Phase 1 · California
Phase 1 clinical trials in California
262 studies have at least one recruiting site in California. Phase 1 (and early Phase 1) trials are usually the first time a medicine is studied in people. They are typically small, closely monitored, and many are run in dedicated research units, sometimes with overnight stays.
262 recruiting studiesSource: ClinicalTrials.gov, refreshed October 26, 2026How we list studies
Studies
- RecruitingPhase 1/Phase 2
Study to Evaluate Safety, Efficacy and Immunogenicity of Acne mRNA Vaccine in Participants With Mild Acne
Sanofi Pasteur, a Sanofi Company
- Location
- Encino, CA + 3 other US sites
- Eligibility basics
- Ages 18–45
- RecruitingPhase 1/Phase 2
A Study of SGT-003 Gene Therapy in Duchenne Muscular Dystrophy (INSPIRE DUCHENNE)
Solid Biosciences Inc.
- Location
- Los Angeles, CA + 11 other US sites
- Eligibility basics
- Ages 0 mo–17 · Men only
- RecruitingPhase 1
A Study to Learn if Bimekizumab Given in Different Ways is Safe and Moves Similarly Throughout the Body Over Time in Adults
UCB Biopharma SRL
- Location
- Apple Valley, CA + 29 other US sites
- Eligibility basics
- Ages 18+
- RecruitingPhase 1/Phase 2
Gene Correction in Autologous CD34+ Hematopoietic Stem Cells (HbS to HbA) to Treat Severe Sickle Cell Disease
Kamau Therapeutics
- Location
- Los Angeles, CA + 5 other US sites
- Eligibility basics
- Ages 12–50
- RecruitingPhase 1/Phase 2
A Phase 1b/2 Study of CAR T Cell Therapy Targeting CD19 and BCMA in Participants With Relapsed or Refractory AL Amyloidosis.
Alexion Pharmaceuticals, Inc.
- Location
- San Francisco, CA + 9 other US sites
- Eligibility basics
- Ages 18+
- RecruitingPhase 1
A Study of CDX-622 in Participants With Mild to Moderate Asthma
Celldex Therapeutics
- Location
- San Francisco, CA + 3 other US sites
- Eligibility basics
- Ages 18+
- RecruitingPhase 1
Study of Single Doses of SBT777101 in Subjects With Rheumatoid Arthritis
Sonoma Biotherapeutics, Inc.
- Location
- San Francisco, CA + 8 other US sites
- Eligibility basics
- Ages 18–70
- RecruitingPhase 1
A Study on the Safety and Immune Response of Investigational mRNA Seasonal Flu/COVID-19 Combination Vaccine in Adults
GlaxoSmithKline
- Location
- Fair Oaks, CA + 11 other US sites
- Eligibility basics
- Ages 65–85
- RecruitingEarly Phase 1
VTP-1000 in Adults With Celiac Disease
Barinthus Biotherapeutics
- Location
- Los Angeles, CA + 15 other US sites
- Eligibility basics
- Ages 18–70
- RecruitingPhase 1
R-3750 in Patients With Mild to Moderate Ulcerative Colitis
Rise Therapeutics LLC
- Location
- Valencia, CA + 4 other US sites
- Eligibility basics
- Ages 18–65
- RecruitingPhase 1
R-2487 in Patients With Rheumatoid Arthritis
Rise Therapeutics LLC
- Location
- San Diego, CA + 5 other US sites
- Eligibility basics
- Ages 18–75
- RecruitingPhase 1
A Study of Efimosfermin Alfa in Adults With Hepatic Impairment
GlaxoSmithKline
- Location
- Rialto, CA + 2 other US sites
- Eligibility basics
- Ages 18–70
- RecruitingPhase 1/Phase 2
A Study Exploring Changes in a Variety of Biomarkers Following Dosing With MT1988 in Participants at Clinical High Risk for Psychosis
Monument Therapeutics Limited
- Location
- Irvine, CA + 14 other US sites
- Eligibility basics
- Ages 17–30
- RecruitingPhase 1/Phase 2
A Phase 1/2 Study of NKX019 in Subjects With Autoimmune Disease (Ntrust-1)
Nkarta, Inc.
- Location
- Tustin, CA + 15 other US sites
- Eligibility basics
- Ages 18–75
- RecruitingPhase 1/Phase 2
Study of EXE-346 Live Biotherapeutic to Reduce High Bowel Movement Frequency in Subjects With an IPAA (PROF)
Exegi Pharma, LLC
- Location
- Los Angeles, CA + 7 other US sites
- Eligibility basics
- Ages 18+
- RecruitingPhase 1
A Phase 1 Study of FT819 in B-cell Mediated Autoimmune Disease
Fate Therapeutics
- Location
- Beverly Hills, CA + 15 other US sites
- Eligibility basics
- Ages 12–70
- RecruitingPhase 1
Evaluating ER-100 for Safety in People With Glaucoma or Non-Arteritic Anterior Ischemic Optic Neuropathy (Optic Nerve Conditions)
Life Biosciences Inc.
- Location
- Glendale, CA + 3 other US sites
- Eligibility basics
- Ages 40–85
- RecruitingPhase 1
A Single Bolus, 12-hour Euglycemic Clamp Study of the Safety, Pharmacokinetics (PK) and Glucodynamics (GD) of Intraperitoneal (IP) Portal Insulin U-500
Portal Diabetes, Inc.
- Location
- Chula Vista, CA
- Eligibility basics
- Ages 18–60
- RecruitingPhase 1/Phase 2
A Study of AAV9 Gene Therapy in Participants With Canavan Disease (CANaspire Clinical Trial)
Aspa Therapeutics
- Location
- Oakland, CA + 2 other US sites
- Eligibility basics
- Up to age 2
- RecruitingPhase 1
A Phase 1, Dose Escalation Trial of RP-A601 in Subjects With PKP2 Variant-Mediated Arrhythmogenic Cardiomyopathy (PKP2-ACM)
Rocket Pharmaceuticals Inc.
- Location
- La Jolla, CA + 1 other US site
- Eligibility basics
- Ages 18+
- RecruitingPhase 1/Phase 2
Phase 1/2 Open-Label Dose-Escalation Study to Evaluate Safety of a Single Intravitreal Injection of RTx-021 in Patients With Stargardt Disease
Ray Therapeutics, Inc.
- Location
- Bakersfield, CA + 2 other US sites
- Eligibility basics
- Ages 16+
- RecruitingPhase 1
AMX0114 in Adult Participants With Amyotrophic Lateral Sclerosis
Amylyx Pharmaceuticals Inc.
- Location
- La Jolla, CA + 9 other US sites
- Eligibility basics
- Ages 18+
- RecruitingPhase 1
Study to Evaluate the Safety and Efficacy of CSB-001 Ophthalmic Solution 0.1% in Subjects With Corneal Scars
Claris Biotherapeutics, Inc.
- Location
- Loma Linda, CA + 6 other US sites
- Eligibility basics
- Ages 18–80
- RecruitingPhase 1/Phase 2
A Study to Assess the Long-term Safety and Clinical Activity of mRNA-3927 in Participants Previously Enrolled in the mRNA-3927-P101 Study
ModernaTX, Inc.
- Location
- Palo Alto, CA + 5 other US sites
- Eligibility basics
- Ages 1+
Who these studies look for
Phase 1 studies often have narrow eligibility: specific age and weight ranges, no recent participation in another study, no nicotine, and limits on medications. Some Phase 1 studies recruit patients rather than healthy volunteers, so check each listing.
Matching a page like this one never means you qualify. Each research team decides eligibility at screening.
Questions
Are Phase 1 trials riskier?
Every study carries risk. Phase 1 studies involve less human data about the product, which is why they are closely monitored. The informed consent document explains the known risks; read it carefully and ask questions before signing.
Why do some Phase 1 studies include overnight stays?
Staying in the unit lets staff dose on a precise schedule and collect samples around the clock. Where a record mentions an inpatient stay we flag it on the listing.