Gedatolisib Combination Treatment for Advanced Hormone

Both cohorts of VIKTORIA-1 have already reported positive PFS. PIK3CA WT cohort published in JCO (March 2026) with triplet HR=0.24, doublet HR=0.33, both p<0.0001. PIK3CA mutant cohort topline announced May 1, 2026 met primary endpoint with statistically significant, clinically meaningful PFS vs alpelisib+fulvestrant. Detailed data at ASCO June 2, 2026. FDA Priority Review PDUFA July 17, 2026. Outcome already disclosed as positive.

Phase 3 PFS endpoint is clinically relevant and relatively objective in a defined post-CDK4/6 HR+/HER2- population, but refractory disease, broad PIK3CA WT/MT scope, combination tolerability risk, and no prior efficacy data in fields keep odds below even.

Phase 3, active-not-recruiting design with PFS in HR+/HER2- metastatic disease is a credible registrational setup and PFS is measurable. But post-CDK4/6 population is hard to treat, combo toxicity/complexity may dilute benefit, and no prior efficacy data are provided.

Phase 3, active/not recruiting, primary completion in 39 days. Dual PFS endpoints in PIK3CA WT/MT post-CDK4/6 + AI population. Gedatolisib + fulvestrant +/- palbociclib targets PI3K/mTOR; similar agents show ~40-55% phase 3 success with variable effect sizes and subset risks.

Phase 3 PFS endpoint in post-CDK4/6 HR+/HER2- population is standard but dual WT/MT readout adds complexity; no disclosed phase 2 PFS data here, active non-recruiting status and 40-day completion window limit upside surprise potential.

Topline results from the Phase 3 VIKTORIA-1 trial have already been announced by Celcuity. In July 2025, they reported the PIK3CA WT cohort achieved its primary PFS endpoint. On May 1, 2026, they announced the PIK3CA MT cohort also met its primary endpoint, demonstrating statistically significant improvement in PFS vs alpelisib plus fulvestrant. The trial is definitively positive.

Celcuity's VIKTORIA-1 Phase 3 trial evaluated gedatolisib combinations in HR+/HER2- advanced breast cancer for both PIK3CA wild-type and mutant cohorts. Statistically significant and clinically meaningful PFS improvements were announced for the WT cohort in July 2025, and positive topline PFS results for the MT cohort were announced on May 1, 2026, meaning both primary endpoints were met.

Phase 3 trial of gedatolisib, a pan-PI3K/mTOR inhibitor, in heavily pretreated HR+/HER2- breast cancer. Prior Phase 1b data showed promising PFS, but broader PI3K inhibition often causes toxicity and mixed efficacy in wild-type PIK3CA. The primary endpoint is PFS in the overall population (WT+MT), which is challenging. Near completion with no early stopping suggests no futility, but success rate for such trials is modest. Estimate ~32% chance of positive result.

Phase 3 trial of gedatolisib, a pan-PI3K/mTOR inhibitor, in all-comer HR+/HER2- breast cancer after CDK4/6 and AI. Historical PI3K inhibitor success is mixed; alpelisib benefited only PIK3CA-mutated patients. Including wild-type may dilute effect. Small biotech sponsor adds risk. Estimate 45% probability of positive PFS.

Phase 2 data supported Phase 3 advancement; dual PI3K/mTOR inhibition targets validated pathway in both PIK3CA WT and MT populations. PFS endpoint is achievable and well-validated in this setting. However, PI3K class has mixed Phase 3 track record, toxicity may limit dose intensity, and benefit in WT subgroup is uncertain despite Phase 2 signals. Near completion reduces operational risk.

Phase 2 data for gedatolisib+fulvestrant±palbociclib showed strong PFS signals in HR+/HER2- post-CDK4/6 setting. Dual PI3K/mTOR inhibition offers rationale for both PIK3CA WT and MT populations, unlike alpelisib. PFS endpoint is achievable. Risks: PI3K inhibitors have mixed Phase 3 history (taselisib failed), and toxicity could limit efficacy. Trial near completion (40 days), data largely locked. Modest edge over market.

Gedatolisib (pan-PI3K/mTOR inhibitor) faces significant toxicity hurdles and modest efficacy in prior studies. In HR+/HER2- breast cancer post-CDK4/6, achieving statistically significant PFS improvement over standard care is challenging. Historical failure rates for this mechanism in this setting are high, suggesting a low probability of success despite the broad inclusion of PIK3CA WT/MT.

Phase 3 evaluates dual PI3K/mTOR inhibitor gedatolisib in heavily pretreated HR+/HER2- breast cancer. The primary endpoint combines PIK3CA WT and MT cohorts, diluting potential treatment signal. Historical PI3K/mTOR data shows modest efficacy and high toxicity, making PFS success unlikely. Results expected in ~40 days.

Phase‑3 study of gedatolisib (PI3K/mTOR inhibitor) combined with fulvestrant ± palbociclib targets a heavily pre‑treated HR+/HER2‑ population. While PI3K inhibition can overcome CDK4/6 resistance, prior data on gedatolisib are modest and the mixed PIK3CA WT/MT cohort dilutes potential benefit. The endpoint (PFS) is hard to shift in this setting, suggesting a sub‑50% chance of a positive result.

Gedatolisib, a PI3K/mTOR inhibitor, has shown limited activity in prior trials, especially in PIK3CA‑wildtype patients. The study enrolls heavily pre‑treated HR+/HER2‑ disease after CDK4/6 and AI failure, where resistance mechanisms are strong. Combining with fulvestrant ± palbociclib adds toxicity risk and dilutes the signal across WT and mutant cohorts, making a robust PFS benefit unlikely.

PI3K pathway inhibitors in HR+/HER2- breast cancer have mixed history (alpelisib modest benefit, limited by toxicity). Gedatolisib is a PI3K/mTOR inhibitor with broader target, potentially more toxicity. Phase 3 design requires PFS benefit in both PIK3CA WT and MT populations—WT is biologically harder to hit. Prior CDK4/6 progression setting is competitive. 39 days to completion with no positive pre-announcement suggests readout imminent, increasing disclosure risk. No strong prior efficacy signal evident.

Phase 3 PI3K/AKT/mTOR inhibitor in heavily pretreated HR+/HER2- breast cancer post-CDK4/6 failure. Gedatolisib is a PI3K/mTOR dual inhibitor; class has modest PFS benefits with toxicity challenges (hyperglycemia, rash). Prior data from Phase 1b/2 showed PFS ~7-9 months but no randomized control. Primary completion in 40 days suggests topline imminent, increasing disclosure risk. Endpoint requires benefit in both PIK3CA WT and MT populations, which is biologically ambitious—PI3K pathway dependence is stronger in MT tumors. No prior Phase 3 validation for this specific combination. Execution by

Phase 3 trial testing gedatolisib (PI3K/mTOR inhibitor) in HR+/HER2- breast cancer post CDK4/6 failure. Sound mechanistic rationale targeting PI3K pathway in a population with limited options. However, competitive PI3K inhibitors exist (alpelisib), and pan-PI3K/mTOR toxicity could limit efficacy. Phase 3 oncology success rates typically 40-55%. Split WT/MT endpoint analysis may dilute signal. Estimated ~40% YES probability, reflecting both biological promise and execution/competitive risk.

Phase 3 trial for gedatolisib in later-line HR+/HER2- breast cancer after CDK4/6 and AI progression. Pan-PI3K/mTOR inhibition is scientifically rational for PIK3CA-altered tumors (present in ~40% of HR+ cases), but similar pathway inhibitors have shown mixed results and tolerability challenges. Phase 3 in post-CDK4/6 setting carries elevated risk. Trial active with data collection underway. Given mechanism validation but execution uncertainty, intrinsic odds slightly favor failure.