The Purpose of This Pilot Study is to Assess the Impact of KUVAN® (Sapropterin Dihydrochloride) on Gastric Relaxation in Women With Diabetic Gastroparesis.

Patients are invited to participate in a research study of Kuvan® (sapropterin
dihydrochloride). We hope to learn whether treatment with Kuvan® is safe and effective in
improving the ability of the stomach to relax after eating and improving the symptoms of
diabetic gastroparesis. Women are selected as a possible participant in this study because
they have diabetes and moderate to severe gastroparesis (meaning stomach empties slowly).

Inclusion Criteria:Inclusion Criteria

Patients with moderate to severe symptoms of diabetic gastroparesis will be studied (GCSI
>21). Patients should not have post-surgical gastroparesis or dyspeptic symptoms with
normal gastric emptying. In order to qualify for inclusion in the trial, patients must
satisfy the following inclusion criteria:

1. Diagnosis of diabetes mellitus > 5 years requiring medical therapy

2. Female gender

3. Ages 18-65 years

4. Documentation of delayed gastric emptying on gastric emptying scintigraphy (within 2
years of enrollment)

5. Symptoms of gastroparesis for at least 6 months with Gastroparesis Cardinal Symptom
Index (GCSI) score > 21 indicating moderate to severe symptoms

6. Recent negative upper endoscopy or upper GI series within 2 years of enrollment (no
evidence of mechanical obstruction or peptic ulcer disease)

Exclusion Criteria:Exclusion Criteria

Patients who satisfy any of the following exclusion criteria will be ineligible for
enrollment in the study:

1. Diabetes diagnosed < 5 years prior to the study

2. Male gender

3. Normal gastric emptying

4. Gastroparesis from post-surgical etiologies

5. Another active disorder, which could explain symptoms in the opinion of the
investigator

6. Pregnancy

7. History of significant cardiac arrhythmias and/or prolonged QTc

8. Daily use of narcotic analgesics for abdominal pain

9. Contraindications to gastric emptying breath test: patients with a known allergy to
egg, wheat, or algae.

10. Underlying seizure disorder

11. Known history of cardiac ischemia

12. Recent clinically significant gastrointestinal bleeding

13. Patients taking Levodopa

14. Any other condition, which in the opinion of the investigator would impede compliance
or hinder the completion of the study

15. Failure to give informed consent

16. Surgery for placement of a gastric stimulator within the past 6 months (patients > 6
months post-op with persistent symptoms and delayed gastric emptying are eligible).

17. A normal upper endoscopy not performed within 2 year of study entry.

18. Patients taking phosphodiesterase inhibitors such as sildenafil, vardenafil,
tadalafil

19. Patients with renal impairment (i.e. Creatinine > 2.5 mg/dL)

20. Patients with hepatic dysfunction (i.e. ALT and AST values > 2.5x ULN and T.
bilirubin > 1.5x ULN)

21. Patients with uncontrolled diabetes, such as HbA1c > 10 mg/dl at screening/baseline
will be excluded.