Real-world outcomes of combined therapy of photodynamic therapy with anti-vascular endothelial growth factor for polypoidal choroidal vasculopathy

Polypoidal Choroidal Vasculopathy: Updates on Risk Factors, Diagnosis, and Treatments

There have been recent advances in basic research and clinical studies in polypoidal choroidal vasculopathy (PCV). A recent, large-scale, population-based study found systemic factors, such as male gender and smoking, were associated with PCV, and a recent systematic review reported plasma C-reactive protein, a systemic biomarker, was associated with PCV. Growing evidence points to an association between pachydrusen, recently proposed extracellular deposits associated with the thick choroid, and the risk of development of PCV. Many recent studies on diagnosis of PCV have focused on applying criteria from noninvasive multimodal retinal imaging without requirement of indocyanine green angiography. There have been attempts to develop deep learning models, a recent subset of artificial intelligence, for detecting PCV from different types of retinal imaging modality. Some of these deep learning models were found to have high performance when they were trained and tested on color retinal images with corresponding images from optical coherence tomography. The treatment of PCV is either a combination therapy using verteporfin photodynamic therapy and anti-vascular endothelial growth factor (VEGF), or anti-VEGF monotherapy, often used with a treat-and-extend regimen. New anti-VEGF agents may provide more durable treatment with similar efficacy, compared with existing anti-VEGF agents. It is not known if they can induce greater closure of polypoidal lesions, in which case, combination therapy may still be a mainstay. Recent evidence supports long-term follow-up of patients with PCV after treatment for early detection of recurrence, particularly in patients with incomplete closure of polypoidal lesions.

Synthesis, Cellular Uptake, and Photodynamic Activity of Oligogalactosyl Zinc(II) Phthalocyanines

A series of di-α-substituted zinc(II) phthalocyanines with different number of galactose moieties, ranging from 1 to 8, namely Pc-gal_n (n=1, 2, 4, and 8) were designed and synthesized. The synthesis involved the copper-catalyzed azide-alkyne cycloaddition reaction of a mono- or dialkynyl zinc(II) phthalocyanine with an acetyl-protected galactosyl azide or its dendritic derivative with four acetyl-protected galactosyl groups, followed by removal of the acetyl protecting groups via alkaline hydrolysis. In N,N-dimethylformamide, these oligogalactosyl phthalocyanines were non-aggregated as shown by the strong Q-band absorption and fluorescence emission. Owing to the di-α-substitution, they also behaved as efficient singlet oxygen generators upon light irradiation with a singlet oxygen quantum yield of 0.84. The spectroscopic and photophysical properties were not affected by the number of galactosyl units. In contrast, the compounds became significantly aggregated and quenched in phosphate-buffered saline. Their cellular uptake was then studied using a range of cell lines, which generally followed the order Pc-gal₁ >Pc-gal₂ ≈Pc-gal₄ >Pc-gal₈ . Interestingly, the di-galactosyl analogue exhibited selective uptake against HeLa human cervical carcinoma cells through an energy-dependent pathway instead of the expected asialoglycoprotein receptor. Upon light irradiation, it could effectively kill the cells with a half-maximal inhibitory concentration of 0.58 μM.

Comparison of 3-year outcomes of photodynamic therapy combined with intravitreal ranibizumab or aflibercept for polypoidal choroidal vasculopathy in a European cohort

PURPOSE

Combined use of photodynamic therapy (PDT) with intravitreal anti-vascular endothelial growth factors (anti-VEGF) agents, such as ranibizumab (IVR) or aflibercept (IVA), has been shown to be effective for treating polypoidal choroidal vasculopathy (PCV). However, it is currently not well established which anti-VEGF agent provides superior outcomes for performing combination therapy. The present study compares the visual outcomes and re-treatment burden of combination therapy of PDT with either IVR or IVA in a European cohort of patients with PCV.

METHODS

A retrospective analysis was done on PCV patients who had received combination therapy of PDT with either IVR or IVA. The demographic characteristics, visual outcome, and anti-VEGF re-treatment exposures were analysed and compared.

RESULTS

A total of forty-four eyes (n = 11 male, 25%) were included in the analysis: 7 patients received IVR, 19 started with IVR but switched to IVA (IVS), and 18 received IVA, in combination with PDT. The BCVA improved in all three groups at 6-, 12-, 18-, 24-, 30-, and 36-month follow-ups after PDT, although the improvement was not statistically significant in the IVR group. The number of intravitreal anti-VEGF injections required/year after PDT was significantly fewer than before PDT. Significantly less eyes in the IVS group attained a good visual acuity of more than 70 ETDRS letters at the final visit.

CONCLUSION

Both IVR and IVA combined with PDT were effective treatments for the European cohort of patients with PCV. In eyes refractory to IVR, performing PDT promptly may be more beneficial than switching to IVA.