We’ve decided to go forward with the Reduced Intensity Conditioning (RIC) for Zoe. As I mentioned yesterday, it came up again in conversation with Dr. M, and after a long meeting at Duke where we discussed both the RIC and the “normal” or Ablative conditioning, we felt pretty strongly that this was the right approach.
Let’s back up a moment.
In our first meeting with Duke, we asked about the potential for a RIC process after doing a bit of research, but we didn’t have any cases to look at which were similar enough to Zoe’s to know if it was something that would work with HLH. At that time the idea was dismissed for the most part, since it’s not how they have done things with HLH patients, and they have had a good track record with their process.
Since then, we’ve spoken with or read about a few different cases where HLH patients took this approach, so we decided to bring it up again for consideration. This time the response was extremely positive, in fact Dr. P felt that it was the best approach having spoken to colleagues and done additional research since we first discussed it.
We’ve rewritten the plan entirely at this point.
Reduced Intensity Conditioning is a process traditionally used for patients who cannot handle the standard ablative (high dose) conditioning in advance of a Bone Marrow or Stem Cell Transplant. It often involves an entirely different set of medications designed to achieve the same goal, but with less damage to the body.
The goal of the conditioning is to prepare the bone marrow for the new cell material, either donated bone marrow or stem cells. If the transplanted material does not take or “graft”, then the process has to be repeated or restarted.
Different diseases require different levels of conditioning. Some require the high dose or ablative conditioning to ensure that the disease is wiped out in the body before beginning. Others, such as immune disorders or non-malignant diseases, might require less intense conditioning since there is not something that has to be eliminated, rather the bone marrow is being prepared for new cell material. Partial elimination might be enough in these cases.
In short, ablative conditioning completely wipes out the bone marrow. RIC can either partially wipe it out, leaving some material but making enough room for the new transplant material, or completely wipe it out, giving the same results of the ablative therapy without the additional risks.
Advantages and Disadvantages
The advantages of RIC are numerous. For starters, all of the disadvantages of normal high-dose conditioning are reduced or eliminated.
- The patient has less increased risk of future malignancy
- Higher chance of remaining fertile
- Reduced damage to the organs
- Less chance of growth retardation and/or puberty delay
Disadvantages are few.
- Chance of needing to repeat or restart the transplant procedure if graft fails
- Longer conditioning process
- Chance of relapse with some conditions or diseases
So why not do RIC? Well, a patient may not qualify for it due to their disease, or they may prefer to take a more conservative approach. RIC is newer and less tested, and the process is still being refined. Traditional conditioning is well tested and established, and it is a more sure approach in terms of the graft.
RIC and HLH
RIC has a relatively short history with HLH so far, due in part to the relative immaturity of HLH research. There are studies, and in some transplant hospitals they do RIC with HLH, but keep in mind that there are very few HLH patients in any given year. This makes it hard to accumulate results.
What sporadic results there are have been fairly positive, as best I can tell. Outcomes seem to be as good or better than ablative conditioning, and Dr. P confirmed our impressions in our discussion. Dangers still exist with any transplant: Graft Versus Host Disease and risk of infection are the two biggest and are no less dangerous on RIC.
Most of the existing studies I was able to find do not use cord blood stem cells as the transplant material however, making the specific combination of Unrelated Cord Blood, RIC and HLH exceedingly rare.
Zoe will be the first HLH case treated with RIC at Duke. They have treated numerous other conditions with RIC however, and the process is very similar. The medications are all well tested and established. The precautions are all in place for GVHD and infection as they would be in any transplant situation, and the team at Duke is great.
What does this mean for Zoe?
Zoe is in about as strong a position as any child could be going into a transplant with HLH. Her organs are in good shape, she has no fever, no other known infections. If there were ever going to be a successful case to do RIC with a cord blood transplant in an HLH patient, we like to think that Zoe is it.
This is a more modern treatment and gives her the greatest chance of walking away from this unscathed. I strongly suspect that HLH will be treated with RIC increasingly, given what I’ve been reading about the results. There just doesn’t seem to be a significant downside.
Worst case scenario related to RIC, she doesn’t graft and we have to start over with conditioning and a new transplant. Obviously GVHD and infection present other worst cases unrelated to the conditioning process.
This means we’ll be starting Zoe on Campath in a couple weeks in the outpatient clinic. After a week of that, she’ll have a week off, then we start the heavier chemo medications and Zoe will be admitted.
Our optimism is now at it’s highest point since we began this journey. We still have a hard path ahead, but we feel better than ever that we’re getting the best treatment we can for Zoe and that our advocacy is working in her favor.