Tracking the immune response to 'seek and destroy' radiotherapy

What you need to know

  • A promising new type of ‘seek and destroy’ targeted treatment, called 177Lu-PSMA, may soon become widely available for men with advanced prostate cancer, but we don’t fully understand its wider effects.
  • Professor Vallis wants to to see if this treatment can also trigger the immune system to attack the cancer.
  • If successful, the results will help to design clinical trials testing the effect of combining this treatment with immunotherapy drugs to further stimulate the immune system.
This project will tell us whether 177Lu-PSMA affects the body’s own cancer-fighting immune response either alone or in combination with other drugs.
Professor Katherine Vallis

Professor Katherine Vallis is aiming to understand whether a new type of targeted radiation drug has the same effects on the immune system as conventional radiotherapy. This could help to stop prostate cancer growing for even longer.

A new ‘seek and destroy’ treatment

Lutetium-177-PSMA is a radioactive drug designed to attach itself to prostate cancer cells. This approach has been described as a ‘seek and destroy’ treatment because of its targeted approach. One part of the drug attaches to a protein called a PSMA receptor, which is commonly produced by prostate cancer cells. This brings the cancer cells into close contact with the other part of the drug – a radioactive Lutetium-177 atom.

The drug delivers radiation from inside the body. This can provide a more targeted treatment than aiming a beam of radiation from outside the body, as we do in conventional radiotherapy. 177Lu-PSMA is not widely available as a treatment but it has been tested in several clinical trials. It has shown promising results in men whose cancer has spread to other parts of the body, when radiotherapy would be difficult if not impossible to use.

Beneficial side effects

Recent research has suggested that traditional radiotherapy can stimulate the immune system to attack cancer cells. Prof. Vallis and her team want to see whether this targeted treatment can do the same.

They will look for anti-cancer immune responses following 177Lu-PSMA treatment in a number of different tumour types. Some will be targeted by 177Lu-PSMA and others will be unaffected by the treatment because they do not produce the PSMA-receptor. If the non-targeted tumours shrink after receiving 177Lu-PSMA, it suggests that it has stimulated an immune response that has attacked these tumours.

Preparing for clinical trials

By the end of the study, Prof. Vallis and her team aim to have analysed the immune responses following 177Lu-PSMA treatment and whether it contributes to controlling the cancer. This will help to design clinical trials in future to test the combination of 177Lu-PSMA with immunotherapy drugs. The immunotherapy drugs should activate the immune system further, giving an even greater effect.

Grant information

Reference – MA-IMM19-009

Researcher – Professor Katherine Vallis

Institution – University of Oxford

Award - £282,522