immune system cytomegalovirus CMV 3d scientific images

Infectious Diseases


Cytomegalovirus is a virus that is commonly transmitted in childhood and early adulthood. Approximately 60% of the U.S. population has been exposed and is latently infected. Worldwide data indicate that while half the people in industrialized countries have been exposed, up to 99% of people in developing countries, including China and India, have been exposed. Infections result in lifelong latent persistence of the virus with few symptoms, if any. However, in unborn children, when infected in utero, CMV infection can lead to significant morbidity and mortality. In addition, in immunosuppressed patients, such as transplant recipients, primary cytomegalovirus infection or reactivation causes significant morbidity, mortality and graft rejection. There are two scenarios in which cytomegalovirus infections are relevant in the transplant setting. In one case, the recipient could be cytomegalovirus negative, or previously uninfected, and the donor cytomegalovirus positive. In this case, introduction of cytomegalovirus into the immunocompromised recipient can lead to rapid virus spread and development of serious complications. In the other case, the recipient is already cytomegalovirus positive, but the immunosuppressive treatments required as part of the transplant procedure lead to reactivation of latent virus.

Cytomegalovirus in Kidney Transplant Patients

High risk kidney transplant recipients are defined as cytomegalovirus-negative patients receiving an organ from a cytomegalovirus-positive donor. In this patient population, approximately 80% develop active cytomegalovirus infection. But also cytomegalovirus-positive individuals undergoing kidney transplantation are at risk of clinically significant CMV infection / re-activation (approximately 40 %). For this population the level of T cell immunity prior to transplantation is predictive of the likelihood that they will develop CMV disease after transplantation. In most solid organ transplant patients, complications from cytomegalovirus develop between 30 and 90 days after transplantation and rarely after 180 days. In 2015, approximately 85,000 of the approximately 126,000 solid organ transplants performed worldwide were kidney transplants, an increase of 5.5% over the previous year.

Our solution: HB-101

HB-101 is a VaxWave®*-based product candidate designed to stimulate the immune system against cytomegalovirus and to protect against future cytomegalovirus infection or reactivation from latency. HB-101 is comprised of two VaxWave®* (LCMV)-based vectors:

  • one vector expresses the gene encoding the cytomegalovirus 65 kD pp65 protein, a validated T cell antigen; and
  • another vector expresses the gene encoding the cytomegalovirus gB protein, a validated B cell / antibody target.

We, and third parties, have shown that pp65 is immunogenic. Adoptive T cell transfer approaches performed by third parties, in which CD8+ T cells directed against pp65 are isolated from exposed individuals and transferred to patients with active cytomegalovirus viremia, have also demonstrated the therapeutic efficacy of pp65. However, no vaccine approach to date has consistently induced CD8+ T cell levels high enough to be protective and has entered clinical Phase 2 testing in solid organ transplantation. gB has been shown in previous third-party clinical trials to be immunogenic and protective by inducing antibody responses but not CD8+ T cells. However, response rates were limited, immunity was transient and protection was incomplete. In our preclinical data, using pp65 and gB as targets, we have observed robust immunogenicity, durability thereby potentially overcoming the limitations of current approaches.

In our Phase 1 clinical trial, HB-101 was well tolerated and elicited a strong cytomegalovirus specific immune responses in all 42 of the treatment arm volunteers. Importantly, we observed robust CD8+ and CD4+ T cell responses as well as cytomegalovirus-neutralizing antibody responses, without meaningful vector neutralizing antibody responses. These responses increased in a statistically significant manner upon repeat administration. The CD8+ T cell levels achieved in our trial were equivalent or higher than those published by third parties, in separately designed and conducted clinical trials, using adoptive T cell transfer approaches for the same antigen which have been shown to be therapeutic. We believe these results demonstrate the differentiating features of our arenavirus platform.

In the fourth quarter of 2018, we commenced a Phase 2 clinical trial for HB-101 in cytomegalovirus-negative patients awaiting kidney transplantation from living cytomegalovirus-positive donors. We expect safety and immunogenicity data from the first cohorts enrolled in this trial in the first half of 2020, and preliminary efficacy data to follow in the second half of 2020.


Hepatitis B

An estimated 257 million people are living with HBV infection (defined as hepatitis B surface antigen positive). In 2015, HBV resulted in 887,000 deaths, mostly from complications including liver cirrhosis and hepatocellular carcinoma. HBV virus is especially common in China and other Asian countries mother-to-child transmission is an important source of viral carriage. HBV is second only to tobacco as a cancer-causing agent.

Our solution: HBV Therapy
The objective of the Hepatitis B virus (HBV) Program is to utilize the HOOKIPA Technologies to design arenavirus vectors (Lymphocytic Choriomeningitis Virus or Pichinde Virus based) suitable for treatment, cure or prevention of HBV. Together with our partner Gilead Sciences we intend to develop functional therapies for patients already infected with the HB Virus.

HOOKIPA has completed the research milestone for HBV by designing and delivering 10 research-grade vectors to Gilead, along with the characterization of these vectors and delivery of a data package for the HBV program. The research vectors delivered by HOOKIPA will be subject to further pre-clinical testing in order to validate a clinical candidate for novel combination therapies for the treatment of HBV.

Human Immunodeficiency Virus (HIV)

Today, HIV continues to be a major global public health issue, having claimed more than 35 million lives so far and affecting approximately 36.9 million people at the end of 2017. HIV research has come a long way since the discovery of the disease in the 1980’s but there is no cure for HIV infection. There are antiretroviral (ARV) drugs that control the virus and help prevent transmission. The goal now is to find a cure for HIV to change the lives of millions affected by the disease.

Our solution: HIV Therapy
The objective of the Human Immunodeficiency Virus (HIV) program is to use HOOKIPA’s technologies to design arenavirus vectors (Lymphocytic Choriomeningitis Virus or Pichinde Virus based) suitable for treatment, cure or prevention of HIV. Together with our partner Gilead Sciences we intend to develop functional therapies for patients already infected with HIV.

HOOKIPA has completed the first research milestone by designing and delivering 14 research-grade vectors to Gilead, along with the characterization of these vectors and delivery of a data package for the HIV program. Pursuant to the terms of the agreement, HOOKIPA achieved its first research milestone in its collaboration and license agreement with Gilead Sciences, Inc. in December 2018.


*Registered in Europe; Pending in the US