A new World Health Organisation report on worldwide antibiotic resistance has been
in the headlines this week. It is a massive issue facing global health, and without urgent action could lead to a new era in which diseases and infections we think of as beaten return once again as major causes of death around the world.
Drug resistance is also one of the biggest challenges in the fight against cancer. Just as bacteria are gaining new genetic mutations that make antibiotics powerless against them on a worldwide level, cancer cells are able to evolve ways to evade cancer drugs and continue to grow and spread through the body in individual people.
Here are some parallels between the research which aims to tackle resistance to both antibiotics and cancer drugs.
Targeting multiple weaknesses
One potential way to overcome the problem of drug resistance in cancer, as in bacteria, is to target several different weaknesses at once. The idea of simultaneous treatment with different drugs is very well-established against bacteria – and unfortunately multiple drug resistance has become extremely common in diseases such as tuberculosis. Chemotherapy for cancer is also often given in combination, but what is newer is using modern targeted cancer drugs in combinations specifically chosen to complement each other’s effects.
Here at The Institute of Cancer Research in London, alongside our hospital partner The Royal Marsden NHS Foundation Trust, we are leading several phase I clinical trials that use new and existing drugs in combination. Some of these trials have shown very encouraging results. In cancer, you can also target multiple weaknesses with the same drug. Hsp90 inhibitors, for example, tackle different cancer pathways at the same time, which is one reason why they have
generated excitement in the cancer research community.
Driving evolution
In theory, it is possible for humans to guide bacterial evolution to favour those which cannot resist drugs, as explained in
this recent review from experts at Harvard. Researchers at our
Centre for Evolution and Cancer will study the same principles in cancer: the ultimate aim would be to use treatments that give an advantage to the less aggressive cells in a tumour, helping them to out-compete their neighbours and preventing metastasis, the spread of cancer cells to new parts of the body which is the actual cause of the vast majority of cancer deaths.
The wane of the ‘blockbuster’ drug
“We haven't had a new class of antibiotics since the late 80s and there are very few antibiotics in the pipeline of the big pharmaceutical companies that develop and make drugs,” Chief Medical Officer
Dame Sally Davies recently said. Pointing to the perceived unprofitability of developing new antibiotics, she called on new ways to incentivise the pharmaceutical industry to develop innovative new antibiotics.
In his recent blog on some of the major issues affecting drug development and approval in the UK, Professor Paul Workman also considers the issue of profitability in the development of future cancer drugs. The number of new blockbuster cancer drugs has also fallen in recent years and in the future, companies may need to build larger portfolios of drugs, each of which is used in smaller numbers of patients and tailored to the molecular profile of their cancer. Smarter, cheaper ways of carrying out drug development will need to become more widespread if new cancer drugs are to remain profitable for companies.
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Image credit B0006626
Annie Cavanagh, Wellcome Images: available under Creative Commons by-nc-nd 4.0. The image shows clusters of methicillin-resistant Staphylococcus aureus (MRSA) bacteria.
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