HOW CANCER SPREADS: Protein JAK Makes Cancer Cells Contract, So They Can Squeeze Out Of A Tumor. Coming soon, I hope: JAK blocking agents.

UPDATE: Derek Lowe emails:

Saw your mention of JAK (Janus Kinase) inhibitors, so I thought I’d send you an update from inside the drug industry. There are indeed such compounds in development, for several different diseases. I haven’t written about them on the blog, but they’re quite interesting.

The thing is, there are three different kinds of JAK (and one other closely related kinase), each of which do different things. The paper you mentioned is a JAK1 effect. There’s a Pfizer compound that hits JAK1/2/3 that’s already been through some Phase III work, a Novartis/Incyte compound that hits JAK1 and JAK2, which is now in Phase III, and a Lilly/Incyte compound that also hits JAK1 and JAK2 that’s in Phase II. There are also selective JAK1 and JAK3 inhibitors a bit further back in the pipeline. These things are going for several indications, chief among them rheumatoid arthritis, but also some rare cancers that look particularly susceptible.

So it’s a very lively area of research, being watched very closely by a lot of different players. There’s a lot of promise, but (as usual) a lot of potential problems. Messing too strongly with various members of the JAK family could (in theory) lead to anemia, heart problems, trouble with the immune system, and other such undesirable things. So far, though, the progress through the clinic has been pretty encouraging. That’s the latest!

Faster, please.