KUVAN® (sapropterin dihydrochloride) Tablets for Oral Use and Powder for Oral Solution for PKU

KUVAN is the first and only FDA-approved medication for PKU to reduce blood Phe levels in patients with hyperphenylalaninemia (HPA) due to tetrahydrobiopterin (BH4-) responsive PKU. KUVAN is a pharmaceutical formulation of BH4, the natural cofactor for the PAH enzyme, which stimulates activity of the residual PAH enzyme to metabolize Phe into tyrosine. KUVAN is to be used in conjunction with a Phe-restricted diet.

KUVAN at a Glance

  • KUVAN Tablets approved in the United States, European Union, Canada, and Japan
  • KUVAN Powder approved in the United States
  • Designated as an orphan drug in the United States and European Union
  • Manufactured and commercialized by BioMarin in the United States and Canada

Regulatory Status

In December 2007, Kuvan received marketing approval from the US Food and Drug Administration making it the first specific therapy for the treatment of PKU patients. A year later, KUVAN received approval in the European Union in December 2008. KUVAN has been designated an orphan drug in the US and EU, which grants market exclusivity for 7 and 10 years, respectively. KUVAN was approved in Canada in April 2010. (Biopten) was approved for PKU in Japan in July 2008. KUVAN Powder was approved in the US in December 2013.

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Commercialization Plan

KUVAN Tablets are commercialized by BioMarin in the United States and Canada, and Merck Serono in the rest of the world outside of Japan. KUVAN Powder is commercialized by BioMarin in the United States. Biopten Granules are commercialized by Daiichi-Sankyo Company, Limited in Japan. 


KUVAN® (sapropterin dihydrochloride) Tablets for Oral Use and Powder for Oral Solution are approved to reduce blood Phe levels in people with a certain type of Phenylketonuria (PKU). KUVAN is to be used with a Phe-restricted diet.

Important Safety Information

It is not possible to know if KUVAN will work for you without a trial of the medicine. Your doctor will check your blood Phe levels when you start taking KUVAN to see if the medicine is working.

Starting KUVAN does not eliminate the need for ongoing dietary management. Any change to your diet may impact your blood Phe level. Follow your doctor's instructions carefully. Your doctor and dietitian will continue to monitor your diet and blood Phe levels throughout your treatment with KUVAN to make sure your blood Phe levels are not too high or too low. If you have a fever, or if you are sick, your Phe level may go up. Tell your doctor and dietitian as soon as possible so they can make any necessary changes to your treatment.

Children younger than 7 years old treated with KUVAN doses of 20 mg/kg per day are at an increased risk for low levels of blood Phe compared with children 7 years and older. Frequent blood monitoring is recommended in this population to ensure that blood Phe levels do not fall too low.

Tell your doctor if you have ever had liver or kidney problems, have poor nutrition or have a loss of appetite, are pregnant or plan to become pregnant, or are breastfeeding or plan to breastfeed.

KUVAN is a prescription medicine and should not be taken by people who are allergic to any of its ingredients. KUVAN and other medicines may interact with each other. Tell your doctor about all the medicines you take, including prescription and over-the-counter medicines, vitamins, herbal and dietary supplements.

If you forget to take your dose of KUVAN, take it as soon as you remember that day. Do not take 2 doses in a day. If you take too much KUVAN, call your doctor for advice.

The most common side effects reported when using KUVAN are headache, runny nose and nasal congestion, sore throat, diarrhea, vomiting, and cough. Additional adverse reactions reported in connection with worldwide marketing include sore throat, heartburn or pain in the esophagus, inflammation of the lining of the stomach, indigestion, stomach pain, and nausea. These are not all the possible side effects seen with KUVAN. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

KUVAN can cause serious side effects, including:

  • Severe allergic reactions. Stop taking KUVAN and get medical help right away if you develop any of these symptoms of a severe allergic reaction:
    • Wheezing or trouble breathing
    • Nausea
    • Flushing
    • Lightheadedness or fainting
    • Coughing
    • Rash
  • Inflammation of the lining of the stomach (gastritis). Gastritis can happen with KUVAN and may be severe. Call your doctor right away if you have any:
    • Severe upper stomach-area discomfort or pain
    • Blood in your vomit or stool
    • Black, tarry stools
    • Nausea and vomiting
  • Too much or constant activity (hyperactivity) can happen with KUVAN. Tell your doctor if you have any signs of hyperactivity, including fidgeting, moving around or talking too much.

For more information, call BioMarin Patient and Physician Support (BPPS) at 1-866-906-6100. Please read the full Patient Information by clicking here.