Diagnosis of idiopathic Parkinson's disease that is optimally treated (motor fluctuations <20% of subject's awake time). Subjects may be on levodopa therapy but must be stable at the time of entry into the study
Sexually active (i.e. =1 attempt/week) males, 40 - 64 years of age (inclusive) at time of screening
Diagnosis of moderate erectile dysfunction (defined according to the NIH Consensus Development Panel on Impotence) for more than 6 months and demonstrating and incomplete response to tadalafil alone
Subject demonstrating an IIEF-5 drug-free baseline score that is = 10 but = 16, and an IIEF-5 tadalafil-alone baseline score that is = 18
Subject in a stable heterosexual relationship for at least 6 months. (2)
Subject motivated to seek treatment for erectile dysfunction.
Subject with a total serum testosterone level = 300 ng/dL, with or without supplementation
Hoehn and Yahr Scale score of 1 - 3
Patient able to consent and comply with protocol requirements

NCT02225548_inc_T1
Condition
idiopathic Parkinson's disease
NCT02225548_inc_T2
Qualifier
treated
NCT02225548_inc_T3
Measurement
motor fluctuations
NCT02225548_inc_T4
Value
<20% of subject's awake time
NCT02225548_inc_T5
Observation
Sexually active
NCT02225548_inc_T6
Person
males
NCT02225548_inc_T7
Person
age
NCT02225548_inc_T8
Value
40 - 64 years
NCT02225548_inc_T9
Multiplier
=1 attempt/week
NCT02225548_inc_T10
Condition
erectile dysfunction
NCT02225548_inc_T11
Qualifier
moderate
NCT02225548_inc_T12
Temporal
for more than 6 months
NCT02225548_inc_T13
Drug
tadalafil
NCT02225548_inc_T14
Condition
response
NCT02225548_inc_T15
Qualifier
incomplete
NCT02225548_inc_T16
Measurement
IIEF-5 drug-free baseline score
NCT02225548_inc_T17
Value
= 10 but = 16
NCT02225548_inc_T18
Measurement
IIEF-5 tadalafil-alone baseline score
NCT02225548_inc_T19
Value
= 18
NCT02225548_inc_T20
Observation
heterosexual relationship
NCT02225548_inc_T21
Qualifier
stable
NCT02225548_inc_T22
Temporal
at least 6 months
NCT02225548_inc_T23
Condition
erectile dysfunction
NCT02225548_inc_T24
Procedure
treatment
NCT02225548_inc_T26
Measurement
total serum testosterone level
NCT02225548_inc_T27
Value
= 300 ng/dL
NCT02225548_inc_T28
Measurement
Hoehn and Yahr Scale score
NCT02225548_inc_T29
Value
1 - 3