New Approaches Coming for Blood Cancers

[BillTre]

This article from the NY Times describes new ways to treat blood cancers (cancers of blood cells). Some of these may be approved in a few months.
They involve manipulating immune system cells (also a form of blood cells) to get them to attack the cancer cells, while trying to avoid unintended concequences (like immune responses against the patient).

The immune system has research advantages since the cells are very easy to obtain (just get blood) and culture (grow in a dish) compared to solid tissues. Although many blood cells look alike, there are many different kinds of immune cells based on their molecular differences and stages of development. These are among the easiest human cells to work with.

The exposed position of blood cancer cells (just floating around in the blood mostly) also makes them very accessible to attack by immune cell (also floating around in the blood) approaches, whereas solid tumors might not allow such access.

Trials of similar approaches are also being attempted on solid tumors.

 

[Ygggdrasil]

Obligatory XKCD reference:

https://xkcd.com/938/

(the comic references some of the preliminary CAR-T trials done in 2011, see http://www.nejm.org/doi/full/10.1056/NEJMoa1103849#t=article)

 

[BillTre]

I also found it interesting that one of the studies had some kind of an off switch (details not explained) for the cells they were going to inject:

"They also have an “off switch,” a gene that will let the researchers shut down the cells with a certain drug if they cause dangerous side effects that cannot be controlled."​

I would expect this kind of approach to become common in the future.

 

[Dr Aaron]

The biggest problem is that we don't always know as much about these types of manipulations as we believe we do. Sometimes when you think you are altering one and only one function, only later do you recognize that there were another set of effects influenced by your "singular" alteration. That is usually when the scientists say "Oops!" and disappear into their lab. We still are not as smart as we think we are!

 

[Laroxe]

These ideas are not new, we have known for quite some time that the immune system is involved in the control of malignancy. However one of the defining features of cancers is that they have evolved strategies of avoiding destruction and as cancers progress and the cells become progressively more distant from one another
any cancer may have cells capable of using a variety of strategies to avoid our immune system. Using the new technology to modify our immune cells generally involves ways of overcoming one of these strategies, such drugs or modified cells would form part of the arsenal of available treatments but would be unlikely to replace them. Also tackling some of these strategies is more risky than others. A perhaps more natural approach is in the development of oncolytic viruses, which preferentially attack the cancer cells and in doing so either kill them or label them for destruction.
We are at the very start of a revolution in medicine based on our greater understanding of some biological processes, its interesting stuff but its still early days.

 

[BillTre]

The FDA has now approved using modified T-cells (from the patient, to avoid rejection problems) to attack B cell acute lymphoblastic leukemia (ALL) as a treatment in the US.
The T-cells had a gene for a chimeric antigen receptor added which targets the leukemia cells. Because the T-cells come from each individual patient, the modified cells are created uniquely for each patient (which makes it expensive and in short supply).
The particular treatment was developed by Novartis.