I had colitis, afib after each infusion, severe dry eye. I completed keytruda August 5 and since then have developed inflammatory arthritis and anemia. I had a total of 9 infusions; every 6 weeks for a year. If they worked (so far yes). If not, then the effect on my quality of life would not have been worth it. But we dont have crystal balls. As of now, the only side effect remaining is the inflammatory arthritis and I'm on prednisone and seeing a rheumatologist