Leronlimab Shows Survival Signal in Advanced Breast Cancer

VANCOUVER, WA – February 20, 2026 – Clinical-stage oncology company CytoDyn Inc. has presented compelling new data suggesting its investigational drug, leronlimab, is associated with long-term survival in patients with metastatic triple-negative breast cancer (mTNBC), one of the most aggressive and difficult-to-treat forms of the disease. The findings, unveiled at the prestigious AACR Immuno-Oncology Conference, offer a glimmer of hope for a patient population with critically unmet medical needs.

The data, derived from a pooled retrospective analysis of 28 heavily pretreated patients, revealed that nearly 18% of participants were still alive after a median follow-up of more than five years. Alongside these encouraging survival signals, the company reported that leronlimab demonstrated a favorable safety profile with no therapy-limiting toxicities.

A New Strategy for a Formidable Foe

Metastatic triple-negative breast cancer is notoriously challenging. Lacking the estrogen, progesterone, and HER2 receptors that fuel other breast cancers, it is unresponsive to common hormone therapies or targeted HER2 drugs. For decades, chemotherapy has been the primary weapon, but for patients whose disease progresses after multiple rounds of treatment, options become scarce and prognoses grim, with median survival often measured in months, not years.

CytoDyn’s announcement centers on a retrospective look at patients from three previous clinical trials. While the cohort of 28 patients is small, the observation that five of them (17.9%) have survived for over 63 months is a significant outlier in this disease space. This durable clinical observation, coupled with a manageable safety profile, has captured the attention of researchers and patient advocates alike.

The current landscape for mTNBC includes immune checkpoint inhibitors (ICIs) like Merck’s Keytruda, which are effective but only for the roughly 40% of patients whose tumors express the PD-L1 protein. For the majority of patients, and for those who have exhausted other options, the need for novel therapeutic strategies is urgent. Antibody-drug conjugates (ADCs) such as Gilead's Trodelvy have offered another major step forward, but the demand for more effective and less toxic treatments remains high.

Unlocking the Immune System's Power

Beyond the survival numbers, the data presented by CytoDyn provides a deep dive into the scientific rationale behind leronlimab's potential. The drug is a monoclonal antibody that targets CCR5, a receptor on immune cells that plays a key role in inflammation and immune function. While CCR5 is best known for its role in HIV, for which leronlimab was initially developed, researchers have increasingly implicated it in cancer progression and immune evasion.

The new preclinical and translational findings suggest leronlimab may work by remodeling the tumor microenvironment. “In this study, we continued to explore how CCR5 signaling may contribute to immune checkpoint resistance in metastatic triple-negative breast cancer,” said Professor Richard Pestell, M.D., Ph.D., Lead Consultant in Preclinical and Clinical Oncology at CytoDyn. “Mechanistic findings suggest that CCR5 blockade with leronlimab may modulate pathways associated with T-cell exhaustion and PD-L1/PD1 regulation, providing a mechanistic rationale for combination strategies with immune checkpoint inhibitors.”

Essentially, the research indicates that leronlimab could act as a primer, making tumors more recognizable and vulnerable to the body's immune system. The data showed that blocking CCR5 with leronlimab increased the abundance of PD-L1 on cancer cells and PD1 on T cells. These are the very targets of blockbuster ICI drugs, suggesting leronlimab could potentially convert "cold" tumors, which are unresponsive to immunotherapy, into "hot" tumors that are, or enhance the response in patients who are already eligible. Furthermore, the treatment was shown to reduce the secretion of several immunosuppressive molecules from cancer cells, further tilting the battlefield in favor of an anti-tumor immune response.

A Pivotal Moment for CytoDyn

For CytoDyn, these findings represent a potentially transformative moment. The company has navigated a complex path, including past regulatory setbacks with the FDA concerning leronlimab's development for other indications like HIV and COVID-19. A full clinical hold on its COVID-19 program in 2022 and the withdrawal of a Biologics License Application for HIV created significant headwinds.

However, the company has since worked to right the ship. The FDA lifted the clinical hold on its HIV program in February 2024, and the leadership has sharpened its focus on oncology, where leronlimab’s immunomodulatory mechanism may hold the most promise. This strategic pivot towards mTNBC and other cancers appears to be gaining traction.

“These data strengthen the clinical case for leronlimab in metastatic TNBC by aligning mechanistic insights with encouraging safety and long-term survival observations,” said Dr. Jacob Lalezari, M.D., Chief Executive Officer of CytoDyn. He noted that the consistency of the findings supports the company's decision to pursue further clinical development, particularly in combination with other immunotherapies.

The road ahead remains challenging. The promising survival signals are from a retrospective analysis and must be validated in larger, prospectively designed clinical trials. CytoDyn is planning a Phase 2 trial in mTNBC to do just that. In a move that signals both confidence and a commitment to patients, the company also recently secured funding to launch an Expanded Access Program (EAP) in March 2026, which will provide leronlimab to eligible mTNBC patients who cannot enroll in clinical trials. This step, funded by an anonymous benefactor, provides a near-term path for patient access while the more rigorous clinical validation proceeds, offering a tangible lifeline for those facing the most difficult prognoses. The true test will be whether these early, encouraging signs can be translated into a proven, approved therapy that can change the standard of care.