It gets kinda technical but this is some great research on ibrutinib resistance by Dr. Woyach.
ascopubs.org/doi/pdf/10.120... will give you access to the whole article
If you want just a very clear and helpful summary, Dr. Wiestner provides it here:
A few highlights:
For treatment naive patients even those with del. 17p, have a very low progression rate of 1.9%
There are blood markers that can predict relapse before it occurs.
Most Richter’s Transformation (RT) occurs early in the first 2 years, while CLL progression is rare in the first year, but increases over time.
Prognosis for RT remains poor, but for CLL progression after ibrutinib it is getting better.
We are all in this together.