Immunotherapy, or antibody treatment that activates the patient’s own immune system against cancer, is increasingly being studied as an alternative to chemotherapy and radiotherapy. This is because it directly targets cancer cells, reducing the negative effects associated with more conventional treatments.
Tumours, such as some breast and ovarian cancers, can express the marker HER2. HER2 is responsible for cancer growth and is the target of existing therapies, such as the most commonly used type of antibodies, IgG. However, this treatment is not always effective in some patients.
Now, scientists have investigated a different antibody type, IgE, which activates the patient’s immune system in different ways than IgG. As they act on different immune cells to IgG, IgE antibodies uniquely stimulate otherwise inactive immune cells in the ‘microenvironment’ surrounding the tumour to target the cancer cells directly.
In the study, led by Dr Heather Bax at King’s College London, the team engineered IgE versions of existing IgG therapies and tested their ability to activate immune cells against HER2-expressing cancer cells.
IgE was shown to direct immune cells against HER2-expressing cancer cells, and slowed tumour growth in mice. The tumours grown in mice are known to be resistant to conventional treatments, suggesting this new treatment could be an option for patients who don’t respond to existing therapy.
Further investigation revealed that IgE antibodies stimulated and reprogrammed the ‘immune microenvironment’ around the tumours themselves, shifting from an immunosuppressive to an immunostimulatory response. This means the immune system was activated to target the cancer cells and overcome the tumour’s actions to suppress attack. The study has shown the potential of IgE as a new therapy for HER2-expressing cancers, including those resistant to other treatments. The researchers believe that, with the right investment and development, this approach could be used in humans in as soon as 3-5 years. Source: ANI