VIKTORIA-1: This phase III study is evaluating how safe and effective targeted therapy (gedatolisib) plus hormone therapy (fulvestrant), with or without additional targeted therapy (palbociclib) is in the treatment of advanced HR+, HER2- breast cancer who have had prior therapyPhase 3, Open-Label, Randomized, Study Comparing Gedatolisib Combined With Fulvestrant & With or Without Palbociclib to Standard-of-Care Therapies in Patients With HR-Positive, HER2-Negative Advanced Breast Cancer Previously Treated With a CDK4/6 Inhibitor in Combination w/Non-Steroidal Aromatase Inhibitor Therapy

Exclusion

1. History of malignancies other than adequately treated non-melanoma skin cancer, curatively treated in situ cancer of the cervix, or other solid tumors curatively treated with no evidence of disease for ≥3 years
2. Prior treatment with a phosphoinositide 3-kinase (PI3K) inhibitor, a protein kinase B (Akt) inhibitor, or a mechanistic target of rapamycin (mTOR) inhibitor
3. Prior treatment with chemotherapy and antibody drug conjugates for advanced disease is not permitted (prior adjuvant or neoadjuvant chemotherapy is permitted)
4. More than 2 lines of prior endocrine therapy treatment
5. Bone only disease that is only blastic with no soft tissue component
6. Subjects with type 1 diabetes or uncontrolled type 2 diabetes

7. Known and untreated, or active, brain or leptomeningeal metastases

   a. Subjects with previously treated central nervous system (CNS) metastases may be enrolled in the study if they meet the following criteria: do not require supportive therapy with steroids; do not have seizures and do not exhibit uncontrolled neurological symptoms; stable disease confirmed by radiographic assessment within at least 4 weeks prior to enrollment

8. Patients with advanced, symptomatic, visceral spread that are at risk of life-threatening complication in the short-term

9. History of clinically significant cardiovascular abnormalities such as: Congestive heart failure (New York Heart Association (NYHA) classification ≥ II within 6 months of study entry

   1. Myocardial infarction within 12 months of study entry
   2. History of any uncontrolled (or untreated) clinically significant cardiac arrhythmias, (e.g., ventricular tachycardia), complete left bundle branch block, high grade AV block (e.g., bifascicular block, Mobitz type II and third degree AV block), supraventricular, nodal arrhythmias, or conduction abnormality in the previous 12 months
   3. Uncontrolled hypertension defined by systolic blood pressure (SBP) ≥160 mmHg and/or diastolic blood pressure (DBP) ≥100 mmHg, with or without antihypertensive medication (initiation or adjustment of antihypertensive medication[s] is allowed prior to screening)

   4. Long QT syndrome, family history of idiopathic sudden death or congenital long QT syndrome, or any of the following:

      • i. Risk factors for Torsades de Pointes (TdP) including uncorrected hypokalemia or hypomagnesemia, or history of clinically significant/symptomatic bradycardia
      • ii. On screening, inability to determine the corrected QT interval using Fridericia's formula (QTcF) on the ECG (i.e., unreadable or not interpretable) or QTcF >480 msec (determined by mean of triplicate ECGs at screening)
10. Known hypersensitivity to the study drugs or their components
11. Pregnant or breast-feeding women

12. Concurrent participation in another interventional clinical trial

    1. Subjects must agree not to participate in another clinical trial (other than observational) at any time during participation in VIKTORIA-1.