Trial Outcomes & Findings for PDC-1421 Treatment in Adult Patients With ADHD (NCT NCT05202327)
NCT ID: NCT05202327
Last Updated: 2026-05-06
Results Overview
The ADHD-RS-IV with Adult Prompts is an 18-item scale based on the DSM-IV-TR criteria for ADHD that provides a rating of the severity of symptoms. The adult prompts serve as a guide to explore more fully the extent and severity of ADHD symptoms and create a framework to ascertain impairment. The odd-numbered 9 items assess inattentive symptoms and the even-numbered 9 items assess hyperactive-impulsive symptoms. Scoring is based on a 4-point, yielding a possible total score of 0-54. Likert-type severity scale: 0 = Never or Rarely, 1 = Sometimes, 2 = Often, 3 = Very Often. Clinicians should score the highest score that is generated for the prompts for each item. The ADHD-RS-IV was assessed from Visit 1 to Visit 7 by the investigator.
COMPLETED
PHASE2
99 participants
8 weeks
2026-05-06
Participant Flow
Participant milestones
| Measure |
Placebo
Two placebo capsules thrice daily for 56 days (8 weeks).
Placebo: The placebo contained corn starch.
|
Low-dose
One placebo capsule and 1 PDC-1421 Capsule, thrice daily for 56 days (8 weeks).
PDC-1421 Capsule: PDC-1421 Capsule is a botanical investigational new drug containing the extract of Radix Polygalae (Polygala tenuifolia Willd.) as the active ingredient.
Placebo: The placebo contained corn starch.
|
High-dose
Two PDC-1421 Capsules thrice daily for 56 days (8 weeks).
PDC-1421 Capsule: PDC-1421 Capsule is a botanical investigational new drug containing the extract of Radix Polygalae (Polygala tenuifolia Willd.) as the active ingredient.
|
|---|---|---|---|
|
Overall Study
STARTED
|
22
|
23
|
24
|
|
Overall Study
COMPLETED
|
19
|
22
|
19
|
|
Overall Study
NOT COMPLETED
|
3
|
1
|
5
|
Reasons for withdrawal
Withdrawal data not reported
Baseline Characteristics
PDC-1421 Treatment in Adult Patients With ADHD
Baseline characteristics by cohort
| Measure |
Placebo
n=22 Participants
Two placebo capsules thrice daily for 56 days (8 weeks).
Placebo: The placebo contained corn starch.
|
Low-dose
n=23 Participants
One placebo capsule and 1 PDC-1421 Capsule, thrice daily for 56 days (8 weeks).
PDC-1421 Capsule: PDC-1421 Capsule is a botanical investigational new drug containing the extract of Radix Polygalae (Polygala tenuifolia Willd.) as the active ingredient.
Placebo: The placebo contained corn starch.
|
High-dose
n=24 Participants
Two PDC-1421 Capsules thrice daily for 56 days (8 weeks).
PDC-1421 Capsule: PDC-1421 Capsule is a botanical investigational new drug containing the extract of Radix Polygalae (Polygala tenuifolia Willd.) as the active ingredient.
|
Total
n=69 Participants
Total of all reporting groups
|
|---|---|---|---|---|
|
Age, Continuous
|
29.3 years
STANDARD_DEVIATION 8.3 • n=54 Participants
|
37.3 years
STANDARD_DEVIATION 10.2 • n=60 Participants
|
33.3 years
STANDARD_DEVIATION 10.8 • n=114 Participants
|
33.4 years
STANDARD_DEVIATION 10.2 • n=480 Participants
|
|
Sex: Female, Male
Female
|
7 Participants
n=54 Participants
|
11 Participants
n=60 Participants
|
16 Participants
n=114 Participants
|
34 Participants
n=480 Participants
|
|
Sex: Female, Male
Male
|
15 Participants
n=54 Participants
|
12 Participants
n=60 Participants
|
8 Participants
n=114 Participants
|
35 Participants
n=480 Participants
|
|
Race (NIH/OMB)
American Indian or Alaska Native
|
0 Participants
n=54 Participants
|
0 Participants
n=60 Participants
|
0 Participants
n=114 Participants
|
0 Participants
n=480 Participants
|
|
Race (NIH/OMB)
Asian
|
19 Participants
n=54 Participants
|
20 Participants
n=60 Participants
|
22 Participants
n=114 Participants
|
61 Participants
n=480 Participants
|
|
Race (NIH/OMB)
Native Hawaiian or Other Pacific Islander
|
0 Participants
n=54 Participants
|
0 Participants
n=60 Participants
|
0 Participants
n=114 Participants
|
0 Participants
n=480 Participants
|
|
Race (NIH/OMB)
Black or African American
|
2 Participants
n=54 Participants
|
0 Participants
n=60 Participants
|
0 Participants
n=114 Participants
|
2 Participants
n=480 Participants
|
|
Race (NIH/OMB)
White
|
1 Participants
n=54 Participants
|
1 Participants
n=60 Participants
|
2 Participants
n=114 Participants
|
4 Participants
n=480 Participants
|
|
Race (NIH/OMB)
More than one race
|
0 Participants
n=54 Participants
|
2 Participants
n=60 Participants
|
0 Participants
n=114 Participants
|
2 Participants
n=480 Participants
|
|
Race (NIH/OMB)
Unknown or Not Reported
|
0 Participants
n=54 Participants
|
0 Participants
n=60 Participants
|
0 Participants
n=114 Participants
|
0 Participants
n=480 Participants
|
|
Region of Enrollment
United States
|
3 participants
n=54 Participants
|
3 participants
n=60 Participants
|
3 participants
n=114 Participants
|
9 participants
n=480 Participants
|
|
Region of Enrollment
Taiwan
|
19 participants
n=54 Participants
|
20 participants
n=60 Participants
|
21 participants
n=114 Participants
|
60 participants
n=480 Participants
|
|
Weight
|
67.8 kg
STANDARD_DEVIATION 13.7 • n=54 Participants
|
72.0 kg
STANDARD_DEVIATION 20.5 • n=60 Participants
|
63.2 kg
STANDARD_DEVIATION 11.1 • n=114 Participants
|
67.6 kg
STANDARD_DEVIATION 15.8 • n=480 Participants
|
|
Height
|
170.5 cm
STANDARD_DEVIATION 8.2 • n=54 Participants
|
167.8 cm
STANDARD_DEVIATION 11.2 • n=60 Participants
|
166.0 cm
STANDARD_DEVIATION 8.3 • n=114 Participants
|
168.0 cm
STANDARD_DEVIATION 9.4 • n=480 Participants
|
|
BMI
|
23.2 kg/m2
STANDARD_DEVIATION 3.6 • n=54 Participants
|
25.2 kg/m2
STANDARD_DEVIATION 4.7 • n=60 Participants
|
22.9 kg/m2
STANDARD_DEVIATION 3.0 • n=114 Participants
|
23.7 kg/m2
STANDARD_DEVIATION 3.9 • n=480 Participants
|
PRIMARY outcome
Timeframe: 8 weeksThe ADHD-RS-IV with Adult Prompts is an 18-item scale based on the DSM-IV-TR criteria for ADHD that provides a rating of the severity of symptoms. The adult prompts serve as a guide to explore more fully the extent and severity of ADHD symptoms and create a framework to ascertain impairment. The odd-numbered 9 items assess inattentive symptoms and the even-numbered 9 items assess hyperactive-impulsive symptoms. Scoring is based on a 4-point, yielding a possible total score of 0-54. Likert-type severity scale: 0 = Never or Rarely, 1 = Sometimes, 2 = Often, 3 = Very Often. Clinicians should score the highest score that is generated for the prompts for each item. The ADHD-RS-IV was assessed from Visit 1 to Visit 7 by the investigator.
Outcome measures
| Measure |
Low-dose
n=23 Participants
One placebo capsule and 1 PDC-1421 Capsule, thrice daily for 56 days (8 weeks).
PDC-1421 Capsule: PDC-1421 Capsule is a botanical investigational new drug containing the extract of Radix Polygalae (Polygala tenuifolia Willd.) as the active ingredient.
Placebo: The placebo contained corn starch.
|
High-dose
n=24 Participants
Two PDC-1421 Capsules thrice daily for 56 days (8 weeks).
PDC-1421 Capsule: PDC-1421 Capsule is a botanical investigational new drug containing the extract of Radix Polygalae (Polygala tenuifolia Willd.) as the active ingredient.
|
Placebo
n=22 Participants
Two placebo capsules thrice daily for 56 days (8 weeks).
Placebo: The placebo contained corn starch.
|
|---|---|---|---|
|
Number of Participants With Improvement ≥ 40% in ADHD-RS-IV From Baseline up to 8 Weeks Treatment
|
9 Participants
|
10 Participants
|
11 Participants
|
SECONDARY outcome
Timeframe: 8 weeksClinical Global Impression-Severity (CGI-S) and Clinical Global Impression-Improvement (CGI-I) score of 2 or lower. The CGI-S is rated on a 7-point scale, with the severity of illness scale using a range of responses from 1 (normal) through to 7 (amongst the most severely ill patients). CGI-I scores range from 1 (very much improved) through to 7 (very much worse).
Outcome measures
| Measure |
Low-dose
n=23 Participants
One placebo capsule and 1 PDC-1421 Capsule, thrice daily for 56 days (8 weeks).
PDC-1421 Capsule: PDC-1421 Capsule is a botanical investigational new drug containing the extract of Radix Polygalae (Polygala tenuifolia Willd.) as the active ingredient.
Placebo: The placebo contained corn starch.
|
High-dose
n=24 Participants
Two PDC-1421 Capsules thrice daily for 56 days (8 weeks).
PDC-1421 Capsule: PDC-1421 Capsule is a botanical investigational new drug containing the extract of Radix Polygalae (Polygala tenuifolia Willd.) as the active ingredient.
|
Placebo
n=22 Participants
Two placebo capsules thrice daily for 56 days (8 weeks).
Placebo: The placebo contained corn starch.
|
|---|---|---|---|
|
Number of Participants With a CGI Score of 2 or Lower From Baseline up to 8 Weeks Treatment
|
9 Participants
|
9 Participants
|
6 Participants
|
SECONDARY outcome
Timeframe: 8 weeksThe K-SCT rating scale queries 15 Sluggish Cognitive Tempo symptoms rated from 0 = Never or Rarely, 1 = Sometimes, 2 = Often, 3 = Very Often, grouped into latent factors of daydreaming, working memory problems, and subjective sleepiness/tiredness. The range for the Total Score is 0-45. The higher values represent a worse outcome for the total score and subscore.
Outcome measures
| Measure |
Low-dose
n=23 Participants
One placebo capsule and 1 PDC-1421 Capsule, thrice daily for 56 days (8 weeks).
PDC-1421 Capsule: PDC-1421 Capsule is a botanical investigational new drug containing the extract of Radix Polygalae (Polygala tenuifolia Willd.) as the active ingredient.
Placebo: The placebo contained corn starch.
|
High-dose
n=24 Participants
Two PDC-1421 Capsules thrice daily for 56 days (8 weeks).
PDC-1421 Capsule: PDC-1421 Capsule is a botanical investigational new drug containing the extract of Radix Polygalae (Polygala tenuifolia Willd.) as the active ingredient.
|
Placebo
n=22 Participants
Two placebo capsules thrice daily for 56 days (8 weeks).
Placebo: The placebo contained corn starch.
|
|---|---|---|---|
|
Change From Baseline up to 8 Weeks in the Sluggish Cognitive Tempo (K-SCT) Score.
|
-6.04 score on a scale
Standard Deviation 8.29
|
-6.54 score on a scale
Standard Deviation 8.04
|
-5.05 score on a scale
Standard Deviation 8.27
|
SECONDARY outcome
Timeframe: 8 weeksThe ADHD-RS-IV with Adult Prompts is an 18-item scale base on the DSM-IV-TR criteria for ADHD that provides a rating of the severity of symptoms. The adult prompts serve as a guide to explore more fully the extent and severity of ADHD symptoms and create a framework to ascertain impairment. The odd-numbered 9 items assess inattentive symptoms and the even-numbered 9 items assess hyperactive-impulsive symptoms. Scoring is based on a 4-point, yielding a possible summed "total score" of 0-54. The higher values represent a worse outcome for the total score and subscore. Likert-type severity scale: 0 = Never or Rarely, 1 = Sometimes, 2 = Often, 3 = Very Often.
Outcome measures
| Measure |
Low-dose
n=23 Participants
One placebo capsule and 1 PDC-1421 Capsule, thrice daily for 56 days (8 weeks).
PDC-1421 Capsule: PDC-1421 Capsule is a botanical investigational new drug containing the extract of Radix Polygalae (Polygala tenuifolia Willd.) as the active ingredient.
Placebo: The placebo contained corn starch.
|
High-dose
n=24 Participants
Two PDC-1421 Capsules thrice daily for 56 days (8 weeks).
PDC-1421 Capsule: PDC-1421 Capsule is a botanical investigational new drug containing the extract of Radix Polygalae (Polygala tenuifolia Willd.) as the active ingredient.
|
Placebo
n=22 Participants
Two placebo capsules thrice daily for 56 days (8 weeks).
Placebo: The placebo contained corn starch.
|
|---|---|---|---|
|
Change From Baseline up to 8 Weeks in the ADHD-RS-IV Total Scale.
|
-13.61 score on a scale
Standard Deviation 10.02
|
-11.75 score on a scale
Standard Deviation 10.20
|
-12.14 score on a scale
Standard Deviation 10.56
|
SECONDARY outcome
Timeframe: 8 weeksThe ADHD-RS-IV with Adult Prompts is an 18-item scale base on the DSM-IV-TR criteria for ADHD that provides a rating of the severity of symptoms. The adult prompts serve as a guide to explore more fully the extent and severity of ADHD symptoms and create a framework to ascertain impairment. The odd-numbered 9 items assess inattentive symptoms and the even-numbered 9 items assess hyperactive-impulsive symptoms. Scoring is based on a 4-point, yielding a possible summed "total score" of 0-54, "inattentive subscore" of 0-27, and "hyperactive-impulsive subscore" of 0-27. The higher values represent a worse outcome for the total score and subscore. Likert-type severity scale: 0 = Never or Rarely, 1 = Sometimes, 2 = Often, 3 = Very Often.
Outcome measures
| Measure |
Low-dose
n=23 Participants
One placebo capsule and 1 PDC-1421 Capsule, thrice daily for 56 days (8 weeks).
PDC-1421 Capsule: PDC-1421 Capsule is a botanical investigational new drug containing the extract of Radix Polygalae (Polygala tenuifolia Willd.) as the active ingredient.
Placebo: The placebo contained corn starch.
|
High-dose
n=24 Participants
Two PDC-1421 Capsules thrice daily for 56 days (8 weeks).
PDC-1421 Capsule: PDC-1421 Capsule is a botanical investigational new drug containing the extract of Radix Polygalae (Polygala tenuifolia Willd.) as the active ingredient.
|
Placebo
n=22 Participants
Two placebo capsules thrice daily for 56 days (8 weeks).
Placebo: The placebo contained corn starch.
|
|---|---|---|---|
|
Number of Participants With Symptom Remission in ADHD-RS-IV From Baseline up to 8 Weeks Treatment
|
4 Participants
|
7 Participants
|
9 Participants
|
SECONDARY outcome
Timeframe: 8 weeksConners' Adult Attention-Deficit/Hyperactivity Disorder Rating Scale-Self Report: Short Version (CAARS-S:S) consists of 26 items rated from 0=not at all, never to 3=very much, very frequently. Four subscales each composed of 5 items (A: inattention/memory problems; B: hyperactivity/restlessness; C: impulsivity/emotional lability; and D: problems with self-concept) as well as a 12-item ADHD index can be computed. The raw scores were converted into standard T-scores. The higher T-scores represent a better or worse outcome. A T-score is a standard score with a mean of 50 and a standard deviation of 10 in all samples and across all scales
Outcome measures
| Measure |
Low-dose
n=23 Participants
One placebo capsule and 1 PDC-1421 Capsule, thrice daily for 56 days (8 weeks).
PDC-1421 Capsule: PDC-1421 Capsule is a botanical investigational new drug containing the extract of Radix Polygalae (Polygala tenuifolia Willd.) as the active ingredient.
Placebo: The placebo contained corn starch.
|
High-dose
n=24 Participants
Two PDC-1421 Capsules thrice daily for 56 days (8 weeks).
PDC-1421 Capsule: PDC-1421 Capsule is a botanical investigational new drug containing the extract of Radix Polygalae (Polygala tenuifolia Willd.) as the active ingredient.
|
Placebo
n=22 Participants
Two placebo capsules thrice daily for 56 days (8 weeks).
Placebo: The placebo contained corn starch.
|
|---|---|---|---|
|
Change From Baseline up to 8 Weeks Treat in the Conners' Adult Attention-Deficit/Hyperactivity Disorder Rating Scale-Self Report: Short Version (CAARS-S:S) ADHD Index of T-score.
|
-7.43 score on a scale
Standard Deviation 10.20
|
-7.67 score on a scale
Standard Deviation 9.56
|
-10.68 score on a scale
Standard Deviation 11.27
|
Adverse Events
Placebo
Low-dose
High-dose
Serious adverse events
Adverse event data not reported
Other adverse events
| Measure |
Placebo
n=22 participants at risk
Two placebo capsules thrice daily for 56 days (8 weeks).
Placebo: The placebo contained corn starch.
|
Low-dose
n=23 participants at risk
One placebo capsule and 1 PDC-1421 Capsule, thrice daily for 56 days (8 weeks).
PDC-1421 Capsule: PDC-1421 Capsule is a botanical investigational new drug containing the extract of Radix Polygalae (Polygala tenuifolia Willd.) as the active ingredient.
Placebo: The placebo contained corn starch.
|
High-dose
n=24 participants at risk
Two PDC-1421 Capsules thrice daily for 56 days (8 weeks).
PDC-1421 Capsule: PDC-1421 Capsule is a botanical investigational new drug containing the extract of Radix Polygalae (Polygala tenuifolia Willd.) as the active ingredient.
|
|---|---|---|---|
|
Gastrointestinal disorders
DRY MOUTH
|
0.00%
0/22 • 8 weeks
|
4.3%
1/23 • Number of events 1 • 8 weeks
|
8.3%
2/24 • Number of events 2 • 8 weeks
|
|
Infections and infestations
COVID-19
|
0.00%
0/22 • 8 weeks
|
8.7%
2/23 • Number of events 2 • 8 weeks
|
12.5%
3/24 • Number of events 3 • 8 weeks
|
|
Nervous system disorders
HEADACHE
|
0.00%
0/22 • 8 weeks
|
0.00%
0/23 • 8 weeks
|
8.3%
2/24 • Number of events 2 • 8 weeks
|
|
Nervous system disorders
LETHARGY
|
0.00%
0/22 • 8 weeks
|
0.00%
0/23 • 8 weeks
|
8.3%
2/24 • Number of events 2 • 8 weeks
|
|
Cardiac disorders
PALPITATIONS
|
9.1%
2/22 • Number of events 2 • 8 weeks
|
0.00%
0/23 • 8 weeks
|
4.2%
1/24 • Number of events 3 • 8 weeks
|
|
Cardiac disorders
TACHYCARDIA
|
0.00%
0/22 • 8 weeks
|
0.00%
0/23 • 8 weeks
|
8.3%
2/24 • Number of events 2 • 8 weeks
|
|
Gastrointestinal disorders
ABDOMINAL DISTENSION
|
4.5%
1/22 • Number of events 1 • 8 weeks
|
8.7%
2/23 • Number of events 2 • 8 weeks
|
4.2%
1/24 • Number of events 1 • 8 weeks
|
|
Gastrointestinal disorders
DIARRHOEA
|
13.6%
3/22 • Number of events 3 • 8 weeks
|
4.3%
1/23 • Number of events 2 • 8 weeks
|
0.00%
0/24 • 8 weeks
|
Additional Information
Results disclosure agreements
- Principal investigator is a sponsor employee
- Publication restrictions are in place