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

6,766

Recruiting Now

6,766

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

Stroke (105) Breast Cancer (102) Cancer (74) Prostate Cancer (73) Heart Failure (72) Obesity (57) Colorectal Cancer (53) Lung Cancer (52) Healthy (50) Hypertension (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

NCT07153614 N/A

Efficacy of Perioperative Opioid Sparing Techniques on Time to Initiation of Che...

Perioperative Opioid Sparing Techniques

University of Tennessee Gradua

NCT05724121 N/A

Observational Study of Cardiac Arrhythmias During Treatment With BTK Inhibitors ...

Chronic Lymphocytic Leukemia (CLL)

National Heart, Lung, and Bloo

NCT06731114 N/A

"Additional Effects of Sternocleidomastoid Release Along With Suboccipital Muscl...

Cervicogenic Headache

Foundation University Islamaba

NCT07629206 N/A

Post-Marketing Study for Early-Stage Low-Risk Breast Cancer Treatment Using ProS...

Low-Risk, Early Stage Breast Cancer

IceCure Medical Ltd.

NCT07249333 N/A

Perioperative Complications After Neoadjuvant Radiotherapy for Colorectal Cancer

Colorectal Cancer

Oncology Institute of Vojvodin

NCT06269952 N/A

Intimate Partner Violence Among People Who Inject Drugs - Prevalence, Risk Facto...

Intimate Partner Violence (IPV)

Region Stockholm

NCT06492148 N/A

Myofascial Release Technique in Women With Primary Dysmenorrhea

Dysmenorrhea Primary

Turkey (Türkiye)

Gazi University

NCT06007248 N/A

Disease Characteristics of IR-CAD: a Case-control Study

Coronary Artery Disease

Peking Union Medical College H

NCT05446155 N/A

BioMEL- Diagnostic and Prognostic Factors in Melanoma.

NCT06979843 N/A

Evaluation of a Psychosocial Support Model for Adolescents and Young Adults Newl...

Karolinska Institutet

NCT07719517 N/A

Morning Activation to Improve Mood After Stroke

The Hong Kong Polytechnic Univ

NCT06663917 N/A

Clinical Evaluation of Frequency Allocation for Bimodal CI Users

Hearing Impairment

NYU Langone Health

NCT05416489 N/A

C-MAC Videolaryngoscopy Versus Direct Laryngoscopy for Percutaneous Tracheostomy

Intubated Patients

Hospital Clinico Universitario

NCT04558450 N/A

Covid-19 Effects on Arterial Stiffness and Vascular Aging (CARTESIAN)

Assistance Publique - Hôpitaux

NCT06664450 N/A

Brain Fog in Sleep Apnea

Obstructive Sleep Apnea

Fondazione Don Carlo Gnocchi E

NCT07551791 N/A

Suction vs Underwater Seal for HemoPneumoThoraX Trial

Hemothorax; Traumatic

Vanderbilt University Medical

NCT07729891 N/A

Real-time Evaluation and Continuous Observation of Vital Signs for Enhanced Reco...

Postoperative Complication

Azienda Ospedaliero-Universita

NCT06202118 N/A

A Study of Diffusing Alpha Radiation Therapy for Patients With Breast Carcinoma ...

Alpha Tau Medical LTD.

NCT04330118 N/A

Origin and Function of Eosinophilic Polynuclear During DRESS Syndrome

Drug Hypersensitivity

University Hospital, Lille

NCT07281118 N/A

Intercostal Cryoanalgesia in Double Lung Transplant Recipients

Post-operative Pain Management

University of California, Los

NCT03586518 N/A

Validating Novel, Non-contrast Cardiac MRI Imaging in Haemodialysis Patients

End Stage Kidney Disease

University of Leicester

NCT02880618 N/A

BAROSTIM THERAPY™ in Heart Failure With Reduced Ejection Fraction

NCT07119710 N/A

Telehealth to Improve Quality of Life in Persons Living in Rural Texas

Mental Health Issue

Texas Tech University

NCT03807310 N/A

Targeted Nutrient Supplement in COPD (NUTRECOVER-trial)

Pulmonary Disease, Chronic Obstructive

Maastricht University Medical

NCT05562310 N/A

Phenylalanine, Methionine and Histidine Requirements in TPN Fed Neonates

Stable Neonates

The Hospital for Sick Children

Page 1 of 271 — 6,766 trials total

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: September 2026 · Data Methodology