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

NCT07674277 N/A

Virtual Reality for SCD VOC

Sickle Cell Disease

University of Maryland, Baltim

NCT07322757 N/A

Outcomes-Based Health Program for Type 2 Diabetes

Type 2 Diabetes

Kuopio University Hospital

NCT04578301 N/A

Predicting Acute-on-Chronic Liver Failure After Surgical Intervention in Chronic...

Liver Cirrhosis

University Hospital, Bonn

NCT06039501 N/A

The Family Perspectives Project Pilot Trial

Respiratory Failure

NCT06978712 N/A

Impact of Periodontal Inflammation on Allostatic Load

Allostatic Load

Postgraduate Institute of Dent

NCT06586281 N/A

Elucidating Shared Mechanisms Contributing to NAFLD and PsA Disease Severity Wit...

Psoriatic Arthritis

University of California, San

NCT06717230 N/A

Digital, Conventional, And Biomimetic Approaches for Restoring Endodontically Tr...

Endodontically Treated Teeth

October University for Modern

NCT05187312 N/A

Registry for Advanced Endoscopy

Cholangiocarcinoma

Region Stockholm

NCT06651112 N/A

The ATP Project (Antipsychotic-TEP-Psychosis)

First Episose Psychosis

Université de Sherbrooke

NCT05842928 N/A

Patient-centred Deprescribing of Psychotropic, Sedative and Anticholinergic Medi...

Deprescriptions

Ludwig-Maximilians - Universit

NCT07819565 N/A

Effects of Pork Protein on Recovery Following Simulated Fireground Activity

Exercise Recovery

Sam Houston State University

NCT06776965 N/A

Ultra Processed Foods Consumption and Impact in Rheumatic Diseases.

Rheumatoid Arthritis

Hospices Civils de Lyon

NCT06703567 N/A

IMproving PAtient UndeRstanding of GEP TEst Results: Phase 4

European Institute of Oncology

NCT07922967 N/A

Proton Re-irradiation in Patients With Recurrent or Second Primary Head and Neck...

Head & Neck Cancer

Oslo University Hospital

NCT07520136 N/A

Evaluation of the Effect of a Structured Yoga Exercise in Young Women With Prima...

Primary Dysmenorrhea

Turkey (Türkiye)

Ankara University

NCT07554911 N/A

Detection and Optimization of Treatment of Severe Cases of Dry Eye Disease

Singapore National Eye Centre

NCT06785311 N/A

Native Spirit: Significant Aim 3: Intervention

Arizona State University

NCT07576244 N/A

Effects of Core Stabilization Exercises and Myofascial Induction Therapy in Post...

Riphah International Universit

NCT06372899 N/A

Noncombustible Nicotine Delivery Systems as Potential Harm Reduction Tools for P...

E-cigarette Use

Abramson Cancer Center at Penn

NCT05309863 N/A

Comparison Between the Efficacy of Residential and Ambulatory Weight Loss Progra...

Pediatric Non-alcoholic Fatty Liver Disease

University Hospital, Ghent

NCT05451563 N/A

Double-S: a Wearable Device for Erectile Dysfunction

Erectile Dysfunction

Stanford University

NCT06245187 N/A

Get With the Guidelines Atrial Fibrillation Registry

Atrial Fibrillation

American Heart Association

NCT06924593 N/A

Study on the Trans-Carotid Artery Occlusion Shunt System

Revascularization

Shenzhen Wecan Medical Technol

NCT06942221 N/A

Digital Solutions in Heart Therapy (DIGNITY)

Heart Failure With Reduced Ejection Fraction

University Hospital, Basel, Sw

NCT06474533 N/A

Fluoroethyltyrosine for the Evaluation of Intracranial Neoplasm

Intracranial Neoplasm

Page 6 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