A Phase Ib Study of Novel Combination (New) of Low Dose Oral CyclophoSphamide (s) to Potentiate Axatilimab (A) + Retifanlimab (R) in Treating Metastatic Triple Negative Breast Cancer (TNBC)

This study is testing a three-drug combination — low-dose oral cyclophosphamide, axatilimab, and retifanlimab — in people with metastatic triple-negative breast cancer (TNBC), a type of breast cancer that lacks the three most common receptors and is harder to treat. The combination aims to break down the cancer's defense against the immune system. **You may be eligible if...** - You have been diagnosed with metastatic or locally recurrent triple-negative breast cancer (ER less than 1%, PR less than 1%, HER2 negative), including inflammatory breast cancer (IBC) with low hormone receptors - Your cancer has not responded to or cannot be treated with standard therapies - You are 18 or older with at least one measurable tumor on imaging - Your overall health (ECOG 0–2) and organ function are adequate **You may NOT be eligible if...** - You have received treatment in the past week (chemotherapy or radiation) - You have untreated cancer in the brain - You have active autoimmune disease or are on immune-suppressing medications - You are pregnant or breastfeeding Talk to your doctor to see if this trial is right for you.