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

6,814

Recruiting Now

6,814

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

Breast Cancer (108) Stroke (98) Cancer (89) Heart Failure (64) Obesity (61) Prostate Cancer (56) Healthy (54) Anxiety (51) Hypertension (48) Coronary Artery Disease (48)

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

NCT02670031 N/A

Response of the Myocardium to Hypertrophic Conditions in the Adult Population

Left Ventricular Hypertrophy

National Heart Centre Singapor

NCT07083531 N/A

Bone Loss, Physical Function and Frailty in Older Women With Sickle Cell Trait S...

Sickle Cell Disease

NCT01730131 N/A

Natural History Study of Progressive Multifocal Leukoencephalopathy (PML)

Progressive Multifocal Leukoencephalopathy

National Institute of Neurolog

NCT05723653 N/A

Hybrid Type I Effectiveness-Implementation Trial of a Social Network Support Int...

HIV Seropositivity

University of Chicago

NCT06881953 N/A

Prevention Strategy for Respiratory Syncytial Virus (RSV) Infections in Infants ...

Assistance Publique - Hôpitaux

NCT06195553 N/A

Application and Effectiveness of the STEPPS in Patients with BPD, Extending to T...

Borderline Personality Disorder (BPD)

Universitat Jaume I

NCT07321353 N/A

Survivors Journey+

Pediatric Brain Tumor

Children's Hospital Medical Ce

NCT04920253 N/A

Real World Evidence with the Debritom+ TM Novel Micro Water Jet Technology At a ...

Diabetic Foot Ulcer

NCT07751172 N/A

Evaluation of Orthokeratology Lenses With a 5MM Optic Zone Diameter

United States, Spain

CooperVision International Lim

NCT06780995 N/A

Power Exercise for Stroke Recovery: The POWER Pilot Trial (POWER-P)

McMaster University

NCT04641039 N/A

Postoperative Scar in the Control Excess of Mobility Induced by Annulus Removal ...

Lumbar Disc Disease

University of Valencia

NCT05725239 N/A

taVNS or TMS or Both for Depression

Medical University of South Ca

NCT06060639 N/A

Variation of Echocardiographic Parameters After Red Blood Cell Transfusion in Em...

Centre Hospitalier Universitai

NCT07212777 N/A

Precision of Pacient-specific Instrumented Open Wedge High Tibial Osteotomy vs C...

Arthritis (Knee)

University of Malaga

NCT06409975 N/A

Feasibility and Acceptability of Mindful Self-Compassion Among Transgender and N...

University of Rhode Island

NCT06778512 N/A

LcProt: Proteomics Longitudinal Cohort Study on Lung Cancer

The First Affiliated Hospital

NCT07924436 N/A

Whole-Body Vibration Training in Women With Obesity With and Without Type 2 Diab...

Turkey (Türkiye)

Pamukkale University

NCT07442734 N/A

Auricular Stimulation for Functional Dyspepsia With Insomnia: Efficacy and Mecha...

Functional Dyspepsia

The First Affiliated Hospital

NCT07219264 N/A

Mental Health CPR for Cancer Survivors

Mental Health Care

Ponce Medical School Foundatio

NCT04523909 N/A

Trajectory of Neuroinflammatory Markers in Cerebrospinal Fluid Prior to and Afte...

Postoperative Delirium

Radboud University Medical Cen

NCT07055009 N/A

Multi-centred Clinico-genetic Study of Actinic Prurigo in Thailand

Actinic Prurigo

Chulalongkorn University

NCT06786663 N/A

MALE Mamm Organoids

Breast Neoplasms, Male

Regina Elena Cancer Institute

NCT04940663 N/A

Neurobehavioral Mechanisms of Social Isolation and Loneliness in Serious Mental ...

Massachusetts General Hospital

NCT04427163 N/A

Assesment of Multiomics Profiles in Health and Disease.

Genetic Predisposition to Disease

The Institute of Molecular and

NCT07463287 N/A

High-Risk Transcriptome Molecular Prediction Study of MASH-Associated Colorectal...

MASH - Metabolic Dysfunction-Associated Steatohepatitis

Shanghai East Hospital

Page 3 of 273 — 6,814 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