Revisiting our RANZCO report on ‘Approaches to anti-VEGF therapy’

??Firstly, the statent that ‘one size does not fit all’ was taken out of context somewhat.?? The point was that if a treatment strategy is adopted that treats all patients as being the same, i.e. not ‘individualized’, e.g. ‘PRN’ or ‘Treat and Extend’, then it must be based on monthly treatment.?? Other regimens, e.g. three consecutive monthly treatments followed by treatment every three months (the PIER study), have been shown to yield inferior results.??
Prof Hunyor believes that the ‘Treat and Extend’ regimen is applicable to all neovascular??AMD patients and gives good results when implented properly.
??To correct the record, our equating ‘PRN’ and ‘Treat and Extend’ is incorrect and an explanation follows.?? ‘PRN’??(Pro Re Nata??- ‘as the circumstance arises’ often translated loosely to ‘as needed’) is a ‘reactive’ regimen in which treatment is given only if signs of ‘deterioration’ are detected (usually a decrease in VA judged to be attributable to the disease, a haorrhage, or signs of recurrent activity detectable by OCT or [sometimes] repeat fluorescein angiography).
??’Treat and Extend’ on the other hand is a ‘proactive’ regimen in which treatment is given monthly until the best possible structural (clinical and OCT) and functional (VA) outcomes are achieved.?? At that time, another treatment is still given but the interval between subsequent visits is extended (by one or two weeks per episode) until signs of recurrent neovascular activity are detected.?? Once that recurrence or ‘break point’ is detected, a further treatment is given and the re-treatment interval is reduced.?? In cases of a severe recurrence, that interval might return to the original four weeks.?? Mild recurrences see the interval revert to the previous interval at which the patient was stable, which may be longer than four weeks.
??The words ‘on average’ were missing from the statent regarding injection rates for years one and two of treatment.?? In fact, the figure of seven to eight injections in the first year of treatment is a mean value, some patients will do well with fewer whereas a significant percentage of the patients will still be getting monthly treatments at year one and will thus have 12 treatments in their first year.
Finally, Prof Hunyor clarified the matter of the tolerance of sub-retinal fluid seen with OCT.?? While it is usual to attpt to ‘dry’ the retina, some clinicians accept a small amount of residual sub-retinal fluid.?? However, that approach has yet to be validated clinically and an Australian clinical trial sponsored by Novartis, the FLUID study, is examining the issue. ??The amount of sub-retinal fluid tolerated in the study is limited to 200 microns.??
The rationale for the study is that a significant percentage of patients in studies published recently, e.g. CATT, still showed some sub-retinal fluid at one or two years while retaining good vision.?? Furthermore, there is the unanswered question as to whether or not ‘overtreatment’ can result in the development of further atrophic retinal changes in the long-term.
??Insight thanks Prof Hunyor for his feedback.