Winfried Amoaku
University of Nottingham
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Featured researches published by Winfried Amoaku.
Ophthalmology | 2011
Frank G. Holz; Winfried Amoaku; Juan Donate; Robyn H. Guymer; Ulrich Kellner; Reinier O. Schlingemann; Andreas Weichselberger; Giovanni Staurenghi
OBJECTIVE To evaluate the safety and efficacy of individualized ranibizumab treatment in patients with neovascular age-related macular degeneration. DESIGN Twelve-month, phase III, multicenter, open-label, single-arm study. PARTICIPANTS A total of 513 ranibizumab-naïve SUSTAIN patients. INTERVENTION Three initial monthly injections of ranibizumab (0.3 mg) and thereafter pro re nata (PRN) retreatment for 9 months based on prespecified retreatment criteria. Patients switched to 0.5 mg ranibizumab after approval in Europe. MAIN OUTCOME MEASURES Frequency of adverse events (AEs), monthly change of best-corrected visual acuity (BCVA) and central retinal thickness (CRT) from baseline, the time to first re-treatment, and the number of treatments were assessed. RESULTS A total of 249 patients (48.5%) reported ocular AEs, and 8 (1.5%) deaths, 5 (1.2%) patients with ocular serious AEs of the study eye (retinal hemorrhage, cataract, retinal pigment epithelial tear, reduced visual acuity [VA], vitreous hemorrhage), and 19 (3.7%) patients with arteriothromboembolic events were observed. Most frequent AEs in the study eye were reduced VA (18.5%), retinal hemorrhage (7.2%), increased intraocular pressure (7.0%), and conjunctival hemorrhage (5.5%). The average number of re-treatments from months 3 to 11 was 2.7. Mean best-corrected visual acuity increased steadily from baseline to month 3 to reach +5.8 letters, decreased slightly from month 3 to 6, and remained stable from month 6 to 12, reaching +3.6 at month 12. Mean change in CRT was -101.1 μm from baseline to month 3 and -91.5 μm from baseline to month 12. CONCLUSIONS The safety results are comparable to the favorable tolerability profile of ranibizumab observed in previous pivotal clinical studies; individualized treatment with less than monthly re-treatments shows a similar safety profile as observed in previous randomized clinical trials with monthly ranibizumab treatment. Efficacy outcomes were achieved with a low average number of re-treatments. Visual acuity in SUSTAIN patients with individualized re-treatment based on VA/optical coherence tomography assessment reached on average a maximum after the first 3 monthly injections, decreased slightly under PRN during the next 2 to 3 months, and was then sustained throughout the treatment period.
Eye | 2004
C T Ntim-Amponsah; Winfried Amoaku; S Ofosu-Amaah; R K Ewusi; R Idirisuriya-Khair; E Nyatepe-Coo; M Adu-Darko
AbstractPurpose To determine the prevalence of primary open-angle glaucoma (POAG) in a Ghanaian population aged 30 years and above and to describe any ethnic variations in glaucoma prevalence in this population.Method A cross-sectional prevalence survey for POAG was carried out on residents of 30 years and above in the Akwapim-South district of Ghana. The principal investigator examined all glaucoma suspects and those diagnosed as glaucoma in the initial screening to determine all definite cases of POAG. All cases had intraocular pressure measurements. Glaucoma cases and suspects and some normal subjects had fundus biomicroscopy with 78 D Volk lens, and Humphrey FDT N-30 visual fields plotted.Results A total of 1843 people aged 30 years were screened from the population. The standardized age-specific prevalence was 7.7% (30 years and above) and 8.5% (40 years and above). The best-fit trend line for prevalence/age relationship was exponential. No gender or ethnic difference in prevalence was found.Conclusions The prevalence of POAG in this population is high and comparable to those in black populations in Barbados and St. Lucia
British Journal of Ophthalmology | 2006
H Shahid; Parwez Hossain; Winfried Amoaku
Retinal vein occlusions (RVO) are the second commonest sight threatening vascular disorder. Despite its frequency treatments for RVO are unsatisfactory and include several that have not been tested by large, well designed, prospective, randomised controlled trials. There is also the lack of long term follow up in many of the available small uncontrolled studies, and the timings of interventions are haphazard. This review aims to evaluate the current knowledge relating to the pathogenesis, suggested treatments for the different types of RVO, and their complications. Isovolaemic haemodilution is of limited benefit and should be avoided in patients with concurrent cardiovascular, renal, or pulmonary morbidity. Evidence to date does not support any therapeutic benefit from radial optic neurotomy, optic nerve decompression, or arteriovenous crossing sheathotomy on its own. Vitrectomy combined with intravenous thrombolysis may offer promise for central RVO. Similarly, vitrectomy combined with arteriovenous sheathotomy intravenous tissue plasminogen activator may offer benefits for branch RVO. RVOs occur at significantly high frequency to allow future prospective randomised controlled studies to be conducted to evaluate the role of different therapeutic modalities singly or in combination.
British Journal of Ophthalmology | 2005
V A Shanmuganathan; E M Casely; Dev Raj; Richard J. Powell; Annie Joseph; Winfried Amoaku; Harminder S Dua
Aims: To determine the efficacy of sirolimus in the treatment of patients with severe non-infectious uveitis. Methods: Eight patients with severe non-infectious uveitis were recruited to an open study. Inclusion criteria were limited to patients whose disease was not controlled with at least two or more separate steroid sparing immunosuppressants (either because of unacceptable side effects or ineffectiveness of the drug) or who required regular doses of corticosteroids either as high dose systemic or orbital floor injections in order to control their disease. Intraocular inflammation, visual acuity, symptoms, corticosteroid burden, drug toxicity, and side effects were monitored. Results: Sirolimus therapy was effective in five of the eight patients, all of whom had their dose of corticosteroids reduced or discontinued. Treatment in three patients was considered a failure as it caused intolerable side effects and/or failed to control the uveitis. Side effects were common and were typically gastrointestinal or cutaneous in nature. The severity of symptoms was dose dependent in most cases and occurred at trough blood levels above 25 ng/ml. Conclusion: Sirolimus is an effective and potent immunosuppressive treatment in the majority of patients with non-infectious uveitis and can reduce the need for long term supplementary corticosteroid therapy. Further studies are required to establish the long term efficacy and safety of sirolimus alone or in combination with other steroid sparing immunosupressants.
Eye | 2015
Winfried Amoaku; Usha Chakravarthy; Richard Gale; M. Gavin; Faruque Ghanchi; Jonathan Gibson; Simon P. Harding; R L Johnston; S. Kelly; Andrew J. Lotery; Sajjad Mahmood; Geeta Menon; Sobha Sivaprasad; James Talks; Adnan Tufail; Yit C. Yang
The introduction of anti-vascular endothelial growth factor (anti-VEGF) has made significant impact on the reduction of the visual loss due to neovascular age-related macular degeneration (n-AMD). There are significant inter-individual differences in response to an anti-VEGF agent, made more complex by the availability of multiple anti-VEGF agents with different molecular configurations. The response to anti-VEGF therapy have been found to be dependent on a variety of factors including patient’s age, lesion characteristics, lesion duration, baseline visual acuity (VA) and the presence of particular genotype risk alleles. Furthermore, a proportion of eyes with n-AMD show a decline in acuity or morphology, despite therapy or require very frequent re-treatment. There is currently no consensus as to how to classify optimal response, or lack of it, with these therapies. There is, in particular, confusion over terms such as ‘responder status’ after treatment for n-AMD, ‘tachyphylaxis’ and ‘recalcitrant’ n-AMD. This document aims to provide a consensus on definition/categorisation of the response of n-AMD to anti-VEGF therapies and on the time points at which response to treatment should be determined. Primary response is best determined at 1 month following the last initiation dose, while maintained treatment (secondary) response is determined any time after the 4th visit. In a particular eye, secondary responses do not mirror and cannot be predicted from that in the primary phase. Morphological and functional responses to anti-VEGF treatments, do not necessarily correlate, and may be dissociated in an individual eye. Furthermore, there is a ceiling effect that can negate the currently used functional metrics such as >5 letters improvement when the baseline VA is good (ETDRS>70 letters). It is therefore important to use a combination of both the parameters in determining the response.The following are proposed definitions: optimal (good) response is defined as when there is resolution of fluid (intraretinal fluid; IRF, subretinal fluid; SRF and retinal thickening), and/or improvement of >5 letters, subject to the ceiling effect of good starting VA. Poor response is defined as <25% reduction from the baseline in the central retinal thickness (CRT), with persistent or new IRF, SRF or minimal or change in VA (that is, change in VA of 0+4 letters). Non-response is defined as an increase in fluid (IRF, SRF and CRT), or increasing haemorrhage compared with the baseline and/or loss of >5 letters compared with the baseline or best corrected vision subsequently. Poor or non-response to anti-VEGF may be due to clinical factors including suboptimal dosing than that required by a particular patient, increased dosing intervals, treatment initiation when disease is already at an advanced or chronic stage), cellular mechanisms, lesion type, genetic variation and potential tachyphylaxis); non-clinical factors including poor access to clinics or delayed appointments may also result in poor treatment outcomes. In eyes classified as good responders, treatment should be continued with the same agent when disease activity is present or reactivation occurs following temporary dose holding. In eyes that show partial response, treatment may be continued, although re-evaluation with further imaging may be required to exclude confounding factors. Where there is persistent, unchanging accumulated fluid following three consecutive injections at monthly intervals, treatment may be withheld temporarily, but recommenced with the same or alternative anti-VEGF if the fluid subsequently increases (lesion considered active). Poor or non-response to anti-VEGF treatments requires re-evaluation of diagnosis and if necessary switch to alternative therapies including other anti-VEGF agents and/or with photodynamic therapy (PDT). Idiopathic polypoidal choroidopathy may require treatment with PDT monotherapy or combination with anti-VEGF. A committee comprised of retinal specialists with experience of managing patients with n-AMD similar to that which developed the Royal College of Ophthalmologists Guidelines to Ranibizumab was assembled. Individual aspects of the guidelines were proposed by the committee lead (WMA) based on relevant reference to published evidence base following a search of Medline and circulated to all committee members for discussion before approval or modification. Each draft was modified according to feedback from committee members until unanimous approval was obtained in the final draft. A system for categorising the range of responsiveness of n-AMD lesions to anti-VEGF therapy is proposed. The proposal is based primarily on morphological criteria but functional criteria have been included. Recommendations have been made on when to consider discontinuation of therapy either because of success or futility. These guidelines should help clinical decision-making and may prevent over and/or undertreatment with anti-VEGF therapy.
Health and Quality of Life Outcomes | 2005
Jan Mitchell; James S. Wolffsohn; Alison Woodcock; Stephen J. Anderson; Carolyn V. McMillan; Timothy ffytche; Martin Rubinstein; Winfried Amoaku; Clare Bradley
BackgroundThe MacDQoL is an individualised measure of the impact of macular degeneration (MD) on quality of life (QoL). There is preliminary evidence of its psychometric properties and sensitivity to severity of MD. The aim of this study was to carry out further psychometric evaluation with a larger sample and investigate the measures sensitivity to MD severity.MethodsPatients with MD (n = 156: 99 women, 57 men, mean age 79 ± 13 years), recruited from eye clinics (one NHS, one private) completed the MacDQoL by telephone interview and later underwent a clinic vision assessment including near and distance visual acuity (VA), comfortable near VA, contrast sensitivity, colour recognition, recovery from glare and presence or absence of distortion or scotoma in the central 10° of the visual field.ResultsThe completion rate for the MacDQoL items was 99.8%. Of the 26 items, three were dropped from the measure due to redundancy. A fourth was retained in the questionnaire but excluded when computing the scale score. Principal components analysis and Cronbachs alpha (0.944) supported combining the remaining 22 items in a single scale. Lower MacDQoL scores, indicating more negative impact of MD on QoL, were associated with poorer distance VA (better eye r = -0.431 p < 0.001; worse eye r = -0.350 p < 0.001; binocular vision r = -0.419 p < 0.001) and near VA (better eye r = -0.326 p < 0.001; worse eye r = -0.226 p < 0.001; binocular vision r = -0.326 p < 0.001). Poorer MacDQoL scores were associated with poorer contrast sensitivity (better eye r = 0.392 p < 0.001; binocular vision r = 0.423 p < 0.001), poorer colour recognition (r = 0.417 p < 0.001) and poorer comfortable near VA (r = -0.283, p < 0.001). The MacDQoL differentiated between those with and without binocular scotoma (U = 1244 p < 0.001).ConclusionThe MacDQoL 22-item scale has excellent internal consistency reliability and a single-factor structure. The measure is acceptable to respondents and the generic QoL item, MD-specific QoL item and average weighted impact score are related to several measures of vision. The MacDQoL demonstrates that MD has considerable negative impact on many aspects of QoL, particularly independence, leisure activities, dealing with personal affairs and mobility. The measure may be valuable for use in clinical trials and routine clinical care.
Ophthalmology | 2013
Adnan Tufail; Nirodhini Narendran; Praveen J. Patel; Sobha Sivaprasad; Winfried Amoaku; Andrew C. Browning; Olayinka Osoba; Richard Gale; Sheena George; Andrew J. Lotery; Mohammed Majid; Martin McKibbin; Geeta Menon; Chris Andrews; Christopher Brittain; Aaron Osborne; Yit C. Yang
pathophysiology in LHON. In this study, we reported that ganglion cell analysis could precisely detect the loss of retinal ganglion cell in a time-dependent manner during early phase of LHON when RNFL thickness had not decreased yet. We also raise the possibility that there might be many more patients>60 years of age with visual loss owing to LHON than we have supposed previously. It may be worth investigating mtDNA point mutations regardless of age if a patient presents with unknown visual acuity loss with central scotoma.
Eye | 2007
A Joseph; S Rogers; Andrew C. Browning; N Hall; C Barber; Andrew J. Lotery; E Foley; Winfried Amoaku
PurposeTo describe the clinical and angiographic features of three cases of secondary syphilis in immunocompetent patients, which presented as acute posterior placoid chorioretinitis (APPC) to the ophthalmologist.MethodsInterventional case series. The aetiology of the APPC was confirmed by serology to be secondary syphilis. Optical coherence tomography, electrophysiology, fundus fluorescein, and indocyanine green (ICG) angiography were performed at presentation and after resolution. Appropriate treatment for secondary syphilis was instituted in each patient.ResultsThe clinical features, fundus fluorescein and ICG angiography, multifocal electroretinography (mfERG), and optical coherence tomography findings of APPC are described. All three patients had a satisfactory resolution of the APPC with improvement in visual acuity.ConclusionsAPPC in secondary syphilis can occur even in immunocompetent patients. A high index of suspicion is required for early diagnosis of this condition resulting in a good visual outcome with adequate treatment. mfERG and optical coherence tomography are useful in the diagnosis and follow-up of these patients.
Experimental Eye Research | 2011
Elizabeth Anne Stewart; Govindi J. Samaranayake; Andrew C. Browning; Andrew Hopkinson; Winfried Amoaku
Neovascular eye diseases such as wet age-related macular degeneration and proliferative diabetic retinopathy are two of the most common causes of irreversible visual loss. Although mediated by vascular endothelial growth factor (VEGF), the mechanisms of these diseases are not fully understood. Molecular inhibitors of VEGF including pegaptanib, ranibizumab and bevacizumab are used as treatments for these diseases. However, there have been very few direct comparisons between these agents, and as dose and treatment regimes differ their relative efficacies are hard to determine. In vitro comparisons tend to use cells from different sites or species, which show heterogeneity in their responses. The aim of this study was to compare the characteristics of primary cultures of isolated human choroidal endothelial cells (hCEC) and retinal endothelial cells (hREC), and their proliferation responses to stimulation with VEGF 121 and 165, and to compare the anti-proliferative effects of these three drugs. hCEC and hREC were positive for the cell markers VEGFR1, VEGFR2, CD31, CD34 and von Willebrands factor (vWF), with greater expression of CD34 on the hREC compared to hCEC. Contrary to previous assumptions VEGF isoforms 121 and 165 were found to be equally potent in stimulating endothelial cell proliferation. However, hREC exhibited higher proliferation with either VEGF isoform compared to hCEC. The anti-VEGF treatments ranibizumab and bevacizumab were effective in decreasing proliferation of hCEC induced by the two VEGF isoforms, individually and in combination, with ranibizumab being moderately more effective, particularly in hREC. Pegaptanib was effective in controlling the proliferation of hCEC stimulated by VEGF 165, but was ineffective against the stimulatory effect of VEGF 121. There were found to be significant differences in microvascular endothelial cells from the retina and choroid, both in the expression of cell markers and their behaviour in response to growth factors and currently available anti-VEGF agents, highlighting the importance of targeting treatments to specific intraocular vascular beds and/or diseases.
The Lancet | 2017
Sobha Sivaprasad; A Toby Prevost; Joana Vasconcelos; Amy Riddell; Caroline Murphy; Joanna Kelly; James W. Bainbridge; Rhiannon Tudor-Edwards; David Hopkins; Philip Hykin; A Bhatnagar; Ben Burton; Usha Chakravarthy; Haralabos Eleftheriadis; T Empeslidis; Richard Gale; Sheena George; Maged Habib; S. Kelly; Andrew J. Lotery; M McKibbin; L Membrey; Geeta Menon; Bushra Mushtaq; Luke Nicholson; Jayashree Ramu; O Osoba; Jignesh I Patel; P Prakash; R Purbrick
BACKGROUND Proliferative diabetic retinopathy is the most common cause of severe sight impairment in people with diabetes. Proliferative diabetic retinopathy has been managed by panretinal laser photocoagulation (PRP) for the past 40 years. We report the 1 year safety and efficacy of intravitreal aflibercept. METHODS In this phase 2b, single-blind, non-inferiority trial (CLARITY), adults (aged ≥18 years) with type 1 or 2 diabetes and previously untreated or post-laser treated active proliferative diabetic retinopathy were recruited from 22 UK ophthalmic centres. Patients were randomly assigned (1:1) to repeated intravitreal aflibercept (2 mg/0·05 mL at baseline, 4 weeks, and 8 weeks, and from week 12 patients were reviewed every 4 weeks and aflibercept injections were given as needed) or PRP standard care (single spot or mutlispot laser at baseline, fractionated fortnightly thereafter, and from week 12 patients were assessed every 8 weeks and treated with PRP as needed) for 52 weeks. Randomisation was by minimisation with a web-based computer generated system. Primary outcome assessors were masked optometrists. The treating ophthalmologists and participants were not masked. The primary outcome was defined as a change in best-corrected visual acuity at 52 weeks with a linear mixed-effect model that estimated adjusted treatment effects at both 12 weeks and 52 weeks, having excluded fluctuations in best corrected visual acuity owing to vitreous haemorrhage. This modified intention-to-treat analysis was reapplied to the per protocol participants. The non-inferiority margin was prespecified as -5 Early Treatment Diabetic Retinopathy Study letters. Safety was assessed in all participants. This trial is registered with ISRCTN registry, number 32207582. FINDINGS We recruited 232 participants (116 per group) between Aug 22, 2014 and Nov 30, 2015. 221 participants (112 in aflibercept group, 109 in PRP group) contributed to the modified intention-to-treat model, and 210 participants (104 in aflibercept group and 106 in PRP group) within per protocol. Aflibercept was non-inferior and superior to PRP in both the modified intention-to-treat population (mean best corrected visual acuity difference 3·9 letters [95% CI 2·3-5·6], p<0·0001) and the per-protocol population (4·0 letters [2·4-5·7], p<0·0001). There were no safety concerns. The 95% CI adjusted difference between groups was more than the prespecified acceptable margin of -5 letters at both 12 weeks and 52 weeks. INTERPRETATION Patients with proliferative diabetic retinopathy who were treated with intravitreal aflibercept had an improved outcome at 1 year compared with those treated with PRP standard care. FUNDING The Efficacy and Mechanism Evaluation Programme, a Medical Research Council and National Institute for Health Research partnership.