Three of five patients with advanced colorectal cancer responded to leronlimab, including one complete response lasting five years, according to new data.
Final results indicate that three out of five patients treated with leronlimab had at least a partial response, including one patient with a complete response who remains alive five years later, for patients with advanced metastatic colorectal cancer (mCRC) previously treated with leronlimab, according to a news release from CytoDyn.
Leronlimab is a CCR5 antagonist with the potential for multiple therapeutic indications.
Associate professor at Georgetown University and lead researcher for CytoDyn’s colorectal cancer program, Dr. Benjamin Weinberg, will present clinical findings at the ESMO Gastrointestinal Cancers Congress 2025, held July 2 to 5 in Barcelona, Spain.
Complete response: disappearance of all signs of cancer in response to treatment.
Microsatellite stable (MSS): a type of colorectal cancer that lacks a certain genetic instability and is often less responsive to immunotherapy.
Partial response: cancer has shrunk but not completely disappeared following treatment.
PD-L1 (programmed death-ligand 1): a protein that can suppress the immune system and affect response to immunotherapy.
“At the 2025 ESMO Gastrointestinal Cancers Congress, Dr. Weinberg will share the data and evidence that form the basis for our belief in the potential of leronlimab as a treatment in CCR5 positive solid tumor oncology,” Dr. Jacob Lalezari, CEO of CytoDyn, said in the news release. “Our ongoing phase 2 trial in patients with mCRC was designed to prospectively confirm these observations, and we look forward to enrolling additional patients as we pursue clinical confirmation of our working theory.”
Leronlimab, administered through a compassionate use program, demonstrated favorable safety and potential clinical benefit among patients with metastatic colorectal cancer, according to recent findings. These results help support the design and therapeutic rationale of a currently enrolling phase 2 trial for patients with relapsed or refractory microsatellite stable colorectal cancer, as per the release. The first patient in the study was recently dosed.
If the observed results in previously treated colorectal cancer patients are confirmed in future studies, the company believes leronlimab could be used effectively across a wide range of solid tumor types. In addition to its potential as a stand-alone therapy, CytoDyn presented evidence of leronlimab’s activity as a priming agent for patients with low PD-L1 levels who were previously unresponsive to, or ineligible for, checkpoint inhibitors. These findings were shared at the 2025 ESMO Breast Cancer meeting and showed particular promise in advanced metastatic triple-negative breast cancer.
According to an earlier news release from the company,
Among 17 patients who received weekly doses of 525 milligrams or more, 15 (88%) showed a notable rise in PD-L1 levels within 30 to 90 days. This rise may help convert tumors from “cold” to “hot,” potentially improving response to immunotherapy.
The National Cancer Institute describes cold tumors as those that fail to trigger a strong immune response. These tumors often have surrounding cells that block immune activity, making them resistant to immunotherapy. In contrast, hot tumors do provoke a strong immune response and display markers that help immune cells recognize and attack them, making them more likely to respond to treatment.
“Leronlimab’s induction of PD-L1 on [circulating tumor cells] in patients with otherwise “cold” tumors opens a promising field of exploration for what could amount to significant improvements to patient care and outcomes in solid tumor oncology,” Dr. Richard Pestell, the company’s lead consultant in preclinical and clinical oncology, said in the news release. “We are hopeful that further short-term investigation will confirm our working theory and open new pathways for patients with a range of common and aggressive forms of cancer to access treatment options that were previously out of reach.”
“CytoDyn Announces Encouraging Survival Data in Patients with Metastatic Colorectal Cancer Previously Treated with Leronlimab” by CytoDyn, et al., GlobeNewswire.
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