I had been been on Acalabrutinib for 3 years, but my numbers were trending up for several months, so my Hematologist recently switched me to Venteclax. I wasn't eager to change because Acalabrutinib was working great for the first 2 years. As my numbers first started heading north of normal, I felt okay, but then one day while on vacation, I suffered seriously inflamed lymph nodes at the base of my skull giving me the worst headache ever. Then, I had to stop taking the Acalabrutinib for a few days prior to starting the new medication and that was really rough. Even though the Acalabrutinib wasn't as effective any longer, it was still better than nothing. Now, 3 weeks into the new medication, my numbers are moving down and I'm feeling better. I wonder why one med stops working and another works better for me.