Orphan Drug Gets FDA Nod for Phenylketonuria

By Belden, Heidi | Drug Topics, February 11, 2008 | Go to article overview

Orphan Drug Gets FDA Nod for Phenylketonuria


Belden, Heidi, Drug Topics


There has never been a drug used to treat phenylketonuria (PKU), a genetic disorder caused by a deficiency of the enzyme phenylalanine hydroxylase (PAH), until now. Last month, the Food & Drug Administration gave its approval to sapropterin dihydrochloride (Kuvan, BioMarin), a new molecular entity indicated to reduce blood phenylalanine levels in patients with hyperphenylalaninemia due to tetrahydrobiopterin (BH4)-responsive PKU. The orphan drug will offer some hope to about 30,000 PKU patients in the United States and 50,000 worldwide.

According to Barbara Burton, M.D., director of the PKU clinic at Children's Memorial Hospital in Chicago, sapropterin helped control blood levels of phenylalanine in PKU patients during clinical trials. Burton, a clinical investigator in the Phase II and Phase III studies for the drug, said that for the first time, a drug therapy option exists to help manage the disease. Left untreated, PKU is toxic to the brain and can lead to mental retardation and other neurological problems.

Composition of drug

Sapropterin is a synthetic form of BH4, the cofactor for the enzyme PAH, which is normally responsible for hydroxylating Phe to form tyrosine. But in patients with PKU, PAH activity is absent or deficient. According to BioMarin, treatment with BH4 can activate residual PAH enzyme, improve the notmal oxidative metabolism of Phe, and decrease Phe levels in some patients. But not all PKU patients will respond to sapropterin.

The efficacy and safety of sapropterin was evaluated in four clinical trials. The first study, which was designed to identify responders (defined as ≥30% decrease in blood Phe from baseline), showed the drug worked in 20% of patients who were treated for eight days. In a second study of the responsive patients, mean blood Phe level dropped from 843 micromoles/L to 607 micromoles/L, while the placebo group stayed about the same. According to FDA's Daniel Shames, M.D., deputy director of the Office of Drug Evaluation III, sapropterin is useful in 20% to 50% of patients, and is due to the fact that many mutations exist for PKU. …

The rest of this article is only available to active members of Questia

Already a member? Log in now.

Notes for this article

Add a new note
If you are trying to select text to create highlights or citations, remember that you must now click or tap on the first word, and then click or tap on the last word.
One moment ...
Default project is now your active project.
Project items

Items saved from this article

This article has been saved
Highlights (0)
Some of your highlights are legacy items.

Highlights saved before July 30, 2012 will not be displayed on their respective source pages.

You can easily re-create the highlights by opening the book page or article, selecting the text, and clicking “Highlight.”

Citations (0)
Some of your citations are legacy items.

Any citation created before July 30, 2012 will labeled as a “Cited page.” New citations will be saved as cited passages, pages or articles.

We also added the ability to view new citations from your projects or the book or article where you created them.

Notes (0)
Bookmarks (0)

You have no saved items from this article

Project items include:
  • Saved book/article
  • Highlights
  • Quotes/citations
  • Notes
  • Bookmarks
Notes
Cite this article

Cited article

Style
Citations are available only to our active members.
Buy instant access to cite pages or passages in MLA, APA and Chicago citation styles.

(Einhorn, 1992, p. 25)

(Einhorn 25)

1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

Cited article

Orphan Drug Gets FDA Nod for Phenylketonuria
Settings

Settings

Typeface
Text size Smaller Larger Reset View mode
Search within

Search within this article

Look up

Look up a word

  • Dictionary
  • Thesaurus
Please submit a word or phrase above.
Print this page

Print this page

Why can't I print more than one page at a time?

Help
Full screen

matching results for page

    Questia reader help

    How to highlight and cite specific passages

    1. Click or tap the first word you want to select.
    2. Click or tap the last word you want to select, and you’ll see everything in between get selected.
    3. You’ll then get a menu of options like creating a highlight or a citation from that passage of text.

    OK, got it!

    Cited passage

    Style
    Citations are available only to our active members.
    Buy instant access to cite pages or passages in MLA, APA and Chicago citation styles.

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn, 1992, p. 25).

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn 25)

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences."1

    1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

    Cited passage

    Thanks for trying Questia!

    Please continue trying out our research tools, but please note, full functionality is available only to our active members.

    Your work will be lost once you leave this Web page.

    Buy instant access to save your work.

    Already a member? Log in now.

    Author Advanced search

    Oops!

    An unknown error has occurred. Please click the button below to reload the page. If the problem persists, please try again in a little while.