Triplex Meets Primary Endpoint in Phase 2 Clinical Trial, Reduces Rate of Cytomegalovirus (CMV) Complications in Transplant Recipients by 50 Percent

March 26, 2019 Off By BusinessWire

First prophylactic vaccine to demonstrate proof of concept for CMV
control independent of human leukocyte antigen (HLA) status in
stem cell transplant recipients

DUARTE, Calif.–(BUSINESS WIRE)–lt;a href=”https://twitter.com/hashtag/CityofHope?src=hash” target=”_blank”gt;#CityofHopelt;/agt;–City
of Hope, a world-renowned cancer research and treatment center,
announced today that Triplex has met its primary endpoint (reduction of
CMV events) in a phase
2 clinical trial evaluating the vaccine for control of CMV
complications in hematopoietic stem cell transplant (HSCT) recipients.
Triplex is a multi-antigen broadly recognized vaccine currently being
developed for CMV control in stem cell and solid organ transplant
recipients.

The multicenter, double-blind, placebo-controlled phase 2 trial was
conducted at three major U.S.-based cancer centers: City of Hope,
Dana-Farber Cancer Institute and MD Anderson Cancer Center. The trial
enrolled 102 allogeneic HSCT recipients with matched related or
unrelated donors who were randomized equally between vaccine and placebo
arms. An independent data monitoring committee confirmed that Triplex
was safe and well-tolerated with no significant difference in adverse
events between arms.

In the trial, patients who received at least one injection of Triplex on
day 28 after HSCT were observed to have 50 percent fewer CMV events
(virus reactivation, antiviral treatment and disease) through day 100
than those who received placebo. There were five subjects with CMV
events in the vaccine arm versus 10 in the placebo arm, one-sided
time-to-event (p=0.08). The trial was designed to have 90 percent power
at a one-sided significance level of 0.10 based on the Cox
proportional-hazard model (time-to-event analysis), deemed appropriate
for an initial phase 2 study.

“CMV is a major complication for many stem cell transplant recipients
that can have severe health consequences,” said Ryotaro
Nakamura, M.D., City of Hope associate professor in the Department
of Hematology & Hematopoietic Cell Transplantation, the trial’s
principal investigator who presented the data at EBMT.

“This City of Hope-led trial demonstrates that Triplex is well tolerated
and displayed potent immunogenicity, providing us with a potential
powerful therapy against CMV,” said City of Hope’s Don
J. Diamond, Ph.D., who invented the vaccine.

The Triplex phase 2 trial results were orally presented at the 45^th
Annual Meeting of the European Society for Blood and Marrow
Transplantation in Frankfurt, Germany. Additional information, including
the presentation abstract, “Multi-antigen vaccine (triplex) based on
attenuated poxvirus prevents cytomegalovirus viremia in a multi-center
placebo-controlled, double blinded, randomized phase 2 clinical trial in
allogeneic HCT recipients,” can be accessed here.

Triplex is a first-in-class, best-in-class, 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 linked to CMV complications
in the transplant setting: UL83 (pp65), UL123 (IE1) and UL122 (IE2).
Helocyte Inc. is the exclusive licensee of Triplex, and provided support
for the completion of the phase 2 trial. Triplex was developed in
partnership with the National Cancer Institute by its lead investigator,
Diamond, of City of Hope. City of Hope acknowledges Bernard Moss, M.D.,
of the National Institute of Allergy and Infectious Disease, Laboratory
of Viral Diseases, who provided materials. In a phase 1 study, Triplex
was found to be safe, well-tolerated and highly immunogenic when
administered to healthy volunteers at multiple dose levels (ClinicalTrials.gov Identifier:
NCT01941056). Triplex is currently the subject of multiple ongoing and
planned studies, one involving vaccination of the donor (followed by the
recipient) in higher-risk stem cell transplant patients (NCT03560752),
potentially introducing CMV immunity sooner and positioning Triplex
ahead of prophylactic antivirals in the standard of care. The lifecycle
of eligible patients is covered with an ongoing trial in pediatric HSCT
patients (NCT03354728).

About City of Hope

City of Hope is an independent biomedical research and treatment center
for cancer, diabetes and other life-threatening diseases. Founded in
1913, City of Hope is a leader in bone
marrow transplantation and immunotherapy such as CAR
T cell therapy. City of Hope’s translational research and
personalized treatment protocols advance care throughout the world.
Human synthetic insulin and numerous
breakthrough cancer drugs are based on technology developed at the
institution. A National Cancer Institute-designated comprehensive cancer
center and a founding member of the National Comprehensive Cancer
Network, City of Hope is ranked one of America’s “Best Hospitals” in
cancer by U.S. News & World Report. Its main campus is
located near Los Angeles, with additional
locations throughout Southern California. For more information about City
of Hope, follow us on Facebook, Twitter, YouTube or Instagram.