CytoDyn to Present on Leronlimab Induction of PD-L1 and Immune Checkpoint Inhibitor Responses in Metastatic Triple-Negative Breast Cancer at the AACR Special Conference: Mechanisms of Cancer Immunity and Cancer-related Autoimmunity

Company to deliver oral and poster presentations for data on leronlimab’s action on PD-L1 expression and patient survival in triple-negative breast cancer

VANCOUVER, Washington, Sept. 25, 2025 (GLOBE NEWSWIRE) — CytoDyn Inc. (OTCQB: CYDY) (“CytoDyn” or the “Company”), a clinical-stage oncology company advancing leronlimab, a first-in-class humanized monoclonal antibody targeting the CCR5 receptor with therapeutic potential across multiple indications, including triple-negative breast cancer (TNBC) and colorectal cancer (CRC), will present a poster and an oral presentation at the AACR Special Conference in Cancer Research: Mechanisms of Cancer Immunity and Cancer-related Autoimmunity, taking place September 24, to September 27, 2025, in Montreal, Canada.

Metastatic triple-negative breast cancer (mTNBC) is associated with a very poor prognosis. The efficacy of a class of drugs called immune checkpoint inhibitors (ICIs) is reduced in patients with mTNBC who have low levels of PD-L1^[1]. An immune cell receptor called CCR5 has been observed in up to 95% of patients with TNBC. A recent review of CytoDyn’s prior oncology trials suggests that treatment with leronlimab, a humanized monoclonal antibody targeting CCR5, combined with an ICI, may improve survival in patients with mTNBC ^[2]. This retrospective analysis of 28 patients demonstrated that leronlimab induced PD-L1 expression on circulating tumor cells in 88% of patients treated at leronlimab doses of > 525mg/week. Moreover, 5/5 patients who induced PD-L1, and received treatment with both leronlimab and an ICI, remain alive after a median of ~60 months since starting leronlimab.

Key Findings:

• CCR5 inhibition combined with ICI therapy increased overall survival in patients with mTNBC, with 18% of heavily pretreated mTNBC patients alive after a median of ~60 months.
• Inhibition of CCR5 by leronlimab induced PD-L1 expression on patient circulating tumor cells.
• Expression levels of CCR5 correlate with T cell infiltration in TNBC.

“These impressive findings on how leronlimab can serve to make metastatic triple-negative breast cancer cells more responsive to checkpoint inhibitors are of great value as we move this asset forward for oncology indications,” said Jacob Lalezari, M.D., CEO of CytoDyn. “Understanding this immune-modulating mechanism not only deepens insight into how leronlimab works, but also supports its potential as a broadly applicable therapy for a range of solid tumors that historically have had limited treatment options.”

“The substantial increases in PD-L1 expression, observed in liquid biopsies of patients treated with leronlimab, may be the key to unlocking the effectiveness of immune checkpoint inhibitors for patient populations previously deemed resistant to such approaches,” said Richard Pestell, M.D., Ph.D., FRCP, AO, Presenter and Lead Consultant in Preclinical and Clinical Oncology at CytoDyn. “These results suggest leronlimab may remodel the tumor immune environment in metastatic triple-negative breast cancer, a particularly challenging form of the disease.”

Details of the oral and poster presentations are as follows:

Abstract Title:
CCR5 inhibition with leronlimab is associated with enhanced PD-L1 expression, ICI response, and long‑term survival in metastatic TNBC

Poster presentation:
September 26, 2025, 6:30 p.m. – 8:30 p.m. EDT

Podium/speaking presentation:
September 27, 2025, 10:25 a.m. – 10:40 a.m. EDT

About CytoDyn

CytoDyn is a clinical-stage oncology company dedicated to advancing leronlimab, a first-in-class humanized monoclonal antibody that targets the CCR5 receptor, a key regulator of immune function implicated in cancer, infectious diseases, and autoimmune disorders. By unlocking a well-validated mechanism of action with broad therapeutic potential, CytoDyn is developing a versatile platform designed to address serious unmet medical needs and serve multiple high-value markets. Guided by a mission to improve patients’ quality of life through therapeutic innovation, CytoDyn is committed to integrity, responsibility, and service as it works to bring transformative treatments to patients worldwide.

For more information, please visit www.cytodyn.com and follow us on LinkedIn.

Note Regarding Forward-Looking Statements

This news release may contain forward-looking statements relating to, among other things, mechanism of action, clinical trial results, product development, market position, future operating and financial performance, and business strategy. The reader is cautioned not to rely on these statements, which are based on current expectations of future events. For important information about these statements and our Company, including the risks, uncertainties and other factors that could cause actual results to vary materially from the assumptions, expectations and projections expressed in any forward-looking statements, the reader should review our Annual Report on Form 10-K for the fiscal year ended May 31, 2025, including the section captioned “Forward-Looking Statements” and in Item 1A, as well as subsequent reports filed with the Securities and Exchange Commission. CytoDyn Inc. does not undertake to update any forward-looking statement as a result of new information or future events or developments except as required by applicable law.

Corporate Contact

CytoDyn Inc.
ir@cytodyn.com

Media Contacts
Rob Haney, Ph.D., or Ignacio Guerrero-Ros, Ph.D.
Russo Partners, LLC
CytoDyn@russopartnersllc.com

1. Winer et al. Lancet Oncol 2021. 22 (4)
2. Pestell, R. et al. 369P ESMO Breast Munich, Germany. May 15, 2025