CytoDyn to Showcase PD-L1 Upregulation and Improved Survival in Metastatic Triple Negative Breast Cancer at the San Antonio Breast Cancer Symposium
Download as PDFDecember 08, 2025 8:30am EST
Leronlimab treatment is associated with upregulation of PD-L1 in circulating tumor cells and cancer-associated macrophage-like cells
Remarkably longer survival was observed in patients treated with leronlimab in combination with or followed by an immune checkpoint inhibitor
VANCOUVER, Washington, Dec. 08, 2025 (GLOBE NEWSWIRE) -- CytoDyn Inc. (OTCQB: CYDY) ("CytoDyn" or the "Company"
“These leronlimab early-phase clinical trials were started pre-pandemic, when immune checkpoint inhibitors (“ICIs”) were still an emerging option in advanced triple-negative breast cancer,” said Dr. Milana V. Dolezal. “In this pooled analysis, we see sustained clinical benefit over five years later, with five participants (17.9%) still alive and disease-free after treatment with leronlimab, either concurrently with or prior to an ICI. The alignment of these outcomes with emerging mechanistic data, showing leronlimab-driven PD-L1 upregulation, suggests potential synergy with ICIs. This is very encouraging and supports further prospective evaluation. The observed PD-L1 upregulation in the tumor microenvironment, including circulating cells, could have broad oncology implications, including expanding eligibility for ICI combination therapies. In addition, weekly leronlimab injections are well tolerated, with few treatment-emergent adverse events.”
The poster presents updated results from a retrospective follow-up analysis of data from 28 women with mTNBC, who were treated across three leronlimab clinical trials and received a median of 2 prior lines of therapy in the metastatic setting. No dose-limiting toxicities (DLTs) were observed, and no patients withdrew due to treatment-related adverse events.
Key Findings:
100% of patients (n=5/5) who demonstrated induction of PD-L1 greater than 400 Relative Fluorescence Units (“RFUs”) on circulating tumor cells (CTCs), and were then treated with an immune checkpoint inhibitor (“ICI”), remain alive after a median of 60.9 months. Three of these patients currently have no evidence of disease.
Median Overall Survival after starting leronlimab was 7.1 months (95% CI: 4.8–17.7 months) with survival at years 1, 2, 3, and 4 of 35.7%, 21.4%, 17.9% and 17.9%, respectively.
Patients treated with either the 525 or 700 mg dose of leronlimab demonstrated significantly longer survival (HR 3.44, 95% CI: 1.2–9.9; P=0.0418) compared to patients treated with the 350 mg dose.
Utilizing a >400 RFU threshold, treatment with leronlimab was associated with the upregulation of PD-L1 in CTCs and cancer-associated macrophage-like cells (CAMLs) in 76% (n=16/21) of patients overall, and 88% (n=15/17) of patients who received leronlimab at a dose of 525 mg or 700 mg.
Seven patients treated with leronlimab in combination with or followed by an ICI demonstrated significantly longer survival compared to patients (N=21) who were not treated with an ICI (HR 4.14, 95% CI: 1.7–10.2; P=0.0041).
“Given the reduced effectiveness of immunotherapy in patients with mTNBC and low PD-L1 expression, the demonstrated ability of leronlimab to upregulate PD-L1 on CTCs could be a crucial factor for enhancing the efficacy of a combined treatment approach of leronlimab with ICIs,” said Jacob Lalezari, M.D., CEO of CytoDyn. “These results indicate that blocking CCR5 with leronlimab may impact tumors and the tumor microenvironment in such a way as to prime these cells to respond to immune checkpoint inhibition. Prospectively confirming these observations is our top priority.”
A copy of the presentation will be made available on CytoDyn’s website under the Publications & Posters section after it is presented at the symposium.