RecruitingPhase 1Drug trialLeflunomide in Patients With PTEN-Altered Advanced Solid Malignancies and HER2 Negative Breast CancerLeflunomide in patients with PTEN-Altered advanced solid tumors or HER2 negative breast cancer. Phase 1A objectives are to determine the safety, tolerability, and the MTD of leflunomide in patients with PTEN-Altered advanced solid malignancies and HER2 negative breast cancer. Phase 1B objective is to assess preliminary evidence of clinical activity of leflunomide in these patient populations.