Phase 3 Study of Gedatolisib as First-Line Treatment for Patients With HR-Positive, HER2-Negative Advanced Breast Cancer (VIKTORIA-2)

This is a Phase 3, open-label, randomized clinical trial evaluating the efficacy and safety of gedatolisib plus endocrine therapy and palbociclib versus endocrine therapy and ribociclib for the treatment of patients with advanced (inoperable) or metastatic hormone receptor positive, human epidermal growth factor receptor 2 negative (HR+/HER2-) breast cancer. Following completion of the screening procedures to determine eligibility, patients will be assigned manually according to their endocrine sensitivity status to either Study 1 (endocrine-resistant) or Study 2 (endocrine-sensitive) and subsequently be randomized 1:1 to either investigational treatment or standard-of-care control. Study 1 is expected to enroll approximately 440 subjects with treatment-naïve endocrine-resistant ABC whose cancer progressed while receiving or within 12 months of completing adjuvant endocrine therapy. The trial will evaluate the efficacy and safety of the investigational arm (gedatolisib combined with palbociclib and fulvestrant - Arm A) compared to the control arm (ribociclib combined with fulvestrant - Arm B). Study 2 is expected to enroll approximately 740 subjects with treatment-naïve endocrine-sensitive ABC whose cancer relapsed or progressed 12 months or more after completion of adjuvant endocrine therapy, or those with de novo metastatic disease without prior endocrine therapy exposure. The trial will evaluate the efficacy and safety of the investigational arm (gedatolisib combined with palbociclib and letrozole - Arm C) compared to the control arm (ribociclib combined with letrozole - Arm D). Gedatolisib is an intravenously administered pan-PI3K/mTOR inhibitor. Palbociclib and ribociclib are CDK4/6 inhibitors. Fulvestrant is a selective estrogen receptor degrader (SERD). Letrozole is an aromatase inhibitor (AI).