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

NCT07463742 N/A

Transcriptomic Profile Changes in Benign Tracheal Stenosis: Wedge Resection vs. ...

Tracheal Stenosis

University of Maryland, Baltim

NCT04274283 N/A

Tessa Jowell BRAIN MATRIX - Platform Study

University of Birmingham

NCT07239141 N/A

Two Video Laryngoscopes (Laringocel® and C-MAC®) for First-Attempt Intubation in...

Airway Management

NCT05364294 N/A

Molecular Diagnosis of Systemic Autoinflammatory Diseases

Inflammatory Disease

Institut National de la Santé

NCT07602894 N/A

Analgesia for Perineal Surgeries in High-risk Pediatric Patients

Zagazig University

NCT07258056 N/A

GUidance In Prostate Cancer DEtection With 18F-PSMA-1007-PET/MRI and Targeted Bi...

Prostate Cancer

Mads Ryo Jochumsen

NCT06699394 N/A

Prospective Study of Teclistamab in the Treatment of Systemic AL Amyloidosis

Peking University People's Hos

NCT07845656 N/A

A Home-based Multicomponent Exercise Intervention Program Based on the Fogg Beha...

Osteosarcopenia; Frailty; Older Adults

NCT06472310 N/A

Clinical and demOgRaphic Features of Patients With Uncontrolled Severe Asthma in...

NCT06829160 N/A

mHealth-CArdiac REhabilitation for INOCA

NYU Langone Health

NCT05834920 N/A

Effects of Neurofeedback and Transcranial Pulse Stimulation on Attention

Attention Difficulties

The University of Hong Kong

NCT05200182 N/A

fNIRS-based Neurofeedback Intervention for Cognitive Control Improvement in Emot...

Rennes University Hospital

NCT07014124 N/A

Smoking Cessation for Fathers of Sick Children

Cigarette Smoking

The University of Hong Kong

NCT06963723 N/A

Longitudinal Screening for Financial Hardship to Improve Outcomes in Patients Wi...

Advanced Cancer

United States, Puerto Rico

Alliance Foundation Trials, LL

NCT06641362 N/A

Ultra-High Frequency - Electrocardiogram (UHF-ECG) for the Diagnosis of Ventricu...

United States, Czechia, Netherlands

VDI Technologies

NCT07059546 N/A

Hypersensitivity to Adrenomedullin in Post-Traumatic Headache

Posttraumatic Headache

Danish Headache Center

NCT07192146 N/A

Patient Reported Outcomes and Associated Factors Following Endodontic Emergency ...

Moderate to Severe Endodontic Pain

Chulalongkorn University

NCT04345627 N/A

Japanese Lead Extraction Registry

Arrhythmia, Cardiac

National Cerebral and Cardiova

NCT03828773 N/A

PTX3-targeted Antifungal Prophylaxis

Belgium, France, Switzerland

Bochud Pierre-Yves

NCT07243769 N/A

A Pilot Randomized Controlled Trial Comparing Core Exercise, Aerobic Exercise, a...

Clinically Stable Myocardial Infarction or Heart Failure Patients

National Taiwan University Hos

NCT06211569 N/A

Study of the Prevalence of Endometriosis and Adenomyosis

Elective Fertility Preservation

Assistance Publique - Hôpitaux

NCT03840083 N/A

Sleep-dependent Learning in Aging

University of Massachusetts, A

NCT06604494 N/A

Rehabilitation Improved by Early Detection of Fisyulas Post (Pharyngo) -Total La...

Cancer, Otorhinolaryngeal

University Hospital, Clermont-

NCT06546813 N/A

Outcomes of ICT Assistive Technology in RehabiliTAtIoN Pathways

Communication Aids for Disabled

Fondazione Don Carlo Gnocchi E

NCT07419360 N/A

DRAIN: DRainage in Acute Decompensated Heart faIlure With Pleural effusioNs

Congestive Heart Failure(CHF)

Albany Medical College

Page 12 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