Today Sam got his first infusion of rituximab.
Let me back up. Our plan was to try high dose prednisone for 3 months to see whether that could shut down the antibody response that is damaging Sam's kidneys. Sam was on 30 mg of prednisone daily. It was terrible. We have so much sympathy now for anyone who has to take prednisone, especially high doses.
We had heard it could make you ornery, but we still weren't ready for the unpredictable mood swings and tantrums. It was like Mt. Vesuvius every fifteen minutes. Sam is a stubborn kid at baseline, but there was a noticeable change on prednisone. And worst of all, it didn't really work. He still has really high levels of protein in his urine. There was a modest decrease that was most likely due to the ACE inhibitor he started taking, lisinopril. His protein/creatinine ratio dropped from 14 to 5. And his serum albumin came back up into the normal levels. But his kidneys are still inflamed and dumping protein like it's going out of style.
There were some benefits to prednisone. Sam started eating a lot more. We were able to stop all his night tube feeds, which was nice. His face definitely got chubbier, with little chipmunk cheeks. We'll see if those hang around now that we are tapering off. We are currently down to 10 mg daily, and it will take us another month to get off prednisone completely.
So prednisone didn't work. That meant we had to move to plan B. Our nephrologist didn't want to use cyclosporine, which is the usual treatment for membranous nephropathy, because it can be toxic to the kidneys. This would be especially risky in a child with cystinosis who is constantly at risk for dehydration. So that left two other options: mycophenolate or rituximab. Our nephrologist went with rituximab.
Rituximab is an antibody against the cells that make antibodies (wrap your head around that). It targets the precursors to B-cells. B-cells are important immune cells that recognize bad guys like bacteria and viruses, and they make antibodies against them. Sometimes they get confused and make antibodies against things in the human body. That's how autoimmune diseases like rheumatoid arthritis and Crohn's disease happen. Rituximab is an effective treatment for autoimmune diseases because it takes out the B-cell precursors. No B-cells, no antibodies. Rituximab was actually originally developed for B-cell lymphomas. In lymphoma the B-cells start proliferating out of control, so rituximab can be given in addition to chemotherapy to get rid of the cancer cells.
Rituximab is expensive, so our nephrologist had to make a special case for Sam to get it. Then Ashton had to call our insurance and Primary Children's a million times to get the pre-authorization processed.
Since rituximab is given through an IV, Sam had to come to the hospital for his infusion. We were admitted to the Rapid Treatment Unit (RTU), which is where he stayed after he got his kidney biopsy. It's like an observation unit for short stays. Since rituximab is an antibody there is always the risk of an allergic reaction. To minimize this risk, Sam got benadryl, tylenol and solumedrol before his infusion. Then they ran the rituximab really, really slow. Luckily Sam didn't have any reactions to it.
Sam was pretty apprehensive about the IV. He brought five of his stuffed animal dogs with him for support. Luckily the IV team got it placed on their first try. Then it was just room service and movie marathon after that. He watched Frozen, Matilda and the Nightmare Before Christmas while chowing down on a cheeseburger and Pringles. We haven't been watching TV at home so this was his opportunity to binge.
The plan from here is to do an infusion once a week for three more weeks. That will be a full course of treatment, and it should knock his immune system down for three to six months. We'll track the protein in his urine and see if it slows down in the next month. If it doesn't work, I don't know what plan C is.
Rituximab has to work. We'll be praying for that and we appreciate your prayers too.