This is a Phase II, open-label, single-arm, study, designed to evaluate the efficacy and safety of tenalisib in patients with metastatic TNBC, who have received at least one but not more than 3 prior therapies in a metastatic setting.

Inclusion Criteria:

1. Patients who have histologically confirmed TNBC.
2. Patients who have received at least 1 but not more than 3 prior chemotherapy regimens in a metastatic setting.
3. Patients with at least one measurable lesion, per RECIST version 1.1 at baseline . Bone-only disease is not permitted.
4. ECOG performance status 0 to 2.
5. Adequate bone marrow, liver, and renal function

Exclusion Criteria:

1. Cancer therapy/ any cancer investigational drug within 3 weeks (21 days) or 5 half-lives (whichever is shorter).
2. Patient who has not recovered from acute toxicities of previous therapy except treatment-related alopecia.
3. Prior exposure to PI3K inhibitors (e.g., alpelisib, buparlisib) for breast cancer.
4. Major surgery within 4 weeks of starting study treatment.
5. Patient with symptomatic uncontrolled brain metastasis.
6. Ongoing immunosuppressive therapy including systemic corticosteroids.
7. History of severe cutaneous reactions.
8. Concurrent disease or condition that would interfere with study participation
9. Pregnancy or lactation.
10. Any severe and/or uncontrolled medical conditions or other conditions that could affect patient participation