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OncoMatch/Clinical Trials/NCT06452394

NEODOXy: Targeting Breast Cancer Stem Cells With Doxycycline

Is NCT06452394 recruiting? Yes, currently enrolling (May 2026). This Phase 2 trial studies Doxycyclin for breast cancer.

Phase 2RecruitingSwiss Cancer InstituteNCT06452394Data as of May 2026

Treatment: DoxycyclinDespite modern surgical and medical treatments, breast cancer can re-occur and lead 20% of patients to death. During the last 20 years, pre-clinical studies have shown that treatment failures may be due to the presence of a sub-type of cancer cells, the cancer stem cells, which are resistant to chemotherapy and radiotherapy. By chance, doxycycline, an old, inexpensive and safe molecule seems to target effectively these cancer stem cells. This study proposes to check for the clinical efficacy of doxycycline to target the cancer stem cells and improve the response to neoadjuvant chemotherapy in ER+/HER2- breast cancers.

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Extracted eligibility criteria

Cancer type

Breast Carcinoma

Biomarker criteria

Required: ESR1 overexpression (ER expression rate  1%)

ER expression rate  1%

Required: HER2 (ERBB2) wild-type (HER2-)

HER2-

Disease stage

Excluded: Stage IV

Patients are candidate for curative surgery and with a tumor size of at least 2 cm and nodal classification cN0-3 according to the 8th edition, January 2017 of the anatomic TNM classification3.

Performance status

ECOG 0–1(Restricted strenuous activity)

Prior therapy

Cannot have received: neoadjuvant endocrine therapy

Patients having received or planned to undergo neoadjuvant endocrine therapy or other investigational therapies before surgery.

Cannot have received: other investigational therapies

Patients having received or planned to undergo neoadjuvant endocrine therapy or other investigational therapies before surgery.

Cannot have received: cyclin family antibiotics (doxycycline)

Patients having received doxycycline or other antibiotics of the cyclin family within 28 days before registration.

Lab requirements

Blood counts

neutrophil count  1.5 x 10^9/L, platelet count  100 x 10^9/L, hemoglobin  90 g/L

Kidney function

estimated glomerular filtration rate (eGFR)  50 mL/min/1.73 m2 (according to CKD-EPI formula)

Liver function

total bilirubin  1.5 x ULN (except for patients with Gilbert's disease max. 3.0 x ULN), AST and ALT  2.5 x ULN

Cardiac function

No known cardiac dysfunction contraindicating the planned neoadjuvant chemotherapy with 4 cycles of EC followed by 12 doses of weekly paclitaxel.

Adequate bone marrow function: neutrophil count  1.5 x 10^9/L, platelet count  100 x 10^9/L, hemoglobin  90 g/L. Adequate hepatic function: total bilirubin  1.5 x ULN (except for patients with Gilbert's disease max. 3.0 x ULN), AST and ALT  2.5 x ULN. Adequate renal function: estimated glomerular filtration rate (eGFR)  50 mL/min/1.73 m2 (according to CKD-EPI formula). No known cardiac dysfunction contraindicating the planned neoadjuvant chemotherapy with 4 cycles of EC followed by 12 doses of weekly paclitaxel.

Structured fields extracted by AI. May contain errors — verify against the official protocol.

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