Morphological and functional analysis of the loading regimen with intravitreal ranibizumab in neovascular AMD Matthias Bolz, Chrisitian Simader, Markus Ritter, Christian Ahlers, Thomas Benesch, Christian Pruente, Ursula M Schmidt-Erfurth
To cite this version:
Matthias Bolz, Chrisitian Simader, Markus Ritter, Christian Ahlers, Thomas Benesch, et al.. Mor- phological and functional analysis of the loading regimen with intravitreal ranibizumab in neovas- cular AMD. British Journal of Ophthalmology, BMJ Publishing Group, 2010, 94 (2), pp.185-n/a. 10.1136/bjo.2008.143974. hal-00508654
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1 Morphological and functional analysis of the loading regimen
2 with intravitreal ranibizumab in neovascular AMD
3
4 Matthias Bolz1, M.D., Christian Simader1, M.D.,
5 Markus Ritter1, M.D., Christian Ahlers1, M.D., Thomas Benesch2, Christian Prünte1,
6 M.D., Ursula Schmidt-Erfurth1, M.D.
7
8 1 Department of Ophthalmology, 14 2 Core Unit of Medical Statistics and
9 Medical University of Vienna, 15 Informatics
10 Währinger Gürtel 18-20, 16 Section of Medical Statistics
11 1090 Vienna 17 Medical University of Vienna
12 Austria 18 Spitalgasse 23
13 19 1090 Vienna
20 Austria
21
22 Corresponding author: Ursula Schmidt-Erfurth
23 Email: [email protected]
24 Phone: 0043/1/40400/7931 o. 7900
25 Text word count: 2445
26 Keywords: Ranibizumab, Loading dose, OCT, microperimetry, fluorescein angiography
27
28
29 None of the authors has a proprietary interest in any of the products mentioned in this study
30 2
1 Background: 2 To quantify and correlate the morphological and functional effects of the 3 recommended loading regimen with intravitreal ranibizumab in neovascular age-related 4 macular degeneration (AMD). 5 6 Methods: 7 In a prospective, interventional, clinical trial, 29 consecutive patients (29 eyes) 8 with choroidal neovascularization (CNV) secondary to AMD received 3 initial monthly 9 intravitreal injections of ranibizumab. During this loading regimen, best corrected visual 10 acuity (BCVA) and microperimetry (MP) testing, as well as optical coherence 11 tomography (OCT) and fluorescein angiography (FA) were performed using a 12 standardized protocol and the results correlated. 13 14 Results: 15 Significant morphological and functional therapeutic effects were observed as 16 early as 1 week following the first treatment. Throughout the loading dose period, central 17 retinal thickness (CRT) including intraretinal cysts and subretinal fluid decreased fast and 18 significantly (p<0.01), PEDs resolved less rapidly. The mean leakage area by FA 19 decreased (p<0.01) and retinal function (BCVA and MP) increased significantly (p<0.01 20 respectively). However, the change in morphology and function was only significant 21 between baseline and week 1. There was no significant additional morphological or 22 functional benefit following the second and third injection. 23 24 Conclusion: 25 The initial administration of intravitreal ranibizumab in neovascular AMD induces
26 a significant effect on intra- and subretinal fluid and visual function, subsequent
27 injections have a less pronounced effect. It remains to be determined whether this loading
28 regimen is mandatory in all patients or if a single dose regimen could lead to a
29 comparable functional and morphological retinal improvement. 3
1 BACKGROUND:
2
3 Since age-related macular degeneration (AMD) is still the leading cause of
4 irreversible vision loss among the elderly population in Europe and North America,
5 finding effective treatment strategies is of high socio-economic interest. The advances in
6 the development of therapies inhibiting vascular endothelial growth factor (VEGF), one
7 of the leading factors in the pathogenesis of neovascular AMD, offer a significant
8 improvement in prognosis regarding the recovery of altered retinal structures as well as
9 visual function.[1-11]
10
11 Ranibizumab, a humanized, monoclonal antibody fragment, has been shown to be
12 an effective inhibitor of VEGF. [9, 12-14] It is derived from the full-length antibody, but
13 consists only of the antigen-binding Fab portion. Similar to the complete antibody,
14 ranibizumab binds all biologically active isoforms of VEGF A such as the cleavage
15 products VEGF 110 and 121 allowing a rapid resolution of leakage documented as a
16 reduction in edematous retinal thickening.
17
18 Several studies on ranibizumab therapy have focused on safety, as well as on
19 morphological and functional effects. In a phase I/II study, Heier and co-authors[9] have
20 shown significant differences in the increase in visual acuity (VA) between patients
21 receiving monthly intravitreal ranibizumab injections and usual care and have described a
22 rapid resolution of retinal edema. Similar results were reported by Rosenfeld and co-
23 authors in a phase III clinical trial, in the PrONTO study, the MARINA as well as in the 4
1 ANCHOR trial.[14-16] In the PIER trial again a similar initial regimen with three
2 consecutive monthly injections was used. A positive response during the early three
3 months was indicative of the long-term prognosis regarding vision maintenance during
4 follow-up in 40% of study patients.[14] Therefore, a so-called loading phase consistent of
5 three initial injections per month was included into the official label of ranibizumab by
6 the FDA for the US as well as the EMEA for the European countries. The label
7 specifically mentions this loading injections followed by quarterly injections as a less
8 effective alternative to monthly dosing for patients unable to do monthly dosing.
9
10 However, solid evidence for this recommended loading phase was not provided,
11 nor was any detailed correlation between morphologic and functional changes offered.
12
13 The aim of this study was to identify and quantify the morphological and
14 functional effects of intravitreal ranibizumab therapy given as a loading regimen with
15 three injections during the first three months in patients with CNV secondary to AMD.
16 As previous studies have shown that significant changes in retinal morphology and
17 functionality can be observed especially and almost only in this short initial time frame,
18 the detailed evaluation of this early treatment response is of particular importance. [9, 14,
19 15]
20
21 5
1 METHODS:
2
3 The study was performed by the department of Ophthalmology of the Medical
4 University of Vienna. All the research and measurements adhered to the tenets of the
5 Helsinki agreement, the study was approved by the local ethics committee and informed
6 consent was obtained from all individuals after detailed discussion of the nature and possible
7 consequences of the study.
8
9 inclusion criteria
10 Patients aged 50 years or older showing primary neovascular AMD were included
11 into this study in a consecutive mode. All lesion types – classic, minimally classic and occult
12 – were permitted. Inclusion and exclusion criteria complied in detail with the protocol
13 instructions of the ANCHOR and MARINA trials. The best corrected visual acuity (BCVA)-
14 score assessed using the ETDRS protocol ranged between 24 and 74 letters. Patients who
15 had received laser or intravitreal antiangiogenic therapy were not included in this study.
16 Significant subfoveal fibrosis, a history of submacular surgery or uncontrolled glaucoma, the
17 presence of angioid streaks, CNV due to other causes or pregnancy were further exclusion
18 criteria.
19
20 ranibizumab treatment
21 All included patients received 3 intravitreal injections with ranibizumab in monthly
22 intervals. After completion of all examinations performed according to the study protocol,
23 1% oxybuprocaine, 4% lidocaine and betaisodona (pH 6.8) eye drops (pharmacy of the 6
1 General Hospital Vienna) were administered to the study eye. Under sterile conditions, a
2 volume of 0.05 ml ranibizumab was injected intravitreally.
3
4 assessment of retinal function
5 Functional retinal changes were assessed by measuring BCVA at baseline, week 1,
6 month 1, 2 and 3. Refraction was assessed using a single chart (“R chart”), BCVA score
7 with two different reading charts (“Chart 1” and “Chart 2”), one for each eye.
8 At each follow-up visit, microperimetry was performed using the perimeter MP-1
9 (Nidek Co., LTD.). A static threshold perimetry of the center and a circle at 3.5 degrees
10 using a Goldmann size III stimulus was provided for all patients and mean values were
11 calculated.
12
13 analysis of morphologic changes of retina and RPE
14 Fluorescein angiography (FA; HRA 2, Heidelberg Engineering) was performed at
15 baseline and month 3. Measurements were done by an experienced examiner by highlighting
16 the area of leakage in each late phase image (at 10 minutes) using the device’s planimetric
17 software.
18
19 Furthermore, morphologic changes in the retinal layers were observed performing
20 optical coherence tomography (Stratus OCT™, Carl Zeiss© Meditec) at baseline, week 1,
21 month 1, 2 and 3. Morphologic parameters defined by protocol were central retinal thickness
22 (CRT) in µm as measured by a Fast Retinal Thickness Map scan and the presence of
23 intraretinal cystic changes and pigment epithelial detachment (PED) as documented by a 7
1 Cross Hair scan. Mean CRT was analyzed using the Fast Retinal Thickness Map Analyzer, a
2 software tool provided by the OCT 3 device. In some (17/145) cases there were alignment
3 errors leading to incorrect central retinal thickness values. In these cases, CRT was re-
4 measured manually using the caliper toll. This enabled the examiner to position 2 cross hairs
5 at individual (central) places in each scan in order to measure the realistic distance in
6 between and to calculate mean values. Using a previously published method[17], cross hair
7 scans were also used to planimetrically evaluate a trend of change in mean maximum PED
8 height and greatest linear diameter (GLD) using the Adobe Photoshop CS software.
9
10 statistical analysis
11 The paired t-test was used for statistic analysis of changes in PED height and GLD and
12 in leakage area compared to baseline. A p-value of 0.05 or less was considered statistically
13 significant. For the variables BCVA and CRT and retinal sensitivity we used a general linear
14 model with fixed effects visits and random effect patient.
15 8
1 RESULTS
2 Twenty nine eyes of 29 consecutive patients (13 female, 16 male) were included in
3 this prospective study. The mean age was 77 ± 7 years. By angiographic composition, 9
4 lesions were identified as predominantly classic, 11 as minimally classic and 9 lesions were
5 defined as purely occult graded by FA.
6
7 treatment response in respect to retinal function
8 At baseline, the mean BCVA score was 58.6±12.5 letters. Already at week one, there
9 was a statistically significant increase in BCVA of +5.1±4.0 letters (p<0.0001). At month
10 one, the increase in BCVA was +4.7±4.5 (p<0.0001), at month two 4.7±5.8 (p<0.0001) and
11 at month three +6.4±5.8 letters (p<0.0001), compared to baseline respectively (figure 1).
12 BCVA increased from baseline ≥10 letters in 6 patients and ≥5 letters in 17 patients. There
13 were no statistically significant differences between BCVA values at week 1, month 1, 2 or
14 3. Furthermore, there was no statistically significant difference in terms of BCVA
15 improvement between the different lesion subtypes at month three.
16
17 By microperimetric assessment of central retinal sensitivity, there was an increase
18 from 4.2±3.3dB at baseline to 5.5±4.2dB at week one (p<0.06), 5.0±4.0dB at month one
19 (p=0.31), 6.1±4.2dB at month two (p<0.003) and 5.0±3.3dB at month three (p=0.08; figure
20 2), compared to baseline values respectively. In one patient, microperimetric testing was not
21 performed due to a dry eye syndrome which impaired the device’s eye tracking system.
22
23 9
1 changes in retina and RPE morphology
2 The mean leakage area as assessed by FA at baseline (n=29) and month 3 (n=22)
3 decreased from 7.80±5.15mm2 to 2.36±2.52mm2 (p<0.01; in eyes with classic lesion: -51%,
4 in eyes with minimally classic lesions: -78%, in eyes with occult lesion: -61% (data not
5 shown).
6
7 OCT evaluation at baseline identified a mean CRT of 324±94µm. Again, as early as
8 at week one, CRT had decreased statistically significantly by -83±85µm (p<0.0001), at
9 month one by -102±89µm (p<0.0001), at month two by -101±112µm (p<0.0001) and at
10 month three by 109±98µm (p<0.0001), compared to baseline respectively (figure 3). At
11 month three, CRT had decreased to values ≤200µm in 14 patients and to values ≤180µm in
12 nine patients. There were no statistically significant differences between CRT values at
13 week 1, month 1, 2 or 3.
14
15 The number of patients showing intraretinal cysts in the cross hair scans decreased
16 from 17 at baseline to 6 at week one, 4 at month one, 5 at month two and to 3 at month
17 three. In the same manner, the number of patients showing PED in the cross hair scans
18 decreased from 14 at baseline to 10 at week one, 9 at month one, 5 at month two and to 6 at
19 month three (figure 4).
20
21 The change in maximum PED height and GLD over time is shown in figure 5. One
22 week after the first drug administration, the mean maximum PED height as measured in the
23 corresponding cross hair scans was decreased from 286±162µm at baseline to 200±229µm 10
1 (p=0.29), at month one to 173±225µm (p=0.03), at month two to 57±114µm (p<0.01) and at
2 month three to 59±99µm (p<0.01). The mean GLD decreased from 1918±615µm at baseline
3 to 1412±1210µm at week one (p=0.20), to 1162±1238µm at month one (p=0.07), to
4 466±961µm at month two (p<0.01) and 489±854µm at month three (p<0.01). compared to
5 baseline respectively. The changes in PED height and GLD between the single study visits
6 following week 1 were not statistically significant.
7
8 correlation of morphologic and functional changes during the loading phase
9 Correlating inter-visit changes in central retinal thickness to inter-visit changes in
10 BCVA did not show any significance. Furthermore, only at the baseline visit CRT values
11 correlated significantly to BCVA values (r=-0,423; p=0.022), a correlation not found to be
12 significant at any visit following treatment initiation. Neither was there a correlation
13 between the relative change in CRT in OCT and the relative change in leakage area in FA
14 and between the relative change in leakage area in FA and the relative change in BCVA
15 (data not shown).
16 11
1 DISCUSSION
2 A prospective study was conducted to evaluate the effects of the recommended
3 loading phase of three initial monthly ranibizumab injections. Functional and morphological
4 changes were documented and correlated following a standardized protocol including central
5 visual acuity and central visual field testing to monitor retinal function and defined
6 morphological parameters such as CRT, presence of CME and serous PED by OCT and
7 leakage area by FA.
8
9 In a population meeting the criteria of the phase III trials, intravitreal ranibizumab
10 administered as a loading dose proved to be an effective therapy leading to significant
11 morphological and functional retinal changes, clearly detectable as early as one week after
12 the first injection. At this point in time, the mean BCVA was increased by 5.1 letters (i.e.
13 one line), the mean central retinal threshold sensitivity assessed by microperimetry was
14 increased by 1.3dB and the mean CRT was decreased by 88µm. After three months, the
15 number of patients showing cysts in the cross hair scans of OCT had decreased from 17 to 3,
16 and the number of patients showing PED from 14 to 6. Furthermore, there was a clear trend
17 of decrease in PED extension, planimetrically assessed as a significant decrease in the mean
18 maximum PED height and mean GLD. These findings indicate that significant treatment-
19 induced morphologic and functional effects following a single intravitreal ranibizumab
20 injection can be expected as early as after one week. In contrast, in the examined population
21 the subsequent two injections of the loading phase did not lead to any significant additional
22 benefit either at the functional or at the anatomical level.
23 12
1 The therapeutic effects of the small monoclonal antibody fragment ranibizumab on
2 retinal morphology could be observed in all retinal layers. Intraretinal edema – assessed via
3 CRT – already decreased significantly after one week. PED height and GLD decreased also,
4 but significant differences were not reached before month one. The trend of morphological
5 retinal improvement continued until month three, which, in part, may be attributed to the
6 repeated monthly treatment strategy.
7
8 Interestingly, in the examined population the improvement in retinal morphology
9 assessed as a decrease in CRT did not correlate with the functional benefit assessed via
10 BCVA. Even if in almost all cases there was a decrease in CRT and an increase in BCVA
11 score, there was no direct statistically significant correlation. Obviously, the CRT value does
12 only reveal the individual anatomical recovery of retinal structures from mechanical and
13 hypoxia-induced stress due to intraretinal and subretinal edema or PED, but not the
14 functional condition. In contrast, a direct correlation between CRT and BCVA was found at
15 baseline presentation The missing correlation after treatment initiation may reflect a loading
16 dose specific effect of ranibizumab when the resolution of fluid occurs rapidly and
17 intensively, irrespectively of the destruction of neurosensory structures relevant for function.
18 Follow-up studies are under way to evaluate the impact of recurrent retinal thickening on
19 visual function during the maintenance phase. Nevertheless, functional recovery was
20 obviously caused by the morphological restoration of intraretinal integrity which may not be
21 assessable in a comprehensive way using CRT values. The morphologic recovery in turn
22 could be explained by a decrease in CNV leakage observed in FA over the time of the
23 loading phase. 13
1
2 In the examined patients, a loading regimen with three initial injections proved to
3 be an effective therapeutic strategy. Also in the MARINA, ANCHOR and PIER study an
4 initial regimen with three consecutive monthly injections was used showing an additional
5 effect on the decrease in CRT and increase in BCVA. The results of this study did not
6 show any significant additional benefit of the subsequent second and third injection. Even
7 if the examined population was comparatively small, this indicates that there seem to be
8 inter-individual differences in the response to intra-vitreal ranibizumab in patients with
9 CNV secondary to AMD. Hence, it remains to be determined whether this multi-injection
10 regimen is mandatory in all patients or if in some cases a single dose regimen could lead
11 to a comparable functional and morphological retinal improvement.
12
13 The early onset of retinal recovery at week one might serve as a prognostic factor
14 for the level of overall improvement to be expected. Disappearance of RPE pathologies
15 should be documented during the first three months as well, but appears to be slower than
16 retinal recovery and may have little impact on visual function. Even if the examined
17 population was relatively small, this prospective study using a standardized set of
18 morphologic and functional parameters provides important information about the specific
19 retinal response, the sequence of events over time and the missing correlation of retinal
20 functional and morphological changes in CRT characteristic for the loading phase of
21 intravitreal ranibizumab therapy. 14
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17
FIGURE LEGENDS
Figure 1:
Relative change in BCVA (letters, ETDRS) at week 1, month 1, 2 and 3. Boxes indicate mean values, error bars indicate standard error.
Figure 2:
Absolute changes in central retinal threshold sensitivity in dB as assessed by microperimetry. Boxes indicate mean values, error bars indicate standard error.
Figure 3:
Relative change in central retinal thickness (CRT) in µm at week 1, month 1, 2 and 3.
Boxes indicate mean values, error bars indicate standard error.
Figure 4:
Number of patients showing cysts (left) or PED in the OCT cross hair scans at week 1, month 1, 2 and 3.
Figure 5:
Absolute change in mean PED height (left) and PED greatest linear diameter (right) in microns assessed at week 1, month 1, 2 and 3. Boxes indicate mean values, error bars indicate standard error.
18
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