PURPOSE: To evaluate the effect of the vitreous in response to intravitreal (IV) injections of ranibizumab 0.5 mg/0.05ml (Lucentis; Genentech, South San Francisco, CA) for the treatment of diabetic macular edema (DME). METHODS: Prospective, observational, multicenter study, conducted at Centro Hospitalar e Universitário do Porto, Portugal. Best-corrected visual acuity and central foveal thickness will be evaluated at baseline and every month until the end of follow-up. OCT biomarkers such as retinal layers thickness will also be analyzed. A p value of 0.05 or less will be considered to be statistically significant. HYPOTHESIS: Vitrectomized patients will improve less than non-vitrectomized patients.
Patients will be included in two different groups according to the vitreous status: group 1 - non vitrectomized eyes; group 2 - vitrectomized eyes. Patients will be followed-up according to the standard of care and a final analysis of the results will be performed at 12+/-1 months of follow-up, which is the minimum follow-up period required for each patient. In group 1 the effect of VMA existence and PVD status will also be analyzed. The recruitment period will be of 6 months. Treatment All patients will be treated with IV ranibizumab injections (0.5 mg/0.05ml) following a PRN regimen. The injections will be performed in the operating room following the standard intravitreal injections protocol. When required, adjunct treatment, with macular and/or peripheral LASER (rescue LASER), will be also admitted at or after 24 weeks if persistent DME not improving after at least 2 injections. Treatment Schedule Repeat injections at every 4-week visit if eye "improves" or "worsens" (defined as ≥5 letter change from last injection or ≥10% CST change on OCT from last injection or CSF\>300 μm at any timepoint). Defer injections if either BCVA of 85 letters and OCT CSF "normal" (CSF≤300 μm and non-existent intra- or sub-retinal fluid); or OCT CSF "normal" (CSF≤300 μm) and stable BCVA (defined as \< 5 letters change from last injection) after two consecutive injections during the first 24 weeks, or after one injection if the initial stability period has already been achieved (OCT CSF "normal" and stable BCVA). Resume injections if BCVA or OCT worsens.
Study Type
OBSERVATIONAL
Enrollment
50
PRN regimen. Treatment Schedule Repeat injections at every 4-week visit if eye "improves" or "worsens" (defined as ≥5 letter change from last injection or ≥10% CST change on OCT from last injection or CSF\>300 μm at any timepoint). Defer injections if either BCVA of 85 letters and OCT CSF "normal" (CSF≤300 μm and non-existent intra- or sub-retinal fluid); or OCT CSF "normal" (CSF≤300 μm) and stable BCVA (defined as \< 5 letters change from last injection) after two consecutive injections during the first 24 weeks, or after one injection if the initial stability period has already been achieved (OCT CSF "normal" and stable BCVA). Resume injections if BCVA or OCT worsens.
Hospital de Santo António
Porto, Portugal
assess the number of IV injections needed to control DME between groups
DME control is defined as 1) BCVA of 85 letters and OCT CFT "normal" (CFT≤300 μm and non-existent intra- or sub-retinal fluid); or 2) OCT CFT "normal" (CFT≤300 μm) and stable BCVA (defined as \<5 letters change from last injection) after two consecutive injections during the first 24 weeks, or after one injection if the initial stability period has already been achieved (OCT CFT "normal" and stable BCVA).
Time frame: 18 months
compare the functional changes at the end of follow-up between groups
Functional change will be measured by the Early Treatment Diabetic Retinopathy Scale (ETDRS) which measures the best-corrected visual acuity with an ETDRS-like chart at 4 meters in number letters or at 1 meter when patients are unable to read any letters on the ETDRS chart at 4 meters. The ETDRS scale varies from 1 to 85 letters (85 letters correspond to a 20/20 in the Snellen scale). The higher the value the better the outcome. A clinical significant functional improvement will be considered for a gain of ≥5 EDTRS letters.
Time frame: 18 months
compare the anatomical changes at the end of follow-up between groups
Anatomical change will be measured by central foveal thickness (CFT), measured by Optical Coherence Tomography, automatically measured by the software in the central 1 mm. A CFT \<240µm or \>300 µm is considered pathological. A CFT between 240 and 300 µm is considered physiological. CFT has no defined minimum or maximum values. Since patients with diabetic macular edema usually have CFT \>300 µm the goal of treatment is to lower the CFT to values between 240 and 300 µm. A clinical significant anatomical improvement will be considered for a change in CFT≥10%.
Time frame: 18 months
compare the percentage of type of responder during the follow-up period between groups
Type of responder is defined as follows: * good responder: when beyond the 24th week of follow-up (maximum 7 injections) there was a complete anatomical response (CFT≤300μm) with an increase in BCVA ≥5 letters; * non-responder: 13 injections and final CFT \>400 um or ≤10% of CFT reduction and BCVA decrease (or BCVA gain \<5 letters) * incomplete responder: between good and non-responder criteria.
Time frame: 18 months
access the percentage, in group 2, of focal VMA and PVD status and type of response
to access the percentage, in group 2, of focal VMA and PVD status, and if those changed during the follow-up period influenced the type of response
Time frame: 18 months
assess retinal layers thickness as prognostic and pathophysiological biomarkers of DME treatment response
* to assess baseline retinal layers thickness correlation with final BCVA * to assess the influence of the variation of retinal layers thickness (baseline versus final) on final BCVA * to assess differences between groups according to the above points; * to associate the type of responder and baseline and final retinal layers thickness.
Time frame: 18 months
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