On February 16, 2023 Helocyte, Inc., ("Helocyte") a subsidiary company of Fortress Biotech, Inc. (Nasdaq: FBIO), reported that data from a Phase 1 pilot trial (see NCT03560752) evaluating the potential safety, immunological response and efficacy of the cytomegalovirus ("CMV") vaccine Triplex to enhance CMV protective immunity in immunosuppressed recipients of allogeneic hematopoietic cell transplants ("HCT") will be presented at the 2023 Tandem Meetings: Transplantation & Cellular Therapy Meetings of ASTCTÔ and CIBMTRâ ("Tandem Meetings"), taking place February 15-19, 2023, in Orlando, Florida (Press release, Helocyte, FEB 16, 2023, View Source [SID1234627332]). Triplex was developed by City of Hope, one of the largest cancer research and treatment organizations in the United States, and exclusively licensed to Helocyte in 2015.

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City of Hope researchers led a pilot trial to explore the vaccination of immunocompetent HCT donors with Triplex to enhance CMV protective immunity in recipients of an allogeneic HCT. Triplex is a recombinant modified vaccinia Ankara ("MVA") viral vector expressing immunodominant CMV antigens, pp65, IE1 and IE2 that has previously been demonstrated to be safe, highly immunogenic and potentially efficacious in both healthy volunteers and HCT recipients. Triplex has been dosed safely in over 100 subjects.

"CMV is still the most common infectious complication in allogeneic HCT and remains of fundamental clinical concern. While preemptive antiviral therapies have greatly reduced the risk of CMV end-organ disease and mortality, such therapies are often associated with significant toxicities, delayed immune reconstitution and even resistance," said Ryotaro Nakamura, M.D., Jan & Mace Siegel Professor in Hematology & Hematopoietic Cell Transplantation, City of Hope. "This novel approach represents a promising strategy to convey CMV protective immunity to HCT recipients early after transplant, and potentially reduce or eliminate the need for antiviral therapy."

The trial, the results of which were also recently published in the American Journal of Hematology, enrolled 17 CMV-seropositive patients who received an HCT from a CMV-seropositive (n=16) or CMV-seronegative (n=1) matched related donor ("MRD") vaccinated with Triplex prior to stem cell harvest.[i] Donor and recipient pairs who participated in the trial were observed to have adhered closely to the protocol. Triplex was generally well-tolerated in stem cell donors who participated in the study with no serious adverse events reported. All HCT recipients were fully engrafted with stem cells of donor origin without delay. On day 28 post-HCT, levels of functional CMV and vaccine-specific CD137+CD8+ T cells were observed to be significantly higher (p=0.017 and for pp65 alone, p<0.0001) in recipients of Triplex-vaccinated MRD compared to a control cohort of recipients of HCT from an unvaccinated MRD. CMV events requiring antiviral intervention in recipients with Triplex-vaccinated donors were observed to be lower (18%) than those in similar cohorts prophylactically treated with the antiviral, letermovir (37%).

Lindsay A. Rosenwald, M.D., Fortress’ Chairman, President and Chief Executive Officer, said, "We are encouraged by the results of this pilot study that further demonstrate the potential safety, immunogenicity, and efficacy of Triplex. The donor vaccination paradigm deployed in the trial may be applicable to other (higher risk) HCT settings, including those involving haploidentical or mis-matched donors – thereby potentially reducing the need for antivirals, which have been associated with significant toxicities and delayed immune reconstitution. We look forward to advancing the development of Triplex, which is currently the subject of multiple ongoing and planned clinical trials in HCT, solid organ transplantation, Human Immunodeficiency Virus and in combination with CAR-T therapy, most of which are supported by funding from the National Institutes of Health."

Details of the presentation are as follows:

Abstract number: 82
Title: CMV-MVA Triplex Vaccination of Stem Cell Donors to Enhance CMV Specific Immunity and Prevent CMV Viremia in Recipients after Stem Cell Transplant
Date and Time: Saturday, February 18, 11:00 a.m. – 11:15 a.m. ET
Location: World Center Marriott – Crystal NPQ
Presenter: Ryotaro Nakamura, M.D., Jan & Mace Siegel Professor in Hematology & Hematopoietic Cell Transplantation, City of Hope, Duarte, CA
For more information about the 2023 Tandem Meetings, please visit: View Source

About Triplex
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 2 trial for CMV control in HCT recipients with haploidentical donors (see NCT04060277); 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 trial for CMV control in HCT recipients in which the donor is vaccinated with Triplex; a Phase 2 for CMV control in recipients of liver transplant; and a Phase 2 trial for CMV control in recipients of kidney transplant.