Helocyte Announces $3.22-Million Grant from the National Cancer Institute for Triplex Phase 2 Clinical Trial Program

Helocyte, Inc. recently announced the National Cancer Institute (NCI) has awarded a $3.22-million grant to City of Hope for clinical studies of Triplex, a cytomegalovirus (CMV) vaccine being developed by Helocyte and City of Hope. This competitive award will fund two planned multicenter, placebo-controlled, randomized Phase 2 studies to evaluate the potential safety and immunological response of Triplex and its ability to enhance CMV-specific T cell immunity in stem cell donors to reduce the risk of CMV events in recipients of allogeneic hematopoietic cell transplant (HCT). Triplex was initially developed by City of Hope, one of the largest cancer research and treatment organizations in the US, and exclusively licensed to Helocyte in 2015.

“Triplex has shown potential to enhance the transfer of CMV immunity from HCT donors to high-risk transplant recipients and reduce the use of antiviral prophylaxis that can impair and delay CMV immune reconstitution,” said Don J. Diamond, PhD, Professor, Hematology & Hematopoietic Cell Transplantation, City of Hope in Los Angeles, California and the grants’ principal investigator. Diamond and his team developed Triplex and he serves as a consultant to Helocyte. “We look forward to further evaluating this novel strategy that may provide a more effective approach to managing CMV events in those undergoing HCT.”

The initial Phase 2 clinical trial will build upon Phase 1 pilot trial data (NCT03560752) that evaluated the potential safety and immunological response of Triplex presented at the 2023 Tandem Meetings: Transplantation & Cellular Therapy Meetings of ASTCT and CIBMTR and published in American Journal of Hematology. The study will be conducted across up to 3 nationally recognized transplant centers in the United States. A second trial, also funded by the award, will formally test the same concept, and will include highest-risk transplant recipients, who are only partially HLA-matched to their donors. Preliminary work for that transplant population was carried out under NCT04060277.

Lindsay A. Rosenwald, MD, Fortress’ Chairman and Chief Executive Officer, said “We are very excited that Triplex, being progressed by Helocyte, is the subject of this NCI grant which will enable the further evaluation of the vaccine’s potential to control CMV in patients undergoing high-risk HCT. CMV is a common opportunistic infection in transplantation, directly impacting post-transplant outcomes and patient mortality. The trial will build upon the growing patient database of Triplex, which has already been dosed safely in over 150 patients and volunteers, and is the subject of multiple other ongoing and planned studies.”

Research reported in this publication was supported by the NCI of the National Institutes of Health under Award Number R01CA266783. The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH. Helocyte will provide clinical materials to support the trial.

Triplex is a universal (non-HLA-restricted) recombinant Modified Vaccinia Ankara viral vector vaccine engineered to induce a robust and durable virus-specific T cell response to three immuno-dominant proteins [UL83 (pp65), UL123 (IE1), UL122 (IE2)] linked to CMV complications in the post-transplant setting. In previous Phase 1 and Phase 2 studies, Triplex was found to be safe, well-tolerated and highly immunogenic. Triplex is currently the subject of multiple ongoing clinical trials, including: a Phase 1/2 trial for CMV control in pediatric recipients of HCT (see NCT03354728); a Phase 2 trial for reduction in viral load of Human Immunodeficiency Virus (“HIV”) in adults co-infected with HIV and CMV (see NCT05099965); and a Phase 1 trial of Triplex in combination with a bi-specific CMV/CD-19 Chimeric Antigen Receptor T Cell for the treatment of Non-Hodgkin Lymphoma (see NCT05432635). Triplex is also the subject of several planned studies, including: a Phase 2 evaluation for CMV control in recipients of liver transplant; and a Phase 2 trial for CMV control in recipients of kidney transplant.

Helocyte is a clinical-stage company developing novel immunotherapies for the prevention and treatment of cancer and infectious disease (and in particular, cytomegalovirus or CMV). The Centers for Disease Control estimate that 50 to 80 percent of Americans are infected with CMV by the age of 40. While the virus is asymptomatic in healthy individuals, it can cause severe and life-threatening disease in those with weakened or uneducated immune systems. Patients undergoing allogeneic stem cell and solid organ transplantation are at particularly high risk of experiencing complications associated with CMV. According to the Center for International Blood and Marrow Transplant Research, there were over 9,000 unrelated and related bone marrow and cord blood transplants performed in the United States in 2020. According to preliminary data from the Organ Procurement and Transplantation Network, there were over 40,000 organ transplants performed in the US in 2021, composed primarily of kidney and liver transplant procedures. Helocyte’s Triplex vaccine is engineered to induce a robust and durable virus-specific T cell response to control CMV in transplant recipients. While current antiviral therapies have reduced the rate of CMV disease-related mortality in transplant recipients, such treatments have been linked to increased toxicity, delayed immune reconstitution and late onset of CMV. The Helocyte vaccines can educate the body’s innate immune system to fight CMV. For more information, visit www.helocyte.com.