A revolution in medicine is picking up steam – a revolution that could transform the prospects of many cancer patients.
For years there have been three main ways to fight cancer: surgery, radiation and chemotherapy. They all boil down to destroying the cancer cells, either by cutting them out, burning them or poisoning them.
In many cases this works, but sadly not for everyone.
The good news is that scientists are now developing a new kind of cancer therapy, one that could make a big difference to survival rates.
And it could also transform the fortunes of one big UK drugs company.
Using the body’s own immune system to fight cancer
Scientists have long suspected that the immune system could be used to fight cancer. As early as 1725, doctors noted that people with syphilis tended to get fewer cancers. Others noted that in many cases, people with cancer who developed a serious fever had then unexpectedly gone into remission.
The first person to actively use this knowledge to fight the disease was William Coley, a New York surgeon and bone cancer specialist. After one of his first patients died of cancer, he searched for treatments that could improve survival rates. He observed that those who developed infections from surgery were, paradoxically, more likely to survive afterwards.
Taking a gamble, he injected streptococcus bacteria into a patient who had cancer. The patient’s malignant tumour shrank. Coley went on to use the method (known as ‘Coley’s Toxins’) on over 1,000 patients until his death in 1937.
Yet his breakthrough was ignored by most of the medical profession. Doctors of the time used case studies rather than proper trials. This made it hard to gauge survival rates for particular therapies. And modern trials of Coley’s Toxins have produced mixed results compared to modern therapies, though the treatment may have some use in advanced cases.
Meanwhile, the development of radiation therapy and early forms of chemotherapy – which seemed to provide more immediate benefits – also reduced interest in Coley’s techniques. Their use finally died out in the 1950s.
Three new approaches to attacking cancer
However, since then, our understanding of the human immune system has evolved greatly. Drug companies are now revisiting the idea of using the immune system to fight cancer. This has triggered a new wave of innovation in cancer treatment.
Basically, there are three distinct strands to this, each of which has produced useful treatments.
The simplest idea is to develop antibodies that can stimulate the immune system to identify, and then then attack, cancer cells. Rituximab, the first antibody targeting blood cancer, was approved in 1998, and is now a standard treatment. Additional antibodies have been released, and several more are in development.
A similar approach which is gaining traction is based on evidence that cancer cells produce molecules (known as PD-1, PD-L1 and PD-L2) that act like brakes on the immune system and prevent them from being destroyed. Targeting and turning off these molecules can allow the body’s defences to do their work.
An even more radical approach is to attempt to re-engineer a person’s immune system altogether. This involves taking white blood cells from the patient’s body and modifying them using genetic engineering, so that they can more effectively deal with the cancer when they’re back in the body.
Make no mistake – these are all high-risk approaches. Trying to find drugs that will allow the immune system to fight cancer is a case of trial and error. Individual cancers vary from person to person. Many people may not receive any benefit at all from these approaches.
And a stimulated immune system can spin out of control, causing auto-immune diseases that attack healthy tissue or even organs. Patients may also develop antibodies that target or interfere with cancer drugs they are using.
As a result, these treatments have mainly been tested on people with advanced cancers that are otherwise untreatable.
However, despite all the caveats, the results for this group have been promising. For instance, one PD-1 inhibitor (ipilimumab) has shrunk the tumours of more than half of people with a sub-type of an incurable lung cancer, and dramatically boosted their survival rates.
Pfizer wasn’t just looking to dodge taxes when it bid for Astra
One company that is betting its future on immune-system based cancer treatments is AstraZeneca (LSE: AZN). Only a few years ago the consensus was that Astra had a relatively poor drugs pipeline compared to its rivals. However, aggressive investment in immune-based drugs means it is now in a prime position to benefit from this revolution.
In 2011 it bought the rights to Tremelimumab, which inhibits molecules that protect cancer cells, from Pfizer. When Pfizer tried to buy Astra earlier this year, it wasn’t just for the tax breaks (attractive though they were). It was partly to get the rights to Tremelimumab back.
In an effort to increase the speed of drug development, Astra has just signed partnership deals with Japanese firm Kyowa Hakko Kirin and Advaxis, which specialises in immunotherapies.
At 17 times 2015 earnings, AstraZeneca is by no means cheap. However, its strong pipeline should allow it to generate enough cash to maintain its dividend of 3.8%.
There are some smaller stocks in this field which, while higher risk, are certainly worth investigating. My colleague Tom Bulford covers one of these – and lots of other exciting medical breakthroughs – in his Red Hot Biotech Alert newsletter. If you’d like to know more about subscribing to his in-depth research, call our customer services team on 020 7633 3602.
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