TauRx's Alzheimer's anti-tau drug, HMTM, appears to slow cognitive decline and reduce brain atrophy. There's just one problem — and it involves blue pee.
TauRx is currently running a Phase 3 trial called LUCIDITY for what they hope will become the first ever Alzheimer’s pill. But they’ve had to grapple with an interesting twist: The drug turns your pee blue.
TauRx’s experimental drug hydromethylthionine mesylate (HMTM), currently in Phase 3 trials, is designed to target tau protein, an Alzheimer’s biomarker protein that causes tangles to muck up the works in the brain. HMTM would prevent these tau tangles from forming. The company hopes the drug will become the first oral disease-modifying therapeutic to make it to market.
They recently announced results from their Phase 3 clinical trial which tested their drug across 598 people with mild cognitive impairment or mild-to-moderate Alzheimer’s. But the fact that the drug turns participants’ urine blue added a little complication when it came to finding a placebo that had the exact same effects.
While the study provided some evidence that the trial slowed cognitive decline and reduced brain atrophy, there was one enormous problem. Their placebo — intended to turn pee blue but remain biologically inert — was metabolized into the active drug by the body.
Per the press release, the company does not believe a placebo-controlled trial would be feasible. Nonetheless, the company is looking to submit these results to receive marketing approval for HMTM.
“This is the first time any treatment has produced evidence of sustained improvement over the individual’s own pre-treatment baseline lasting 18 months at an early clinically detectable stage of Alzheimer’s disease, and stabilization of disease progression at more severe stages,” TauRx Executive Chairman and co-founder Professor Claude Wischik said in a statement.
The majority of disease-modifying Alzheimer’s drugs that have made it to Phase 3 trials have used antibody-based drugs to clear amyloid or tau pathology. While Aduhelm has received approval from the FDA and lecanemab looks promising, these drugs require expensive infusions and follow-up brain scans to monitor potential adverse effects. This makes them inaccessible to many patients. The pill is a fresh and promising approach — but it is yet to be seen how regulators will respond. Approval of a drug without a proper placebo trial is a large hurdle to overcome.