Data sourced from ClinicalTrials.gov (NIH registry) Updated weekly IRB-supervised studies only
Home/CA/Ontario
Updated July 2026 from ClinicalTrials.gov

Paid Clinical Trials in Ontario, CA

Studies commonly pay $75 to $4,500 per completed study

1,685 clinical trials are currently recruiting participants within 30 miles of Ontario. Listings below come straight from the official NIH registry, alongside the area's top-rated research centers with real Google reviews.

1,685studies recruiting
9+research centers nearby
5condition categories
Live from the NIH registry

Studies recruiting near Ontario right now

Top 25 of 1,685 recruiting studies, sorted by proximity — each links to its official registry page

Phase 3 Study of RLY-2608 + Fulvestrant vs Capivasertib + Fulvestrant as Treatment for Locally Advanced or Metastatic PIK3CA-mutant HR+/HER2- Breast Cancer

PIK3CA Mutation, HER2- Negative Breast Cancer Phase 3 Interventional 540 participants sought
City of Hope National Medical Center — Duarte, California (22.3 mi) · Sponsor: Relay Therapeutics, Inc.
See eligibility & contact on ClinicalTrials.gov (NCT06982521)

A Study Assessing Corneal Endothelial Cells in Participants With Neovascular Age-related Macular Degeneration (nAMD) Treated With the Port Delivery System With Ranibizumab (PDS)

Neovascular Age-related Macular Degeneration Phase 4 Interventional 188 participants sought
Orange County Retina Med Group — Santa Ana, California (25.2 mi) · Sponsor: Genentech, Inc.
See eligibility & contact on ClinicalTrials.gov (NCT04853251)

Fibromyalgia Response With Esreboxetine Evaluated Using a Randomized Withdrawal Research Design

Fibromyalgia Phase 3 Interventional 620 participants sought
Clinical Research Site — Santa Ana, California (25.2 mi) · Sponsor: Axsome Therapeutics, Inc.
See eligibility & contact on ClinicalTrials.gov (NCT07398417)

Phase 2, Efficacy and Safety Study of ACP-204 in Lewy Body Dementia Psychosis

Lewy Body Dementia Psychosis Phase 2 Interventional 180 participants sought
ATP Clinical Research Inc. — Irvine, California (28.4 mi) · Sponsor: ACADIA Pharmaceuticals Inc.
See eligibility & contact on ClinicalTrials.gov (NCT07029581)

A Phase 1 Study of UB-VV111 With and Without Rapamycin in Relapsed/Refractory CD19+ B-cell Malignancies

Lymphoma, B-Cell, Lymphoma, Non-Hodgkin (NHL) Phase 1 Interventional 106 participants sought
City of Hope — Duarte, California (22.3 mi) · Sponsor: Umoja Biopharma
See eligibility & contact on ClinicalTrials.gov (NCT06528301)

A Clinical Study of Belzutifan and Zanzalintinib in People With Recurrent Kidney Cancer Following Adjuvant Therapy (MK-6482-033)

Renal Cell Carcinoma Phase 3 Interventional 904 participants sought
Providence Medical Foundation ( Site 0141) — Fullerton, California (21.7 mi) · Sponsor: Merck Sharp & Dohme LLC
See eligibility & contact on ClinicalTrials.gov (NCT07227402)

A Study of NX-2127 in Adults With Relapsed/Refractory B-cell Malignancies

Chronic Lymphocytic Leukemia (CLL), Small Lymphocytic Lymphoma (SLL) Phase 1 Interventional 248 participants sought
City of Hope — Duarte, California (22.3 mi) · Sponsor: Nurix Therapeutics, Inc.
See eligibility & contact on ClinicalTrials.gov (NCT04830137)

Testing Different Dosing Schedules of the Anti-cancer Drug, Lutetium 177Lu PSMA RLT and Its Effect on Patients With Advanced Prostate Cancer, RECIPROCAL Trial

Metastatic Castration-Resistant Prostate Carcinoma, Metastatic Prostate Adenocarcinoma Phase 3 Interventional 1,524 participants sought
UC Irvine Health/Chao Family Comprehensive Cancer Center — Orange, California (22.4 mi) · Sponsor: Alliance for Clinical Trials in Oncology
See eligibility & contact on ClinicalTrials.gov (NCT07200830)

BAFFR-targeting CAR T Cells for Patients With Relapsed or Refractory B-NHL

Relapsed or Refractory B-cell Non-Hodgkin's Lymphoma Phase 1 Interventional 36 participants sought
City of Hope Medical Center — Duarte, California (22.3 mi) · Sponsor: PeproMene Bio, Inc.
See eligibility & contact on ClinicalTrials.gov (NCT05370430)

Phase 3 Extension Study to Evaluate Long-term Safety of Ianalumab in Participants With Systemic Lupus Erythematosus (SIRIUS-SLE Extension).

Systemic Lupus Erythematosus Phase 3 Interventional 550 participants sought
Advanced Medical Research — La Palma, California (28.5 mi) · Sponsor: Novartis Pharmaceuticals
See eligibility & contact on ClinicalTrials.gov (NCT06133972)

A Study to Learn How Avacincaptad Pegol (Izervay™) is Used in Clinical Practice in People Who Have Geographic Atrophy

Geographic Atrophy, Macular Degeneration N/A Observational 500 participants sought
University of California Irvine Medical Center — Orange, California (22.4 mi) · Sponsor: Astellas Pharma Global Development, Inc.
See eligibility & contact on ClinicalTrials.gov (NCT06779773)

Adjuvant Sacituzumab Govitecan and Nivolumab in Muscle-Invasive Urothelial Carcinoma at High-Risk Recurrence

Urothelial Carcinoma, Muscle-invasive Bladder Cancer Phase 2 Interventional 23 participants sought
Chao Family Comprehensive Cancer Center, University of California, Irvine — Orange, California (22.4 mi) · Sponsor: University of California, Irvine
See eligibility & contact on ClinicalTrials.gov (NCT06682728)

A Study of Sigvotatug Vedotin in Advanced Solid Tumors

Carcinoma, Non-Small Cell Lung, Squamous Cell Carcinoma of Head and Neck Phase 1 Interventional 1,006 participants sought
Providence Medical Foundation — Fullerton, California (21.7 mi) · Sponsor: Seagen, a wholly owned subsidiary of Pfizer
See eligibility & contact on ClinicalTrials.gov (NCT04389632)

Coordinating Outpatient bupreNorphiNe for Emergency Care and Continuing Treatment

Opioid Use Disorder N/A Interventional 3,492 participants sought
University of California Irvine Emergency Department — Irvine, California (28.4 mi) · Sponsor: University of California, Davis
See eligibility & contact on ClinicalTrials.gov (NCT07024498)

ENdoluminal LIGHT ActivatED Treatment of Upper Tract Urothelial Cancer (ENLIGHTED) Study

Transitional Cell Cancer of Renal Pelvis and Ureter Phase 3 Interventional 100 participants sought
University of California - Irvine Medical Center — Irvine, California (28.4 mi) · Sponsor: Steba Biotech S.A.
See eligibility & contact on ClinicalTrials.gov (NCT04620239)

Testing What Happens When an Immunotherapy Drug (Pembrolizumab) is Given by Itself Compared to the Usual Treatment of Chemotherapy With Radiation After Surgery for Recurrent Head and Neck Squamous Cell Carcinoma

Recurrent Head and Neck Squamous Cell Carcinoma, Recurrent Hypopharyngeal Squamous Cell Carcinoma Phase 2 Interventional 188 participants sought
Kaiser Permanente-Ontario — Ontario, California (3.0 mi) · Sponsor: National Cancer Institute (NCI)
See eligibility & contact on ClinicalTrials.gov (NCT04671667)

Study of AZD4512 Monotherapy or in Combination With Anticancer Agents in Participants With Acute Lymphoblastic Leukemia

B-cell Acute Lymphoblastic Leukemia (B-ALL) Phase 1, Phase 2 Interventional 83 participants sought
Research Site — Duarte, California (22.3 mi) · Sponsor: AstraZeneca
See eligibility & contact on ClinicalTrials.gov (NCT07109219)

Phase 2 Trial of Icovamenib in Participants With Type 2 Diabetes Who Are Not Achieving Glycemic Targets

Type 2 Diabetes Phase 2 Interventional 60 participants sought
Catalina Research Institute, LLC — Montclair, California (5.5 mi) · Sponsor: Biomea Fusion Inc.
See eligibility & contact on ClinicalTrials.gov (NCT07502495)

Comparison of Uncomplicated Candidemia Therapy Duration in Children

Invasive Candidiasis N/A Interventional 420 participants sought
Children's Hospital of Orange County — Orange, California (22.4 mi) · Sponsor: Arkansas Children's Hospital Research Institute
See eligibility & contact on ClinicalTrials.gov (NCT05763251)

PhI Pilot Study Pafolacianine Inject for Intraoperative Imaging on Outcomes of GI Cancer Peritoneal Carcinomatosis

Gastrointestinal Cancer, Peritoneal Carcinomatosis EARLY/Phase 1 Interventional 10 participants sought
Chao Family Comprehensive Cancer Center, University of California, Irvine — Orange, California (22.4 mi) · Sponsor: University of California, Irvine
See eligibility & contact on ClinicalTrials.gov (NCT06511037)
Google-rated

Top-rated research centers in Ontario

Dedicated clinical research sites near you — with their real Google ratings, reviews and contact details

Catalina Research Institute

★ 4.5
9525 Monte Vista Ave Ste 200, Montclair, CA 91763
(909) 590-8409
"Hi my name is Lionel Thomas I value innovation, data, and helping people, participating in a clinical trial with Catalina Research Institute has been…"
— Lionel Thomas, 5★

Brio Clinical

★ 3.6
1910 S Archibald Ave # U, Ontario, CA 91761
(951) 465-3500
"It seems like the staffing team doesn't really know how to properly update or communicate regarding referrals—or perhaps they just don't prioritize t…"
— Dezza Barredo-Alcala, 1★

Empire Clinical Research

★ 4.2 (39 reviews)
2740 N Garey Ave #203, Pomona, CA 91767
(909) 981-5321
"Absolutely awful.. the staff is very good, kind, but they waste your time and do not pay"
— Jeffrey Marquez, 1★

Dream Team Clinical Research

★ 5.0
1800 N Orange Grove Ave, Pomona, CA 91767
(714) 780-0076

WesternU Health Center for Clinical & Translational Research

★ 5.0
795 E 2nd St Second Floor, Suite 2003, Pomona, CA 91766
(909) 469-8626

Critical Care Research Inc

★ 5.0
10743 Civic Center Dr, Rancho Cucamonga, CA 91730
(909) 987-3883
"Now look at my problem<br>Hello I am interested in attending the Friday May 29 @ 1pm information session @ University of South Alabama. My Bachelor o…"
— Kel Moy, 5★

Prospective Research Innovations Inc.

★ 5.0
8577 Haven Ave Suite 301, 8577 Haven Ave #301, Rancho Cucamonga, CA 91730
(626) 559-2770
"I've had an amazing experience with Prospective Research. The staff were really nice and caring, and the facilities were top-notch. Everything was re…"
— Ajwa Khalil, 5★

Infinity Clinical Research

★ 3.5
1901 Town and Country Dr Ste 104, Norco, CA 92860
(714) 252-6689
"I just completed a year-long clinical research trial and had an excellent experience! The staff at the Norco location were always professional, knowl…"
— Jonnine Eras, 5★

National Institute of Clinical Research - Pomona

★ 5.0
630 N Park Ave, Pomona, CA 91768
(909) 766-8042
"Awesome clinical trial office the staff are incredible courteous and professional lots of trials to participate in or be on the list. All in all tops…"
— James Marquez, 5★

Clinical trials in Ontario: what's recruiting

The Ontario area currently has 1,685 studies open to new participants, according to the ClinicalTrials.gov registry maintained by the U.S. National Institutes of Health. Among the studies closest to Ontario, the most active research areas are:

  • Cancer & Oncology13 studies
  • Liver & Kidney3 studies
  • Heart & Vascular2 studies
  • Immune & Skin1 studies
  • Diabetes & Metabolism1 studies

Every listing shows the study phase, the recruiting site and its distance from Ontario, and links to the official registry page where eligibility criteria and study contacts are published. Compensation is set by each sponsor: industry surveys report typical payments of $75 to $4,500 per completed study, with short observational studies at the low end and multi-visit or overnight Phase 1 studies at the high end.

How to enroll in a paid study in Ontario

Start with a study whose condition matches your profile — or a healthy-volunteer study if you have no diagnosis. Contact the research site through the registry page, complete a short phone screen, then attend an in-person screening visit. If you qualify, the study team walks you through the informed consent document, which details every procedure, risk and payment before you commit. You can withdraw at any point, and enrollment is always free.

Ontario participants can also register with the dedicated research centers listed above — many maintain volunteer databases and call when a matching study opens — or sign up for our email alert below to hear when a new study starts recruiting within 30 miles of your ZIP code.

Frequently asked questions

Are clinical trials in Ontario safe?
Every trial on this page is registered on ClinicalTrials.gov, the official NIH registry, and is overseen by an Institutional Review Board (IRB). Before joining you receive an informed consent document detailing procedures, risks and compensation. Participation is voluntary and you can withdraw at any time.
How do I join a study in Ontario, CA?
Pick a study that matches your profile, contact the research site (or apply through the study links on this page), pass a phone pre-screen, then attend an in-person screening visit. If you qualify, you review and sign the informed consent and the study begins. The process typically takes 1-3 weeks.
Is compensation for clinical trials taxable?
In the U.S., clinical trial compensation is generally considered taxable income, and research sites may issue a 1099 form for payments above $600 in a year. Reimbursements for travel or meals are typically treated differently. Consult a tax professional for your situation.
What is the difference between a research center and a hospital study in Ontario?
Dedicated research centers (listed on this page with their Google ratings) run studies as their core business — often healthy-volunteer and vaccine studies with structured compensation. Hospital and university studies tend to focus on patients with specific conditions. Both types are registered and IRB-supervised.
Can I be in more than one clinical trial at a time?
Generally no — most studies exclude participants currently enrolled in another trial, and paid Phase 1 studies enforce a washout period (often 30 days or more) between studies. Frequent healthy volunteers in Ontario typically complete one or two studies per year.

Paid clinical trials near Ontario

Other metros within reach

Rancho Cucamonga, CA1,457 Pomona, CA3,119 Fontana, CA958 Corona, CA1,557 Riverside, CA934 Anaheim, CA3,155 San Bernardino, CA464 Fullerton, CA3,223

More of CA

Long Beach3,341 Torrance3,236 Fullerton3,223 Anaheim3,155 Garden Grove3,152 Pomona3,119 Glendale2,957 Los Angeles2,943 Huntington Beach2,841 Santa Clarita2,395 Hayward2,256 Oakland2,249

New paid studies open every week

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