June 27th, 2023

Here's update #7 on our study! I seem to have gravitated to a four-week interval between updates - I may speed up again in due course.

I promised last time that the next update would be the first to include survival curves, and I am a man of my word, so here is where things stand as of a couple of days ago. The first thing I want to say about what you see here is that IT MEANS NOTHING YET!! I know that a lot of you are not statisticians, or even scientists, and that most people who do not have training in such matters are highly prone to over-interpret preliminary data. But I also know, and this is even though I myself have plenty of such training, that it's still fun to look at the numbers and speculate frivolously about what the future may hold - and hey, we owe it to so interested an audience to give you a good time.

First, note that I've drawn these with the x-axis starting at the age at which we started treating the mice, and the y-axis starting at 75%. This obviously just avoids wasting space on uninformative ages, but it could be confusing until you notice it, so I thought I should point it out.

One thing you will notice here is that the various treatment groups stop at different ages. Those of you who have been following this project since it began will know why, but for more recent arrivals I should explain that we divided the ten groups into four cohorts, spaced by intervals of two weeks in date of birth. This was easier for our suppliers Jackson Labs, and it also minimised the spikes in manpower for our partners at Ichor who are performing the study. The x-axis on these plots is age, rather than calendar date, so they all begin at the same point (on the left) but they end at different points (on the right).

Another detail is that the plots for some of the groups have slightly different step sizes. That's because, in order to cope with some logistical issues early on in the treatment schedule, we had to move a few mice around, such that we did not actually start with 50 mice in each group: six of the 20 groups had slightly different numbers. See an earlier update for more details on this.

Other than that, all I can really say about what is shown here is, again, that IT MEANS NOTHING YET!! For example, you may notice that we have almost as many deaths among the females that are receiving our senolytic (galactose-conjugated Navitoclax) as among those that are receiving nothing - but the best evidence that that means nothing is that the same is NOT so among males.

Finally a look ahead to the next update. As you can see here, we have for the first time reached the first "cull point" for one group, namely the all-control females. That, as explained in the original description of the project at levf.org, is when we kill four of the remaining 40 mice and preserve a dozen tissues, some fixed and some frozen, for future analysis. At these points we also do all the host of non-invasive "in-life" analyses listed on the project description, assessing cognitive and physical function and such like. So I'll be reporting on the results of those analyses next time; what we will be looking for is any detectable change relative to the baseline measurements we did back in February. As with today's report, what I tell you then will mean essentially nothing - partly because of the small numbers, but also because the purpose of these analyses only emerges as we get to a given cull point for multiple groups and can detect differences between them.

So, bye for now and enjoy your speculations on the survival curves. Did I mention that IT MEANS NOTHING YET!!