But, despite initial setbacks, the therapeutic potential of these cancer vaccines is far from over. Buoyed by recent technological advancements and a broadened understanding of tumour-associated antigens, therapeutic vaccines have undergone a resurgence of interest.
For Christopher Oelkrug, director of business development for Advanced Clinical, it’s an exciting time to investigate the clinical efficacy of therapeutic cancer vaccines. Particularly as recent results indicate that these treatments can help researchers address one of the biggest challenges in oncology – cancers’ so-called ‘stealth-mode’.
“The main challenge is to reactivate the immune system to see the tumour cell and recognise it as a threat,” says Oelkrug. “Cancer cells express tumour associated antigens and/or neoantigens. Even if you use these as a vaccine, you don’t really have an immunogenicity to them. You somehow have to increase that, so that the immune system gets primed.”
Mobilising the immune system is a primary function of therapeutic cancer vaccines. Whereas preventative vaccines work to prevent healthy cells transforming into tumour cells through viral infections, therapeutic vaccines are specifically designed to target tumour-induced immunosuppression, exposing the camouflaged cancer cells and jump-starting the immune response.
For Oelkrug, the disruption of COVID-19 has also contributed to growing interest and innovation in cancer vaccines. At the height of the pandemic, novel platforms received a surge of interest and investment, which ultimately led to the development and approval of a COVID-19 vaccine in just a few short months. Beyond the scope of this one disease, the mRNA vaccine technology has also been noted for its potential in developing cancer vaccines.
Metronomic chemotherapy – the process of administering specific chemotherapy in a low dose – has been shown to eliminate immunosuppressive cells in the tumour microenvironment. When used alongside therapeutic vaccines, the two treatment approaches work in tandem to reveal the presence of a tumour to the immune system and stimulate a timely response.
“Combination is key here,” says Oelkrug. “If you look at clinical trials to enhance the survival of patients, studies have shown that patients have an enhanced survival rate when they were treated besides the cancer vaccines, for example, with cyclophosphamide, which is a type of chemotherapy that depletes regulatory T cells in the tumour microenvironment and leads to an enhanced T cell infiltration.
“The main problem of older generations of cancer vaccines was the low level of antigen production,” says Oelkrug. “Previous studies have shown an inefficient cellular delivery of plasmids when you look at, for example, DNA cancer vaccines, which led to an insufficient stimulation of the immune system.
“Therefore, you want to change different points within the whole development of cancer vaccines, and you can do that by the antigen design itself. You can look at different antigens, and the vector system you’re using, such as viral vectors, the dose, and how the vaccine is actually delivered.”
Moreover, it is important to acknowledge that cancer vaccines are more suitable for patients with a functioning immune system. Each patient will have individual needs, and while different routes of delivery make it possible to elicit specific immune responses, clinical trials of cancer vaccines should fully consider the patient’s immune system function, risk of recurrence, and tumour burden.
If the current trajectory of progress is maintained, therapeutic vaccines could become a reality for cancer patients around the world. Moreover, a greater understanding of the immune system will allow researchers to explore additional areas where vaccines could be impactful.
“More vaccines getting approved will lead to a huge impact on how we can treat cancer,” says Oelkrug. “Getting away from really harsh treatments and looking at cancers that are not operable, or where the survival rate is really low.”
For Oelkrug, this tenacity is an encouraging sign that further progress is attainable as each seemingly small step brings the industry and patients closer to the ultimate goal of eradicating cancer.
“There is no golden bullet to target tumour cells, like cancer,” he concludes. “It’s always the next challenge to try and get rid of them.”
Christopher Oelkrug is a director of business development at Advanced Clinical. His main focus is on identifying new opportunities with clients to provide a better clinical experience. Based on his broad experience in Cancer Immunotherapy and Immunology and his entrepreneurial mindset, Christopher brings a unique perspective to novel developments within these therapeutic fields. He has a M.Sc. in Cancer Immunotherapy and was head of immunotherapy and oncology at a German research institute. Furthermore, Christopher is the holder of two patents in gut microbiome modulation and antibiotic resistance via IgY mediated therapy.
Advanced Clinical is a clinical development and strategic resourcing organisation committed to providing a better clinical experience across the drug development journey. Our goal is to improve the lives of all those touched by clinical research – approaching each opportunity with foresight, character, resilience, and innovation. Based on decades of experience, we help our clients achieve better outcomes by conducting candid conversations and anticipating potential issues through our customised solutions. Visit our website to learn more: www.advancedclinical.com.