Comparison study: AMPLIPHY
Comparing SEPHIENCE vs sapropterin
The AMPLIPHY study looked at the safety and potential benefits of SEPHIENCE compared with another treatment, sapropterin, in people with PKU. This study helped researchers understand how SEPHIENCE affects blood Phe levels compared with an existing treatment.
AMPLIPHY was a 2-part study in people 2 years of age and older with PKU.
In Part 1 of the trial
Participants took SEPHIENCE for 2 weeks to see how they responded.
Most people saw substantial reductions in blood Phe levels
- 82% achieved at least a 20% reduction
- 76% achieved at least a 30% reduction
In Part 2 of the trial
People who responded with a 20% or greater reduction in their blood Phe levels moved on to Part 2 and were assigned to one of two sequences:
Group 1
- SEPHIENCE for 4 weeks
- 14-day washout period
- SEPHIENCE for 4 weeks
Group 2
- Sapropterin for 4 weeks
- 14-day washout period
- SEPHIENCE for 4 weeks
The washout period allowed the first treatment to clear from the body before starting the next treatment.
Researchers looked at:
How much blood Phe levels changed during treatment, and how many people reached blood Phe levels below 360 µmol/L (6 mg/dL).
Clinical trial results
Part 2 of the AMPLIPHY study looked at participants from Part 1 who had at least a 20% reduction in blood Phe levels. It compared blood Phe changes with SEPHIENCE versus sapropterin from the start of treatment through Weeks 3–4.
greater reduction in blood Phe levels with SEPHIENCE compared to sapropterin during the trial period
Consistent reductions in blood Phe levels across key groups
SEPHIENCE was also studied in groups with different prior experiences with BH4, including those who had responded to BH4 before or were taking BH4 at study screening. Across these groups, blood Phe levels went down more with SEPHIENCE than with sapropterin from the start of treatment to Weeks 3–4.
Responded to BH4 previously
greater reduction with SEPHIENCE vs sapropterin
Taking BH4 at study entry
greater reduction with SEPHIENCE vs sapropterin
Individual results may vary.
Achieving guideline levels
More people reached target blood Phe levels with SEPHIENCE vs sapropterin.
Among those starting at or above the recommended target range
69%
with SEPHIENCE
reached blood Phe levels below 360 µmol/L (6 mg/dL) (36/52 participants)
39%
with sapropterin
reached blood Phe levels below 360 µmol/L (6 mg/dL) (20/51 participants)
Additional study details
From the AMPLIPHY Study
Objective: To compare how well SEPHIENCE lowered blood Phe levels versus sapropterin in children and adults living with PKU.
Method: AMPLIPHY was a Phase 3, randomized, open-label, crossover study in people 2 years of age and older with PKU. In Part 1, participants took SEPHIENCE once daily for 14 days to see how they responded.
Those who had a 20% or greater reduction in blood Phe levels moved on to Part 2, where SEPHIENCE was compared with sapropterin during 4-week treatment periods separated by a 14-day break.
Results: SEPHIENCE lowered blood Phe levels more than sapropterin. In the main analysis group, SEPHIENCE provided a 70% greater average reduction in blood Phe compared with sapropterin. More people reached blood Phe levels below 360 µmol/L while taking SEPHIENCE than while taking sapropterin. Both treatments were generally well tolerated.
PLEASE NOTE: Individual results may vary. This study is not in the approved Prescribing Information for SEPHIENCE, but it is consistent with the information included. Please talk to your healthcare provider if you have any questions.
Side effects with SEPHIENCE were similar to those with sapropterin and in prior studies*
Upper respiratory tract infection
SEPHIENCE: 12.9% sapropterin: 15.0%
Nausea
SEPHIENCE: 9.7% sapropterin: 3.3%
Diarrhea
SEPHIENCE: 9.7% sapropterin: 1.7%
Headache
SEPHIENCE: 8.1% sapropterin: 13.3%
Nasopharyngitis
SEPHIENCE: 8.1% sapropterin: 6.7%
No serious side effects were reported. No side effects led to stopping treatment, and no deaths were reported.
*Percentages are based on participants who received at least one dose of study drug, including in Part 1 (62 took SEPHIENCE and 60 took
sapropterin in Part 2).
Real stories. Real possibilities
Hear firsthand stories from families living with PKU and taking SEPHIENCE.