Safety and Efficacy of SGN-LIV1A Plus Pembrolizumab for Patients With Locally-Advanced or Metastatic Triple-Negative Breast Cancer

This trial studies ladiratuzumab vedotin (LV) with pembrolizumab in patients with triple-negative breast cancer. It will find out what side effects happen when participants get these two drugs. A side effect is anything the drugs do besides treating cancer. Pembrolizumab is a drug that can be used to treat triple-negative breast cancer. The trial will also find out if these drugs work to treat this type of cancer. Participants in this study have metastatic breast cancer. This means the cancer has spread to other parts of the body.