New York, US and Vienna, Austria, April 10, 2021 - HOOKIPA Pharma Inc. (NASDAQ: HOOK, ‘HOOKIPA’), a company developing a new class of immunotherapeutics based on its proprietary arenavirus platform, today announced positive preliminary Phase 1 immunogenicity data for its lead oncology candidates, HB-201 and HB-202, to treat Human Papillomavirus 16-positive (HPV16+) cancers. The results are from an ongoing Phase 1/2 study (NCT04180215) currently investigating HB-201 as a single-vector therapy and HB-201 and HB-202 as an alternating two-vector therapy for the treatment of advanced metastatic HPV16+ cancers. The data were presented today at a late-breaker poster session at the virtual American Association for Cancer Research Annual Meeting.
“We’re excited to see the quantity and quality of a targeted immune response, particularly the directly measured increase in HPV16+-specific CD8+ T cells, generated by a single dose of our lead oncology candidates, HB-201 or HB-202. As we are still exploring optimal dosing, these early responses are particularly encouraging,” said Joern Aldag, Chief Executive Officer of HOOKIPA. “We believe our novel arenavirus platform has the potential to introduce a new class of immunotherapeutics that could considerably advance how physicians care for people with HPV16+ cancers. Building on the early clinical results reported on HB-201 in December, we look forward to additional data read-outs from our first clinical oncology program in the coming months.”
Preliminary data showed a strong antigen-specific T cell response after one dose of HB-201 or HB-202, based on direct Enzyme-Linked ImmunoSpot (ELISpot) T cell analysis. (ELISpot is used to quantify antigen-specific T cells in the blood.) All 5 patients who received a single dose of HB-201 or HB-202 had a strong induction of T cells specific to HPV16+ cancer 2 weeks after administration. An up to 250-fold increase in antigen-specific T cells was observed 2 weeks after a single dose of HB-201 in 4 patients. One patient who received a single dose of HB-202 showed a 150-fold increase in antigen-specific T cells 2 weeks after administration. Importantly, the results are based on direct ELISpot without ex vivo expansion of T cells, underscoring the magnitude of T cell response generated by one dose of HB-201 or HB-202. (Ex vivo expansion is often used to amplify responses so that they are more easily measured.) The data are derived from dose level 2 of ongoing dose escalation, and the recommended Phase 2 doses for HB-201 and HB-202 have not been reached.
In addition, analysis of the antigen-specific T cell response showed an increase in CD8+ T cells specific to HPV16+ cancer after a single dose of HB-201 (baseline 0% to 2.8% two weeks later) and HB-202 (baseline 0% to 8.1% two weeks later). These data were assessed using intracellular cytokine staining (ICS) followed by flow cytometry, which differentiates antigen-specific CD8+ T cells (cytotoxic/killer T cells) from antigen-specific CD4+ T cells (helper T cells). Of note, the HPV16+ cancer patients included in this analysis had negligible levels of antigen-specific CD8+ T cells prior to treatment with HB-201 or HB-202.
Other preliminary immunogenicity data highlight immune system activation following a single dose of HB-201. Blood samples from 12 patients were assessed across 13 timepoints for levels of 30 different cytokines and chemokines, which play critical roles in activating an immune response. At the time of data cut-off, baseline and day 4 samples were available for 9 of the 12 patients. The analysis showed that, 4 days after a single dose of HB-201, interferon-gamma levels increased in 90% of patients, and an increase in other immune stimulatory cytokines and chemokines was observed. These data comprise an early sign of natural killer (NK) cell and/or T cell activation by HB-201.
“Treatment options are limited for people with metastatic HPV16+ cancers, and the likelihood for long-term survival is low,” said Dmitriy Zamarin, MD, PhD, Translational Research Director in Gynecologic Medical Oncology at Memorial Sloan Kettering Cancer Center and co-investigator in this study. “We don’t often see this robust and high-quality immune response, particularly in antigen-specific CD8+ T cells, from a single dose and without any combination therapy. I’m excited to see how these early immunogenicity data may translate to clinical outcomes in the future.”
These preliminary immunogenicity data reinforce the promising anti-tumor activity reported from this trial in December 2020 and are consistent with recently published preclinical data, which showed that intravenous HB-201 administration induced single digit percentage of antigen-specific CD8+ T cells, while alternating administration of HB-201 and HB-202 induced a potent CD8+ T cell response, exceeding 50% of the circulating T cell pool. As the HB-201/HB-202 clinical trial is ongoing, HOOKIPA expects to present additional translational and clinical data at upcoming medical conferences in 2021. The company anticipates these data to further inform the HPV program, as well as other earlier stage programs in its oncology pipeline, including therapeutics for prostate cancer, as it seeks to deliver transformational therapies through induction of antigen-specific CD8+ T cells. The poster and audio review are available at https://ir.hookipapharma.com/events/event-details/aacr-annual-meeting-2021.
HOOKIPA Pharma Inc. (NASDAQ: HOOK) is a clinical-stage biopharmaceutical company developing a new class of immunotherapeutics based on its proprietary arenavirus platform that reprograms the body’s immune system.
HOOKIPA’s proprietary arenavirus-based technologies, non-replicating and replicating, induce robust antigen-specific CD8+ T cells and pathogen-neutralizing antibodies. HOOKIPA’s viral vectors target antigen presenting cells in vivo to activate the immune system. Both technologies enable repeat administration to augment and refresh immune responses. As a monotherapy not used in combination, our replicating arenavirus technology has the potential to induce CD8+ T cell response levels previously not achieved by other immuno-therapy approaches.
HOOKIPA is building a proprietary immuno-oncology pipeline by targeting virally mediated cancer antigens, self-antigens and next-generation antigens. The lead replicating arenavirus oncology product candidates, HB-201 and HB-202, are in development for the treatment of Human Papilloma Virus 16-positive cancers in a Phase 1/2 clinical trial.
HOOKIPA’s non-replicating prophylactic Cytomegalovirus (CMV) vaccine candidate, HB-101, is currently in a Phase 2 clinical trial for patients awaiting kidney transplantation. To expand its infectious disease portfolio, HOOKIPA entered into a collaboration and licensing agreement with Gilead Sciences, Inc. to research arenavirus-based functional cures for HIV and chronic Hepatitis B infections.
Find out more about HOOKIPA online at www.hookipapharma.com.
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