Common diabetes and acne drugs tested against cancer
NCT ID NCT02874430
First seen Jun 27, 2026 · Last updated Jun 27, 2026
Summary
This phase 2 trial tested whether combining metformin (a diabetes drug) with doxycycline (an antibiotic) could help treat localized breast and uterine cancers. The study enrolled 29 people who were scheduled for surgery. Researchers looked at changes in certain proteins in the tumor's supportive tissue. The trial was terminated early, so the findings are not conclusive.
What this could mean
Our plain-language read of the trial. This is informational only, not medical advice or a prediction.
- Active substance
- Metformin and doxycycline
- What this could lead to
- If successful, this combination could point toward a new way to slow or control certain breast and uterine cancers by targeting supportive cells around tumors.
- What could go wrong
- The trial was terminated early with only 29 participants, so results are very limited. It is unclear if the combination works better than standard care, and side effects are possible.
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Study facts
What this study's own registry entry says, in plain language.
- Phase
-
Phase 2
Tests whether the treatment actually works, and watches for side effects, in a larger group.
- Participants
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29 people
The number who actually took part.
- Started
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Jun 2016
- Finished
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Dec 2020
- Lead sponsor
-
Other sponsor
The registry's catch-all category, for sponsors it does not file as a company, a government agency, or a research network.
Who can take part
This study's own entry requirements. Only the study team can say for certain whether you qualify.
- Ages
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18 years and older
- Sex
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Female participants only
- Healthy volunteers
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Not accepted
This study is not open to healthy volunteers. The entry requirements below say who it is open to.
Show the full entry requirements Hide the full entry requirements
Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.
Inclusion Criteria: In order to be eligible for participation in this trial, the subject must: 1. Diagnosis of localized breast or uterine cancer that is either biopsy proven or suspected based on history, physical, and or radiographic findings, and who are planned for definitive resection of the tumor without the use of neoadjuvant chemotherapy or radiation therapy at TJUH are eligible to participate. 2. Subjects must be ≥ 18 years of age at time of consent. 3. Subjects must be newly diagnosed or suspected to have breast, uterine (endometrial cancer with histologies including endometrioid, serous, clear cell, and carcinosarcoma) or cervical cancer. 4. Patient must be able to swallow pills. 5. Patients with serum creatinine levels less than 1.5 mg/dL. 6. Women of child bearing potential must have a negative urine or blood pregnancy test within 14 days of study enrollment. 7. Informed Consent: All subjects must be able to comprehend and sign a written informed consent document. 8. ECOG Performance status \<1 Exclusion Criteria: The subject must be excluded from participating in the trial if the subject: 1. Received any prior cancer therapy for the breast or uterine cancer that is being resected, including progesterone therapy for endometrial cancer patients. a. Patients may have had prior therapy for other contra-lateral breast cancer. 2. Subjects who are pregnant or breastfeeding or may become pregnant during metformin and doxycycline administration. 3. Subjects on metformin or doxycycline for any reason during the preceding 4 weeks. 4. Diabetic subjects that are managed by taking metformin or insulin. 5. Subjects who have received iodinated contrast dye must wait 12 hours prior to starting Metformin. If a CT scan with contrast is scheduled after screening and consent, the metformin cannot be taken until after the CT with contrast has been completed and they have waited 12 hours. 6. Patients with serum creatinine level greater than 1.5 mg/dL. 7. Patients with history of lactic or any other metabolic acidosis. 8. Patients with history of congestive heart failure stage III or greater. 9. Patients scheduled for definitive cancer surgical resection less than 7 days from beginning of study drug administration or greater than 6 weeks from beginning study drug administration. 10. Patients with history of hepatic dysfunction or hepatic disease and abnormal liver function tests defined as AST, ALT, Alk Phos, and or total bilirubin greater than 2.5 times the upper limit of normal. a. Patients who have a history of hepatic dysfunction or hepatic disease and normal liver function tests will be eligible to participate. 11. Patients with a current history (in the past 30 days) of heavy drinking which is defined in accordance with CDC definition as more than 8 drinks per week for women and more than 15 drinks per week for men. A standard drink contains .6 ounces of pure alcohol. Generally, this amount of pure alcohol is found in 12-ounces of beer, 8-ounces of malt liquor, 5-ounces of wine, 1.5-ounces or a "shot" of 80-proof distilled spirits or liquor (e.g., gin, rum, vodka, or whiskey). While on study, patients should limit their alcohol consumption to no more than 8 drinks per week for women and no more than 15 drinks per week for men. Patients who feel they cannot comply with this recommendation are not eligible. 12. Prior allergic reaction to metformin, doxycycline, or any other tetracycline antibiotic in the past. 13. Patient is on medications that are contraindicated with metformin or doxycycline under current FDA recommendations. The following is a list of medications identified as class D (consider therapy modification) when treatment with metformin or doxycycline is considered: * Class D: * Bismuth Subsalicylate * Cimetidine * Iodinated contrast agents * Somatropin
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Conditions
The condition(s) this trial relates to.
As listed by the trial registrant
The condition terms exactly as the trial's registrant entered them.
Contacts and locations
Locations
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Thomas Jefferson University
Philadelphia, Pennsylvania, 19107, United States
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