New age for nuclear medicine

Mention the term nuclear medicine and it conjures up images of radioactive isotopes, such as iodine, deployed since the 1950s to treat thyroid cancer. But today there’s a small, yet growing, class of drugs, called radiopharmaceuticals, that are ushering in a new age in oncology, way beyond treating this type of cancer.

What’s groundbreaking about these treatments is that unlike regular radiation therapies, which attack all cells with larger doses of radiation, these are usually extremely targeted. They carry small doses of radioactive substances (isotopes) directly to tumour cells, allowing them to zero in and attack the cancer at close range. This normally means fewer side effects and less damage to healthier parts of the body.

Radiopharmaceuticals are already used for diagnosing diseases of the heart and kidneys, as well as some cancers, where a harmless amount of radiation is delivered precisely to an organ so you can get an accurate picture of it. If you see a bunch of bright spots on a screen image, they typically indicate a tumour, then you know you have the right type of cancer for potential treatment with that specific radiopharmaceutical.

Up the dose and you can use the same strategy to deliver radiation directly to treat the disease. Scientists pair isotopes  (radioactivity) with a protein or antibody that specifically targets cancer cells. The treatment works by breaking bonds in cancer cell DNA (instructions for developing and function of the cell), killing them from the inside out; this is called systemic radiation therapy.

The good thing is that the image derived from the diagnostic phase can now be used as a biomarker to identify the patients who may benefit most from treatment. Systemic radiation therapy is therefore the first and best example we have of personalised medicine.

It’s difficult to imagine a world without cancer, but new radiopharmaceuticals could help in this journey

This is considered the Holy Grail of medicine whereby targeted treatments are based on the unique characteristics of each patient’s disease, rather than a one-size-fits-all approach. Labelled theranostics, it’s about providing the right treatment for the right patient at the right time, where the right dose is the goal; it’s the reason why radiopharmaceuticals have been called smart drugs.

It also helps that there’s a growing acceptance of this type of nuclear medicine globally. This is because of the greater burden of new cases of cancer, as we live longer, and that there are more drugs available. Radiopharmaceutical treatments are also increasingly accepted and tolerated by patients, as well as their families. Toxicity is generally low in many patients. They can also be used in combination with other drugs.

The number of cancers that could be treated this way is potentially significant. In the process, the normally devastating side effects of chemotherapy and radiation may be drastically reduced.

Radiopharmaceuticals have moved beyond just treating thyroid cancer, they’re now used for cancers of the neuro endocrine system, prostrate and bone. Systemic radiation therapy is a platform technology that can be applied to many different types of tumour.

Pancreatic cancer is a major focus, since there are few treatments that bring more than short-term benefits to patients. At Ipsen we believe that radiopharmaceuticals have immense potential to significantly improve the lives of patients with rare and difficult-to-treat cancers. There are still many people with cancer who have a poor prognosis and lack of treatment options.

Recently there’s been a stronger commitment by big pharma to nuclear medicine and a greater recognition that radiopharmaceuticals are real cancer drugs, no different in efficacy or development complexity, which is in fact greater than many of the modern generation of anti-cancer agents.

Developing this class of drugs is no small feat; they require complex manufacturing and supply chains. Because of their radioactive nature, they have a short shelf live and have to be handled carefully; shipments are regulated and staff have to be trained.

We’re also getting better at developing drugs that can target particular cancer cells more precisely. That’s because there’s increasing realisation that receptor-binding molecules can be exquisitely designed. There are also more therapeutic radioactive elements now available.

Therefore, radiopharmaceuticals appear to have a great future, especially targeting diseases where outcomes have not improved significantly in the last 20 years, such as biliary and pancreatic cancer, as well as glioblastoma, a cancer of the brain.

These drugs have to be seen in a wider context. The development of the field of nuclear oncology, where medical specialists are trained in the use of systemic radiation therapies and learn how to care for their patients with this exciting technology is crucial. There are currently initiatives underway to help bolster
this discipline.

It’s difficult to imagine a world without cancer, but new radiopharmaceuticals could help in this journey. These are exciting times.

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