Celcuity details phase 3 VIKTORIA-1 gedatolisib breast cancer data
Bottom line
Celcuity reported detailed phase 3 VIKTORIA-1 data showing that gedatolisib-based regimens improved progression-free survival in adults with HR-positive, HER2-negative, PIK3CA-mutant advanced breast cancer after prior CDK4/6 inhibitor and aromatase inhibitor treatment. In the mutant cohort, the gedatolisib triplet of gedatolisib, palbociclib, and fulvestrant cut the risk of progression or death by 50% versus alpelisib plus fulvestrant, while the gedatolisib doublet of gedatolisib plus fulvestrant reduced that risk by 33%, according to Celcuity’s June 2 presentation tied to ASCO 2026. The company had previously reported positive VIKTORIA-1 results in the PIK3CA wild-type population, and the FDA is already reviewing an NDA for gedatolisib in that wild-type setting under Priority Review, with a July 17, 2026, PDUFA date. (globenewswire.com)
Why it matters: Although this is a human oncology story rather than a veterinary one, it’s relevant to clinicians tracking targeted therapy development, biomarker-driven trial design, and the regulatory path for PI3K-pathway inhibitors. VIKTORIA-1 is a randomized phase 3 study, registered as NCT05501886, that stratified patients by PIK3CA status and tested whether broader PI3K/mTOR pathway inhibition could improve on existing post-CDK4/6 options. The data also matter because alpelisib has been limited in practice by tolerability concerns, especially hyperglycemia, and Celcuity is positioning gedatolisib as a potentially differentiated option if regulators agree. (clinicaltrials.gov)
What to watch: Celcuity has said it plans to submit the mutant-cohort data to the FDA in the third quarter of 2026, while the separate wild-type NDA faces a July 17, 2026, decision date. (ir.celcuity.com)
Key facts
- Company
- Celcuity
- Study
- VIKTORIA-1, phase 3, randomized, open-label
- Population
- Adults with HR-positive, HER2-negative, PIK3CA-mutant advanced breast cancer
- Prior treatment
- CDK4/6 inhibitor and aromatase inhibitor
- Triplet regimen
- Gedatolisib, palbociclib, and fulvestrant
- Comparator
- Alpelisib plus fulvestrant
- Triplet result
- 50% lower risk of progression or death; hazard ratio 0.50; p<0.0001
- Doublet result
- 33% lower risk of progression or death; hazard ratio 0.67
- Regulatory timing
- Celcuity plans to submit the mutant-cohort data to the FDA in the third quarter of 2026
Celcuity used ASCO 2026 to release detailed phase 3 VIKTORIA-1 results for gedatolisib combinations in HR-positive, HER2-negative, PIK3CA-mutant advanced breast cancer, arguing the regimen could reshape treatment after progression on a CDK4/6 inhibitor and an aromatase inhibitor. The headline result was a statistically significant progression-free survival benefit in the mutant cohort, where gedatolisib plus palbociclib and fulvestrant outperformed alpelisib plus fulvestrant, the current biomarker-matched comparator in this setting. (globenewswire.com)
The update builds on a broader VIKTORIA-1 program that has already produced positive data in PIK3CA wild-type disease. In March 2026, results from the wild-type cohort were published in the Journal of Clinical Oncology, showing that gedatolisib plus fulvestrant, with or without palbociclib, improved progression-free survival versus fulvestrant alone after prior CDK4/6 inhibitor and nonsteroidal aromatase inhibitor therapy. That earlier success helped support Celcuity’s NDA in the wild-type setting, which the FDA accepted in January 2026 and granted Priority Review, with a target action date of July 17, 2026. (ascopubs.org)
In the newly detailed mutant-cohort data, Celcuity said the gedatolisib triplet reduced the risk of progression or death by 50% compared with alpelisib plus fulvestrant, with a hazard ratio of 0.50 and a p-value below 0.0001. The gedatolisib doublet also beat the comparator, reducing the risk by 33% with a hazard ratio of 0.67. The company framed the result as notable because the trial used an active comparator in a genomically defined population, rather than comparing against endocrine therapy alone. ClinicalTrials.gov describes VIKTORIA-1 as a phase 3, open-label, randomized study in patients with advanced or metastatic HR-positive, HER2-negative breast cancer, with treatment assignment based on confirmed PIK3CA mutation status. (globenewswire.com)
Celcuity and outside oncology coverage have also emphasized tolerability and workflow implications. OncLive’s reporting on the FDA review noted that the agency included gedatolisib in the Real-Time Oncology Review program for the wild-type NDA, a sign of regulatory interest in the dataset. The ASCO Post’s coverage of the wild-type results highlighted investigator Sara Hurvitz’s view that the study showed meaningful benefit from PI3K/AKT/mTOR-pathway inhibition after CDK4/6 therapy. Those reactions don’t amount to independent validation of the mutant-cohort findings, but they do suggest the program is being taken seriously by the oncology community. (onclive.com)
Why it matters: For clinicians, the bigger story is less about one conference presentation and more about whether gedatolisib can establish a broader role across both PIK3CA-mutant and wild-type disease. If the efficacy and safety profile hold up under regulatory review, the drug could give oncologists a new option in a crowded but still unsatisfying post-CDK4/6 setting. The trial also reinforces a trend that veterinary professionals who follow translational oncology will recognize: precision medicine is moving beyond mutation matching alone and toward pathway-level inhibition, combination regimens, and tighter patient segmentation. (globenewswire.com)
There’s also a business and regulatory angle. Celcuity has said it intends to submit the PIK3CA-mutant data to the FDA in the third quarter of 2026 as a supplemental NDA, while preparing for a potential commercial launch tied first to the wild-type application. That means the company is trying to turn one phase 3 platform study into a broader franchise, with VIKTORIA-2 already expanding in first-line disease. (ir.celcuity.com)
What to watch: The immediate milestone is the FDA’s July 17, 2026, decision on gedatolisib in HR-positive, HER2-negative, PIK3CA wild-type advanced breast cancer, followed by the expected third-quarter 2026 supplemental filing for the mutant population and, potentially, closer scrutiny of whether the safety profile is differentiated enough from existing PI3K-pathway therapies to support broad uptake. (ir.celcuity.com)