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Metformin with neoadjuvant chemotherapy in localized triple-negative and Her2neu-positive breast cancer: A
B M Mouna1, Atul Batra1, Vinod Sharma2
1Department of Medical Oncology, BRAIRCH, All India Institute of Medical Sciences, New Delhi, India.
Purpose:
HER2-positive and triple-negative breast cancers (TNBC) are aggressive subtypes with poor outcomes. Metformin, a commonly used antidiabetic agent, has demonstrated anticancer potential in preclinical studies. This trial evaluated whether the addition of metformin to neoadjuvant chemotherapy (NACT) improves pathological complete response (pCR) rates in nondiabetic patients with localized HER2-positive or TNBC.
Patients And Methods:
In this open-label, phase 2 randomized controlled trial, 242 chemotherapy-naïve, nondiabetic women aged 18-65 years with localized, resectable HER2-positive or TNBC were randomized 1:1 to receive standard NACT with or without metformin (850 mg orally twice daily until surgery). The primary endpoint was pCR (ypT0/ypN0). Secondary endpoints included subgroup pCR rates, clinical response, breast-conserving surgery rates, adverse events, patient-reported outcomes (ESAS-r), and cognitive function (FACT-Cog v3).
Results:
A total of 112 patients in the metformin arm and 115 in the standard arm underwent surgery and were included in the efficacy analysis. The metformin group had a higher proportion of advanced T3/T4 tumors (55.4% vs. 42.3%). Overall pCR rates were 43.7% in the metformin group and 41.7% in the control group (p = .75). In the HER2-positive subgroup, pCR was higher with metformin (46.3% vs. 36.5%, p = .27). Breast-conserving surgery rates, clinical response, and patient-reported outcomes were similar between groups. Metformin was well tolerated; fewer patients experienced peripheral neuropathy (37.2% vs. 45.5%), but diarrhea was more frequent (26.6% vs. 10.7%).
Conclusion:
Metformin did not significantly improve pCR when added to standard NACT. However, trends in HER2-positive patients and reduced neuropathy merit further investigation.
Insights
Metformin did not improve pathological complete response (pCR) in HER2-positive or triple-negative breast cancer patients receiving neoadjuvant chemotherapy. However, trends suggest potential benefits in HER2-positive cases and reduced neuropathy.
Area of Science:
- Oncology
- Pharmacology
Background:
- HER2-positive and triple-negative breast cancers (TNBC) are aggressive subtypes with poor prognoses.
- Metformin, an antidiabetic drug, shows preclinical anticancer activity.
- Investigating metformin's role in neoadjuvant chemotherapy (NACT) for these breast cancer subtypes is crucial.
Purpose of the Study:
- To evaluate if adding metformin to NACT improves pathological complete response (pCR) rates in nondiabetic patients with localized HER2-positive or TNBC.
- To assess secondary endpoints including clinical response, breast-conserving surgery rates, and patient-reported outcomes.
Main Methods:
- An open-label, phase 2 randomized controlled trial involving 242 chemotherapy-naïve, nondiabetic women (18-65 years) with localized HER2-positive or TNBC.
- Patients were randomized to receive standard NACT with or without metformin (850 mg twice daily).
- The primary endpoint was pCR (ypT0/ypN0).
Main Results:
- Overall pCR rates were similar between the metformin (43.7%) and control (41.7%) groups (p=0.75).
- In the HER2-positive subgroup, pCR was numerically higher with metformin (46.3% vs. 36.5%, p=0.27).
- Metformin was well tolerated, with less peripheral neuropathy but more diarrhea.
Conclusions:
- Metformin addition to NACT did not significantly improve pCR in HER2-positive or TNBC.
- Observed trends in HER2-positive patients and reduced neuropathy warrant further investigation.
- Metformin may offer a tolerable option with potential benefits in specific breast cancer subgroups.
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