Imugene Limited (ASX:IMU) medical investigators have delivered a number of poster presentations on findings from laboratory and Phase 1b study of the clinical-stage company’s HER-Vaxx cancer vaccine.
The immuno-oncology company’s investigators gave three poster presentations over the five-day European Society of Medical Oncology Congress (ESMO19), which concludes today in Spain.
HER-Vaxx cancer vaccine results
HER-Vaxx lead inventor Professor Ursula Wiedermann of the Medical University Vienna, Austria, presented findings in Barcelona from a phase 1b study of the vaccine in gastric cancer patients over-expressing the vaccine’s HER2 target protein.
All three patients in an objective response test responded to the optimal 50-microgram dosing, experiencing a reduction in their tumour size over a minimum time period.
In 5 of 11 patients assessed for tumour responses, their tumour size reduction was also associated with high HER2-specific antibody levels.
Imugene believes this shows promise for the vaccine’s ability to inhibit HER2-phosphorylation – a vital mechanism of HER2-targeting drugs that inhibit cancer cell growth.
Imugene managing director and CEO Leslie Chong reported today: “We are pleased to share this promising new clinical data with the international medical community at ESMO.
“Together with our dedicated investigators and research teams we are building an impressive library of evidence to support the clinical potential our unique B-cell cancer vaccine pipeline and clinical development strategy.”
A follow-on open-label phase II study of HER-Vaxx in 68 patients with metastatic gastric cancer that over-expresses the HER-2 protein was started in March 2019.
The company aims to wrap up the study in 2020.
Dr Wiedermann’s poster had abstract number 1212P and was titled 'Comprehensive results of a Phase Ib study with a HER2/neu B-cell peptide vaccine administered with cisplatin and 5-fluorouracil or capecitabine chemotherapy show safety, immunogenicity and clinical response in patients with HER2/neu overexpressing advanced gastric cancer'.
It is available from the Imugene website.
HER-Vaxx has potential in a number of cancers
The HER-Vaxx vaccine is a B-cell peptide cancer vaccine designed to treat tumours that over-express the HER2/neu receptor.
These cancers include gastric, breast, ovarian, lung and pancreatic cancers.
The immunotherapy is constructed from B-cell epitopes derived from the extracellular domain of well-known validated cancer target HER-2/neu.
HER-Vaxx has been shown in pre-clinical and Phase I studies to stimulate a potent polyclonal antibody response to cancer target HER-2/neu.
Vaccine combinations show promise
Medical investigators, doctors Tanios Bekaii-Saab and Joshua Tobias, also delivered poster presentations during ESMO, showing that when HER2 vaccines were combined with PD1 vaccines in preclinical models they reduced cancer growth in a number of standard models.
Doctors Bekaii-Saab, of the Mayo Clinic in Phoenix, Arizona in the US, and Tobias, of Medical University Vienna, Austria, presented findings from the early-phase study.
Dr Bekaii-Saab focused on safety and antimour activity in a presentation titled 'Antitumor activity and safety of a novel PD-1 vaccine (PD1-Vaxx) alone and in combination with two chimeric HER-2 peptide vaccine (B-Vaxx) in syngeneic Balb/c mice and canines'.
Investigators found that when Imugene’s PD1-Vaxx was combined with B-Vaxx it was more effective in reducing tumour growth in a HER2 positive colon cancer model than in the PD1-Vaxx vaccine alone or in the positive control standard anti-mouse PD-1 monoclonal antibody.
The vaccine combination was judged safe and did not appear to show any toxicity or autoimmunity.
Imugene hopes to evaluate PD1-Vaxx and its possible efficacy in a range of human cancers.
Dr Tobias looks at immunisation in a presentation titled 'Active immunisation with immune checkpoint inhibitors-mimotope elicits strong in vivo anti-tumour effect against Her-2/neu-expressing tumours'.
Investigators found immunisation with a PD1-derived mimotope vaccine and Imugene’s HER-Vaxx together increased the anti-tumour effect of the combination vaccine compared to each vaccine alone when used in a model of HER2-positive breast cancer.
Active immunisation with the PD1-derived mimotope vaccine also increased cancer cell death and the anti-proliferative effect of the HER2 positive cancer cells in breast cancer tumours.
A monotherapy Phase I trial of PD1-Vaxx will start next year.
Combination study with other immunotherapies is also in the works, along with research to assess safety and efficacy.
Chong highlighted the potential value of the company’s vaccine, saying: “The promising new B-cell vaccine data presented at this year’s ESMO congress and other major cancer research conferences has helped raise the profile of our promising anti-cancer pipeline and its potential clinical value when used in combination with other immune-oncology therapies.
“These latest presentations of comprehensive vaccine combination results help further demonstrate the significant value of Imugene’s B-cell vaccine strategy and the strength of our pipeline.”