Raptor Pharma Reports Data in Journal of Pediatrics Showed Procysbi Improved Life Quality
Raptor Pharmaceutical Corp.
(Nasdaq: RPTP) today announced that data from its open label extension study of
delayed-release cysteamine bitartrate (PROCYSBI^®) has been published in the
Journal of Pediatrics [DOI: 10.1016/j.jpeds.2014.05.013]. The study
demonstrated that patients with nephropathic cystinosis who took PROCYSBI for
two years were able to sustain optimal cystine control in their white blood
cells and preserve kidney function over the long term, and had significant
improvements in social, school and total functioning based on validated
quality of life measurement scales.
The prospective, controlled, open label, single-arm study followed 40 patients
with nephropathic cystinosis treated with PROCYSBI for two years to assess
efficacy in cystine depletion in peripheral white blood cells, to assess the
dose required to maintain white blood cell (WBC) content of cystine below 1
nmol ½ cystine/mg protein, to measure quality of life using the Pediatric
Quality of Life Inventory (PedsQL™), change in estimated glomerular filtration
rate, and change in height Z-score. The objective was to determine the
long-term effects of PROCYSBI therapy in patients with the disease.
Control of WBC Cystine
Over two years of treatment, the mean WBC cystine was maintained under optimal
control of <1 nmol ½ cystine/mg protein, and the dose of PROCYSBI decreased
from 43.5 to 40.1 mg/kg/d (p = .05).
Maintenance of Kidney Function
Kidney function deteriorates over time in nephropathic cystinosis patients who
often require a kidney transplant early in life. In this study, kidney
function as monitored by eGFR remained stable over two years of treatment.
Change in Quality of Life
Using the validated PedsQL™ score, investigators documented a significant and
persistent improvement in patients who had switched from immediate-release
cysteamine to PROCYSBI, over two years of treatment, in three measures: social
function (p = .049), school function (p = .004), and in total function (p =
.048). Investigators assessed the subsequent change from all baseline values
in the PedsQL™ and demonstrated that the changes persisted after two years of
PROCYSBI therapy. Changes in physical and emotional quality of life scales
over the two years of study were not changed.
"Long-term control of WBC cystine depletion below 1 nmol has never been
reported in a prospective manner in a cohort of patients," said Craig B.
Langman, M.D., the Isaac A. Abt, M.D. professor of Kidney Diseases and head of
pediatric kidney diseases at Northwestern University Feinberg School of
Medicine and the Ann and Robert H. Lurie Children's Hospital of Chicago, and
the lead author on the paper. "Here, with delayed-release cysteamine, we
provide two years of data demonstrating disease control, preservation of
kidney function, stable somatic growth, and quality of life improvements.
These data demonstrate that patients were able to remain adherent to their
delayed-release cysteamine therapy for two years, something never before
demonstrated in a controlled clinical trial in this population."
There were no unexpected or serious safety concerns attributable to PROCYSBI.
All 40 patients experienced one or more treatment-emergent adverse events: GI
disorders in 35 (87.5%), emesis in 28 (70.0%), headache in 14 (35.0%), upper
respiratory tract symptoms in 9 (22.5%), and diarrhea in 8 (20.0%).
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