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Active, not recruitingNCT05851365Updated May 4, 2026

Magnetic Resonance (MR) Imaging With Hyperpolarized Bicarbonate (13C) to Measure Tissue pH in Prostate Cancer

An Early Phase 1 interventional study of Hyperpolarized Bicarbonate (13C) and Magnetic Resonance imaging in Prostate Cancer and Localized Prostate Carcinoma, sponsored by Robert Flavell, MD, PhD. Active, not recruiting at 1 site in United States. Open to male participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-05-04.

Sponsored by Robert Flavell, MD, PhD · Early Phase 1, Interventional, and Diagnostic

Phase
Early Phase 1
Study type
Interventional
Enrollment
1
Allocation
Not applicable
Ages
18 Years and older
Sex
Male
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Study summary

This is a single site, prospective pilot study to determine the feasibility and safety of the administration of HP 13C bicarbonate in 10 patients with prostate cancer to determine potential hydrogen (pH) values in surrounding tissue. The proposed study will evaluate pre-surgical participants with histologically confirmed localized prostate cancer who receive infusion of hyperpolarized 13C injection prior to MR imaging with endorectal coil.

Read the detailed description

PRIMARY OBJECTIVE:

I. To determine the feasibility of tumor pH measurement in men with prostate cancer using hyperpolarized 13C bicarbonate imaging.

SECONDARY OBJECTIVE:

I. To determine the safety of administration of hyperpolarized 13C-bicarbonate.

EXPLORATORY OBJECTIVES:

I. To correlate the measurement of tissue pH with pathologic grade.

II. To correlate tissue pH maps with immunohistochemistry staining (IHC), gene expression (RNA-Seq), and spatial transcriptomics. *Bristol Myers Squibb (BMS) collaboration

OUTLINE:

Men with biopsy-proven adenocarcinoma of the prostate scheduled to undergo radical prostatectomy at University of California, San Francisco (UCSF) within 12 weeks of enrollment will receive infusion with hyperpolarized 13C bicarbonate and undergo metabolic MR imaging with endorectal coil. Participants will be followed for 5-9 days after the hyperpolarized 13C-bicarbonate injection, or removal from study, or until death, whichever occurs first. Participants removed from study for unacceptable study related adverse event(s) will be followed until resolution or stabilization (as determined by the investigator) or until initiation of new anti-cancer therapy, whichever occurs first.

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Conditions studied

  • Prostate Cancer
  • Localized Prostate Carcinoma

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Keywords

  • Tissue pH
  • Magnetic Resonance (MR) Imaging
03

In context

Prostatic Neoplasms

6,370 studies on the registry are indexed under Prostatic Neoplasms; 1,400 are open to participants now.

This study's enrollment of 1 is below the median of 58 across 4,822 interventional studies indexed under Prostatic Neoplasms.

Browse Prostatic Neoplasms studies →

Lead sponsor

Robert Flavell, MD, PhD is the lead sponsor of 6 studies on the registry; 3 are open to participants now.

Counted across the registry records on this site, refreshed daily.

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Who can participate

Ages eligible
18 Years and older
Sexes eligible
Male
Accepts healthy volunteers
No

Inclusion criteria

  1. Patients age >=18 years.
  2. Patients must have biopsy-proven adenocarcinoma of the prostate; biopsy may be performed outside of University of California, San Francisco (UCSF) if detailed results of sextant biopsy are available.
  3. Tumor size of at least 1.0 cm in long axis on Magnetic resonance imaging (MRI) or ultrasound; if no prior imaging is available, at least 3 cores positive on biopsy.
  4. Patients must have planned radical prostatectomy at UCSF within 12 weeks following protocol MRI/ magnetic resonance spectroscopy imaging) (MRSI).
  5. Eastern Cooperative Oncology Group (ECOG) Performance Status of 0 or 1.
  6. Demonstrates adequate organ function as defined below:

    1. Adequate bone marrow function:

      • Absolute neutrophil count >=1,500 cells/µL.
      • Platelets >=75,000 cells/µL.
      • Hemoglobin >=9.0 gm/dL.
    2. Adequate hepatic function:

      • Total bilirubin \<1.5x upper limits of normal (ULN) (within normal institutional limits, unless elevated due to Gilbert's syndrome and direct bilirubin is within normal limits).
      • Aspartate aminotransferase (AST)/serum glutamic-oxaloacetic transaminase (SGOT) \<=1.5 X institutional upper limit of normal.
      • Alanine aminotransferase (ALT)/serum glutamic-pyruvic transaminase (SGPT) \<=1.5 X institutional upper limit of normal.
    3. Adequate renal function:

      • Creatinine clearance >= 50 calculated using the Cockcroft-Gault equation, unless data exists supporting safe use at lower kidney function values, no lower than 30 mL/min/1.73 m\^2.
  7. Ability to understand and the willingness to sign a written informed consent document.

Exclusion criteria

Exclusion Criteria:

  1. Patients who because of general medical or psychiatric condition, or physiologic status, cannot give valid informed consent.
  2. Patients unwilling or unable to undergo MR imaging, including patients with contraindications to Magnetic resonance imaging (MRI) as per UCSF radiology departmental guidelines.
  3. Patients who cannot tolerate or have contra-indications to endorectal coil insertion, for example, patients with a prior abdominoperineal resection of the rectum or latex allergy.
  4. Patients with contra-indications to injection of gadolinium contrast as per UCSF radiology departmental guidelines.
  5. Patients who take carbonic anhydrase inhibitors (e.g. acetazolamide, dichlorphenamide, methazolamide).
  6. Metallic hip implant or any other metallic implant or device that distorts local magnetic field and compromises the quality of MR imaging.
  7. Cryosurgery, surgery for prostate cancer, prostatic or pelvic radiotherapy prior to study enrollment. No limit on number of prior prostate biopsies. Prior Transurethral Resection of the Prostate (TURP) is not allowed.
  8. Poorly controlled hypertension, with blood pressure at study entry >160/100. The addition of anti-hypertensives to control blood pressure is allowed for eligibility determination.
  9. Congestive heart failure or New York Heart Association (NYHA) status >= 2. A history of clinically significant electrocardiogram (EKG) abnormalities, including QT prolongation, a family history of prolonged QT interval syndrome, or myocardial infarction (MI) within 6 months of study entry. Patients with rate-controlled atrial fibrillation/flutter will be allowed on study.
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Study design

Phase
Early Phase 1
Primary purpose
Diagnostic
Allocation
Not applicable
Intervention model
Single group
Masking
None (open label)
Enrollment
1 participant (actual)

Study arms

  • Experimental
    Pre-surgical participants with prostate cancer

    The hyperpolarized 13C bicarbonate injection includes the administration of 35 mL injected intravenously (IV) at a rate of 5 mL/second followed by a 20 mL saline flush at 5 mL/second, followed by magnetic resonance (MR) imaging. The intervention will include routine and safety assessments 5 to 9 days after the injection.

    Drug: Hyperpolarized Bicarbonate (13C) · Procedure: Magnetic Resonance imaging

Interventions

  • DrugHyperpolarized Bicarbonate (13C)

    Given IV

    Also known as: Hyperpolarized (HP) bicarbonate 13 (13C), HP C13

  • ProcedureMagnetic Resonance imaging

    Magnetic resonance imaging is a medical imaging technique used in radiology to form pictures of the anatomy and the physiological processes of the body

    Also known as: Magnetic Resonance scan, MR scan

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What researchers measure

Primary outcomes

  1. Proportion of participants with a signal to noise ratio > 2

    The feasibility of a study will be determined by the ability to generate adequate signal to noise ratio to measure acidity (pH) in tumor or adjacent healthy tissue. This study will be considered successful if the 13C bicarbonate (CO2) and 13C-CO2 resonances in tumor or normal prostate are qualitatively detectable and signal to noise ratios are greater than 2. The point estimation and 95% confidence intervals (CI) of the participants having sufficient signal to noise ratio will be obtained using the Wilson Score confidence interval method.

    Time frame: Day of MR imaging (1 day)

Secondary outcomes

  1. Percentage of participants with reported treatment-emergent adverse events

    To assess the safety of the administration of hyperpolarized 13C bicarbonate; adverse events will be collected and recorded by type, severity (grade) and attribution according to the NCI Common Terminology Criteria for Adverse Events (CTCAE) version 5.0. The percentage of participants with grade 2 and higher, treatment-emergent adverse events will be reported.

    Time frame: Up to 9 days

07

Study locations

1 site
  • University of California, San Francisco
    San Francisco, California 94143, United States
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References and documents

Individual participant data

Plan to share: No

No publications or documents are linked to this record.

09

Updates

Tracking since Sep 25, 2026
No changes since tracking began. The registry record was last updated on May 4, 2026, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
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Registry details

Key details

Study ID
NCT05851365
Lead sponsor
Robert Flavell, MD, PhD
Collaborators
U.S. Army Medical Research Acquisition Activity, Bristol-Myers Squibb
Responsible party
Robert Flavell, MD, PhD (Principal Investigator, University of California, San Francisco) — Sponsor-investigator
First posted
May 9, 2023
Start date
Jul 6, 2023
Primary completion
Dec 31, 2027 (estimated)
Completion
Dec 31, 2027 (estimated)
Last update
May 4, 2026

Study contacts

Robert Flavell, MD, PhD
principal investigator · University of California, San Francisco

Oversight

Data monitoring committee
Yes
FDA-regulated drug
Yes
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

Not currently enrolling

This study is active, not recruiting, as verified in Apr 2026. You cannot join it, but the record below documents what was studied.

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