Gedatolisib delivered a hazard ratio of 0.24 for progression-free survival in the PIK3CA wild-type cohort of the Phase 3 VIKTORIA-1 trial when used as a triplet with fulvestrant and palbociclib, translating to a median PFS of 9.3 months versus 2.0 months for fulvestrant alone. The doublet of gedatolisib plus fulvestrant posted a hazard ratio of 0.33 and a median PFS of 7.4 months versus 2.0 months. No safety data were released with these topline results.
Celcuity will submit a New Drug Application for gedatolisib in HR+/HER2- advanced breast cancer under FDA’s Real-Time Oncology Review program, with a rolling submission starting in September and completion targeted for the fourth quarter of 2025. The filing will be based on the VIKTORIA-1 PIK3CA wild-type cohort results; a separate PIK3CA-mutant cohort remains ongoing. The candidate, a pan-PI3K and mTORC1/2 inhibitor, already holds Breakthrough Therapy and Fast Track designations.
Strategically, this is a bid to claim ground in the post-CDK4/6 setting for the large population not eligible for alpelisib due to absence of PIK3CA mutations. RTOR selection signals FDA’s view that the dataset is clean and endpoints are straightforward, but it also reflects Celcuity’s push to convert an unusually large PFS signal into regulatory momentum before competitors tighten their post-CDK4/6 narratives. The design choices matter: the triplet reintroduces CDK4/6 inhibition after prior exposure, a practice area that remains unsettled clinically, while the doublet’s strong hazard ratio could offer a simpler path if tolerability or label constraints limit triplet use.
For sites, a potential approval in a biomarker-defined wild-type population will hinge on operational clarity. If the label is confined to PIK3CA wild-type, upfront testing becomes a gating requirement; if broader, the therapy could be positioned without molecular triage. Either way, sites should plan for monitoring demands associated with PI3K/mTOR pathway inhibition layered onto endocrine therapy, and, for the triplet, the cytopenia management typical of CDK4/6 inhibitors. CROs and sponsors should note that RTOR compresses timelines for data cleaning, eCTD packaging, and CMC readiness; rolling submissions expose any manufacturing or stability gaps early. Vendors supporting safety labs, metabolic monitoring, and mutation testing workflows will need to align with whichever label architecture FDA endorses.
The broader market implication is a recalibration of the post-CDK4/6 playbook. Recent approvals have leaned into targeted add-ons for genomically selected subgroups; a pan-PI3K/mTOR approach with robust PFS in PIK3CA wild-type could widen the addressable pool and pressure sequencing decisions versus options like AKT-pathway inhibitors and selective estrogen receptor degraders. Payer scrutiny will center on absolute benefit, durability, and real-world tolerability, especially for a triplet.
Next, watch for the full VIKTORIA-1 dataset with safety detail, FDA’s stance on triplet versus doublet labeling, and how regulators treat CDK4/6 continuation after progression. Timing matters: with submission completion planned for late 2025, an RTOR-enabled review could be completed by mid-2026 if the package is cohesive. Readouts from the PIK3CA-mutant cohort and the first-line VIKTORIA-2 program will shape lifecycle breadth. The key risks are toxicity management typical of PI3K/mTOR inhibition, the translatability of a 2.0-month control arm PFS to broader practice, and CMC execution under RTOR pace.
Jon Napitupulu is Director of Media Relations at The Clinical Trial Vanguard. Jon, a computer data scientist, focuses on the latest clinical trial industry news and trends.
