CytoDyn to Showcase PD-L1 Upregulation and Improved Survival in Metastatic Triple Negative Breast Cancer at the San Antonio Breast Cancer Symposium

Rhea-AI Summary

CytoDyn (OTCQB: CYDY) announced a poster presentation at the San Antonio Breast Cancer Symposium showing cleronlimab (leronlimab) treatment associated with PD-L1 upregulation on circulating tumor cells and cancer-associated macrophage-like cells in metastatic triple-negative breast cancer (mTNBC).

Key reported outcomes from a pooled retrospective analysis of 28 women: median overall survival 7.1 months (95% CI: 4.8–17.7), survival at years 1–4 of 35.7%, 21.4%, 17.9%, 17.9%; 100% (5/5) of patients with PD-L1 induction >400 RFU who then received an ICI remain alive after median 60.9 months; PD-L1 upregulation seen in 76% (16/21) overall and 88% (15/17) at 525/700 mg; higher doses showed longer survival (HR 3.44; P=0.0418) and ICI-treated patients had longer survival (HR 4.14; P=0.0041).

Positive

• 100% (5/5) with PD-L1 >400 RFU then treated with ICI alive at median 60.9 months
• PD-L1 upregulation in 76% (16/21) of patients overall
• PD-L1 upregulation in 88% (15/17) at 525/700 mg doses
• Patients receiving 525/700 mg showed longer survival (HR 3.44; P=0.0418)
• ICI-treated subgroup showed longer survival (HR 4.14; P=0.0041)

Negative

• Median overall survival after starting leronlimab was 7.1 months (95% CI: 4.8–17.7)
• Small cohort: pooled analysis of 28 patients limits statistical power
• Only 7 patients received ICI after leronlimab, constraining subgroup conclusions

News Market Reaction

+2.97%

1 alert

+2.97% News Effect

On the day this news was published, CYDY gained 2.97%, reflecting a moderate positive market reaction.

Data tracked by StockTitan Argus on the day of publication.

Key Figures

Patient sample size: 28 women with mTNBC Prior therapy lines: Median 2 prior lines High PD-L1 responders: 5/5 with >400 RFU PD-L1 +5 more

8 metrics

Patient sample size 28 women with mTNBC Retrospective pooled analysis across three leronlimab trials

Prior therapy lines Median 2 prior lines Metastatic treatment setting before leronlimab

High PD-L1 responders 5/5 with >400 RFU PD-L1 CTCs with PD-L1 induction then treated with an ICI

Long-term survival Median 60.9 months Follow-up in 5 high PD-L1 patients receiving an ICI

No evidence of disease 3 patients Among high PD-L1 patients alive after leronlimab + ICI

Median overall survival 7.1 months (95% CI: 4.8–17.7) From start of leronlimab in 28 mTNBC patients

Higher dose benefit HR 3.44; P=0.0418 525/700 mg leronlimab vs 350 mg on survival

Equity facility size $30.0 million Standby Equity Purchase Agreement tied to S-3 registration

Market Reality Check

Price: $0.2444 Vol: Volume 561,649 is about 0...

low vol

$0.2444 Last Close

Volume Volume 561,649 is about 0.25x the 20-day average of 2,205,058, showing muted trading interest before this update. low

Technical Price 0.32724 is trading above the 200-day MA of 0.29 and 33.82% below the 52-week high.

Peers on Argus

CYDY was up 0.92% while close peers showed mixed, mostly small moves: NWBO down ...

CYDY was up 0.92% while close peers showed mixed, mostly small moves: NWBO down 0.21%, NGENF up 0.64%, others flat. This points to a stock-specific reaction rather than a broad biotech move.

Historical Context

5 past events · Latest: Dec 08 (Positive)

Pattern 5 events

Date	Event	Sentiment	Move	Catalyst
Dec 08	Clinical poster data	Positive	+3.0%	Detailed SABCS poster data linking PD-L1 upregulation with improved survival.
Dec 01	Litigation settlement	Positive	+0.5%	Agreement in principle to settle long‑running securities class action.
Nov 24	Clinical poster preview	Positive	+9.6%	Advance notice of SABCS poster showing prolonged survival with leronlimab.
Nov 03	Financing commitment	Positive	+11.3%	$30 million Standby Equity Purchase Agreement to fund leronlimab programs.
Oct 09	Investor conference	Neutral	-2.3%	Planned LD Micro presentation outlining leronlimab development strategy.

Pattern Detected

Recent positive clinical and financing news for CYDY has generally aligned with positive next-day price reactions, suggesting the stock has tended to respond constructively to favorable updates.

Recent Company History

This announcement adds detailed survival and biomarker data for leronlimab in metastatic triple‑negative breast cancer, following prior disclosures about the same SABCS poster on Nov 24, 2025 and today’s own earlier summary. Over recent months, CytoDyn secured a $30 million equity commitment, flagged going‑concern risks in its Oct 10, 2025 10‑Q, and advanced oncology programs. It also reached an agreement in principle on a securities class action settlement, outlined in an 8‑K on Dec 1, 2025. Together, these events show simultaneous clinical progress and significant financing and legal overhangs.

Regulatory & Risk Context

Active S-3 Shelf · $30.0 million

Shelf Active

Active S-3 Shelf Registration 2025-11-04

$30.0 million registered capacity

An effective S-3 shelf prospectus has been filed to register up to 120,000,000 shares for resale tied to a Standby Equity Purchase Agreement of up to $30.0 million. While CytoDyn will not receive proceeds from resales by YA II PN, Ltd., the arrangement supports potential future share issuance under the Yorkville commitment and highlights ongoing reliance on equity for funding.

Market Pulse Summary

This announcement highlights updated leronlimab data in metastatic triple‑negative breast cancer, in...

Analysis

This announcement highlights updated leronlimab data in metastatic triple‑negative breast cancer, including PD‑L1 upregulation and prolonged survival in a subset of 28 patients, with 5 high PD‑L1 responders alive at a median of 60.9 months and 3 showing no evidence of disease. It follows earlier SABCS previews and sits alongside notable financing steps, such as the $30.0 million equity facility, and legal developments including a proposed class‑action settlement. Investors may watch for prospective trials to confirm these retrospective findings and for future capital‑raising or dilution.

Key Terms

pd-l1, circulating tumor cells, cancer-associated macrophage-like cells, immune checkpoint inhibitor, +4 more

8 terms

pd-l1 medical

"Leronlimab treatment is associated with upregulation of PD-L1 in circulating tumor cells"

PD-L1 is a protein found on the surface of some cells that acts like a stop sign for the immune system, telling certain immune cells to back off. It matters to investors because many cancer drugs and diagnostic tests target or measure PD-L1 to unlock immune responses or predict which patients will benefit, affecting clinical success, regulatory approval, and potential sales in the oncology market.

circulating tumor cells medical

"upregulation of PD-L1 in circulating tumor cells and cancer-associated macrophage-like cells"

Circulating tumor cells are cancer cells that break away from a tumor and travel in the bloodstream, detectable through a blood test. Investors care because their presence and number can act like a real-time signal — similar to footprints showing where a person has been — revealing disease progression, response to treatment, or risk of metastasis, which influences the market value of diagnostics, therapies and clinical trial outcomes.

cancer-associated macrophage-like cells medical

"in circulating tumor cells and cancer-associated macrophage-like cells"

Cancer-associated macrophage-like cells are unusually large cells found circulating in the blood that resemble immune cells and are shed from tumors or the tumor environment. For investors, their presence and number can act like a real-time warning light — offering a noninvasive signal about cancer presence, how aggressive it may be, and whether a treatment is working, which can inform the value of diagnostics, monitoring tools, or therapies tied to oncology markets.

immune checkpoint inhibitor medical

"treated with leronlimab in combination with or followed by an immune checkpoint inhibitor"

An immune checkpoint inhibitor is a type of medicine that helps the body's immune system recognize and attack cancer cells more effectively. It works by blocking certain signals that cancer uses to hide from immune defenses, allowing the immune system to target tumors. This breakthrough has led to new cancer treatments, making immune checkpoint inhibitors an important area of growth and innovation in the healthcare industry.

dose-limiting toxicities medical

"No dose-limiting toxicities (DLTs) were observed"

Dose-limiting toxicities are the harmful side effects seen in early clinical trials that are severe enough to stop researchers from raising a drug’s dose. Like a car’s speed limiter marking the safe top speed, DLTs define the maximum tolerable dose, and they matter to investors because they determine whether a medicine can reach effective levels, influence development timelines, costs, and regulatory chances, and thus affect a drug’s commercial prospects.

hazard ratio medical

"demonstrated significantly longer survival (HR 3.44, 95% CI: 1.2–9.9; P=0.0418)"

A hazard ratio is a way scientists compare the chance of something happening over time between two groups, like patients taking different medicines. If the ratio is high, it means one group is more likely to experience the event sooner or more often, which helps determine how effective a treatment is or how risky a situation might be.

tumor microenvironment medical

"may impact tumors and the tumor microenvironment in such a way as to prime"

The tumor microenvironment is the immediate area surrounding a cancer cell, made up of nearby cells, blood vessels, and support structures that influence how the cancer grows and spreads. It functions like a bustling neighborhood that can either help or hinder the tumor’s development. For investors, understanding changes in this environment can signal the effectiveness of treatments and potential shifts in a cancer-related market.

relative fluorescence units technical

"induction of PD-L1 greater than 400 Relative Fluorescence Units (“RFUs”) on circulating tumor cells"

Relative fluorescence units (RFU) are a laboratory measure of how much fluorescent light a sample gives off when exposed to specific light, reported as a numerical readout rather than an absolute physical unit. For investors, RFU values matter because they show how strongly a diagnostic test, drug assay, or research experiment is detecting a target—like a brightness reading on a light meter—helping judge a product's sensitivity, consistency and the reliability of reported lab results.

AI-generated analysis. Not financial advice.

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"), 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 metastatic triple-negative breast cancer (“mTNBC”) and colorectal cancer (“mCRC”), today announced that breast cancer specialist and medical oncologist, Milana V. Dolezal, MD, MSci, is presenting a poster entitled “Prolonged survival following PD-L1/PD-1 immune checkpoint inhibitor therapy after leronlimab induced PD-L1 upregulation on cancer-associated macrophage-like cells and circulating tumor cells in patients with metastatic or locally advanced triple-negative breast cancer” at the San Antonio Breast Cancer Symposium (SABCS). The poster (ID: PS5-02-30) will be presented in the Exhibit Hall on December 12, 2025, from 12:30 p.m. – 2 p.m. CST.

“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.

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. 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, the mechanism of action of leronlimab, 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
David Schull or Ignacio Guerrero-Ros, Ph.D.
Russo Partners, LLC
CytoDyn@russopartnersllc.com

FAQ

What did CytoDyn (CYDY) report about leronlimab at SABCS on December 12, 2025?

CytoDyn presented pooled data showing leronlimab-associated PD-L1 upregulation on CTCs/CAMLs and reported survival metrics including median OS 7.1 months.

How common was PD-L1 upregulation after leronlimab in the CYDY mTNBC analysis?

PD-L1 upregulation occurred in 76% (16/21) overall and 88% (15/17) for patients dosed at 525 or 700 mg.

What survival benefit was seen for CYDY patients receiving higher leronlimab doses?

Patients treated with 525/700 mg showed significantly longer survival versus 350 mg (HR 3.44, P=0.0418).

Did any CYDY patients respond to immune checkpoint inhibitors after leronlimab?

Yes; 7 patients who received an ICI after or with leronlimab had significantly longer survival (HR 4.14, P=0.0041), and 5 patients with PD-L1 >400 RFU who received ICI remain alive at median 60.9 months.

How many mTNBC patients were included in CytoDyn's pooled leronlimab analysis?

The retrospective pooled analysis included 28 women with metastatic triple-negative breast cancer treated across three leronlimab trials.