What Does a Positive Reading for Leronlimab Mean for How the Industry Thinks About Repurposing Old Biologics Into Oncology?

Dr. Jay Lalezari, CEO and CMO, CytoDyn, describes the company’s circulating tumor DNA readouts in MSS colorectal cancer as compelling evidence that Leronlimab is doing something unprecedented, serving as a proof of concept that could extend to other solid tumors if the mechanism holds.

Dr. Lalezari is careful, to frame this as a one-off story rather than a template for repurposing biologics broadly, saying, no other HIV or inflammatory drug shares Leronlimab’s specific ability to competitively bind the CCR5 receptor and disrupt the signaling cancer uses to build a protective microenvironment that keeps the host immune system out. Once that blockade happens, he says, everything observed in breast and colon cancer follows from that single mechanistic step, something unique to this drug.

Reflecting on moving CCR5 blockade into FDA-level trial design for metastatic colorectal cancer, Lalezari says the science itself has exceeded his expectations, describing a narrative that connects CCR5’s discovery in HIV-resistant sex workers, Dr. Pastel’s work on cancer’s use of the receptor, and CytoDyn’s own finding that breast cancer patients who received Leronlimab and later a checkpoint inhibitor after expressing PD-L1 are still alive today, a finding he links conceptually to how fetuses use PD-L1 to evade the maternal immune system.

What’s proven harder than anticipated, he says, is simply navigating institutional friction in today’s environment, noting that despite having far more primitive tools decades ago, getting things done now feels more difficult, which he attributes partly to a broader post-Covid societal shift toward caution and resistance. Despite that friction, he remains highly optimistic, citing public data on DNA declines, comparator and dose-response data, and tumor shrinkage data heading into the ASCO GI meeting, stating he believes Leronlimab’s success is now inexorable regardless of broader institutional dysfunction.