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Fluoxetine for Colorectal Cancer Immune Cells Before Surgery

This study is looking at whether fluoxetine (Prozac), a common antidepressant, can change the immune cells in colorectal tumors before surgery. We want to see if giving fluoxetine might affect the immune system around the tumor and potentially interfere with how cancer cells grow and spread. You might be able to join if you are 18 or older, have colorectal adenocarcinoma that hasn't been treated yet, and are able to follow study requirements. The main goal is to understand how fluoxetine changes the immune cells and their activity within the tumor. This study is currently recruiting about 10 participants.

Study design
This is an interventional study, meaning participants will receive a specific treatment. It is a single-arm study, where all participants receive fluoxetine, and involves about 10 people.
What's involved
Participants will take fluoxetine by mouth once daily for 10 days before their surgery.
Compensation
Not stated in the trial record.
Follow-up
Immune cell changes will be measured within a year of surgery.

AI-generated from the public study record. Only the study team can confirm whether you're eligible — confirm details with them before making decisions.

NCT06225011

Fluoxetine for the Modification of Colorectal Tumor Immune Cells Before Surgery in Patients With Colorectal Cancer

Recruiting
PHASE1Ages 18+InterventionalTreatment
Jonsson Comprehensive Cancer Center
~10 participants
Updated 2026-08-20 on ClinicalTrials.gov
What's tested:Fluoxetine

At a glance

Recruiting sites
1 of 1 listed site is recruiting right now
RecruitingSuspended, closed, or not yet open
What they're measuring
Immune cell composition and microenvironment
Measured over within a year of surgery

Conditions

Colorectal Adenocarcinoma

Explore related trials

Colorectal Adenocarcinoma

NCT06225011

Where you'd take part

This study runs at 1 site. They're the same protocol — you choose where, and that choice sets who your contact draft is addressed to.

  • UCLA / Jonsson Comprehensive Cancer Center

    Los Angeles, Californiastudy coordinator listed

    Recruiting

Sites open and close at different times, so the status above is per site — it can differ from the study's overall status.

Study leadership

  • Jasmine Mitchell, MD · PRINCIPAL_INVESTIGATOR · UCLA / Jonsson Comprehensive Cancer Center

Who to contact

Jasmine Mitchell, MD
[email protected]
310-825-0712
Email the study team

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Eligibility criteria

Inclusion

Male or female ≥ 18 years of age at visit 1
Previously untreated cytologically or histologically confirmed colorectal adenocarcinoma that will not need neoadjuvant therapy
Written informed consent (and assent when applicable) obtained from subject or subject's legal representative and ability for subject to comply with the requirements of the study
World Health Organization (WHO) Eastern Cooperative Oncology Group (ECOG) performance status 0-2
Absolute neutrophil count (ANC) ≥ 1.5x10\^9/L
Platelets ≥ 100x10\^9/L
Hemoglobin ≥ 9 g/dL
Serum creatinine (sCr) ≤ 1.5 x upper limit of normal (ULN)
Creatinine clearance (Ccr) ≥ 40 mL/min (as calculated by Modified Cockcroft-Gault formula)
Serum total bilirubin ≤ 1.5 x ULN
Aspartate aminotransferase (AST)(serum glutamic-oxaloacetic transaminase \[SGOT\]) / alanine aminotransferase (ALT)(serum glutamate pyruvate transaminase \[SGPT\]) ≤ 2.5 x ULN
Baseline corrected QT (QTc) within normal limits per the Bazett formula. Any electrocardiogram (EKG) done prior to consent is acceptable for baseline QTc monitoring.
Normal QTc ranges from 350-450 ms for adult men and from 360-460 ms for adult women

Exclusion

Presence of a condition or abnormality that in the opinion of the investigator would compromise the safety of the participant or the quality of the data
A diagnosis of metastatic colorectal adenocarcinoma
Individuals who have received neoadjuvant chemotherapy prior to the planned colon cancer resection
Individuals with absolute or relative contraindications to fluoxetine
Baseline prolonged QTc
Concurrently taking tamoxifen, pimozide, or thioridazine
Individuals using other SSRIs, serotonin and norepinephrine reuptake inhibitors (SNRIs), monoamine oxidase inhibitors (MAOIs), lithium or other antidepressants at time of initial biopsy
Currently active second primary malignancy or history of malignancy less than 5 years prior to the time of study eligibility (Patients with history of skin cancers excluding melanoma will be eligible for participation)

What this trial measures

  • Immune cell composition and microenvironmentwithin a year of surgery

    Will be assessed by changes in the immune cell composition in the tumor and its microenvironment before and after exposure to selective serotonin reuptake inhibitors therapy. Fixed tumor samples will be analyzed by immunohistochemistry for immune cell tumor infiltration and relevant lineage/activation/exhaustion markers. Will use descriptive statistics and graphical displays to compare the changes in tumor immune markers between the pre- and post-treatment tissue.