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
RESET-SLE: A Phase 1/2 Open-Label Study to Evaluate the Safety and Efficacy of CABA-201 in Subjects With Active Systemic Lupus Erythematosus
Cabaletta Bio
- Location
- Orange, CA + 17 other US sites
- Eligibility basics
- Ages 12–65
- RecruitingPhase 1
A Study to Assess Sulbactam-durlobactam in Pediatric Patients With Acinetobacter Baumannii-calcoaceticus Complex Infection
Innoviva Specialty Therapeutics
- Location
- Los Angeles, CA + 3 other US sites
- Eligibility basics
- Ages 0 mo–18
- RecruitingPhase 1
A Phase 1b, Open-Label Study of DISC-3405 in Participants With Sickle Cell Disease (SCD)
Disc Medicine, Inc
- Location
- San Francisco, CA + 10 other US sites
- Eligibility basics
- Ages 18+
- RecruitingPhase 1/Phase 2
A Study of Oral Nuvisertib (TP-3654) in Patients With Myelofibrosis
Sumitomo Pharma America, Inc.
- Location
- Duarte, CA + 29 other US sites
- Eligibility basics
- Ages 18+
- RecruitingPhase 1/Phase 2
Clinical Study of SNK01 in Participants With Moderate Alzheimer's Disease
NKGen Biotech, Inc.
- Location
- Glendale, CA + 5 other US sites
- Eligibility basics
- Ages 40–85
- RecruitingPhase 1
A Study to Evaluate the Efficacy and Safety of Cannabidiol Oral Solution (CBD-OS [GWP42003-P, JZP926]) for the Treatment of Focal-Onset Seizures
Jazz Pharmaceuticals
- Location
- La Jolla, CA + 20 other US sites
- Eligibility basics
- Ages 12–75
- RecruitingPhase 1
A Phase 1 AAV Gene Therapy Trial Evaluating Safety and Preliminary Efficacy of RP-A701 in Subjects With BAG3 Dilated Cardiomyopathy
Rocket Pharmaceuticals Inc.
- Location
- San Diego, CA + 2 other US sites
- Eligibility basics
- Ages 18–65
- RecruitingPhase 1/Phase 2
A Study of AAVB-039 in Participants With Stargardt Disease (STGD1)
AAVantgarde Bio Srl
- Location
- Los Angeles, CA + 7 other US sites
- Eligibility basics
- Ages 8–55
- RecruitingPhase 1
NEXUS Study: A Study to Test Single and Multiple Doses of MER511 Given to Adults With Graves' Disease
Merida Biosciences
- Location
- Torrance, CA + 10 other US sites
- Eligibility basics
- Ages 18–65
- RecruitingPhase 1
A Study of SGT-212 Gene Therapy in Friedreich's Ataxia
Solid Biosciences Inc.
- Location
- Los Angeles, CA + 2 other US sites
- Eligibility basics
- Ages 18–40
- RecruitingPhase 1
A Phase 1 Study of VK3019 in Overweight and Obese Adults Without Comorbidities
Viking Therapeutics, Inc.
- Location
- Lake Forest, CA
- Eligibility basics
- Ages 18–60
- RecruitingPhase 1
A Study of the Feasibility, Safety and Tolerability of Aticaprant as Adjunctive Treatment in Participants With Schizophrenia
Janssen Research & Development, LLC
- Location
- Garden Grove, CA + 7 other US sites
- Eligibility basics
- Ages 18–55
- RecruitingPhase 1
A Study to Assess the Safety, Tolerability, and Pharmacokinetics of GIGA-2339 in Participants With Chronic Hepatitis B Virus Infection
GigaGen, Inc.
- Location
- Huntington Beach, CA + 10 other US sites
- Eligibility basics
- Ages 18+
- RecruitingPhase 1/Phase 2
Safety, PK/PD, and Exploratory Efficacy Study of AMT-191 in Classic Fabry Disease
UniQure Biopharma B.V.
- Location
- Los Angeles, CA + 9 other US sites
- Eligibility basics
- Ages 18–65 · Men only
- RecruitingPhase 1/Phase 2
Safety and Tolerability of Subretinally Injected OPGx-BEST1 in Patients With Best Vitelliform Macular Dystrophy (BVMD) or Autosomal-Recessive Bestrophinopathy (ARB)
Opus Genetics, Inc
- Location
- Los Angeles, CA + 3 other US sites
- Eligibility basics
- Ages 18+
- RecruitingPhase 1
A Phase 1 Study of VK2735 in Obese Adults Without Comorbidities
Viking Therapeutics, Inc.
- Location
- Lake Forest, CA + 1 other US site
- Eligibility basics
- Ages 18–60
- RecruitingPhase 1
A Study to Investigate the Safety and Pharmacodynamics of a Single Intrathecal Injection (IT) of INS1202 in Participants With Amyotrophic Lateral Sclerosis (ALS)
Insmed Gene Therapy LLC
- Location
- La Jolla, CA + 6 other US sites
- Eligibility basics
- Ages 18–79
- RecruitingPhase 1
Study of GS-0415 and How It Works in People With HIV
Gilead Sciences
- Location
- Los Angeles, CA + 14 other US sites
- Eligibility basics
- Ages 18–65
- RecruitingPhase 1
A Study to Learn How Different Amounts of the Study Medicine Called PF-08642534 Are Tolerated and Act in the Body of People Who Have Obesity
Pfizer
- Location
- Lake Forest, CA
- Eligibility basics
- Ages 18–70
- RecruitingPhase 1/Phase 2
A First-in-human Study of KK8123 in Adults With X-linked Hypophosphatemia
Kyowa Kirin Co., Ltd.
- Location
- San Francisco, CA + 3 other US sites
- Eligibility basics
- Ages 18–65
- RecruitingPhase 1/Phase 2
Treatment of Participants With Primary or Secondary Progressive Multiple Sclerosis
Tr1X, Inc.
- Location
- La Jolla, CA + 7 other US sites
- Eligibility basics
- Ages 18–65
- RecruitingPhase 1/Phase 2
A Phase I/II Trial of JR-446 in Mucopolysaccharidosis Type IIIB (MPS IIIB)
JCR Pharmaceuticals Co., Ltd.
- Location
- Oakland, CA
- Eligibility basics
- Up to age 5
- RecruitingPhase 1
A Study to Assess the Concentration of Bimekizumab in Mature Breast Milk From Mothers Receiving Treatment With Bimzelx® (Bimekizumab)
UCB Biopharma SRL
- Location
- Santa Monica, CA + 5 other US sites
- Eligibility basics
- Ages 18+ · Women only
- RecruitingPhase 1
Study Evaluating Safety, Tolerability, PK/PD of Surovatamig in Adult RA or SLE Participants
AstraZeneca
- Location
- Fullerton, CA + 2 other US sites
- Eligibility basics
- Ages 18–65
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.