HOOKIPA Announces Positive Phase 2 Interim Safety and Immunogenicity Results for its CMV Vaccine Candidate HB-101 Interim data demonstrate that HB-101 is well tolerated HB-101 elicits T cell and B cell responses in the t

HOOKIPA Announces Positive Phase

2 Interim Safety and Immunogenicity Results for its CMV Vaccine Candidate HB-101

York, US and Vienna, Austria, June 22, 2020 - HOOKIPA Pharma Inc. (NASDAQ: HOOK, HOOKIPA'), a company developing

a new class of immunotherapeutics targeting infectious diseases and cancers based on its proprietary arenavirus platform, today

announced positive interim results on its prophylactic Cytomegalovirus (CMV) vaccine candidate HB-101. HB-101 is being investigated

in a double-blind Phase 2 clinical trial (NCT03629080) to assess safety, immunogenicity and efficacy in patients receiving a kidney

transplant from a live donor. HOOKIPA reported interim data on the trial's primary endpoints, safety and B cell and T cell

Trial participants were blinded and randomized

2:1 to receive either HB-101 or placebo. Patients received either 2 or 3 doses prior to transplantation, depending on the transplantation

Tolerability profile of HB-101

Safety and tolerability were evaluated

in 51 CMV-negative patients prior to kidney transplantation. Of the 51 patients, only eight patients (16%) across the combined,

blinded HB-101 and placebo groups showed adverse events related to the administration. Most of these adverse events were of mild

intensity, indicating that HB-101 is generally well tolerated in this patient population. Of note, this target patient population

reported fewer adverse events than the 54 healthy volunteers in HOOKIPA's recently published Phase 1 trial results1.

CMV-neutralizing antibody response to

For the interim analysis, CMV-neutralizing

antibody titers on the day of transplantation were evaluated in all of the 30 CMV-negative patients who had been transplanted by

the cutoff date and had valid results. Nineteen of the 30 patients received HB-101 and eleven received placebo. All five patients

(100%) who received three doses of HB-101 mounted CMV-neutralizing antibodies. Three of the fourteen patients (21%) who received

only two doses of HB-101 also mounted CMV-neutralizing antibodies. The antibody response of the kidney transplant recipients who

completed the three-dose regimen was comparable to the antibody response observed in the Phase 1 trial.

T cell responses to HB-101

Cellular immune responses to CMV on the

day of transplantation were evaluated in 25 CMV-negative patients who had been transplanted in time for this interim analysis.

Technically valid results from T cell assays on the day of transplantation were available for seven recipients (as a consequence

of sample logistics and assay performance). Two of the seven patients received placebo and five received HB-101. All three patients

(100%) who received three doses of HB-101 and one of the two patients who received only two doses (50%) mounted a

Schwendinger M, et al. J Infect Dis. 2020. pii: jiaa121. doi: 10.1093/infdis/jiaa121

cellular immune response.

interim data demonstrate that HB-101 is well tolerated with fewer adverse events in patients with end-stage kidney disease than

in the previous healthy volunteer trial. Patients who received three doses of HB-101 show comparable immunogenicity to healthy

volunteers in HOOKIPA's Phase 1 clinical trial of HB-101.

interim results demonstrate that the vaccine is well-tolerated and immunogenic in patients with end-stage kidney disease,"

said Joern Aldag, CEO. "We are excited that we are seeing strong antibody

and T cell responses, in particular in patients who received three administrations. We continue patient accrual and plan to report

preliminary efficacy data and updated safety and immunogenicity data by the end of 2020."

or CMV, 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 half the people in industrialized countries and up to 99%

of people in developing countries, including China and India, have been infected. Infections typically 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 CMV

infection or reactivation of CMV causes significant morbidity, mortality and graft rejection.

Pharma Inc. (NASDAQ: HOOK) is a clinical stage biopharmaceutical company developing a new class of immunotherapeutics targeting

infectious diseases and cancers based on its proprietary arenavirus platform that is designed to reprogram the body's immune

proprietary arenavirus-based technologies, VaxWave , a replication-deficient viral vector, and TheraT ,

a replication-attenuated viral vector, are designed to induce robust antigen specific CD8+ T cells and pathogen-neutralizing

antibodies. Both technologies are designed to allow for repeat administration to augment and refresh immune responses. TheraT

has the potential to induce CD8+ T cell response levels previously not achieved by other immuno-therapy approaches.

HOOKIPA's "off-the-shelf" viral vectors target dendritic cells in vivo to activate the immune system.

VaxWave -based prophylactic Cytomegalovirus (CMV) vaccine candidate is currently in a Phase 2 clinical trial in

CMV-negative patients awaiting kidney transplantation from living CMV-positive donors as well as CMV-positive patients awaiting

kidney transplantation from CMV-positive or -negative donors. To expand its infectious disease portfolio, HOOKIPA has entered

into a collaboration and licensing agreement with Gilead Sciences, Inc. to jointly research and develop functional cures for HIV

and chronic Hepatitis B infections.

addition, HOOKIPA is building a proprietary immuno-oncology pipeline by targeting virally mediated cancer antigens, self-antigens

and next-generation antigens. The TheraT based lead oncology product candidates, HB-201 and HB-202, are in development

of Human Papilloma Virus 16-positive cancers. The Phase 1/2 clinical trial for HB-201 was initiated in December

2019. The HB-202 IND application was cleared by the FDA in June 2020.

out more about HOOKIPA online at www.hookipapharma.com.

Forward Looking Statements

statements set forth in this press release constitute "forward-looking" statements within the meaning of the Private

Securities Litigation Reform Act of 1995, as amended. Forward-looking statements can be identified by terms such as "believes,"

"expects," "plans," "potential," "would" or similar expressions and the negative

of those terms. Such forward-looking statements involve substantial risks and uncertainties that could cause HOOKIPA's research

and clinical development programs, future results, performance or achievements to differ significantly from those expressed or

implied by the forward-looking statements. Such risks and uncertainties include, among others, the uncertainties inherent in the

drug development process, including HOOKIPA's programs' early stage of development, the process of designing and conducting

preclinical and clinical trials, the regulatory approval processes, the timing of regulatory filings, the challenges associated

with manufacturing drug products, HOOKIPA's ability to successfully establish, protect and defend its intellectual property,

risks relating to business interruptions resulting from the coronavirus (COVID-19) disease outbreak or similar public health crises,

the impact of COVID-19 on the enrollment of patients and timing of clinical results for HB-101 and other programs, and other matters

that could affect the sufficiency of existing cash to fund operations and HOOKIPA's ability to achieve the milestones under

the agreement with Gilead. HOOKIPA undertakes no obligation to update or revise any forward-looking statements. For a further

description of the risks and uncertainties that could cause actual results to differ from those expressed in these forward-looking

statements, as well as risks relating to the business of the company in general, see HOOKIPA's quarterly report on Form

10-Q for the quarter ended March 31, 2020 which is available on the Security and Exchange Commission's website at www.sec.gov

and HOOKIPA's website at www.hookipapharma.com.

and others should note that we announce material financial information to our investors using our investor relations website (https://ir.hookipapharma.com/),

SEC filings, press releases, public conference calls and webcasts. We use these channels, as well as social media, to communicate

with our members and the public about our company, our services and other issues. It is possible that the information we post

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