaningful outcomes with a promising safety profile9. In addition, intravitreal PB administered every 6 weeks according to protocol minimizes the required number of injections per year, compared with the pan-VEGF inhibitors that require monthly injections determining cost sparing in a world in which mean age of population is becoming higher. Our results are encouraging, achieved in a large amount of patients, led to the use of this protocol in a wider population of affected patients.

In our study the efficacy and tolerability of PB was reported similarly to that evidentiated in a phase IV, prospective, open-label, uncontrolled study called LEVEL (evaluation of efficacy and safety in maintaining visual acuity with sequential treatment of neovascular AMD).

The effects of PB maintenance therapy â&#x20AC;&#x201C; PG 0.3mg every 6 weeks for 48 weeks with follow-up to week 54, was investigated in 568 patients with wet-AMD. Patients had one to three induction treatments 30â&#x20AC;&#x201C;120 days before entry and 42% received induction with RB; 36% with BB and 22% with other single or multiple agents as well as PB6.

In this study the Authors evidentiated improvements in visual outcomes including a mean visual acuity (VA) improvement of 12.2 letters at 12-month follow-up. In addition, 41% of patients gained 3 early treatment diabetic retinopathy scale (ETDRS) lines. In our study we noted similar data not only for visual acuity but also for retinal thickness, fixation stability and most important thing in reading speed. In our opinion need to be stressed that VA gains are a result of induction therapy with pan anti VEGF agents, while PB maintained long-term remission of the

CNV. In addition, the protocol allowed the use of unscheduled treatments with other agents used to treat wetAMD (booster therapy) at the discretion of the investigator to fight performances deterioration in AMD patients.

Anatomical responses, as assessed by OCT retinal measurements, were similarly maintained. Moreover, PB was well tolerated, with few minor ocular or systemic events and no serious adverse events recorded6. Our patients were regularly followed and treated with either drug showed benefits also after post injection period (3 years of follow-up). Since wet-AMD is considered to be a chronic disease and the population still became elder these kind of treatments need to be repeated several times, moreover the economic side of treatment represent an important issue for most of the countries even in western and more rich world. For this reason of financial impact on national security system often the availability of these treatments based on repeated injections of pan antiVEGF drugs is limited because their cost10. There is general agreement on the utility of BB based on its low cost and comparable efficacy/safety studies2.

However, there is still concern regarding the potential local and systemic adverse ischemic events with the long-term use of the pan-VEGF inhibitors which has not yet been evaluated because of their very recent introduction to the market.

In our study safety of the combination of booster dose with pan antiVEGF followed by maintenance with selective antiVEGF is underlined by the 0% of ischemic events on more of 1500 intravitreal injections, while efficacy is well demonstrated by high incidence of improvements at the end of follow up. Yearly injections for patient was lower than presented in Marina and Anchor studies and lover of recommended doses of pro-re nata scheduling.

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11. Vingolo, E.M.a, Salvatore, S.b , Cavarretta, S. Low-vision rehabilitation by means of MP-1 biofeedback examination in patients with different macular diseases: A pilot study Applied Psychophysiology Biofeedback Volume 34, Issue 2, June 2009, Pages 127-133 12. Vingolo, E.M.a, Rocco, M.b, Grenga, P.L.a, Salvatore, S.ac , Pelaia, P.b Slowing the degenerative process, long lasting effect of hyperbaric oxygen therapy in retinitis pigmentosaGraefe's Archive for Clinical and Experimental Ophthalmology Volume 246, Issue 1, January 2008, Pages 93-98 13. Zachary I. Neuroprotective role of vascular endothelial growth factor: signalling mechanisms, biological function, and therapeutic potential. Neurosignals 2005;14:207-211