Change Control

PML risk shown in a scatter plot.
PML risk shown in a scatter plot.

It is funny how studying a subject can alter how you think about problem identification and solving. For example, I studied economics in college, and I evaluate many situations and choices from an opportunity cost perspective. If I do this, what am I not able to do? Now I am a project manager, and I routinely look for setting up decision points and metrics by which I will decide whether or not to change and how to change. I look at the strongest part of my management style is a clear but agile change control process.

So when I get involved in a project, the nice part is the defined end-point possibly with decision points along the way. If it is a well planned project, I have various decision points preplanned. Then it is just a question of gathering the information to make the best choice possible. Thinking like this is what started me taking Tysabri.

When I started taking Tysabri, I was flaring frequently and had just been in the hospital for problems swallowing. People who know me are probably sick of the “losing 13 pounds in 6 days when no on Biggest Loser” line. I was having at least two flares a year, and the last one had been on my brain stem. I couldn’t exercise much, and I was miserable. Talking with J, we decided, “Give me five good years over thirty crappy ones.” Over the years, I regained enough balance to run and exercise. I felt more healthy or at least able to fake it well enough to surprise people when they heard I had MS. After five relatively stable years, J and I said the “Give me five good years over thirty crappy ones” mantra still applies.

Now, after eight years on Tysabri, I am back to looking at other treatments. Why? It is not because I am notably flaring. In fact, my progression of symptoms has slowed down to what I always thought aging would be like albeit slightly faster. For that matter, I plan on running a half marathon at Yellowstone this summer.

A couple of years after I started taking Tysabri, a test came out to see if patients have been exposed to the JC virus. Over half of us have been, but for those who have not there is no significant risk of getting the brain infection PML which is the biggest risk factor for those taking Tysabri. I did not want the test because the risk of getting PML, even if positive, was one I was willing to take. Eventually, it was mandated that I take the test so they could track people taking the drug to better understand and quantify the risks. I was positive, but that did not matter in terms of deciding to stay on Tysabri.

Progress is a marvelous thing. As the years have passed, they have refined the test to look at how many antibodies are present. With that information, they are able to assign different categories for the likelihood a patient will develop PML. I have always been OK, as my odds have never gotten worse than my admittedly arbitrary threshold of 1 in 200. That is the mortality rate of chemo recommended to treat the most treatable cancers (recommended if going solely on mortality charts).

However, when looked at over time, my readings are a bit concerning. In July 2014, my reading was 1.10. In three successive tests since then, my count has increased in each to 1.41 in March 2016. Now the accuracy of the tests is something I question, but I admit that is my bias from looking at government stats for a living. I believe everything after the decimal point is suspect. However, each of the successive readings has been higher than the last reading and the trend of multiple readings is something I have a harder time ignoring. This sent me back to look at MS Research Blog for the most recent data I can find.

A few things leap out at me as I review the data. The first is the data only accounts for patients who have taken Tysabri for up to 72 months (6 years). The odds get worse with time on Tysabri, so it seems likely my odds for getting PML are worse than the stated odds for people in my titre tier. The second concern is the big jump in risk between 1.3 and 1.5. Given the risk categories get worse with each titre tier, it seems likely there is no magic number where 1.4999999 is fine, but 1.50 is much riskier. Does my risk really go from 1 in 769 to 1 in 118 with just a tiny bit higher reading (leaving off my questioning the accuracy)? I suspect it follows the trend line between each of the tiers.

Given my time on Tysabri and my reading, I suspect I am nearing my 1 in 200 threshold. However, I feel OK. I like to think of myself making logic based decisions, and I tend to think these decisions are best made before emotion enters. For example, when I buy a stock, I do so only when I can identify selling points high and low. At the high or low point, I have a decision to make on keeping or selling based on what I think my options are at the time with a bias towards getting out. It always seems important to me to set expectations and recognize when they have been met to a “good enough” extent.

The 1 in 200 is supposed to be my decision point with a bias towards getting out based on how my odds are trending. It is just hard to make decisions based on odds when the decision likely involves worsening conditions… they are just less worse than a likely alternative. So pardon me while I take a few months to enjoy the relative calm in my MS, to be thankful for the 8 years of comparatively good health, to research my next steps, and to run because I still can. Deciding to change need not always be instant, and maybe the time to change is what I buy myself by deciding now. That is the point of a change control process, to have in place a set time to change and a method for determining how to change.

However, change control does not make the change and contemplating what it portends easier.