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Protocol Details

Protocol C614: An Open-Label Study of DCCR (Diazoxide Choline) Extended-Release Tablets in Patients with Prader-Willi Syndrome

This study is NOT currently recruiting participants.

Summary | Eligibility | Citations | Contacts




Sponsoring Institute

National Institute of Child Health and Human Development (NICHD)

Recruitment Detail

Type: No longer recruiting/follow-up only
Gender: Male & Female
Min Age: 6 Years
Max Age: 100 Years

Referral Letter Required


Population Exclusion(s)

Pregnant Women


Prader-Willi Syndrome;
Weight Loss

Recruitment Keyword(s)



Prader-Willi Syndrome

Investigational Drug(s)


Investigational Device(s)



Drug: DCCR

Supporting Site

National Institute of Child Health and Human Development


Prader-Willi syndrome (PWS) is a complex genetic disorder. It can cause problems including uncontrollable hunger, short stature, and decreased muscle tone. Better treatments are needed.


To study the long-term effects of diazoxide choline (DCCR) extended-release tablets in people with PWS.


People with PWS who participated in protocol 19-CH-0026 at the NIH Clinical Center.


Participants will be in this study for up to 5 years.

Participants will have yearly visits to the NIH clinic. They will have a physical exam with blood and urine tests. They will have tests of their heart function. The study doctor will press a finger onto the participant s foot, ankle, and shin to check for excess fluid under the skin (edema). Participants will be checked for an unusual amount of hair and signs of blood clots.

DCCR is a tablet taken by mouth. Participants will be given a supply of DCCR to take at home. They will be given a diary; they will write down when they take each dose. They will write down any adverse effects they may have.

Other study visits can be by telephone or telemedicine. These visits will be every 2 weeks for the first 6 weeks of the study, with 3 more in the first year. Then there will be 2 visits per year.

In the morning before each call, participants will prick their finger to draw blood to test their blood sugar at home. They will talk about their symptoms and check for edema and blood clots. For some visits, participants may to go a local clinic for blood and urine tests.

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Potential participants must meet all of the following inclusion criteria to be enrolled:

-Provide voluntary, written informed consent (parent(s) / legal guardian(s) of the participant as appropriate); provide voluntary, written assent (participant as needed).

-Participant must be willing to have telemedicine visits at 3, 6 and 12 months after Visit 1 then at 12-month intervals thereafter.

-Participant must:

--Have participated in and completed the Study C602 RW Period;

--Have participated in but discontinued from the Study C602 RW Period and at least 16 weeks have elapsed since the date of their randomization into the C602 RW Period; or

--Have participated in Study C602 OLE period, did not consent to participate in the RW Period, and at least 16 weeks have elapsed since the date of their C602 OLE End of Treatment Visit.


Eligible participants must not meet any of the following exclusion criteria to be enrolled:

-Positive urine pregnancy test (in females of child-bearing potential).

-Females who are pregnant or breastfeeding, and/or plan to become pregnant or to breast-feed during or within 30 days after study participation.

-Anticipated requirement for use at any time during the study of the following prohibited medications:

--Medications known to prolong the QTc interval (Refer to QT Drugs List on, except citalopram or escitalopram

--Medications, including homeopathy and herbal preparations, that are strong inhibitors of CYP450 1A2 (Refer to, Drug Interactions Flockhart Table (Trademark))

--Systemic steroids (i.e., oral, IM, or IV) for > 7 days

-Participation in a clinical study of an investigational drug (including approved drugs for unapproved uses), investigational device, or therapeutic intervention subsequent to the C602 OLE EOT Visit.

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Bischof JM, Wevrick R. Chronic diazoxide treatment decreases fat mass and improves endurance capacity in an obese mouse model of Prader-Willi syndrome. Mol Genet Metab. 2018 Apr;123(4):511-517. doi: 10.1016/j.ymgme.2018.02.018. Epub 2018 Feb 27. PMID: 29506955.

Cowen N, Bhatnagar A. The Potential Role of Activating the ATP-Sensitive Potassium Channel in the Treatment of Hyperphagic Obesity. Genes (Basel). 2020 Apr 21;11(4):450. doi: 10.3390/genes11040450. PMID: 32326226; PMCID: PMC7230375.

Miller JL, Gevers E, Bridges N, Yanovski JA, Salehi P, Obrynba KS, Felner EI, Bird LM, Shoemaker AH, Angulo M, Butler MG, Stevenson D, Abuzzahab J, Barrett T, Lah M, Littlejohn E, Mathew V, Cowen NM, Bhatnagar A. Diazoxide Choline Extended-Release Tablet in People with Prader-Willi Syndrome: A Double-Blind, Placebo-Controlled Trial. J Clin Endocrinol Metab. 2023 Jan 14:dgad014. doi: 10.1210/clinem/dgad014. Epub ahead of print. PMID: 36639249.

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Principal Investigator

Referral Contact

For more information:

Jack A. Yanovski, M.D.
National Institute of Child Health and Human Development (NICHD)
NIHBC 10 - CRC BG RM 2-3142
(301) 496-0858

Sheila M. Brady, C.R.N.P.
National Institute of Child Health and Human Development (NICHD)
NIHBC 10 - CRC BG RM 2-3130
(301) 451-3783

Office of Patient Recruitment
National Institutes of Health Clinical Center (CC)
Building 61, 10 Cloister Court
Bethesda, Maryland 20892
Toll Free: 1-800-411-1222
Local Phone: 301-451-4383
TTY: TTY Users Dial 7-1-1

Clinical Trials Number:


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