The National PXE Expertise Centre (LEP) is located at UMC Utrecht. The center has a multi-disciplinary team consisting of a specialist in internal medicine and vascular diseases, ophthalmologists, radiologists, a vascular surgeon, clinical geneticist and dermatologist. As a result of this unique form of cooperation, patients have access to all necessary expertise regarding this rare disease at one central location. Patients can undergo all necessary tests within a single day, and therefore have the clearest possible indication of any possible damage to their eyes, blood vessels and skin. Depending on the test findings, patients can receive preventative treatment that is geared to their own needs. The further objectives of the LEP include initiating scientific study aimed at improving the diagnosis and treatment of PXE patients.
Contact LEP at 088-7556312 or email to: email@example.com
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In recent years researchers from LEP have worked tirelessly with patients to complete the TEMP study. This study, the purpose of which was to research the efficacy and safety of bisphosphonate etidronate in the treatment of patients with PXE, has now been completed and published in the Journal of the American College of Cardiology .
Treatment with etidronate slowed the calcification of blood vessels in patients’ legs. In the course of the year-long TEMP study, the build-up of plaque in leg arteries rose by an average of 8% in people who received no treatment (the placebo group). People who were treated with etidronate (the etidronate group) saw a 4% decrease in the build-up of plaque in the leg arteries. The difference between the two groups was therefore 12%.
The effects of etidronate on the eyes were less clear. A relatively high number of people with “bad eyes” participated in the study, making it somewhat unclear what the effects of etidronate are on the eyes. We hope that treating patients for longer than one year will produce a better picture of the effects of etidronate on the eyes, particularly with respect to calcification and the effect of calcification on vision.
During the year-long TEMP study, we saw no major differences in terms of safety between the etidronate group and the placebo group, including with respect to the eyes. However, 18 participants, all in the etidronate group, were found to have a high level of phosphate while taking the medicine. This is a benign side effect, which disappeared in all cases once the treatment stopped. There were no other differences in blood counts between the two groups. Side effects were rare, and were equally distributed over the two groups.
Now that we know that treatment with etidronate slows the calcification of the arteries of PXE patients, has virtually no side effects, and appears to be safe, we would like to offer this treatment to suitable interested patients in a controlled environment. Etidronate is not licensed for sale in the Netherlands, which means that it cannot be prescribed in the usual manner. This past year we have worked hard to make etidronate available once again to PXE patients in the Netherlands. In cooperation with Apotheek De Ad Hoc Bereider, we have been able to start producing etidronate again, exclusively for PXE patients in the Netherlands. Unfortunately, there have been problems securing sufficient amounts of the raw materials needed to produce etidronate, but every effort is being made to solve this problem.
In the near future, patients who participated in the TEMP study will be asked if they are interested in the follow-up phase, which we are calling TEMP 2, although this will not be an official scientific research project. In conjunction with the Medisch Ethische Toetsingscommissie(The Medical Ethics Board) it has been agreed that we can offer etidronate to suitable patients, and that a placebo group is no longer required. We have already demonstrated that etidronate is effective in the treatment of PXE patients. We do however require your written permission to collect your data and use it for research purposes. Patients in the placebo group will be contacted first, followed by the patients in the etidronate group, and finally other suitable patients. No action is necessary on your part; we will contact you.
The TEMP study has been a very successful, unique collaborative effort between the research team of the National PXE Expertise Centre in the UMC in Utrecht, the patients association and Stichting PXE Fonds(The Netherlands PXE Foundation). The TEMP study is an important step in the development of the treatment of PXE, and something that all of us can be exceptionally proud of.
Research in the ophthalmology department
The UMC Utrecht conducts research in PXE, also regarding the ocular manifestations. The research is focused on gaining insight in the prevalence of ocular disease and visual impairment, and finding a causal treatment. Another focus is to unravel the calcification process in PXE eyes, by studying ocular imaging (OCT scans, for example) and histopathological research.
Since PXE is a rare disease, not much is known about the ocular manifestations in PXE. However, no causal PXE treatment exists yet to prevent the ocular complications, and more research to gain insight in this disease is essential. The UMC Utrecht conducts research in PXE, also regarding the ocular manifestations. The research is focused on gaining insight in the prevalence of ocular disease and visual impairment, and finding a causal treatment. Another focus is to unravel the calcification process in PXE eyes, by studying ocular imaging (OCT scans, for example) and histopathological research.
We already investigated the prevalence of visual impairment in PXE patients. Visual impairment is often present in patients over 50 years (35% is visually impaired). Also, we studied the effect of a natural delivery on the eyes in women with PXE, since this has been part of debate for a long time. Luckily, we found that a natural delivery is not harmful for PXE eyes (without signs of neovascularization). Furthermore, we studied a possible effect of the drug etidronate on calcification in the eyes. However, this effect Is hard to measure since there is no endpoint for the severity of calcification yet.
Therefore, we focus on investigating imaging in order to find an endpoint. This will help gaining insight in measuring calcification, which is essential for further research. Furthermore, there is a large, unexplained, heterogeneity in ocular manifestations in PXE. We will be investigating different characteristics of PXE, to be able to gain more insight in the course of disease.
Further research is now required. For example, a study is now being conducted into the role of pyrophosphate in PXE, and the long term effects of etidronate as a new means of treating PXE. In addition to etidronate, alternative treatments are being developed, but they still require a great deal of research. Your financial contribution to PXE research can help to accelerate this process.