"Does Deferiprone provide a clinical benefit to the superficial siderosis patient?"
If you remember, the April 2017 edition of The Neurology Journal, gave us an early peek at what the study findings might be in the final revision of Two-year Observational Study Of Deferiprone In Superficial Siderosis¹. The study was released this past December 28th, and the results have been published. This blog post is our cliff note version of the study, keeping in mind, we're not medical researchers or doctors.
Initial recruitment included 48 participants.
Nine withdrew from the study because their insurance wouldn't cover the off-label use of Ferriprox and one for other reasons. 38 people began the investigation, and over the course, two dropped out because of neutropenia concerns, four dropped for cost issues and one left for unrelated health reasons. 31 people completed the study.
Each participant submitted a current neurological exam along with a baseline MRI and was prescribed the same beginning dosage; 1,000 mg of Deferiprone taken twice daily on a five day on two days off dosage cycle. Adjustments were made to the dosage schedule for those with fatigue complaints to 500mg in the morning and 1,500mg in the evening.
All participants had their neutrophil levels monitored weekly, with liver function, zinc, and ferritin level testing monthly. The subjects physicians relayed all data to the study team.
Clinical symptoms reported before the study began hearing loss, balance, nystagmus, bowel, and bladder problems. 100% of the study participants suffered from hearing loss and 95% had symptoms of ataxia. During the investigation, eight participants had repairs performed on an active bleed.
If you would like to read the complete study, you may access it here. We're going to skip over most of the details and go on to the findings.
Most noteworthy, the results of the study were positive. The research team concluded there was enough evidence to support Deferiprone was clinically useful.
The research team recognized the need to create a standardized MRI protocol due to the differences in some scans. Those chosen identified the same echo time and brain volume in both the baseline and completion scan. 50% of this grouping showed a reduction in hemosiderin from the beginning of the study.
Of the eight participants who had active bleeds repaired only one showed clinical improvement in symptoms. There was no way to investigate if the repairs were successful. Researchers suspect, in patients who have an active source of blood, Deferiprone first works to stabilize neurodegeneration, but the healing necessary for improvement can't occur.
The report suggests some patients neurodegeneration may reach a "point-of-no-return." Therefore, the existing damage in these patients might be so severe removing the iron would produce no clinical benefit because the brain system can no longer repair itself.
Most of all, the study confirmed patients could stay on a long-term course of Deferiprone with no severe ill effects. 40% reported their hearing loss had stabilized and 30% demonstrated an improvement or slowing of decline in their walking.
In conclusion, the gold standard of trials is the Randomized Double-Blind Placebo Control (RDBPC). Hopefully, by conducting a two-year double-blind study, it will permanently settle the question."Does Deferiprone provide a clinical benefit to the superficial siderosis patient?"
¹Kessler RA, Li X, Schwartz K, Huang H, Mealy MA, Levy M. Two-year observational study of deferiprone in superficial siderosis. CNS Neurosci Ther. 2017;00:1-6. https://doi.org/10.1111/cns.12792
