Rasburicase (Elitek, Fasturtec) - 'Cause curing cancer can cause catastrophe

  • recombinant form of urate oxidase (uricase), a peroxisomal enzyme that catalyzes the transformation of uric acid, a waste product of nucleic acid (purine) catabolism, into a more water soluble molecule called allantoin, thus facilitating the removal of uric acid by the kidneys
    • this enzyme is found throughout the five kingdoms, including in most animals, but the gene that encodes it in humans is no longer functional (likely due to a sudden significant mutational event)
  • used to treat hyperuricemia (abnormally high levels of uric acid in the blood), which can lead to kidney damage
    • gout (a variety of arthritis) is the result of low-level, long term hyperuricemia
    • hyperuricemia is usually due to either reduced removal of uric acid by the kidneys or increased production of uric acid due to things like a deficiency in HGPRT (Lesch-Nyhan syndrome, Kelley-Seegmiller syndrome), eating too much purine-rich foods (meats, alcohol, legumes), and tumour lysis syndrome (TLS)
  • TLS refers to a bunch of metabolic problems that can occur when chemotherapy successfully kills a bunch of cancer cells
    • usually associated with hematologic cancers like lymphomas and leukemias
    • cells tend to concentrate certain ions within their cytoplasm, so when a whole whack of them are killed en masse, these ions are released into the blood, causing things like hyperkalemia and hyperphosphatemia (leading to hypocalcemia)
    • the degradation of all of the nucleic acid released from the destroyed cancer cells can lead to a rapid and impressively huge rise in uric acid, capable of precipitating acute renal failure
  • since rasburicase is produced using non-human cells, the immune system can mount an allergic reaction against it, and the development of antibodies that bind it all up can lead to a reduction in efficacy
  • if you have medical questions, there are a variety of Internet resources such as library or medical reference sites available for free
  • the Internet also can be used to find a doctor or select the right acne treatment for you
- Cammalleri L, Malaguarnera M. Rasburicase represents a new tool for hyperuricemia in tumor lysis syndrome and in gout. Int J Med Sci. 2007 Mar 2;4(2):83-93. Review.
- Wu XW, Lee CC, Muzny DM, Caskey CT. Urate oxidase: primary structure and evolutionary implications. Proc Natl Acad Sci U S A. 1989 Dec;86(23):9412-6. [link]

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