This study has 3 parts:
1. Screening - Lasts up to 28 days. You'll get heart tests, scans, and blood and urine tests.
2. Treatment - You'll be randomly picked to get either a new medicine (iza-bren) or a cancer medicine your doctor chooses. You'll visit the clinic 2-3 times every few weeks.
3. Follow-up - After treatment ends, you'll have:

• A safety check 30 days later
• Regular checkups every 12 weeks
• More tests like scans and heart checks

Adults with advanced solid tumors

Who can join this study?
Adults with a kind of advanced breast cancer called Triple-Negative Breast Cancer (TNBC) can join if:

• Their cancer is confirmed and has spread or come back and can’t be removed with surgery
• Their cancer came back at least 6 months after their last treatment
• Their cancer came back 6 to 12 months after getting a special kind of treatment called anti-PD(L)1 therapy

Why is this study happening?
Doctors want to find out if a new medicine called iza-bren helps people with a certain kind of breast cancer called Triple-Negative Breast Cancer (TNBC) or ER-low breast cancer—especially for those who can’t get treatments like immunotherapy or hormone therapy.