PDC-1421 Treatment in Adult Patients With ADHD

Part II is a double-blind, randomized, parallel-group, placebo-controlled study. The primary objective of this trial is to determine the effective doses and treatment period of PDC-1421 Capsule in subjects with ADHD. The secondary objective is to evaluate the safety of PDC-1421 Capsule in subjects receiving PDC-1421 at various dose levels.

The screening phase is intended for diagnosing and assessing the patient for possible inclusion in the study and for providing an adequate washout period.

At the first stage, a number of 69 subjects will be randomly assigned on a 1:1:1 basis to one of the three arms (1 PDC-1421 Capsule plus 1 placebo TID, 2 PDC-1421 Capsules TID, 2 placebo TID) for 8 weeks and evaluated the safety and efficacy every two weeks during the treatment period. An interim analysis will be conducted to evaluate the efficacy of PDC-1421 and to decide whether it is necessary to enter the second stage of the Part II study in which 30 subjects will be randomly assigned on a 1:1:1 basis to one of the three treatment arms and receive the same treatment.

Simple descriptive statistics with a 95% confidence interval will be performed with data collected in this study wherever applicable. The safety and efficacy data will be analyzed using the non-parametric method wherever appropriate.

The primary endpoint will be analyzed by chi-square test, while the secondary endpoints will be analyzed using the ANOVA or Kruskal-Wallis non-parametric ANOVA test for continuous endpoints and chi-square test for binary endpoints.

Eligibility Criteria:
Inclusion Criteria:

1. Aged 18-70 years
2. Female subjects of child-bearing potential must test negative to pregnancy and use appropriate birth control method from the beginning of study to the 15 days later after ending of study
3. Subjects must be able to understand and willing to sign informed consent
4. Able to discontinue the use of any psychotropic medications for the treatment of ADHD symptoms at screening
5. Meet strict operational criteria for adult ADHD according to the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5)
6. A total score of 28 or higher of ADHD Rating Scale-Investigator Rated (ADHD-RS-IV) at screening
7. Have a moderate or severe symptom of ADHD with score of 4 or higher in Clinical Global Impression- Severity (CGI-S) at screening

Exclusion Criteria:

1. Have any clinically significant concurrent medical condition (endocrine, renal, respiratory, cardiovascular, hematological, immunological, cerebrovascular, neurological, anorexia, obesity or malignancy) that has become unstable and may interfere with the interpretation of safety and efficacy evaluations
2. Have any clinically significant abnormal laboratory, vital sign, physical examination, or electrocardiogram (ECG) findings at screening that, in the opinion of the investigator, may interfere with the interpretation of safety or efficacy evaluations
3. Have known serological evidence of human immunodeficiency virus (HIV) antibody
4. Are pregnant as confirmed by a positive pregnancy test at screening
5. Have QTc values \>450 msec at screening using Fridericia's QTc formula
6. Have current of bipolar and psychotic disorders
7. Have a current major depression disorder, obsessive-compulsive disorder, post-traumatic stress disorder, generalized anxiety disorder, panic disorder and eating disorder (also if treated but not currently symptomatic) NOTE: Comorbid diagnoses identified during screening and baseline are acceptable provided that ADHD is the primary diagnosis and the comorbid diagnoses will not confound study data or impair subject's ability to participate (per the Investigator's judgement and documented in source note).
8. Have any history of a significant suicide attempt, or possess a current risk of attempting suicide, in the investigator's opinion, based on clinical interview and responses provided on the Columbia-Suicide Severity Rating Scale (C-SSRS).
9. Have a history of jailing or imprisonment in the past 6 months due to worsening of symptoms of ADHD