Ultragenyx: Phase 1/2 RhGUS Study Shows Proof Of Clearance Of Lysosomal Storage

(RTTNews) - Ultragenyx Pharmaceutical Inc (RARE), a development-stage biopharmaceutical company, Thursday announced preliminary data from the Phase 1/2 study of recombinant human beta-glucuronidase or rhGUS, UX003.

This is an investigational therapy for the treatment of mucopolysaccharidosis 7 or MPS 7, Sly syndrome.

MPS 7 is a rare genetic, metabolic disorder, caused by the deficiency of beta-glucuronidase, an enzyme required for the breakdown of the glycosaminoglycans dermatan sulfate and heparan sulfate.

Preliminary results from three patients who have been administered 2 mg/kg of rhGUS every other week for two, six, and 12 weeks showed evidence of clearance of lysosomal storage as indicated by the decline in urinary glycosaminoglycan excretion beginning at two weeks of treatment of around 30-50 percent.

At the 12 week assessment of the first patient, absolute liver size was reduced by approximately 11 percent. This represents a 46 percent decrease in the excess liver size above normal for age and gender. The remaining patients have not yet reached the 12 week time point for liver size assessment.

No serious adverse events were observed during up to 12 weeks of treatment, and no infusion-associated reactions were observed after 13 infusions so far in these three subjects.

The study will continue and additional 12-week interim data are expected in 2014.

If the efficacy and safety results for all treated subjects are supportive and the dose confirmed, the company intends to initiate a pivotal Phase 3 study enrolling at least 12 patients in 2014.