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Positive Results in Plant-based ERT Study Treating Fabry Patients

AUGUST 10, 2016
James Radke, PhD
Exciting news for the Fabry community. Protalix, shared some of the data from their phase I/II clinical trial of PRX-102 for the treatment of Fabry disease.  
 
PRX-102 is a plant-derived enzyme replace therapy for alpha-Galactosidase-A, the enzyme missing in Fabry disease.
 
The phase I/II clinical trial was an open-label, dose-ranging study (intravenous infusions of PRX-102 0.2 mg/kg, 1mg/kg and 2mg/kg every two weeks).

Sixteen patients were enrolled in the study with 10 patients meeting the criteria for the classic definition of Fabry disease. Classic Fabry disease is characterized by having less than 30% residual enzyme activity, and typical manifestations involve neurological, skin, ophthalmic and Fabry-specific biomarkers.

Efficacy Results

Following 12 months of treatment, Improvements or stabilization in efficacy were demonstrated across all disease parameters. Reductions of plasma Lyso-Gb3 ranged from 66.7 to 22.6 ng/ml in all patients and from 102.0 to 33.1 ng/ml in classic patients. Stable kidney function was also observed, as measured by estimated glomerular filtration rate (eGFR), with change from mean eGFR value of 110.78 at base line to 110.23 after 12 months for all patients, and from mean eGFR value of 117.37 to 117.36 for classic patients. All patients had stable cardiac function as measured by left ventricular mass (LVM) and left ventricular mass index (LVMI). PRX-102 also demonstrated, using the well-established BPI index, a substantial improvement in all pain parameters for all patients.

  change in
eGRF
Change in
LVM
Change in
LMVI
Change in
Gb3
Change in
lyso
All patients (n=16) -0.5% 0% 0.4% -22.2% -48.9%
Classic Fabry (n=10) -0.1% -2.6% -3.1% -33,3% -57.6%

 
  Worst
Pain
Average
Pain
Pain
interference
All patients (n=16) -29% -26% -39%
Classic Fabry (n=10) -38% -41% -44%

Safety Results

PRX-102 was well tolerated, with the majority of adverse events being mild and moderate. One patient experienced hypersensitivity. Three patients developed antibodies and, after competing 12 months of treatment. One of those patients has subsequently tested negative for antibodies.

Future clinical trials

Currently, all 16 patients in the trial are receiving 1 mg/kg of PRX-102 in an open label extension trial. 
 
 A phase III pivotal trial is currently recruiting patients in the United States and elsewhere. That study will compare PRX-102 with Fabrazyme,

What is Fabry disease?

Fabry disease is an X-linked lysosomal storage disorder that leads to excessive deposition of globotriaosylceramide ( GL-3) throughout the body. Skin, eye, kidney, heart, brain, and peripheral nervous system are highly vulnerable. Currently, the only treatment available is Fabrazyme (agalsidase alfa) which is an enzyme replacement therapy infused over several hours every two weeks.

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