100 Days and 13 Years

Aaron hit two big milestones this past week: He turned 13 years old, making him an official teenager. And he made it to Day +100.

100 days post-transplant is significant for a bunch of reasons: the threat for GVHD goes down; blood counts generally stabilize; certain medications are reduced or even eliminated; the central line is removed; another bone marrow biopsy is performed to check the cellularity and chimerism; restrictions from the low-microbial diet are lessened; and, in some cases, the weaning process of the immunosuppressant (in this case, tacrolimus) begins.

There's an emotional reward that comes with 100 days as well. We've come so far, and it feels like maybe, hopefully, we're through the worst part of the storm. We can just begin to make out the line of the horizon after a long night. We are pointing our boat towards the future.

With Aaron's first transplant, the bone marrow team chose to wait until he was six months post-transplant before beginning to wean him off of tacro. This is the normal procedure for patients with bone marrow failure (in contrast with leukemia patients, who usually begin the weaning process at Day +100). 

At this point, it is that immunosuppressant that is keeping Aaron tied to home more than anything else. Even though he feels well and his counts look relatively good, his lack of immune system puts him in a very vulnerable state. 

As just an example of what the immunosuppressant does, let's take a look at the Covid-19 vaccine. With cases surging right now, I would love for Aaron to be able to have the protection offered by the vaccine. But even though he is old enough, the immunosuppressant would make it completely ineffective. A vaccine works because it triggers an immune response and the body builds up antibodies, which can later be called on to fight the virus if it is encountered. But with Aaron, his immune system is asleep. So if he got the vaccine, there would be no immune response. His body would ignore it. 

Unfortunately, if his immune system won't pay attention to a vaccine, it also won't pay attention to a virus. Something could be wreaking havoc inside of him, and his immune system, particularly his T-cells, would just sleep right through it. This is exactly why the doctors were so proactive with treating CMV a couple of months ago. His immune system wasn't paying any attention to it, so it could have stealthily wiped out his transplant. 

Anyway, all this to say that we were staring down another three months on this drug while Aaron sat around at home, twirling his thumbs, waiting for something to happen.

But then on Friday, Dr. R. burst into the exam room with, in Mike's words, "guns a-blazing." I'm not sure that's exactly the right idiom, but basically what he meant was that the doctor came in with a plan of action, which he intended to implement immediately, to get things moving for Aaron.

At the heart of this plan was to begin tapering the tacro. 

And just like that, three months of waiting vanished. How can I describe to you the feeling of thinking you're going to be waiting until the end of October but then having it suddenly jump forward to that very day? It was a gift: "Here, you can resume your life three months sooner than originally planned." 

To be honest, Mike and I had wondered if tapering the tacro early was a possibility, since we knew that it was done with cancer patients. We had discussed it several times between ourselves but ultimately decided not to bring it up with the doctor because it didn't seem likely to get a good response. 

But then that's exactly the plan he came up with.

As I mentioned last week, we've been thinking about the school situation a lot, trying to determine if there's a safe way for Aaron to go at least part of the time. I think this got the team thinking about Aaron's particular situation and if it was wise to wait until six months post-transplant to begin the taper. 

And what they ultimately decided was it would be beneficial to get Aaron off of tacro as soon as it was safely possible. In Dr. R's words, "This is not a compromise. It is what I'm advising you to do." I think he wanted to make sure we knew that he wouldn't consider jeopardizing Aaron's health just to get him back in school sooner. 

Instead, the reason why they decided to taper tacro three months early was the answer to this question: "What is the one thing we are most concerned about?" Graft failure. This is what happened in January, and we are doing everything we can to ensure it doesn't happen again. 

In a couple of weeks, Aaron will have another bone marrow biopsy. This will give us key information about the health of his bone marrow. Particularly, we will be able to see what his T-cells are up to. What percentage of them are Aaron's vs. Maxwell's? When they drew a blood chimerism in June, it looked like the T-cells were 100% Maxwell's, but the biopsy will give us a more accurate picture, particularly if anything is starting to go wrong and Aaron's cells are making a comeback. If this is the case, then we actually want the immune system to be back up and running to knock Aaron's cells back down.

And if that's not the case and things still look good on the bone marrow front, then we still want to restore his immune system so he can protect himself from illnesses this fall and winter. Either way, it's a win-win.

Maybe.

There is, unfortunately, always the threat of GVHD, and the risk of this actually goes up as the immunosuppressant goes down. GVHD can be mild and treatable, but sometimes in can cause chronic complications that are very debilitating. The good news is that Aaron's individual risk is relatively low because: he didn't experience any GVHD the first time, this is his second transplant, and we used the same donor. 

Even though it looks like we're shaving three months off of Aaron's sentence, there are still a lot of things that could happen to slow it back down. So we're trying really hard not get ahead of ourselves or celebrate too early. 

But we have to celebrate a little, right? He is at Day +100, after all.