Here is an interesting article about the expanding field of BTK inhibitors that are in the pipeline. Some look very promising as superior alternatives to ibrutinib. This is good news. Even more good news is that they offer potential price competition for ibrutinib.
This also raises the question about how will all of these companies be able to recruit enough trial subjects in order to fill these trials? This is a big market with significant financial opportunity. Plus all of these drugs have limited patent protection lifetimes. This means that there will be big pressure to get these trials staffed and completed as soon as possible. The early birds will get the worm!