Minneapolis, USA – March 9, 2026
Celcuity Inc. has announced the publication of positive Phase 3 VIKTORIA-1 clinical trial results evaluating gedatolisib-based regimens in patients with HR+/HER2- advanced breast cancer. The results, published in the Journal of Clinical Oncology, demonstrate that gedatolisib in combination with fulvestrant and palbociclib significantly reduced the risk of disease progression or death compared with standard therapy, offering new hope for patients with limited treatment options following CDK4/6 inhibitor therapy. The findings highlight the potential of gedatolisib, a potent pan-PI3K/mTORC1/2 inhibitor, to deliver improved clinical outcomes by targeting key oncogenic signaling pathways responsible for tumor growth and therapy resistance in advanced breast cancer.
Phase 3 VIKTORIA-1 Trial Shows Strong Clinical Outcomes
The VIKTORIA-1 Phase 3 clinical trial evaluated the safety and efficacy of gedatolisib-based combination therapies in patients with hormone receptor-positive (HR+), HER2-negative advanced breast cancer who experienced disease progression after treatment with CDK4/6 inhibitors and aromatase inhibitors. This subgroup represents a significant portion of metastatic breast cancer patients with limited therapeutic options.
Clinical results showed that the gedatolisib triplet regimen (gedatolisib + palbociclib + fulvestrant) produced a median progression-free survival (PFS) of 9.3 months, compared with 2.0 months for fulvestrant alone, representing an improvement of 7.3 months and a 76% reduction in the risk of disease progression or death. The objective response rate (ORR) for the triplet therapy reached 31.5%, significantly higher than the 1% response rate observed in the control group.
A second treatment arm evaluating the gedatolisib doublet regimen (gedatolisib + fulvestrant) also demonstrated strong results, achieving a median progression-free survival of 7.4 months, representing a 67% reduction in progression risk compared with fulvestrant alone. These findings highlight the potential value of PI3K/AKT/mTOR pathway inhibition as a strategy for improving outcomes in patients with advanced hormone-driven breast cancer.
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Targeting the PI3K/AKT/mTOR Pathway in Breast Cancer
Breast cancer remains one of the most common cancers worldwide, with more than two million cases diagnosed globally each year. Among these, HR+/HER2- breast cancer accounts for nearly 70% of all diagnoses, making it the most prevalent subtype of the disease. Despite advances in targeted therapies, many patients eventually develop resistance to CDK4/6 inhibitors and endocrine therapies, highlighting the need for new treatment approaches.
Gedatolisib addresses this challenge by targeting the PI3K/AKT/mTOR (PAM) signaling pathway, a critical driver of tumor growth and therapy resistance. Unlike currently approved inhibitors that focus on a single component of the pathway, gedatolisib simultaneously inhibits all class I PI3K isoforms and both mTOR complexes (mTORC1 and mTORC2). This multi-target mechanism enables comprehensive blockade of the PAM pathway, potentially preventing the adaptive resistance mechanisms that occur with single-target inhibitors.
Preclinical and early clinical data indicate that gedatolisib demonstrates equal potency in both PIK3CA-mutant and wild-type breast tumor cells, suggesting that the therapy could benefit a broader patient population than currently available PAM-pathway inhibitors. This differentiated mechanism of action positions gedatolisib as a potential next-generation targeted therapy for advanced breast cancer.
Safety Profile and Regulatory Outlook
The safety results from the VIKTORIA-1 trial showed that the gedatolisib-based regimens were generally well tolerated, with most treatment-related adverse events classified as low grade and manageable. The most frequently observed adverse events included neutropenia, stomatitis, rash, and hyperglycemia, which are commonly associated with targeted cancer therapies affecting immune and metabolic pathways.
Importantly, treatment discontinuation due to adverse events occurred in a small percentage of participants, suggesting that the therapy maintains an acceptable safety profile when used in combination regimens. These encouraging findings support continued development of gedatolisib in multiple oncology settings.
Celcuity has also submitted a New Drug Application (NDA) to the U.S. Food and Drug Administration for gedatolisib, which has been granted Priority Review. The agency has assigned a Prescription Drug User Fee Act (PDUFA) target action date of July 17, 2026, potentially paving the way for regulatory approval and commercialization if the therapy demonstrates continued clinical benefit.
The VIKTORIA-1 results mark a significant milestone in the advancement of targeted oncology therapies, reinforcing the importance of precision medicine approaches that inhibit multiple cancer signaling pathways simultaneously. If approved, gedatolisib could become a new treatment option for patients with advanced HR+/HER2- breast cancer, particularly those who have developed resistance to current standard therapies.
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Source: Celcuity Inc. press release
