Starting my Kuvan Responder Trial

Kuvan LogoUp until four years ago, the only method for treating people with Phenylketonuria (PKU) was the low-protein diet. I remember being a young girl and my mother telling me that the second there was a cure, she would immediately sign me up. Nowadays, we still don’t have a cure, but we do have the first prescription drug for the treatment of PKU. It’s called Kuvan and it was developed by a pharmaceutical company called BioMarin. Here’s a brief video clip from the U.S. Food and Drug Administration announcing its approval.

Unfortunately, Kuvan doesn’t work for everyone, so before you can receive a prescription, you are required to go through trial to see if you actually respond to the medication. I will be starting my Kuvan trial this week and here’s how it breaks down:

PKU Kuvan Responder Trial

  • I should be receiving my package of Kuvan on Monday (that’s tomorrow)
  • Then on Thursday, I’ll start keeping a very specific food diary (notepad icon). I’m not yet on the low-protein diet, but my clinic advised that as long as I consume close to the same amount of protein each day then we should be in good shape. Otherwise, it would be impossible to tell if Kuvan was working or if I just ate less protein.
  • In addition to the food diary, I also have to take 7 blood samples (red circles). The blood work is pretty intensive in the beginning, but that’s to make sure we get a good baseline reading.
  • Then about three days into the trial, I’ll start taking my Kuvan (yellow circles). The number of pills you take depends on your body weight. I was prescribed to take 13 pills. I need to take Kuvan at about the same time every day and with food since it is acidic and can cause stomach problems.

At the end of the trial, we should know whether I have responded to Kuvan or not. I have some concerns about possible side effects, some of which can be very serious, and I haven’t made any final decisions whether I will take Kuvan even if I am a responder. I am confident that I will not take Kuvan during any pregnancies. Nonetheless, the more information I have, then the better my decisions will be.

Stay tuned and I’ll let you know how it goes!



Filed under Kuvan

9 responses to “Starting my Kuvan Responder Trial

  1. Really looking forward to seeing how you do, would love to see a success story with Kuvan! Good luck.

  2. Pingback: Kuvan Responder Trial Delayed | PKU Parlor

  3. Pingback: Today’s the day – Kuvan Responder Trial Begins! | PKU Parlor

  4. Pingback: Keeping an Off-Diet Food Diary during a PKU Kuvan Responder Trial | PKU Parlor

  5. Sherese Stepney

    Hi Nicole,
    I am writing to you today after discovering your website. I am a parent of two boys with PKU who will be trying Kuvan for the 4 week trial period. How do you feel it went for you? Did you decide to stay on the medication? Do you have any advice for a very nervous parent? I would love your feedback.

  6. Hi Sherese,

    Thanks for taking time to comment! The results of my Kuvan responder trial were determined to be “inconclusive” by my dietician. Some of the reasons cited were the fact I had a 24-hour stomach virus in the middle of it, I tended to exercise (which some believe will burn protein faster than those who don’t exercise) and as an off-diet patient, my daily intake of protein wasn’t as consistent as it needed to be. Personally, I did feel better mentally…but I also realize that because I was expecting Kuvan to make me feel better, it may have also been a placebo-effect. The folks at BioMarin have asked me to consider a second attempt at the trial. I have also heard from other PKU parents who said that they too had to do a second responder trial; however, what appeared to be the secret to their successes the second time around were they actually had their son/daughter eat almost exactly the same foods throughout the entire trial. I’m currently thinking over my options and will probably try again sometime later this year, but not before I graduate with my master’s this May. Tracking food, eating the same meals every day and trying to graduate sounds like too much all at the same time. 🙂

    If you’d like to continue chatting via email, please feel free to email me directly at


  7. Pingback: Maternal PKU and Sapropterin | PKU Parlor

  8. Pingback: National PKU Awareness Day: My Wish List for the Future of PKU | PKU Parlor

  9. Very good article. I’m dealing with a few of these issues as well..

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s