CancerPhase 1/2(BLOOM)NCT07354100
Lactulose to Improve Gut Health in Cancer Patients Receiving Immunotherapy
A Phase 1/2 study testing Lactulose in people with Cancer, run by University of Chicago at 1 site in United States.
Trial summary
The purpose of this study is to see if lactulose can improve the effectiveness of immunotherapy in patients with advanced cancer. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Cancer
- What is being tested?
- Lactulose
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 55 participants
- Where
- 1 siteUnited States
- Study dates
- 15 Dec 2026to 13 Apr 2029
- Phase
- Phase 1/2
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Patients must have a histologically confirmed malignancy that is to receive exclusively ICIs (no chemotherapy or RT in combination) per standard of care during the time in which lactulose will be administered. This includes, but is not limited to, melanoma, cutaneous squamous cell carcinoma, non-small cell lung cancer, mesothelioma, head and neck squamous cell carcinoma, classical Hodgkin lymphoma, primary mediastinal large B-cell lymphoma, urothelial cancer, MSI/MMRd cancer, cancers with high tumor mutational burden (>=10 muts/mB), esophageal cancer, hepatocellular carcinoma, and renal cell carcinoma. Anti-PD-1 or anti-PD-L-1 therapy combinations with anti-LAG-3 or anti-CTLA-4 combinations are permitted.
- Age ≥18 years. Because no dosing or adverse event data are currently available on the use of lactulose in combination with ICIs in patients <18 years of age, children are excluded from this study.
- ECOG performance status ≤2 (Karnofsky ≥60%, see Appendix A).
- Patients must be able to ingest liquids.
- Patients must have a histologically confirmed cutaneous or mucosal melanoma. Uveal melanoma is excluded.
- Measurable disease per RECIST 1.1.32
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- Documented primary or acquired resistance to anti-PD-1 and anti-CTLA4 therapy per SITC guidelines.21 Primary resistance is defined as disease progression after a minimum of 6 weeks of therapy, provided the patient has received at least two full cycles of treatment, and there has been no prior evidence of clinical benefit (partial response, complete response, or stable disease lasting at least 6 months). Acquired resistance is defined as disease progression after an initial clinical benefit while still on therapy or within 12 weeks of discontinuing therapy, provided the patient received at least two cycles and 6 weeks of therapy.
- Patients with a prior or concurrent malignancy whose natural history or treatment does not have the potential to interfere with the safety or efficacy assessment of the investigational regimen are eligible for this trial.
- Planned to receive standard ICI therapy (no RT/ICI or chemotherapy/ICI combinations).
- Age ≥18 years. Because no dosing or adverse event data are currently available on the use of lactulose in combination with ICIs in patients <18 years of age, children are excluded from this study.
- ECOG performance status ≤2 (Karnofsky ≥60%, see Appendix A).
- Patients must be able to ingest liquids.
Who cannot join
- History of allergic reactions attributed to compounds of similar chemical or biologic composition to ICIs or lactulose.
- Current serious concomitant illnesses include cardiovascular diseases (such as uncontrolled congestive heart failure, hypertension, cardiac ischemia, myocardial infarction, and severe cardiac arrhythmias), bleeding disorders, autoimmune diseases, severe obstructive or restrictive pulmonary diseases, active systemic infections, and inflammatory bowel disorders, including HIV or AIDS-related illnesses or active hepatitis B or C virus.
- The ongoing use of systemic antibiotics or the previous use of antibiotics in the 2 weeks before enrollment.
- Presence of a chronic intestinal disease (for example, celiac, or malabsorption) where the frequency of bowel movements would interfere with study assessments.
- Absence of the large bowel.
- The presence of absolute contraindications to lactulose administration includes galactosemia or other conditions that necessitate a low intake of galactose.
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- Expected to require any other form of systemic anti-neoplastic therapy while in the study (i.e., chemotherapy or radiation therapy).
- Symptomatic CNS metastases and/or leptomeningeal involvement. Patients with CNS metastases and/or leptomeningeal involvement may participate if they are clinically stable, as judged by the enrolling investigator.
- Has an active autoimmune disease or a documented history of autoimmune disease or syndrome that requires systemic steroids or immunosuppressive agents. Patients with vitiligo, type I diabetes, or resolved childhood asthma/atopy are exceptions to this rule.
- A history of immune-related adverse events to ICIs that precludes the investigator from comfortably re-challenging with ICIs.
- Has known psychiatric or substance abuse disorders that would interfere with cooperation with the requirements of the trial.
- Patients with a "currently active" second malignancy other than non-melanoma skin cancers. Patients are not considered to have a "currently active" malignancy if they have completed therapy and are free of disease for ≥ 2 years.
- History of allergic reactions attributed to compounds of similar chemical or biologic composition to ICIs or lactulose.
- Current serious concomitant illnesses include cardiovascular diseases (such as uncontrolled congestive heart failure, hypertension, cardiac ischemia, myocardial infarction, and severe cardiac arrhythmias), bleeding disorders, autoimmune diseases, severe obstructive or restrictive pulmonary diseases, active systemic infections, and inflammatory bowel disorders, including HIV or AIDS-related illnesses or active hepatitis B or C virus.
- The ongoing use of systemic antibiotics or the previous use of antibiotics in the 2 weeks before enrollment.
- Presence of a chronic intestinal disease (for example, celiac, or malabsorption) where the frequency of bowel movements would interfere with study assessments.
- Absence of the large bowel
- The presence of absolute contraindications to lactulose administration includes galactosemia or other conditions that necessitate a low intake of galactose.
- Expected to require any other form of systemic anti-neoplastic therapy while in the study (i.e., chemotherapy or radiation therapy).
- Symptomatic CNS metastases and/or leptomeningeal involvement. Patients with CNS metastases and/or leptomeningeal involvement may participate if they are clinically stable, as judged by the enrolling investigator.
- Has an active autoimmune disease or a documented history of autoimmune disease or syndrome that requires systemic steroids or immunosuppressive agents. Patients with vitiligo, type I diabetes, or resolved childhood asthma/atopy are exceptions to this rule.
- A history of immune-related adverse events to ICIs that precludes the investigator from comfortably re-challenging with ICIs.
- Has known psychiatric or substance abuse disorders that would interfere with cooperation with the requirements of the trial.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site, 1 recruiting
- Recruiting
University of Chicago Medicine Comprehensive Cancer Center
Chicago, Illinois, 60637
About this study
Official title: Bifidobacterium Lactulose Optimization in Oncology and Microbiome (BLOOM)
The purpose of this study is to see if lactulose can improve the effectiveness of immunotherapy in patients with advanced cancer.
- Conditions
- Cancer
- Being tested
- Lactulose
- Medical subject headings
- Neoplasms
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
LactuloseDrug
Lactulose 10 g daily with standard-of-care Immune checkpoint inhibitors (ICIs).
| Study group | Role | What they receive |
|---|---|---|
| Phase 1 Arm | Experimental | Patients with solid tumor cancers receiving routine immunotherapy will be enrolled to receive lactulose (10 mg daily). Receives: Drug: Lactulose |
| Phase 2 Arm | Experimental | o Patients with melanoma receiving routine immunotherapy will be enrolled to receive lactulose (10 mg daily). Receives: Drug: Lactulose |
What is being measured
The primary outcome is the main question the study is designed to answer.
Phase 1-
Change in Bifidobacterium abundance in stool from baseline to week 3.
Measured: Baseline to week 3
Overall Response Rate
Assessment of cancer response based on Response Evaluation Criteria in Solid Tumors (RECIST) v1.1
Measured: Through study completion, an average of 2 years
Secondary outcomes (8)
Phase 1-Safety and tolerability
Incidence and severity of adverse events (Common Terminology Criteria for Adverse Events (CTCAE) v5.0) and dose limiting toxicities.
Measured: 3 weeks
Phase 1- Effects of lactulose
Change from baseline to week 3 in stool and blood metabolite profiles.
Measured: Baseline to week 3
Phase 1- Effects of lactulose
Change from baseline to week 3 in the abundance of secondary gut microbial taxa and change in alpha diversity indices from baseline to week 3.
Measured: Baseline to week 3
Phase 1- Anti-Tumor Evalution
Evaluating the duration of response, disease control, overall survival, progression free survival and best Response Evaluation Criteria in Solid Tumors (RECIST) v1.1 response.
Measured: Baseline to week 3
Phase 2- Safety and tolerability
Incidence and severity of adverse events (Common Terminology Criteria for Adverse Events (CTCAE) v5.0) and dose limiting toxicities.
Measured: 12 weeks
Phase 2- Evaluate changes of stool and serum
Change from baseline to week 3 in stool and blood metabolite profiles.
Measured: Baseline to week 12
Phase 2- Secondary Gut Evaluation
Change from baseline to week 3 in the abundance of gut microbial tax.
Measured: Baseline to week 3
Phase 2- Gut Evaluation
Change in alpha diversity indices from baseline to week 12.
Measured: Baseline to week 12
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted21 Jan 2026
- Study start15 Dec 2026 (estimated)
- Primary completion13 Apr 2029 (estimated)
- Study completion13 Apr 2029 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for CancerStudies of the same condition, open and under way.
- More trials run by University of ChicagoThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 1/2
- Primary purpose
- Treatment
- Allocation
- Non-randomised
- Intervention model
- Sequential
- Masking
- None (open label)
- Enrolment
- 55 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of Chicago
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Daniel Olson, Principal investigator, University of Chicago
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07354100
- Sponsor's protocol ID
- IRB25-1467
- Acronym
- (BLOOM)
- Status last verified
- Jan 2026
- First submitted
- 15 Jan 2026
- Last updated
- 16 Jun 2026
- Results posted
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 16 Jun 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Bifidobacterium Lactulose Optimization in Oncology and Microbiome (BLOOM)
- ClinicalTrials.gov ID
- NCT07354100
- Acronym / sponsor ID
- (BLOOM) / IRB25-1467
- Conditions
- Cancer
- Phase
- Phase 1/2
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 55 participants (estimated)
- Lead sponsor
- University of ChicagoUniversity, hospital or other
- Study start
- 15 Dec 2026 (estimated)
- Primary completion
- 13 Apr 2029 (estimated)
- Study completion
- 13 Apr 2029 (estimated)
- First posted
- 21 Jan 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The purpose of this study is to see if lactulose can improve the effectiveness of immunotherapy in patients with advanced cancer.
Study design
- Primary purpose
- Treatment
- Allocation
- Non-randomised
- Intervention model
- Sequential
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Phase 1 Arm | Experimental | Drug: LactulosePatients with solid tumor cancers receiving routine immunotherapy will be enrolled to receive lactulose (10 mg daily). |
| Phase 2 Arm | Experimental | Drug: Lactuloseo Patients with melanoma receiving routine immunotherapy will be enrolled to receive lactulose (10 mg daily). |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (12 listed)
- Patients must have a histologically confirmed malignancy that is to receive exclusively ICIs (no chemotherapy or RT in combination) per standard of care during the time in which lactulose will be administered. This includes, but is not limited to, melanoma, cutaneous squamous cell carcinoma, non-small cell lung cancer, mesothelioma, head and neck squamous cell carcinoma, classical Hodgkin lymphoma, primary mediastinal large B-cell lymphoma, urothelial cancer, MSI/MMRd cancer, cancers with high tumor mutational burden (>=10 muts/mB), esophageal cancer, hepatocellular carcinoma, and renal cell carcinoma. Anti-PD-1 or anti-PD-L-1 therapy combinations with anti-LAG-3 or anti-CTLA-4 combinations are permitted.
- Age ≥18 years. Because no dosing or adverse event data are currently available on the use of lactulose in combination with ICIs in patients <18 years of age, children are excluded from this study.
- ECOG performance status ≤2 (Karnofsky ≥60%, see Appendix A).
- Patients must be able to ingest liquids.
- Patients must have a histologically confirmed cutaneous or mucosal melanoma. Uveal melanoma is excluded.
Key exclusion criteria (23 listed)
- History of allergic reactions attributed to compounds of similar chemical or biologic composition to ICIs or lactulose.
- Current serious concomitant illnesses include cardiovascular diseases (such as uncontrolled congestive heart failure, hypertension, cardiac ischemia, myocardial infarction, and severe cardiac arrhythmias), bleeding disorders, autoimmune diseases, severe obstructive or restrictive pulmonary diseases, active systemic infections, and inflammatory bowel disorders, including HIV or AIDS-related illnesses or active hepatitis B or C virus.
- The ongoing use of systemic antibiotics or the previous use of antibiotics in the 2 weeks before enrollment.
- Presence of a chronic intestinal disease (for example, celiac, or malabsorption) where the frequency of bowel movements would interfere with study assessments.
- Absence of the large bowel.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| LactuloseLactulose 10 g daily with standard-of-care Immune checkpoint inhibitors (ICIs). | Drug | Phase 1 Arm, Phase 2 Arm |
Primary outcome
Phase 1-
Time frame: Baseline to week 3
Change in Bifidobacterium abundance in stool from baseline to week 3.
Overall Response Rate
Time frame: Through study completion, an average of 2 years
Assessment of cancer response based on Response Evaluation Criteria in Solid Tumors (RECIST) v1.1
8 secondary outcomes
Phase 1-Safety and tolerability
Time frame: 3 weeks
Phase 1- Effects of lactulose
Time frame: Baseline to week 3
Phase 1- Effects of lactulose
Time frame: Baseline to week 3
Phase 1- Anti-Tumor Evalution
Time frame: Baseline to week 3
Phase 2- Safety and tolerability
Time frame: 12 weeks
Phase 2- Evaluate changes of stool and serum
Time frame: Baseline to week 12
Phase 2- Secondary Gut Evaluation
Time frame: Baseline to week 3
Phase 2- Gut Evaluation
Time frame: Baseline to week 12
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 16 Jun 2026.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Daniel Olson principal investigator
University of Chicago
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 1/2 study testing Lactulose in people with Cancer, run by University of Chicago at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 12 inclusion and 23 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 16 Jun 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this combined phase mean?
Phase 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Clinical Trials Intake Intake (8557028222, cancerclinicaltrials@bsd.uchicago.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Phase 1- (time frame: Baseline to week 3). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 16 Jun 2026.