Leronlimab Decreases Circulating Tumors Cells and Extends Survival in mTNBC

In a compassionate use study, leronlimab demonstrated major improvement in survival outcomes in patients with metastatic triple-negative breast cancer.

In a compassionate use study, leronlimab (PRO 140) demonstrated major improvement in survival outcomes in patients with metastatic triple-negative breast cancer (mTNBC), according to a press release issued by CytoDyn Inc.1

As detected by the LifeTracDx test following leronlimab induction therapy, a 73% decrease in circulating tumors cells assessed in 30 patients correlated with a 400% to 660% increase in the 12-month progression-free survival (PFS), and an increase of 570% to 980% in the 12-month overall survival (OS). Based on these findings, the LifeTracDx test may be able to identify patients who are likely to respond to leronlimab.

“We are delighted with the results of both [median] PFS and [median] OS when compared to the standard-of-care treatment for mTNBC across Emergency Use, Compassionate Use, mTNBC, and our basket rrial. We anticipate the demand for new therapeutic options with limited toxicity and enhanced convenience for the patient to grow exponentially over the next decade. We believe this is further evidence that leronlimab has a promising role in the future of oncology to help alleviate the burden of cancer on patients and their loved ones. We are exploring opportunities to enhance our oncology platform through pharmacological partnerships, academic partnerships, and research on combining synergistic benefits of leronlimab in the tumor microenvironment, said Scott Kelly, MD, chief medical officer and chairman of the board at CtyoDyn, Inc, in a press release.

The compassionate use study of leronlimab in combination with physician’s choice of single-agent chemotherapy in patients with CCR5-positive mTNBC (NCT0431307) has expanded the access of leronlimab to an intermediate-sized population. In the study, leronlimab is administered subcutaneously at a dose of 350 mg until disease progression or intolerable toxicity. Options for physician’s choice include eribulin, gemcitabine, capecitabine, paclitaxel, nab-paclitaxel, vinorelbine, ixabepilone, or carboplatin.2

“This report of results for 30 patients suggests that, with one blood test, we may be able to predict which mTNBC patients will respond well to leronlimab, which is a truly remarkable finding. These exploratory findings will now enable us to proceed for further regulatory review, said Nader Purhassan, PhD, president, and CEO of CytoDyn, Inc, in a press release.

Patients in the study are evaluated every 3 months for tumor response via CT, PET-CT, or MRI with contrast. Tumor measurements are also conducted according to RECIST v1.1.

To be offered expanded access to leronlimab, patients are required to have histologically confirmed disease that is identified as CCR5-positive by immunohistochemistry. Patients must also have measurable disease per RECST v1.1, be female aged 18 years or older with an ECOG performance status of 0 or 1, a life expectancy of 6 months, and adequate organ and bone marrow function.

Individuals with HER2 overexpression mBC tumors are not eligible to enroll in the study, nor are patients with estrogen-receptor of progesterone-receptor expressing tumors. Patients with PD-L1-positive mTNBC who are eligible to receive atezolizumab (Tecentriq) are excluded from this compassionate use program along with patients who have comorbidities that may interfere with leronlimab treatment.

Leronlimab works by binding to CCR5 to protect healthy T cells. Outside of breast cancer, the agent has been instrumental in the fight against the spread of the coronavirus disease 2019 (COVID-19). In a phase 2 study, leronlimab showed promise for treating patients who are suffering from long-hauler symptoms of COVID-19.


1. CytoDyn’s final mTNBC report indicates as much as 980% increase in 12-month overall survival and up to 660% in 12-month modified progression free survival. New release. CytoDyn, Inc. August 25, 2021. Accessed August 26, 2021. https://bit.ly/2Y1zez1

2. A compassionate use study of leronlimab in breast cancer. Clinicaltrials.gov. Accessed August 26, 2021. https://bit.ly/2Wrdmwx