ClinicalTrials.gg
CompletedNCT03435952Updated Nov 3, 2026

Pembrolizumab With Intratumoral Injection of Clostridium Novyi-NT

A Phase 1 interventional study of Pembrolizumab and Clostridium Novyi-NT in Malignant Neoplasm of Breast, Malignant Neoplasms of Digestive Organs and Malignant Neoplasms of Eye Brain and Other Parts of Central Nervous System, sponsored by M.D. Anderson Cancer Center. Completed at 1 site in United States. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-11-03.

Sponsored by M.D. Anderson Cancer Center · Phase 1, Interventional, and Treatment

Updated Nov 3, 2026Now CompletedPrimary completion moved+1 moreGo to Updates ↓
Phase
Phase 1
Study type
Interventional
Enrollment
18
Allocation
Not applicable
Ages
18 Years and older
Sex
All
01

Where this study stands

Counted across the records on this site · 2026-11-12

Among 230 studies in Breast Neoplasms by M.D. Anderson Cancer Center — 29 open to participants now, 71 under way, 3 of them phase 3. Breast Neoplasms · M.D. Anderson Cancer Center.

Enrollment
133rd of 177
18 · median 40
Started
2018
with 5 others
Phase 1
34 of 230
5 open now
Registered
159th of 230
by date

Among the 230 studies in Breast Neoplasms by M.D. Anderson Cancer Center, this one is the 133rd largest by enrollment of the 177 interventional ones, is one of 6 that started in 2018, is one of 34 in phase 1, and was the 159th registered.

By phase

230 studies; the count open now beside each. This study's row is marked.

No phase61 · 10 open
Phase 255 · 5 open
Observational47 · 6 open
Phase 1this study34 · 5 open
Phase 312 · 1 open
Phase 1/211 · 0 open
Other kind6 · 1 open
Phase 2/33 · 1 open
Phase 41 · 0 open

By the year they started

First in 1995; this study’s year is marked. 6 started in 2018.

Size and results

Median enrollment 40 across the 177 interventional studies, 60 across the 53 observational. Of the 134 that completed or were terminated, 50 (37%) have results posted.

Watch this landscapeDownload CSVWith an account: a weekly mail of what changed among 230 studies in Breast Neoplasms by M.D. Anderson Cancer Center, or all of them as a file.
02

Study summary

Some tumors are difficult to treat with chemotherapy or radiation. One of the reasons is that areas of the tumor do not have many blood vessels, which makes it difficult for drugs to reach those areas. One way that researchers have recently tried to overcome this problem is by injecting special kinds of bacteria into the tumors. These bacteria have been genetically changed to remove the chemicals that are poisonous to humans, but are still able to cause tumor cells to break down and die. The idea is that these bacteria may be able to assist chemotherapy drugs in fighting cancer.

The goal of this clinical research study is to find the highest tolerable dose of one of these bacterial therapies (Clostridium novyi-NT spores) that can be given in combination with pembrolizumab to patients with advanced solid tumors. The safety of this drug will also be studied, as well as whether it can help to control the disease.

This is an investigational study. Clostridium novyi-NT is not FDA approved or commercially available. It is currently being used for research purposes only. Pembrolizumab is FDA approved for the treatment of melanoma and different types of head and neck and non-small cell lung cancers. It is investigational to use these drugs in combination with each other in various types of advanced cancers.

The study doctor can describe how the study drugs are designed to work.

Up to 18 participants will be enrolled in this study. All will take part at MD Anderson.

Read the detailed description

Study Drug Dose Levels:

If you are found to be eligible to take part in this study, you will be assigned to a dose level of Clostridium novyi-NT based on when you join this study. Up to 4 dose levels will be tested. Up to 6 participants will be enrolled at each dose level. The first group of participants will receive the lowest dose level of Clostridium novyi-NT. Each new group will receive a higher dose than the group before it, if no intolerable side effects were seen. This will continue until the highest tolerable dose of Clostridium novyi-NT is found, or all 4 dose levels are filled.

During the study, the supporting company (BioMed Valley Discoveries, Inc.) and study doctors may increase the number of patients in a dose group based on the available study results. This will not change your participation while on study.

All participants will receive the same dose level of pembrolizumab.

Study Drug Administration:

You will receive pembrolizumab by vein over about 30 minutes on Day 0 and then every 3 weeks for up to 12 months.

Clostridium novyi-NT will be injected into the tumor on Day 8. This is the only injection into the tumor you will receive. Your doctors may use an x-ray or ultrasound to help place the needle into the tumor. You will be in the hospital for 7 days to check for side effects, or possibly longer if your study doctor thinks it is needed. You will be able to go home if you have no signs or symptoms of infection. If the study doctor thinks it is needed (for example, based on your tests or any infection symptoms), you may need to return to the hospital at a later time.

Starting on Day 15, you will take an antibiotic (doxycycline) by mouth 2 times a day for the rest of your life to lower the risk of further growth of Clostridium novyi-NT. This is because the study drug is a changed form of bacteria. If you miss a dose or forget to take doxycycline, take it as soon as you can. If it is almost time for your next dose, wait until then to take it and you should skip the missed dose. Do not take an extra dose to make up for a missed dose.

If the doctor thinks it is needed, you will also take additional antibiotics, piperacillin/tazobactam and metronidazole. The antibiotic that is given and the length of time you need to take it will depend on your reaction to the study drug. You should still continue to take doxycycline. Your doctor will discuss this with you. You may receive piperacillin/tazobactam by vein over about 30 minutes and metronidazole by vein over about 30-60 minutes as often as your doctor tells you to, until your doctor thinks it is acceptable for you to change to taking the antibiotics by mouth. In some cases, if you need to receive antibiotics by vein for more than a week or two, your doctor may ask you to have a central venous catheter placed. A central venous catheter is a sterile flexible tube that will be placed into a large vein while you are under local anesthesia. Your doctor will explain this procedure to you in more detail, and you will be required to sign a separate consent form.

You may also be given other standard drugs to help decrease the risk of side effects. You may ask the study staff for information about how the drugs are given and their risks.

Length of Study Participation:

You may receive 1 dose of Clostridium novyi-NT and receive pembrolizumab every 3 weeks for up to 12 months. You will then have 12 months of follow-up after you receive the last dose of pembrolizumab. You will be taken off study early if the disease gets worse, if you have intolerable side effects, or if you are unable to follow study directions.

Your participation on the study will be over after the Month 12 post-dosing follow-up visit.

If you leave the study early, you or your family will be called every 3 months for up to 12 months to see how you are doing. These calls should last less than 30 minutes each time.

Study Visits and Calls:

For your safety, you must stay within 45 minutes driving distance from an emergency room and also have a caregiver available for at least 28 days after you receive your dose of Clostridium novyi-NT spores.

If an abscess (a swollen area of infection that contains pus) forms in the tumor and it needs to be drained, the study doctor may decide to collect some of the drainage for research tests to study the infection and test your immune system response.

Tumor biopsy samples (described below) may be collected at different times than listed, or not at all, depending on the inflammation around the tumor, the amount of tissue available, or how easily it can be collected.

On Days 0 and 1:

  • You will have a physical exam.
  • You will have an EKG to check your heart function.
  • You will have a biopsy sample collected from the target tumor before you receive pembrolizumab. The tumor sample will be used for biomarker testing, including genetic biomarkers and to check your body's inflammatory and immune responses to the study drug. Biomarkers are found in the blood/tissue and may be related to your reaction to the study drug. The type of biopsy you have will depend on the location of the disease. The study staff will describe this procedure in more detail, including its risks.
  • If you can become pregnant, you will have a blood (about 1 teaspoon) or urine pregnancy test.

On Day 8:

  • You will have a physical exam.
  • Blood (about 4 ½ tablespoons) will be drawn for routine tests, to find out how long the Clostridium novyi-NT spores and bacteria stay in your body, and to measure your risk for bacteremia at 1 hour and 12 hours after the study drug dose.

On Days 9-15 daily:

  • You will have a physical exam.
  • Blood (about 1½ teaspoons) will be drawn for routine tests.
  • You will have either a CT scan or MRI to check the status of the disease (Day 15 only).
  • If you have any skin lesions, photographs will be taken of these lesions.

After you leave the hospital and during the first 28 days after you receive Clostridium novyi-NT spores, the study staff will call you 1 time each day on the days you do not have study visits. You will be asked how you are doing. The calls should last less than 30 minutes each time.

On Days 18 and 25, you will have a physical exam.

On Days 21 and 28:

  • You will have a physical exam.
  • Blood (about 1½ teaspoons) will be drawn for routine tests.

On Days 35:

  • You will have a physical exam.
  • Blood (about 4 ½ tablespoons) will be drawn for routine tests, to check your body's inflammatory and immune system response to the study drug, to find out how long the Clostridium novyi-NT spores and bacteria stay in your body, and to measure your risk for bacteremia.

At Weeks 6, 9, 15, 24, 39, 45, and 48, you will have a physical exam.

Every 3 weeks beginning with Week 6, blood (about 1 tablespoon) will be drawn for routine testing.

Every 6 weeks beginning with Week 6:

  • You will have either a CT scan or MRI to check the status of the disease.
  • If you have any skin lesions, photographs will be taken of these lesions.

At Week 9, blood (about 1 teaspoon) will also be drawn for HLA testing.

At Week 12, you will have a tumor tissue biopsy sample collected of the injected tumor and a non-injected tumor for biomarker testing and to help learn how your body is responding to the study drug.

At Weeks 9, 24, 33 and 48, blood (about 4 ½ tablespoons) will be drawn for routine tests, to check your body's inflammatory and immune system response to the study drug, to find out how long the Clostridium novyi-NT spores and bacteria stay in your body, and to measure your risk for bacteremia.

The tests and procedures may be repeated anytime the doctor thinks it is needed.

End of Study Visit:

After you stop receiving the study drug(s):

  • Blood (about 3½ tablespoons) will be drawn for routine tests, to check your body's inflammatory and immune system response to the study drug, to find out how long the Clostridium novyi-NT spores and bacteria stay in your body, and to measure your risk for bacteremia.
  • You will have either a CT scan or MRI to check the status of the disease.
  • If you have any skin lesions, photographs will be taken of these lesions.

Follow Up Visit:

About 30 days after your last dose of pembrolizumab:

  • You will have a physical exam.
  • Blood (about 1 tablespoon) and urine will be collected for routine tests.
  • You will have either a CT scan or MRI to check the status of the disease. It will be repeated every 3 months for up to 12 months.
  • If you have any skin lesions, photographs will be taken of these lesions.

After the last follow-up visit, you or a family member will be called every 3 months for an additional year and asked about how you are doing. Each call should last about 15 minutes.

03

Conditions studied

  • Malignant Neoplasm of Breast
  • Malignant Neoplasms of Digestive Organs
  • Malignant Neoplasms of Eye Brain and Other Parts of Central Nervous System
  • Malignant Neoplasms of Female Genital Organs
  • Malignant Neoplasms of Ill-defined Secondary and Unspecified Sites
  • Malignant Neoplasms of Independent (Primary) Multiple Sites
  • Malignant Neoplasms of Lip Oral Cavity and Pharynx
  • Malignant Neoplasms of Male Genital Organs
  • Malignant Neoplasms of Mesothelial and Soft Tissue
  • Malignant Neoplasms of Respiratory and Intrathoracic Organs
  • Malignant Neoplasms of Thyroid and Other Endocrine Glands
  • Malignant Neoplasms of Urinary Tract

Keywords

  • Pembrolizumab
  • Keytruda
  • MK-3475
  • SCH-900475
  • Clostridium Novyi-NT
  • C. novyi-NT
  • Doxycycline
  • Vibramycin
  • Periostat
  • Doryx
  • Solid tumor malignancies
04

Who can participate

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

Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.

Inclusion criteria

  1. Diagnosis of an advanced solid tumor . There must be a target tumor which is measureable, palpable or clearly identifiable under ultrasound or radiographic guidance and amenable to percutaneous injection of C. novyi-NT spores. The targeted lesion must have a longest diameter >/= 1 cm and \< 12 cm and be measurable as defined by 1.1 criteria. The target lesion must not be located in either the thoracic, abdominal or pelvic cavities or in the brain. There must be no clinical, no functional, and no radiographic evidence of bone involvement at the site of the target lesion.
  2. History of prior treatment with at least one line of systemic anticancer therapy, when an approved systemic therapy is available, and no curative option is available for continued treatment.
  3. At least 4 weeks have elapsed since the completion of major surgery, and the patient has fully recovered from this surgery and any post-surgical complications.
  4. Patient must have adequate organ function as indicated by the following laboratory values. Hematological: (ANC) >/=1,500/mcL; >/=100,000/mcL; >/=9g/dL or >/= 5.6 mmol/L. Renal: Serum creatinine \</= 1.5 X (ULN. Hepatic: serum total \</= 1.5 X ULN OR Direct bilirubin \</= ULN for patients with total bilirubin levels > 1.5 ULN; (SGOT) and ALT (SPGT) \</= 2.5 X ULN OR \</= 5 X ULN for patients with liver . Coagulation: International Normalized ration () or Prothrombin Time (PT) \</= 1.5 X ULN unless patient is receiving anticoagulant therapy as long as PT of PTT is within therapeutic range of intended use of anticoagulants; Activated partial Thromboplastin Time (aPTT) \</= 1.5 X ULN unless patient is receiving anticoagulant therapy as long as PT of PTT is within therapeutic range of intended use of anticoagulants.
  5. (ECOG) performance status of 0 or 1.
  6. Patient is at least 18 years of age.
  7. Patient is capable of giving .
  8. Female patient of has a negative urine or serum pregnancy test. If the urine test is positive or cannot be confirmed as negative, a serum pregnancy test will be required. The serum pregnancy test must be negative for the patient to be eligible.
  9. Patient of childbearing potential is using either 2 adequate barrier methods or a barrier method plus a hormonal method of to prevent pregnancy or to abstain from heterosexual activity throughout the study, starting with Visit 1 through 120 days after the last dose of study therapy. Approved contraceptive methods include 2 of the following barrier methods or one barrier method combined with a hormonal contraceptive: a. Intra uterine device, diaphragm with spermicide, cervical cap with spermicide, male condoms, or female condom with spermicide. Spermicides or condoms alone are not an acceptable method of contraception. b. Male patients must agree to use an adequate method of contraception starting with the first dose of study drug through 120 days after the last dose of study therapy.
  10. Patient has no significant valvular heart disease (trace or mild valvular stenosis or regurgitation is allowed).
  11. Patient is able to stay within 45 minutes driving time of an emergency room for 28 days after dosing with C. novyi-NT.
  12. The patient has a caregiver for 28 days after dosing with C. novyi-NT.
  13. Patient has a tumor sample from C. novyi-NT planned injected tumor lesion (newly obtained ) for and immunologic response assessments. Patients must submit the tumor sample during screening at a central pathology laboratory.

Exclusion criteria

Exclusion Criteria:

  1. Patient who has had chemotherapy, radiation therapy, or biological cancer therapy within four weeks prior to the first dose of study drug, or who has not recovered to Grade 1 or better from the AEs due to cancer therapeutics administered more than four weeks earlier.
  2. Patient is currently participating or has participated in a study of an agent or using an investigational device within 30 days of the first dose of study drug. (A patient in the survival Follow up phase of an investigational agent where no further treatment is expected is eligible).
  3. Patient is on any systemic therapy within one week before the planned date for first dose of treatment or on any other form of medication.
  4. Documented primary brain or .
  5. Patient previously had a severe reaction to treatment with another mAb.
  6. Patient has an active disease or a documented history of autoimmune disease or syndrome that requires systemic steroids or immunosuppressive agents. Patients with vitiligo or resolved childhood asthma/atopy would be an exception to this rule. Patients that require intermittent use of bronchodilators or local steroid injections would not be excluded from the study. Patients with hypothyroidism stable on hormone replacement will not be excluded from the study.
  7. Patient has an active infection requiring systemic therapy.
  8. Patient has known history of (HIV) (HIV ½ antibodies).
  9. Patient has a known history of or is positive for (HBsAg reactive) or (HCV RNA [qualitative] is detected).
  10. Patient is pregnant or breastfeeding, or expecting to conceive or father children within the projected duration of the study.
  11. Patient has received a within 30 days prior to first dose.
  12. Patient has a foreign body which in the opinion of the treating investigator could be difficult to manage in case of infection.
  13. pleural effusion.
  14. Clinically significant pericardial effusion, circumferential pericardial effusion, or any effusion greater than 1.0 cm at any location around the heart.
  15. Need for ongoing treatment with an immunosuppressive agent.
  16. History of solid organ transplantation (with the exception of a corneal transplant > 3 months prior to screening).
  17. History of an ischemic insult in the previous 12 months (myocardial infarction, cerebral vascular accident, ischemic tissue from injury, ).
  18. History of a significant medical illness deemed by the PI as unsuitable for the trial. For example: i. Symptomatic congestive heart failure ii. Psychiatric Illness/social situation that may make study dangerous iii. Unstable angina pectoris.
  19. History of asplenia.
  20. Antibiotic allergies that would preclude treatment for a C. novyi-NT infection.
  21. Treatment with antibiotics within 2 weeks (14 days) of dosing.
  22. Oxygen saturation (Sp02) of less than 95% on room air.
  23. Mean arterial blood pressure (BP) of less than 70 mmHg.
  24. Glasgow Coma Score of less than 15.
  25. History of (non-infectious) pneumonitis that required steroids or current pneumonitis.
Terms in these criteria, in plain language(29)

Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.

Cancer (malignancy)

Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.

Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.

RECIST

The standard rules for measuring tumours on CT or MRI scans, to tell whether a cancer is shrinking, stable or growing during treatment.

“Measurable disease per RECIST 1.1” usually means at least one tumour 10 mm or more at its longest on a CT scan, or a lymph node 15 mm or more across its short axis.

Absolute neutrophil count (ANC)

The number of neutrophils, white blood cells that help fight infection, in a given amount of blood. Too few raises the risk of infection.

It is a count, not a percentage of the white cells. Limits are written in units that mean the same: ≥ 1.5 × 10⁹/L is ≥ 1,500 per mm³ (µL). Each lab has its own reference range.

Platelets

Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.

Hemoglobin (Hb)

The protein in red blood cells that carries oxygen. A low level is anaemia, which can cause tiredness and breathlessness. Measured in g/dL or g/L (9 g/dL is 90 g/L).

ULN (upper limit of normal)

The top of the normal range for a blood test, as set by the laboratory that runs it. Each lab prints its own range next to your result.

“≤ 2.5 × ULN” means the result can be up to two and a half times that top value.

Bilirubin

A yellow substance made when red blood cells are broken down, which the liver clears. A high level can mean a problem with the liver or the bile ducts.

Criteria often allow more for people with Gilbert’s syndrome, a harmless inherited condition that raises bilirubin.

ALT and AST (liver enzymes)

Two enzymes measured in a routine blood test of the liver. Higher levels can mean the liver is under strain or damaged. SGPT and SGOT are older names for ALT and AST.

Criteria usually give a limit as a multiple of the upper limit of normal (ULN), often higher when cancer has spread to the liver.

Metastases

Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.

INR, PT and aPTT (clotting tests)

Blood tests of how long blood takes to clot. The INR is the prothrombin time (PT) put on a common scale; about 1 is usual for someone not taking a blood thinner.

Criteria often make an exception for people on a blood thinner such as warfarin, whose INR is raised on purpose.

ECOG performance status

A scale of how much an illness limits everyday activity. For people being assessed to join a study, scores run from 0 (fully active) to 4; lower is more active.

0
Fully active, no restrictions.
1
Limited in strenuous activity, but walking and able to do light work, such as housework or office work.
2
Walking and able to look after yourself, but unable to work; up and about more than half of waking hours.
3
Able to look after yourself only in part; in bed or a chair more than half of waking hours.
4
Unable to look after yourself at all; in bed or a chair all day.

Studies most often ask for 0–1 or 0–2. Your doctor gives the score; the WHO scale uses the same steps. The full scale also has 5, which records death.

Informed consent

Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.

You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.

Childbearing potential

Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).

Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.

Contraception

Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.

Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.

Biopsy and archival tissue

A biopsy takes a small piece of tissue to examine. “Archival tissue” is a sample already taken, for example at diagnosis, and kept by the hospital.

Whether a stored sample will do depends on when it was taken, how much there is and what the study needs. Ask whether the study accepts your stored sample or needs a new biopsy.

PD-1, PD-L1 and checkpoint inhibitors

PD-1, PD-L1 and CTLA-4 are proteins that act as brakes on the immune system. Checkpoint inhibitors, such as pembrolizumab or nivolumab, block them so the immune system can attack a cancer.

PD-L1 can also be measured in a tumour sample. Some scores count stained tumour cells only (TPS); others also count certain immune cells (CPS). The study names the score and the minimum it uses.

CTCAE grade

The US National Cancer Institute’s scale of how severe an adverse event is — any unwanted medical event during a study, such as a symptom, an illness or an abnormal test result, whether or not a treatment caused it. Whether it did is judged separately.

1
Mild.
2
Moderate.
3
Severe.
4
Life-threatening.
5
Death due to the event.

“Side effects of earlier treatment resolved to grade 1 or less” means they have settled to mild or gone.

Investigational drug or device

A drug or device being studied in a clinical trial.

It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.

Corticosteroids (steroids)

Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.

Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.

Immunosuppression

A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.

Read whether the line is about a condition or about medicines, and which medicines and doses it means.

Brain metastases

Cancer deposits in the brain from a cancer that started elsewhere in the body (CNS metastases include the spinal cord).

Studies differ: some leave out any brain metastases, some accept ones treated and stable for some weeks. Check what this study allows.

Hypersensitivity

An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.

Autoimmune disease

A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.

Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.

HIV

The human immunodeficiency virus, which weakens the immune system.

Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.

Hepatitis B tests

Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.

Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.

Hepatitis C tests

Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.

After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.

Live vaccines

Vaccines made with a weakened form of the germ, such as measles–mumps–rubella (MMR), chickenpox and yellow fever. They can be risky when the immune system is weakened. Flu injections are not live; the nasal flu spray is.

Clinically significant

Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.

TIA (transient ischaemic attack)

A “mini-stroke”: temporary stroke-like symptoms caused by reduced blood flow to part of the brain, spinal cord or eye, without signs of a new stroke on a scan.

Stroke symptoms need emergency care at once, even if they go away.

05

Study design

Phase
Phase 1
Primary purpose
Treatment
Allocation
Not applicable
Intervention model
Single group
Masking
None (open label)
Enrollment
18 participants (actual)

Study arms

  • Experimental
    Pembrolizumab + Clostridium novyi-NT

    Participants receive Pembrolizumab by vein over about 30 minutes on Day 0 and then every 3 weeks for up to 12 months. Clostridium novyi-NT injected into the tumor on Day 8. Starting on Day 15, participant takes Doxycycline by mouth 2 times a day for the rest of participant's life to lower the risk of further growth of Clostridium novyi-NT

    Drug: Pembrolizumab · Biological: Clostridium Novyi-NT · Drug: Doxycycline

Interventions

  • 200 mg by intravenous infusion starting on Day 0, and continuing every 3 weeks for up to 12 months.

    Also known as: Keytruda, MK-3475, SCH-900475

  • BiologicalClostridium Novyi-NT

    Participants given a single dose of Clostridium Novyi-NT by intratumoral injection on Day 8. Clostridium Novyi-NT administered starting with Cohort 1 at a dose of 3 x 10\^4 spores followed by dose escalation.

  • Starting on Day 15, participant takes Doxycycline by mouth 2 times a day for the rest of participant's life to lower the risk of further growth of Clostridium novyi-NT

    Also known as: Vibramycin, Periostat, Doryx

06

What researchers measure

Primary outcomes

  1. Maximum Tolerated Dose (MTD) of Intratumoral Injection of Clostridium Novyi-NT with Pembrolizumab

    MTD defined as the highest dose studied in which the incidence of DLT was less than 33%.

    Time frame: 6 weeks

Secondary outcomes

  1. Preliminary Anti-Tumor Activity of Pembrolizumab in Combination with C. novyi-NT in the Injected Tumor and an Overall Response by RECIST 1.1

    Time frame: 6 weeks

07

Study locations

1 site
  • University of Texas MD Anderson Cancer Center
    Houston, Texas 77030, United States
08

References and documents

09

Updates

1 registry update since Sep 25, 2026
Status
Active, not recruiting→Completed
changed Nov 3, 2026
Primary completion
Oct 1, 2026→Oct 30, 2026 (actual)
Nov 3, 2026
Study completion
Oct 1, 2026→Oct 30, 2026 (actual)
Nov 3, 2026
Show all 1 update
  1. Nov 3, 2026
    Active, not recruiting→Completed
    Primary completion Oct 1, 2026→Oct 30, 2026 (now actual)
    Study completion Oct 1, 2026→Oct 30, 2026 (now actual)
    + 1 other change: verification date

From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗

10

Registry details

Key details

Study ID
NCT03435952
Collaborators
BioMed Valley Discoveries, Inc, Merck Sharp & Dohme LLC
Responsible party
Sponsor
First posted
Feb 19, 2018
Start date
Jul 10, 2018
Primary completion
Oct 30, 2026
Completion
Oct 30, 2026
Last update
Nov 3, 2026

Study contacts

Sarina Piha-Paul, MD, PHD
principal investigator · M.D. Anderson Cancer Center
Sarina Piha-Paul, MD
principal investigator · M.D. Anderson Cancer Center

Oversight

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

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This study is completed, as verified in Oct 2026. You cannot join it, but the record below documents what was studied.

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