Effects of Kuvan on Melatonin Secretion
Study Details
Study Description
Brief Summary
This study examines the effect of tetrahydrobiopterin (Kuvan) and Large Neutral Amino Acid (LNAA) therapy on melatonin and dopamine levels in individuals with Phenylketonuria (PKU). The investigators hypothesize that Kuvan therapy will improve melatonin secretion and urine dopamine levels to some extent. However significantly greater responses in melatonin and dopamine secretions may be observed with combined treatment with Kuvan and supplementation of LNAA.
| Condition or Disease | Intervention/Treatment | Phase |
|---|---|---|
|
Phase 4 |
Detailed Description
Background: Phenylketonuria (PKU) is a genetic condition due to missing one of the key enzymes of phenylalanine (Phe) degradation. The missing enzyme is phenylalanine hydroxylase (PAH). Because of the deficiency of the enzyme, plasma Phe is highly elevated compared with other plasma amino acids. This abnormal ratio i.e., Phe vs. each of the other large neutral amino acids (LNAA) which are transported into the brain as precursors of neurotransmitters through the common transporter LAT1, is likely to contribute to neurotransmitter deficiencies in individuals with PKU. Patients who do not restrict Phe intake develop mental retardation and neuropsychological disorders. Treatment of PKU has been historically limited to restriction of Phe intake, meaning protein restriction.
The FDA recently approved a new medication, Kuvan, a synthetic form of tetrahydrobiopterin (BH4) manufactured by BioMarin Pharmaceutical Inc., for patients with PKU. Kuvan is a cofactor for PAH, tyrosine hydroxylase, and tryptophan hydroxylase. Patients with PKU typically undergo a month-long trial of Kuvan to determine if they are responders to the drug, meaning blood phenylalanine drops by more than 30 percent. Those who are not responders do not usually continue Kuvan, however our recent study (HS 08-00147) showed that classical PKU patients who are not Kuvan responders demonstrated improvement in their maladaptive behaviors, suggesting some effects of Kuvan in the CNS system without reducing blood phenylalanine concentrations (Moseley et al, manuscript under preparation). Seven subjects who did not respond to Kuvan with lower blood Phe levels had significant increases in blood tyrosine after 6 months (p=0.015), along with improvement in the Vineland Internalizing and Overall Maladaptive Behavior Indexes at 12 months (p=0.032 and 0.049, respectively). Kaufman reported that Kuvan at dose of 20 mg/kg/day increased CSF BH4 levels (1). Based on these observations, it is likely that Kuvan has some effects on neurotransmitter metabolism.
Supplementation of large neutral amino acids (LNAA) as a medical food has been used in Europe for the past 25 years and it is believed to be effective in treating patients with PKU. In the article by Shindeler et al. (2), 16 individuals (7 males and 9 females; age 11y to 45 y) participated in the study which consisted 4 weeks wash-out and 4 two-weeks stages (on phenylalanine restricted diet and with/without LNAA, and on no phenylalanine restricted diet and with/without LNAA). No specific adverse effects are reported in the article. Large neutral amino acid therapy for the treatment of PKU has been done in the past (3). LNAA is used primarily for adolescents and adults who cannot adhere to the standard phe-restricted diet. LNAA treatment has been approved for PKU patients just like other special formulas. Our previous studies have demonstrated deficiency of serotonin in the brain, as evidenced by low nocturnal melatonin secretion and reduced urine dopamine compared to controls, and that supplementation with LNAA improves, but does not normalize these markers.
Rationale: Patients with PKU are thought to be deficient in tyrosine and tryptophan in the brain tissue level because of the abnormal phe/tyrosine and phe/tryptophan ratios. Previous studies showed low serotonin levels in cerebrospinal fluid in PKU individuals and some improvement was observed after tryptophan supplementation (4). Our prior study suggested deficiency of tryptophan in the brain tissue was demonstrated by low nocturnal melatonin secretion and 6-sulfatoxymelatonin, which is a stable metabolite of melatonin (5). LNAA supplementation resulted in some improvement in melatonin secretion, however, melatonin secretion in patients with PKU on LNAA was still significantly lower than the control group. Supplementation of Kuvan may activate the brain tyrosine and tryptophan hydroxylases (6), resulting in improvement of nocturnal melatonin secretion and urine melatonin and dopamine concentrations. By supplementing LNAA increased amount of neurotransmitter precursor amino acids will be transported into the brain and activated brain tyrosine and tryptophan hydroxylases by Kuvan will act on these precursors to produce neurotransmitters, i.e., serotonin and dopamine. These synergistic effects may increase melatonin and dopamine levels to closer to the control levels.
Aims of the Study: To show scientific evidence of improvement in metabolism of neurotransmitters including serotonin and dopamine in patients with PKU treated with LNAA only, Kuvan only, and Kuvan and LNAA.
Objectives: This investigator initiated study has three objectives: (1) To evaluate if tetrahydrobiopterin (Kuvan) supplementation has beneficial effects on melatonin secretion and urine dopamine levels in individuals with PKU when they are and are not treated with large neutral amino acids; (2) To demonstrate synergistic effects of LNAA supplementation and Kuvan therapy in improvement of neurotransmitter metabolism in individuals with PKU; and (3) To gather pilot information necessary to design a larger, multicenter trial of these interventions, should results of these pilot studies indicate further study is warranted.
Study Methodology: This study will be conducted in adult patients with PKU in four 4-week phases: phase I (large neutral amino acid/LNAA), phase II (Washout), phase III (Kuvan only) and phase IV (Kuvan and LNAA). Kuvan supplementation will be adjusted to provide 20 mg/kg/day. LNAA therapy is adjusted to the manufacturer's instruction (total tablets of LNAA is 1/2 X BW kg). On the last day of each phase, subjects will stay approximately 14 to 18 hours overnight at the CTU at USC University Hospital. Blood specimens will be collected every 2 hours from 7:00 pm to 7:00 am. First void urine will be collected on the day of discharge (patients will be asked to void urine at 11:00 pm and the first void urine will be collected).
Blood will be collected in a red top tube (5 ml) through an IV line which is saline locked during the study period. Avoid hemolysis by collecting blood through an IV line into a reasonably large peripheral vein. Blood will be left to clot for 45 minutes at room temperature (18-28 C) and protected from light (a dim flash light or a yellow light < 100 lux). Serum will be collected and stored at - 20 C until they are subjected to analysis for plasma melatonin and plasma amino acids. Urine 20 ml first void sample will be collected into two plain tubes (10 ml per each tube) and stored in a deep freezer (-20 C) until subjected to be analyzed for dopamine and 6-sulfatoxymelatonin.
This is an open-labeled study. During all four 4-week phases, subjects will remain on their protein-restricted diet. LNAA tablets are not considered a medicine, but are under the category of medical foods; examples include low protein foods. LNAA tablets will be provided by the LNAA manufacture (Applied Nutrition). Kuvan will be taken per orally with breakfast and LNAA tablets will be taken with meals three times per day.
Study Design
Arms and Interventions
| Arm | Intervention/Treatment |
|---|---|
| Experimental: LNAA, washout, Kuvan, and LNAA+Kuvan One group of 12 subjects, each under 4 conditions (each phase is 4 weeks) |
Drug: Kuvan
Dosed at 20 mg/kg; PO; Phase 3, Phase 4
Other Names:
Dietary Supplement: Large Neutral Amino Acid Therapy
Dosed by weight: weight x .5 = total tablets per day; PO; Phase 1, Phase 4; taken with food
Other Names:
|
Outcome Measures
Primary Outcome Measures
- Serum Melatonin at the End of 4 Weeks [measured every 4 weeks up to 16 weeks]
Evaluated for each subject under 4 conditions (washout, LNAA only, Kuvan only and LNAA+Kuvan)
- Urine 6-sulfatoxymelatonin at the End of 4 Weeks [measured every 4 weeks up to 16 weeks]
Evaluated for each subject under 4 conditions (washout, LNAA only, Kuvan only and LNAA+Kuvan)
- Urine Dopamine at the End of 4 Weeks [measured every 4 weeks up to 16 weeks]
Evaluated for each subject under 4 conditions (washout, LNAA only, Kuvan only and LNAA+Kuvan)
Eligibility Criteria
Criteria
Inclusion Criteria:
-
Adult English-speaking patients who have confirmed PKU, and have tolerated Kuvan therapy at 20 mg/kg/day in the past, and are currently on the LNAA supplements will be considered as candidates for the study.
-
Subjects must be able to stop LNAA therapy for 4 weeks.
-
This will be determined by the subjects themselves, based on their past personal experiences.
Exclusion Criteria:
-
Individuals who have never taken Kuvan, who have never been on LNAA therapy, who are under the age of 18, or who do not speak English will be excluded.
-
Subjects who cannot stop LNAA therapy for 4 weeks will be excluded.
Contacts and Locations
Locations
| Site | City | State | Country | Postal Code | |
|---|---|---|---|---|---|
| 1 | Keck School of Medicine, Clinical Trials Unit at Keck Medical Center of USC | Los Angeles | California | United States | 90033 |
Sponsors and Collaborators
- University of Southern California
- BioMarin Pharmaceutical
Investigators
- Principal Investigator: Shoji Yano, M.D., Ph.D., USC Keck School of Medicine, Dept. of Pediatrics, Genetics Division
Study Documents (Full-Text)
None provided.More Information
Publications
- Katz I, Lloyd T, Kaufman S. Studies on phenylalanine and tyrosine hydroxylation by rat brain tyrosine hydroxylase. Biochim Biophys Acta. 1976 Oct 11;445(3):567-78.
- Kaufman S, Kapatos G, McInnes RR, Schulman JD, Rizzo WB. Use of tetrahydropterins in the treatment of hyperphenylalaninemia due to defective synthesis of tetrahydrobiopterin: evidence that peripherally administered tetrahydropterins enter the brain. Pediatrics. 1982 Sep;70(3):376-80.
- Lou H. Large doses of tryptophan and tyrosine as potential therapeutic alternative to dietary phenylalanine restriction in phenylketonuria. Lancet. 1985 Jul 20;2(8447):150-1.
- Nielsen JB, Lou H, Güttler F. Effects of diet discontinuation and dietary tryptophan supplementation on neurotransmitter metabolism in phenylketonuria. Brain Dysfunction 1:51-56. 1988.
- Schindeler S, Ghosh-Jerath S, Thompson S, Rocca A, Joy P, Kemp A, Rae C, Green K, Wilcken B, Christodoulou J. The effects of large neutral amino acid supplements in PKU: an MRS and neuropsychological study. Mol Genet Metab. 2007 May;91(1):48-54. Epub 2007 Mar 23.
- Zimmermann RC, McDougle CJ, Schumacher M, Olcese J, Heninger GR, Price LH. Urinary 6-hydroxymelatonin sulfate as a measure of melatonin secretion during acute tryptophan depletion. Psychoneuroendocrinology. 1993;18(8):567-78.
- USC Kuvan Melatonin
Study Results
Participant Flow
| Recruitment Details | |
|---|---|
| Pre-assignment Detail |
| Arm/Group Title | All Study Participants |
|---|---|
| Arm/Group Description | LNAA, washout, Kuvan, and LNAA+Kuvan One group of 10 subjects, each under 4 conditions (each phase is 4 weeks) Kuvan: Dosed at 20 mg/kg; PO; Phase 3, Phase 4 Large Neutral Amino Acid Therapy: Dosed by weight: weight x .5 = total tablets per day; PO; Phase 1, Phase 4; taken with food |
| Period Title: LNAA (4 Weeks) | |
| STARTED | 10 |
| COMPLETED | 10 |
| NOT COMPLETED | 0 |
| Period Title: LNAA (4 Weeks) | |
| STARTED | 10 |
| COMPLETED | 10 |
| NOT COMPLETED | 0 |
| Period Title: LNAA (4 Weeks) | |
| STARTED | 10 |
| COMPLETED | 10 |
| NOT COMPLETED | 0 |
| Period Title: LNAA (4 Weeks) | |
| STARTED | 10 |
| COMPLETED | 9 |
| NOT COMPLETED | 1 |
Baseline Characteristics
| Arm/Group Title | All Study Participants |
|---|---|
| Arm/Group Description | LNAA, washout, Kuvan, and LNAA+Kuvan One group of 10 subjects, each under 4 conditions (each phase is 4 weeks) Kuvan: Dosed at 20 mg/kg; PO; Phase 3, Phase 4 Large Neutral Amino Acid Therapy: Dosed by weight: weight x .5 = total tablets per day; PO; Phase 1, Phase 4; taken with food |
| Overall Participants | 10 |
| Age (Count of Participants) | |
| <=18 years |
0
0%
|
| Between 18 and 65 years |
10
100%
|
| >=65 years |
0
0%
|
| Gender (Count of Participants) | |
| Female |
3
30%
|
| Male |
7
70%
|
| Region of Enrollment (Count of Participants) | |
| United States |
10
100%
|
Outcome Measures
| Title | Serum Melatonin at the End of 4 Weeks |
|---|---|
| Description | Evaluated for each subject under 4 conditions (washout, LNAA only, Kuvan only and LNAA+Kuvan) |
| Time Frame | measured every 4 weeks up to 16 weeks |
Outcome Measure Data
| Analysis Population Description |
|---|
| Participates who completed all phases were measured. |
| Arm/Group Title | LNAA | Washout | BH4 (Kuvan) | BH4 and LNAA |
|---|---|---|---|---|
| Arm/Group Description | LNAA Large Neutral Amino Acid Therapy: Dosed by weight: weight x .5 = total tablets per day; PO; Phase 1, Phase 4; taken with food | no Kuvan or LNAA or any medical food products. Limited protein intake diet. | Kuvan (BH4): Dosed at 20 mg/kg; PO; Phase 3, Phase 4 | Kuvan: Dosed at 20 mg/kg; PO; Phase 3, Phase 4 Large Neutral Amino Acid Therapy: Dosed by weight: weight x .5 = total tablets per day; PO; Phase 1, Phase 4; taken with food |
| Measure Participants | 9 | 9 | 9 | 9 |
| Mean (Standard Deviation) [pg/ml] |
266.9
(165.7)
|
205.7
(133.1)
|
220.4
(138.5)
|
301.2
(179.4)
|
| Title | Urine 6-sulfatoxymelatonin at the End of 4 Weeks |
|---|---|
| Description | Evaluated for each subject under 4 conditions (washout, LNAA only, Kuvan only and LNAA+Kuvan) |
| Time Frame | measured every 4 weeks up to 16 weeks |
Outcome Measure Data
| Analysis Population Description |
|---|
| Participates who completed all phases were measured. |
| Arm/Group Title | LNAA | Washout | BH4 (Kuvan) | BH4 and LNAA |
|---|---|---|---|---|
| Arm/Group Description | LNAA Large Neutral Amino Acid Therapy: Dosed by weight: weight x .5 = total tablets per day; PO; Phase 1, Phase 4; taken with food | no Kuvan or LNAA or any medical food products. Limited protein intake diet. | Kuvan (BH4): Dosed at 20 mg/kg; PO; Phase 3, Phase 4 | Kuvan: Dosed at 20 mg/kg; PO; Phase 3, Phase 4 Large Neutral Amino Acid Therapy: Dosed by weight: weight x .5 = total tablets per day; PO; Phase 1, Phase 4; taken with food |
| Measure Participants | 9 | 9 | 9 | 9 |
| Mean (Standard Deviation) [ng/mg Creatinine] |
14.5
(9.0)
|
8.2
(4.8)
|
8.6
(5.7)
|
13.2
(9.3)
|
| Title | Urine Dopamine at the End of 4 Weeks |
|---|---|
| Description | Evaluated for each subject under 4 conditions (washout, LNAA only, Kuvan only and LNAA+Kuvan) |
| Time Frame | measured every 4 weeks up to 16 weeks |
Outcome Measure Data
| Analysis Population Description |
|---|
| Participates who completed all phases were measured. |
| Arm/Group Title | LNAA | Washout | BH4 (Kuvan) | BH4 and LNAA |
|---|---|---|---|---|
| Arm/Group Description | LNAA Large Neutral Amino Acid Therapy: Dosed by weight: weight x .5 = total tablets per day; PO; Phase 1, Phase 4; taken with food | no Kuvan or LNAA or any medical food products. Limited protein intake diet. | Kuvan (BH4): Dosed at 20 mg/kg; PO; Phase 3, Phase 4 | Kuvan: Dosed at 20 mg/kg; PO; Phase 3, Phase 4 Large Neutral Amino Acid Therapy: Dosed by weight: weight x .5 = total tablets per day; PO; Phase 1, Phase 4; taken with food |
| Measure Participants | 9 | 9 | 9 | 9 |
| Mean (Standard Deviation) [ug/gCreatinine] |
63.7
(26.7)
|
42.6
(19.3)
|
46.0
(16.8)
|
67.6
(28.4)
|
Adverse Events
| Time Frame | ||||||||
|---|---|---|---|---|---|---|---|---|
| Adverse Event Reporting Description | ||||||||
| Arm/Group Title | LNAA | Washout | BH4 (Kuvan) | BH4 and LNAA | ||||
| Arm/Group Description | LNAA Large Neutral Amino Acid Therapy: Dosed by weight: weight x .5 = total tablets per day; PO; Phase 1, Phase 4; taken with food | no Kuvan or LNAA or any medical food products. Limited protein intake diet. | Kuvan (BH4): Dosed at 20 mg/kg; PO; Phase 3, Phase 4 | Kuvan: Dosed at 20 mg/kg; PO; Phase 3, Phase 4 Large Neutral Amino Acid Therapy: Dosed by weight: weight x .5 = total tablets per day; PO; Phase 1, Phase 4; taken with food | ||||
All Cause Mortality |
||||||||
| LNAA | Washout | BH4 (Kuvan) | BH4 and LNAA | |||||
| Affected / at Risk (%) | # Events | Affected / at Risk (%) | # Events | Affected / at Risk (%) | # Events | Affected / at Risk (%) | # Events | |
| Total | / (NaN) | / (NaN) | / (NaN) | / (NaN) | ||||
Serious Adverse Events |
||||||||
| LNAA | Washout | BH4 (Kuvan) | BH4 and LNAA | |||||
| Affected / at Risk (%) | # Events | Affected / at Risk (%) | # Events | Affected / at Risk (%) | # Events | Affected / at Risk (%) | # Events | |
| Total | 0/9 (0%) | 0/9 (0%) | 0/9 (0%) | 0/9 (0%) | ||||
Other (Not Including Serious) Adverse Events |
||||||||
| LNAA | Washout | BH4 (Kuvan) | BH4 and LNAA | |||||
| Affected / at Risk (%) | # Events | Affected / at Risk (%) | # Events | Affected / at Risk (%) | # Events | Affected / at Risk (%) | # Events | |
| Total | 0/9 (0%) | 0/9 (0%) | 0/9 (0%) | 0/9 (0%) | ||||
Limitations/Caveats
More Information
Certain Agreements
All Principal Investigators ARE employed by the organization sponsoring the study.
There is NOT an agreement between Principal Investigators and the Sponsor (or its agents) that restricts the PI's rights to discuss or publish trial results after the trial is completed.
Results Point of Contact
| Name/Title | Shoji Yano |
|---|---|
| Organization | USC/Keck School of Medicine |
| Phone | 323-226-3816 |
| syano@usc.edu |
- USC Kuvan Melatonin