Pegylated Recombinant Mammalian Uricase (PEG-uricase) as Treatment for Refractory Gout

This study has been completed.
Sponsor:
Collaborator:
Savient Pharmaceuticals
Information provided by (Responsible Party):
John Sundy, Duke University Medical Center
ClinicalTrials.gov Identifier:
NCT00111657
First received: May 24, 2005
Last updated: March 21, 2013
Last verified: March 2013
  Purpose

The purpose of this study is to determine whether PEG-uricase (a chemically modified recombinant mammalian enzyme that degrades uric acid) is effective in controlling hyperuricemia in patients with chronic gout, who cannot tolerate, or have not responded adequately, to conventional therapy for gout.

Funding Source - FDA OOPD


Condition Intervention Phase
Gout
Biological: Pegloticase
Phase 2

Study Type: Interventional
Study Design: Allocation: Non-Randomized
Endpoint Classification: Safety/Efficacy Study
Intervention Model: Single Group Assignment
Masking: Open Label
Primary Purpose: Treatment
Official Title: A Phase II Multidose Study of Intravenous PEG-uricase in Patients With Refractory Gout

Resource links provided by NLM:


Further study details as provided by Duke University:

Primary Outcome Measures:
  • Reduction in Plasma Uric Acid to Less Than 6 mg/dL. [ Time Frame: Baseline to Day 105 ] [ Designated as safety issue: No ]

Secondary Outcome Measures:
  • Clinical Response Will be Evaluated, Including the Frequency of Gout Flares, Number and Distribution of Swollen/Tender Joints, Change in Size of Tophi, Change in Functional Status [ Time Frame: weekly through 7 weeks after last infusion ] [ Designated as safety issue: No ]
  • In a Subset of Subjects Who Volunteer Separately, Change in Uric Acid Pool Size Will be Assessed by a Method That Involves Infusion of Uric Acid Labeled With N15, a Stable (Nonradioactive) Isotope of Nitrogen. [ Time Frame: baseline and 7 weeks after last infusion ] [ Designated as safety issue: No ]
  • Reduction of the Ratio of Uric Acid:Creatinine in Urine [ Time Frame: baseline then weekly ] [ Designated as safety issue: No ]
  • Development of Antibodies to PEG-uricase [ Time Frame: baseline, then prior to infusions and 7 wks after last infusion ] [ Designated as safety issue: No ]
  • Pharmacokinetics of PEG-uricase [ Time Frame: weekly ] [ Designated as safety issue: No ]

Enrollment: 30
Study Start Date: December 2004
Study Completion Date: July 2009
Primary Completion Date: July 2009 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: pegloticase

All study participants received intravenous pegloticase at dose of 8 mg, administered every 21 days for a maximum of 5 doses.

There was no control group for this open label study.

Biological: Pegloticase
8 mg of Pegloticase administered IV every 3 weeks; total number of infusions is 5
Other Names:
  • PEG-uricase
  • PEGylated recombinant mammalian urate oxidase

Detailed Description:

Inflammatory arthritis in patients with gout is caused by crystals of monosodium urate (MSU) that form as a result of chronically elevated levels of uric acid in plasma and extracellular fluids. Recurrent attacks can usually be prevented by treatment with drugs that block urate synthesis by inhibiting xanthine oxidase, or that promote uric acid excretion. If for various reasons (noncompliance, drug intolerance, inadequate dosage, or inefficacy) therapy fails to maintain serum urate concentration below about 6 mg/dL, gout can progress to a chronic stage characterized by destructive arthropathy, deposition of urate crystals in soft tissues (tophi), and nephropathy. The management of chronic gout in such patients is often complicated by co-morbidities such as hypertension, heart disease, diabetes, and renal insufficiency, which may limit the use of anti-inflammatory agents to treat arthritis.

Urate levels are low and gout does not occur in species that express the enzyme urate oxidase (uricase), which converts urate to the more soluble and easily excreted compound allantoin. Humans do not express this enzyme owing to a mutation of the uricase gene during evolution. Parenteral uricase is thus a potential means of controlling hyperuricemia and depleting urate stores in patients with chronic, refractory gout. Infusion of recombinant fungal uricase is effective in preventing acute uric acid nephropathy due to tumor lysis in patients with malignancies. However, the short circulating life and potential immunogenicity of fungal uricase prevents its chronic use for treating gout.

PEG-uricase is a recombinant porcine urate oxidase to which multiple strands of polyethylene glycol (PEG) of average molecular weight 10,000 have been attached. "PEGylation" is intended to reduce the immunogenicity of uricase, and greatly prolong its circulating life. This "mammalian" PEG-uricase was non-immunogenic and effective in preventing uric acid nephropathy in a uricase-deficient strain of mice (Kelly et al, J Am Soc Nephrol 12:1001-09, 2001). It has been licensed to Savient Pharmaceuticals for clinical development, and has received Orphan Drug designation for the treatment of refractory gout by the FDA Office of Orphan Product Development.

In a Phase I trial sponsored by Savient Pharmaceuticals in 24 subjects with symptomatic gout, single intravenous (IV) infusions of 0.5 to 12 mg of PEG-uricase were well tolerated, and at doses of 4 mg to 12 mg, were effective in normalizing plasma and urinary uric acid levels over a 21-day period post-infusion. Some subjects in this trial developed antibodies to PEG-uricase, but the only serious adverse events observed were attacks of gout. The present Phase II clinical trial in subjects with refractory gout will evaluate the efficacy, safety, and immunogenicity of PEG-uricase when administered at a dose of 8 mg by IV infusion once every 3 weeks, for a total of 5 infusions. The primary measure of efficacy will be a reduction in plasma uric acid to less than 6 mg/dL, and reduction in the ratio of uric acid to creatinine in urine to <0.2. In addition, the ability of PEG-uricase to lower the total uric acid pool size will be evaluated in a subset of treatment subjects. Uric acid pool size will be measured by a method that involves an infusion of uric acid labeled with N15, a stable (non-radioactive) isotope of nitrogen.

  Eligibility

Ages Eligible for Study:   18 Years and older
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   No
Criteria

Inclusion Criteria:

  • Age >18 years
  • Symptomatic gout
  • Serum uric acid >7 mg/dL
  • Intolerance of, or inadequate response to, conventional therapy for gout
  • Women of childbearing potential must have a negative serum pregnancy test and must use an approved birth control method

Exclusion Criteria:

  • End stage renal failure that requires dialysis
  • Concurrent use of uric-acid lowering agents
  • Glucose-6-phosphate dehydrogenase (G6PD) deficiency
  • A history of anaphylactic reaction to a recombinant protein
  • Concurrent use of immunosuppressive therapy (except as needed for prevention of rejection of a transplanted organ, or prednisone at 10 mg a day or less for treatment of gout flares)
  • A medical or psychological condition which, in the opinion of the investigator, might create undue risk to the subject
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT00111657

Locations
United States, North Carolina
Duke University Medical Center
Durham, North Carolina, United States, 27710
Sponsors and Collaborators
John Sundy
Savient Pharmaceuticals
Investigators
Principal Investigator: John S. Sundy, MD, PhD Duke University
  More Information

Publications:
Additional publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):
Responsible Party: John Sundy, Associate Professor of Medicine, Duke University Medical Center
ClinicalTrials.gov Identifier: NCT00111657     History of Changes
Other Study ID Numbers: Pro00006845, FD-R-0002537
Study First Received: May 24, 2005
Results First Received: December 12, 2012
Last Updated: March 21, 2013
Health Authority: United States: Food and Drug Administration
United States: Institutional Reveiw Board

Keywords provided by Duke University:
Gout
Tophi
Tophaceous gout
Allergy to allopurinol
Post-transplant gout

Additional relevant MeSH terms:
Gout
Arthritis
Joint Diseases
Musculoskeletal Diseases
Rheumatic Diseases
Purine-Pyrimidine Metabolism, Inborn Errors
Metabolism, Inborn Errors
Genetic Diseases, Inborn
Metabolic Diseases

ClinicalTrials.gov processed this record on September 29, 2014