An Open-Label, Multicenter, Non-Randomized Expanded Access Protocol (EAP) Designed to Provide Leronlimab to Patients With Locally Advanced or Metastatic Triple-Negative Breast Cancer (mTNBC)

Inclusion Criteria: * Adult participants \> 18 years of age. * Histologically confirmed HR-/HER2- metastatic TNBC using ASCO/CAP criteria, Stage IIIB-IV. * Must have experienced disease progression on prior standard of care (SoC) therapy, be ineligible for SoC due to intolerance or contraindications, or have no remaining SoC treatment options available. * Be willing to provide tissue from a newly obtained core or excisional biopsy of an accessible tumor lesion if archival tissue is not available. * Must not be eligible for or able to enroll in any trials investigating leronlimab that are currently recruiting. * Participant must have adequate organ and bone marrow function within 14 days prior to enrollment as determined by the investigator. * ECOG performance status 0-2. * Participants of childbearing potential (POCBP) and males must agree to use two medically accepted methods of contraception with hormonal or barrier method of birth control, or abstinence, prior to study entry, for the duration of study participation and 4 months after the last dose of study drug. * Willingness and ability to comply with protocol requirements and attend follow-up visits. * Participants must have the ability to understand and the willingness to sign a written informed consent prior to registration on study. Exclusion Criteria: * Participants who have a history of allergic reactions attributed to compounds of similar chemical or biologic composition to leronlimab (PRO 140) are not eligible.…