Jonathan in our patient services team discusses emerging treatments for cancer, using cell therapy and new ‘super cells’.
When developing a new cancer treatment, one of the most important things to consider is how well it can be tolerated by patients. Often the amount of drug that can be given is limited by the side effects it causes and how they affect the patient’s quality of life.
Although often highly effective, treatments like chemotherapy and radiotherapy work better on cells that grow and divide quickly. This is why they’re used to remove cancer cells, but they have the potential to affect any cell in the body.
This has led to drugs that target individual proteins. which are only found on cancer cells. This generally cause less side effects. However, it’s often difficult to deliver enough drug straight to the cancer. This is because the body is naturally very good at filtering and removing drugs them from the blood.
Now, scientists in California have fused two different types of blood cell together to create a new way of delivering cancer drugs. This new ‘super cell’ has allowed them to take advantage of the natural properties of stem cells and platelets. This mean they can deliver more drug to where it’s needed most. This could have a big impact on how we treat blood cancer in the future.
What does the new treatment involve?
The new drug delivery system is made up of three parts:
- An anti-cancer drug – The scientists use antibodies that target a protein called PD-1 (programmed cell death protein-1) as a way to stop cancer cells. PD-1 is often activated by cancer cells to help them shut down the immune system. The antibody stops PD-1 from working, which means white blood cells can recognise the cancer cells and destroy them.
- Platelets – The PD-1 antibodies are chemically joined to platelets. When the platelets become activated they release the antibodies into the blood, allowing them to do their job.
- Stem cells – The platelets are then fused to stem cells. Just like during a stem cell transplant, when these ‘super cells’ enter the blood they naturally travel to the bone marrow and engraft (attach and get to work). This means the PD-1 antibodies are delivered to the place in the body where they can have maximum effect. The two cell types work together. The stem cells help deliver the drug to blood cancer cells and the platelets helps to release it.
How effective was the treatment?
So far, this treatment has only been tested on mice with leukaemia, but the early results are very promising.
87.5% of the mice treated with the fused ‘super’ cells were still alive at the end of the experiment, which lasted for 80 days. At this time cancer cells could not be detected in the blood of these mice. In comparison, the control mice that were not treated didn’t survive beyond day 40.
When the scientists looked at which genes were activated in these mice after treatment, they found that many of them were linked to an active immune response. The activated cells are known as T-cells which are responsible for removing cancer cells. Specifically, these T-cells are part of our long term immune response, suggesting this treatment might have longer term benefits.
What will happen next?
This early research using mice cells acts as a ‘proof of principle’, which means the same approach could also work in humans. However, further work will now be needed to show that similar ‘super cells’ can be made by fusing human stem cells and platelets. Clinical trials will then be needed to confirm they are safe to use in patients and effective at treating blood cancer.
Although the results so far look promising, it could be several years before this treatment is approved for use in patients.
The idea of modifying our own immune cells as a treatment for blood cancer is the basis of an exciting new area of research known as cell therapy. It involves taking immune cells (which identify and remove cancer cells) from the blood and making them more efficient.
One of the most promising early examples of these treatments are CAR-T cells, which have been approved to treat certain types of leukaemia. You can read more about CAR-T cells in our blog.