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CytoDyn’s PRO 140 Monoclonal Antibody Prevents Graft-Versus-Host Disease in Model of Bone Marrow Stem Cell Transplantation

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PRO 140 Currently in Phase 2 Clinical Trial in Leukemia Patients Receiving Bone Marrow Transplants

Preclinical Proof-of-Concept Published in Biology of Blood and Marrow Transplantation

VANCOUVER, Washington, Nov. 14, 2017 (GLOBE NEWSWIRE) -- Newly published research provides preclinical proof-of-concept for the ability of PRO 140, a humanized anti-CCR5 monoclonal antibody under development by CytoDyn Inc. (OTC.QB:CYDY), to effectively block the development of graft-versus-host disease (GvHD), a potentially lethal complication of bone marrow stem cell (BMSC) transplantation. CytoDyn is currently enrolling patients in a Phase 2 clinical trial with PRO 140 for the prevention of GvHD in leukemia patients undergoing BMSC transplantation.

The new publication shows that when immunocompromised mice transplanted with human BMSCs received PRO 140 at a dosing schedule that approximates that being used in the ongoing human clinical trial, the mice showed successful engraftment of human hematopoietic (blood forming) cells without any signs of GvHD. At the same time, control mice all exhibited classical signs of GvHD and none survived (p?0.01). A 10-fold reduction in PRO 140 dose still showed a significant inhibitory effect on GvHD in treated mice, but to a lesser extent.

The study (click on link) by Denis R. Burger, Ph.D., CytoDyn Chief Science Officer, and Daniel Lindner, M.D., Ph.D. of the Department of Translational Hematology and Oncology Research, The Cleveland Clinic, has been published online in the peer-reviewed journal, Biology of Blood and Marrow Transplantation. (Also see: http://www.bbmt.org/article/S1083-8791(17)30810-8/fulltext)

“This research provided CytoDyn with strong rationale for exploring the use of PRO 140 in its second clinical indication, the prevention of GvHD in BMSC transplantation, following our focus on the treatment of HIV infection,” said Dr. Burger. “GvHD is a serious complication that limits the use of BMSC transplantation in patients with blood cancers. The potential of PRO 140 to prevent this life-threatening condition could help extend the use of BMSC transplantation, an important and effective therapy, to more patients.”

PRO 140 targets the CCR5 receptor, a molecule that modulates the immune cell trafficking crucial for the development of acute GvHD and other inflammatory conditions. Previous clinical studies by others have shown that blocking CCR5 using a chemical inhibitor can reduce the clinical impact of acute GvHD without significantly affecting the engraftment of transplanted BMSCs. This new study with PRO 140 further supports the concept that the CCR5 receptor on engrafted cells is critical for the development of acute GvHD and that blocking this receptor from recognizing certain immune signaling molecules is a viable approach to mitigating acute GvHD.

About GvHD

Graft-versus-host disease is a risk when patients receive bone marrow stem cells donated from another person. GvHD occurs when the donor’s immune cells attack the patient’s normal tissues (skin, liver, gut). GvHD can be acute or chronic. Its severity depends on the differences in tissue type between patient and donor. Acute GvHD can occur soon after the transplanted cells begin to appear in the recipient and can range from mild to severe and can be life-threatening. Certain immunosuppressive drugs may help prevent or lessen GvHD. However, GvHD doesn't always respond to these treatments, and it can still result in fatal outcomes. Furthermore, many deaths related to GvHD occur because of infections that develop in patients whose immune systems are suppressed by such drugs.