Photodynamic therapy with verteporfin in age-related macular degeneration: a systematic review of efficacy, safety, treatment modifications and pharmacoeconomic properties

The significance of external limiting membrane status for visual acuity in age-related macular degeneration

PURPOSE

To evaluate status of the external limiting membrane (ELM) as a contributor of visual acuity (VA) in age-related macular degeneration (AMD).

DESIGN

Hospital-based, cross-sectional study.

METHODS

We retrospectively reviewed spectral-domain optical coherence tomography images of 158 patients with AMD who had undergone photodynamic therapy and classified them based on the status of the ELM: absent, discontinuous, or complete. We simultaneously assessed foveal thickness, presence or absence of subretinal fluid/mass, presence or absence of subretinal pigment epithelium fluid/mass, status of the inner segment/outer segment (IS/OS) junction, and status of the intermediate line between the IS/OS junction and retinal pigment epithelium. Correlation coefficients between each parameter and VA were analyzed.

RESULTS

There was a strong correlation between ELM status and VA (r = -0.75, P < .001), and that was higher than that of the IS/OS (r = -0.69, P < .001). Multivariate analysis showed that ELM status is the most important factor for VA. Other parameters that correlated with VA included age, status of the intermediate line, and presence of subretinal or subretinal pigment epithelium fibrosis. Foveal thickness showed V-shaped correlation, with the dividing line around 200 mum.

CONCLUSION

ELM status may be more useful than is IS/OS status in evaluation of retinal morphology and function in patients with AMD.

Oncologic photodynamic therapy photosensitizers: a clinical review

A myriad of naturally occurring and synthetic structures are capable of transferring the energy of light. Few, however, allow for this energy transfer to enable a type II photochemical reaction which, as currently practiced, is a fundamental component of photodynamic therapy. Even fewer of these agents, aptly termed photosensitizers, have found success in the treatment of patients. This review will focus on the oncologic photosensitizers that have come to clinical trial with outcomes published in peer reviewed journals. Based on a clinical orientation the qualities of successful photosensitizers will be examined, how current drugs fare and potential future options explored.

Photodynamic therapy as an innovative treatment for malignant pleural mesothelioma

Photodynamic therapy (PDT) of the pleura is an experimental treatment aimed at eradicating residual microscopic disease after macroscopic complete resection of malignant pleural mesothelioma (MPM) by means of intracavitary administration. A light-based treatment, PDT consists of 3 components: a nontoxic photosensitizing compound, oxygen, and visible light. The treatment is FDA-approved for several oncological targets, but remains experimental for MPM. PDT can be combined with lung-sparing pleurectomy and decortication and does not preclude other treatments such as adjuvant chemotherapy and/or radiation therapy. Additionally, PDT appears to bolster an immunologic effect by rendering the cancer cells that have been destroyed by the light-activated photosensitizer more presentable to the immune system. Local control and survival rates have been sufficiently rewarding to merit ongoing development of this combination of surgical technique and PDT.

Defining the therapeutic window of vertebral photodynamic therapy in a murine pre-clinical model of breast cancer metastasis using the photosensitizer BPD-MA (Verteporfin)

Breast cancer is known to cause metastatic lesions in the bone, which can lead to skeletal-related events. Currently, radiation therapy and surgery are the treatment of choice, but the success rate varies and additional adjuncts are desirable. Photodynamic therapy (PDT) has been applied successfully as a non-radiative treatment for numerous cancers. Earlier work has shown that the athymic rat model is suitable to investigate the effect of PDT on bone metastasis and benzoporphyrin-derivative monoacid ring A (BPD-MA; verteporfin) has been shown to be a selective photosensitizer. The aim of this study was to define the therapeutic window of photosensitizer with regard to drug and light dose. Human breast carcinoma cells (MT-1)-stable transfected with the luciferase gene-were injected intra-cardiacally into athymic rats. At 14 days, the largest vertebral lesion by bioluminescence imaging was targeted for single treatment PDT. A drug escalating-de-escalating scheme was used (starting drug dose and light energy of 0.2 mg/kg and 50 J, respectively). Outcomes included 48 h post-treatment bioluminescence of remaining viable tumour, histomorphometric assessment of tumour burden, and neurologic evaluation. The region of effect by bioluminescence and histology increased with increasing drug dose and light energy. A safe and effective drug-light dose combination in this model appears to be 0.5 mg/kg BPD-MA and applied light energy of less than 50 J for the thoracic spine and 1.0 mg/kg and 75 J for the lumbar spine. For translation to clinical use, it is an advantage that BPD-MA (verteporfin), a second-generation photosensitizer, is already approved to treat age-related macular degeneration. Overall, PDT represents an exciting potential new minimally-invasive local, safe and effective therapy in the management of patients with spinal metastases.