Question:medium
A patient with tumor lysis syndrome has elevated uric acid levels and is prescribed Pegloticase. What is the mechanism of action of Pegloticase?
A patient with tumor lysis syndrome has elevated uric acid levels and is prescribed Pegloticase. What is the mechanism of action of Pegloticase?
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Pegloticase is recombinant uricase; it oxidizes uric acid to soluble allantoin.
Updated On: May 14, 2026
- Xanthine oxidase inhibition
- URAT-1 receptor inhibition
- Oxidizes uric acid
- Hydrolysis of uric acid
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The Correct Option is C
Solution and Explanation
Step 1: Understanding the Question:
The question asks for the mechanism by which the drug Pegloticase reduces blood uric acid levels in severe cases like Tumor Lysis Syndrome or refractory gout.
Step 2: Detailed Explanation:
Urate Oxidase (Uricase): In most mammals, uric acid is broken down by the enzyme urate oxidase into allantoin. Humans lack this enzyme due to an evolutionary mutation, which is why we are prone to hyperuricemia.
Pegloticase Mechanism: Pegloticase is a recombinant, pegylated form of the urate oxidase enzyme. It catalyzes the oxidation of uric acid into allantoin.
Why Allantoin? Allantoin is a highly water-soluble, inert metabolite that is easily excreted by the kidneys, unlike uric acid which can crystallize and cause renal failure or gouty tophi.
Clinical Use: It is reserved for severe, chronic, treatment-refractory gout and as a "rescue" therapy for acute hyperuricemia in Tumor Lysis Syndrome.
Other mechanisms: Allopurinol and Febuxostat work by inhibiting Xanthine Oxidase (preventing the formation of uric acid). Probenecid inhibits the URAT-1 transporter (preventing reabsorption in the kidney). Pegloticase is unique because it destroys already existing uric acid.
Step 3: Final Answer:
Pegloticase works by enzymatically oxidizing uric acid into the more soluble form, allantoin.
The question asks for the mechanism by which the drug Pegloticase reduces blood uric acid levels in severe cases like Tumor Lysis Syndrome or refractory gout.
Step 2: Detailed Explanation:
Urate Oxidase (Uricase): In most mammals, uric acid is broken down by the enzyme urate oxidase into allantoin. Humans lack this enzyme due to an evolutionary mutation, which is why we are prone to hyperuricemia.
Pegloticase Mechanism: Pegloticase is a recombinant, pegylated form of the urate oxidase enzyme. It catalyzes the oxidation of uric acid into allantoin.
Why Allantoin? Allantoin is a highly water-soluble, inert metabolite that is easily excreted by the kidneys, unlike uric acid which can crystallize and cause renal failure or gouty tophi.
Clinical Use: It is reserved for severe, chronic, treatment-refractory gout and as a "rescue" therapy for acute hyperuricemia in Tumor Lysis Syndrome.
Other mechanisms: Allopurinol and Febuxostat work by inhibiting Xanthine Oxidase (preventing the formation of uric acid). Probenecid inhibits the URAT-1 transporter (preventing reabsorption in the kidney). Pegloticase is unique because it destroys already existing uric acid.
Step 3: Final Answer:
Pegloticase works by enzymatically oxidizing uric acid into the more soluble form, allantoin.
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