Clinical Trials / Browse by Phase / N/A (Early Phase / Not Applicable)

Browse by Phase

N/A (Early Phase / Not Applicable) Clinical Trials

Browse currently recruiting N/A (Early Phase / Not Applicable) clinical trials registered on ClinicalTrials.gov.

Total Trials

6,771

Recruiting Now

6,771

Top Conditions in N/A (Early Phase / Not Applicable)

Breast Cancer (110) Stroke (104) Obesity (80) Cancer (65) Heart Failure (63) Prostate Cancer (53) Lung Cancer (52) Healthy (51) Depression (49) Hypertension (47)

Frequently Asked Questions — N/A (Early Phase / Not Applicable) Trials

What does "N/A" mean for a clinical trial phase?

"N/A" or "Not Applicable" in the phase field indicates the trial does not follow the traditional Phase 1–4 drug development pathway. This applies to observational studies, epidemiological research, behavioral interventions, device studies, or exploratory work not yet assigned a formal phase. These studies are still registered on ClinicalTrials.gov and follow IRB-approved protocols.

Are N/A phase trials safe to participate in?

N/A phase trials encompass a wide range of study types, many involving minimal risk—such as observational studies, questionnaire-based research, or registry enrollment. Some may involve investigational devices or early-stage interventions. Review the trial's protocol, risks and benefits section, and informed consent documents carefully before enrolling. All ClinicalTrials.gov-registered studies must comply with applicable safety oversight requirements.

How do I find N/A phase trials for my condition?

Browse ClinicalMetric by condition to find all trials—regardless of phase—that are recruiting for a specific disease. Many N/A phase trials are observational or behavioral studies with fewer eligibility restrictions than phase-designated drug trials, making them more accessible to a broader range of participants.

Active N/A (Early Phase / Not Applicable) Studies

NCT06779435 N/A

A Multicenter, Prospective, Real-world Study of a Regimen Containing Tucidinosta...

Ruijin Hospital

NCT04114435 N/A

Pulmonary Vascular Disease and Cardiac Performance in Extreme Preterm Infants

Prematurity; Extreme

McGill University Health Centr

NCT06915935 N/A

Epidemiological Study of Osteoporosis in the Elderly Population of Shandong Prov...

The Second Hospital of Shandon

NCT03979235 N/A

Developing Effectiveness Evaluation and Therapeutic Programs of Rehabilitation

Healthy Volunteers

National Research Center for R

NCT07261735 N/A

Clinical Evaluation of Customized Attachment Composites in Clear Aligner Therapy

Clear Aligner Therapy

Turkey (Türkiye)

Saglik Bilimleri Universitesi

NCT06790108 N/A

Validation of an AI-Assisted Mediastinal EUS System for Training Improvement: a ...

Mediastinal Disease

The Third Xiangya Hospital of

NCT06591117 N/A

The Vizio Clinical Study

Refractory Glaucoma

NCT07750717 N/A

Bedside Spirometry for Acute Lung Injury

Respiratory Insufficiency

Centre Hospitalier Departement

NCT07304050 N/A

Predicting ICU Transfers and Other Unforeseen Events (PICTURE)-Pediatric

Clinical Deterioration

University of Michigan

NCT03465774 N/A

Indwelling Pleural Catheters With or Without Doxycycline in Treating Patients Wi...

Pleural Neoplasm

M.D. Anderson Cancer Center

NCT06096233 N/A

Effect of Exercise on Appetite in Response to Meals

University of Glasgow

NCT06972147 N/A

Prevalence and Description of FIRE (Food Induced Immediate Response of the Esoph...

Eosinophilic Esophagitis

University Hospital, Angers

NCT02851758 N/A

Transplantation of Autologously Derived Mitochondria Following Ischemia

Extracorporeal Membrane Oxygenation Complication

Boston Children's Hospital

NCT06032455 N/A

Effectiveness of Multisystemic Therapy for Adolescents From Families With Intell...

Behavioural Problems

NCT07040215 N/A

Effects on Subacute Stroke With Robotic Assistive Gait Training

Changhua Christian Hospital

NCT07495735 N/A

Intelligence System for Predicting Atezolizumab-Bevacizumab Response and Clinica...

HCC - Hepatocellular Carcinoma

First Affiliated Hospital of W

NCT06850025 N/A

Heat Waves, Urban Heat Islands, and Wellbeing and Health: a Mobile Sensing Appro...

General Population, no Specific Condition

Institut National de la Santé

NCT07827417 N/A

Comparative Effects of Reactive Balance Training and Task-Oriented Training on P...

Diabetic Neuropathies

Foundation University Islamaba

NCT07256717 N/A

BPIT 5-Week Multi-Site Study: Movement Efficiency, Mobility & Neuromuscular Adap...

Physical Fitness

United States, India

MMSx Authority Institute for M

NCT07092540 N/A

The Baby Duchenne Study: Characterizing Developmental and Clinical Outcomes in t...

Duchenne Muscular Dystrophy (DMD)

University of Rochester

NCT06163989 N/A

Protecting the Eyes of Gamers With Lubricating Eyedrops

Dry Eye Syndromes

Aston University

NCT05619068 N/A

The Evolution and Prognosis of Moyamoya Disease

Moyamoya Disease

Chinese PLA General Hospital

NCT07286968 N/A

Gastro-Intestinal Digestion and Physiology After Bariatric Surgery

Bariatric Surgery

Universitaire Ziekenhuizen KU

NCT05340868 N/A

Genetics of the Acute Response to Oral Semaglutide

Medical University of Bialysto

NCT04833491 N/A

Study of the Correlation Between Preoperative Precise Biometrics, Spatial Assess...

Recruitment of Participants

Second Affiliated Hospital, Zh

Page 14 of 271 — 6,771 trials total

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ClinicalMetric — Independent clinical trial intelligence platform. Not affiliated with NIH, ClinicalTrials.gov, the U.S. FDA, or any pharmaceutical company, hospital, or clinical research organization. Trial data is sourced from ClinicalTrials.gov for informational purposes only and does not constitute medical advice. Do not make any treatment, enrollment, or health decisions based solely on information found here — always consult a qualified healthcare professional. Full Disclaimer · Last Reviewed: November 2026 · Data Methodology