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Study of Benfooxythiamine Monosodium Added to Lutetium‑177 Vipivotide Tetraxetan in Adults with Metastatic Castration‑Resistant Prostate Cancer and Stable Disease

Verified siteInvestigationalNo placebo
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What is this trial about?

A plain-language summary of the goals, design and what participants do

The study examines adults with advanced prostate cancer that continues to grow despite hormone therapy, known as metastatic castration-resistant prostate cancer. These individuals have already received two cycles of a standard radioactive drug treatment called Pluvicto®, which contains lutetium (177Lu) vipivotide tetraxetan. The trial adds an oral capsule named Benfo-oxythiamine (code name B‑OT) to evaluate its potential benefit.

The purpose is to determine a safe dose of the new capsule when used together with the standard therapy and to assess whether it helps control the cancer.

Participants who meet the disease criteria will keep receiving their regular Pluvicto® infusions while taking the test capsule in gradually increasing amounts during the early phase. Once the appropriate dose is identified, patients will continue that dose alongside the standard therapy for several cycles, with regular check‑ups, blood tests, and imaging scans to monitor side effects and any changes in the cancer.

The research process

The trial runs in 7 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Enrollment and Baseline Assessments

    After joining the study, you will undergo a series of baseline examinations to confirm eligibility and record your current health status. These examinations include blood tests, physical measurements, and imaging studies.

    Your medical history and current medications will be reviewed, and you will receive information about the study procedures.

  2. Step 2

    First Study Treatment Cycle

    On Day 1 of the first cycle, you will receive the standard cancer therapy Pluvicto® by intravenous infusion, as prescribed in your regular treatment plan.

    At the same time, you will start taking the investigational drug Benfo‑oxythiamine (B‑OT) in hard capsule form. The exact dose will be assigned by the study protocol and taken orally as directed.

  3. Step 3

    Daily Oral Benfo‑oxythiamine Administration

    You will take the assigned dose of Benfo‑oxythiamine each day for the duration of the 21‑day treatment cycle. The capsules are swallowed with water and should be taken at the same time each day.

    If the study reaches a higher dose level, the amount of the drug may be increased in later cycles according to the dose‑escalation schedule.

  4. Step 4

    Safety Monitoring During the 21‑Day Cycle

    Throughout the 21‑day period, you will have regular visits for safety checks. These include blood samples to measure drug levels and organ function, physical examinations, vital‑sign measurements, and an electrocardiogram (ECG) to assess heart activity.

    Any side effects, known as adverse events, will be recorded and graded according to standard criteria.

  5. Step 5

    Subsequent Treatment Cycles and Dose Escalation

    If the initial dose is well tolerated, you may receive additional cycles of Pluvicto® together with a higher dose of Benfo‑oxythiamine as defined by the dose‑escalation plan. Each cycle repeats the 21‑day schedule described above.

    Safety monitoring is performed in every cycle to determine the recommended dose for later phases of the study.

  6. Step 6

    Efficacy Evaluations

    At predefined times, imaging studies (such as CT scans or PET scans) will be performed to assess the size of cancer lesions.

    Blood tests for prostate‑specific antigen (PSA) will be taken to evaluate changes in tumor activity.

    These assessments help determine whether the combination therapy is having a beneficial effect.

  7. Step 7

    Study Completion and Final Assessments

    After the planned number of cycles or if the study ends early, you will undergo a final set of examinations similar to the baseline assessments.

    The results of safety and efficacy evaluations will be compiled to inform the next stage of research.

Who can join the trial?

11 criteria

  • Willing and able to read, understand, and sign the informed consent (a document that explains the study and shows you agree to join).
  • Have an Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 2 (a scale that measures how well you can do daily activities, where 0 means fully active and 2 means you can take care of yourself but cannot work).
  • Expected to live at least 3 months, as judged by the doctor (life expectancy).
  • Be at least 18 years old when signing the consent.
  • Have prostate cancer that was confirmed by a tissue test showing adenocarcinoma (a type of cancer that starts in gland cells).
  • Diagnosed with metastatic castration‑resistant prostate cancer (mCRPC) and have low testosterone (<50 ng/dL) or be receiving androgen deprivation therapy (ADT) such as hormone injections, drugs that block hormone signals (gonadotropin‑releasing hormone analogues or antagonists), or have had both testicles removed (bilateral orchiectomy).
  • Show a positive result on a PSMA‑PET/CT scan (a special imaging test that looks for a protein called PSMA on cancer cells) that matches the approved use of Pluvicto®.
  • Previously received treatments that block the androgen receptor (androgen receptor pathway inhibition, ARPi) and chemotherapy that includes taxanes (taxane‑based chemotherapy), as required for Pluvicto® use.
  • Completed the first two cycles of standard Pluvicto® therapy and, in the doctor’s opinion, remain eligible to continue more cycles.
  • Have stable disease on a follow‑up scan, meaning the cancer has not grown, according to RECIST 1.1 criteria (a set of rules doctors use to measure tumor size on scans).
  • Have at least one measurable metastatic lesion (a tumor spot that can be measured) seen on the follow‑up contrast‑enhanced high‑resolution CT scan after the first two cycles of Pluvicto®.

Who cannot join the trial?

11 criteria

  • Has a scan result showing a complete response, partial response, or disease that is getting worse (progressive disease) on a detailed CT scan after the first two cycles of Pluvicto, compared with the scan taken before treatment. (CT = a special X‑ray that creates detailed pictures of the inside of the body; complete response (CR) = no visible cancer; partial response (PR) = cancer has shrunk; progressive disease = cancer has grown; RECIST 1.1 = a standard set of rules doctors use to judge these changes.)
  • Is taking any other cancer medicines at the same time, such as chemotherapy, targeted therapy, immunotherapy, or radiotherapy. (These are different ways to treat cancer that are not part of the study drug.)
  • Has received an experimental drug or medical device within the last 4 weeks, or within five drug “half‑lives” (the time it takes for half of the drug to leave the body), whichever is shorter, before the first dose of B‑OT.
  • Shows new cancer spots on a special PET scan that looks for PSMA (a protein often found on prostate cancer cells), defined as six or more new bone, lymph‑node, or lung spots, or any new spot in the liver or other organs, after the first two cycles of Pluvicto. (PSMA‑PET = a scan that highlights cancer cells that have the PSMA protein; lesion = a spot of disease.)
  • Has symptoms or untreated/unstable compression of the spinal cord, or cancer that has spread to the brain or the thin membranes covering the brain and spinal cord (leptomeningeal metastases), unless the brain spots have been treated, are stable on recent imaging, and cause no symptoms.
  • Has a heart test (ECG) that shows a prolonged QT interval (QTcF > 470 ms) or a past episode of a dangerous heart rhythm called Torsade de Pointes. (ECG = a test that records the heart’s electrical activity; QTc = a measurement of heart rhythm timing; Torsade de Pointes = a specific type of abnormal fast heartbeat.)
  • Has received a blood transfusion or growth‑factor medication only to meet lab test limits within 4 weeks before the first B‑OT dose.
  • Has ongoing side effects from previous cancer treatment that are at least grade 2 in severity (moderate), except for hair loss or other stable grade‑2 side effects that the doctor considers acceptable. (Grade 2 = moderate severity; CTCAE v6.0 = the standard system doctors use to rate side‑effect severity.)
  • Has had another type of cancer in the past 2 years, except for common skin cancers called basal‑cell or squamous‑cell carcinoma.
  • Cannot swallow pills or has stomach or intestinal problems that would prevent the study medication from being absorbed properly.
  • Is known to be allergic (hypersensitive) to B‑OT or any of its inactive ingredients.
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Investigated drugs

  • Benfo-Oxythiamine (B-OT)

    is an experimental oral capsule being tested to see if it can help treat prostate cancer that has spread and no longer responds to hormone therapy. In this study, participants take the capsule together with their regular cancer medication. Researchers are looking at how safe the capsule is, how well patients tolerate it, and whether it improves the effect of the standard treatment.

  • Lutetium (177Lu) vipivotide tetraxetan (Pluvicto®)

    is an approved therapy for advanced prostate cancer. It is given by an injection and works by delivering targeted radiation directly to cancer cells that have a specific marker. In this trial, it is used as the standard of care that all participants receive, and the new drug is added on top of it to see if the combination works better.

What is already known about the treatment

  • Benfo-Oxythiamine

    This investigational drug is taken orally in a hard‑filled capsule. It is not yet approved and is currently being studied in early‑phase clinical trials for metastatic castration‑resistant prostate cancer. Benfo‑oxythiamine works by blocking a key enzyme that cancer cells use to process sugars, which can slow their growth. It belongs to the class of metabolic enzyme inhibitors, specifically a thiamine (vitamin B1) analog.

  • Lutetium‑177 vipivotide tetraxetan (Pluvicto)

    This medication is given by a slow intravenous injection. It is an approved radiopharmaceutical used for men with metastatic castration‑resistant prostate cancer who have progressed after other treatments. The drug delivers tiny amounts of radioactive lutetium directly to cancer cells by binding to a protein called PSMA, thereby destroying the cells with targeted radiation. It is classified as a targeted radioligand therapy.

Investigated diseases

Metastatic castration‑resistant prostate cancer (mCRPC) - This is prostate cancer that has spread beyond the prostate gland and continues to grow even when testosterone levels are very low. The disease typically progresses from an earlier stage to involvement of bones, lymph nodes, or other organs. Tumor growth is reflected by rising prostate‑specific antigen levels and visible lesions on imaging studies. Over time, the cancer can become more widespread, leading to further organ involvement.
Trial detailsLast updated 19 Oct 2026
Age18+ yearsPhasePhase ITrial ID2026-527059-25-00Protocol codeBV-01-106Estimated enrolment48 patients

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