Trial results for metformin hydrochloride in preventing breast cancer in patients with atypical hyperplasia or in situ disease were posted on ClinicalTrials.gov on 2025-04-13. The Phase 3 study (NCT01905046) showed no significant difference between metformin hydrochloride and placebo, with an Odds Ratio of 0.97 (95.0% CI: 0.36 to 2.62) and a p-value of 0.951.
Background
The trial (NCT01905046) investigated metformin hydrochloride as a potential chemopreventive agent for breast cancer. Chemoprevention involves using drugs to prevent cancer formation. This study specifically focused on patients diagnosed with conditions such as atypical ductal breast hyperplasia, ductal breast carcinoma in situ, or lobular breast carcinoma in situ, including those who are BRCA1 mutation carriers or BRCA2 mutation carriers.
Trial design
The study, NCT01905046, was a Phase 3, randomized trial designed to compare metformin hydrochloride with placebo. It enrolled 86 participants diagnosed with conditions including atypical ductal breast hyperplasia, BRCA1 mutation carrier status, BRCA2 mutation carrier status, ductal breast carcinoma in situ, or lobular breast carcinoma in situ. The trial aimed to evaluate how well metformin hydrochloride works compared to placebo in preventing breast cancer in this patient population.
Key results
The trial evaluated the "Test for the Presence or Absence of Cytological Atypia in Unilateral or Bilateral RPFNA Aspirates After 12 Months." For this outcome, Arm I reported 20 participants and 12 participants, while Arm II reported 21 participants and 13 participants. A statistical analysis using the Chi-squared method showed an Odds Ratio (OR) of 0.97 (95.0% CI: 0.36 to 2.62) with a p-value of 0.951.
What this means
The results of this Phase 3 trial indicate that metformin hydrochloride did not demonstrate a statistically significant difference compared to placebo in preventing breast cancer, as measured by the presence or absence of cytological atypia after 12 months. The Odds Ratio of 0.97 with a 95.0% confidence interval that includes 1 (0.36 to 2.62), coupled with a p-value of 0.951, suggests that there was no clear benefit observed for metformin hydrochloride in this specific patient population under the study conditions. Clinicians and patients should consider these findings when evaluating chemoprevention strategies for atypical hyperplasia or in situ breast cancer.
Source
The information regarding these trial results was obtained from ClinicalTrials.gov, a public database of clinical studies. The results for study NCT01905046, titled "Metformin Hydrochloride in Preventing Breast Cancer in Patients With Atypical Hyperplasia or In Situ Breast Cancer," were posted on 2025-04-13 on clinicaltrials.gov.