Rapamycin fails to raise regulatory T-cell levels in RAP-ALS trial

Rapamycin may not work for everything… but it may have been due to Covid period blood testing delays and related issues:

Rapamycin, an approved medication used to prevent organ rejection after a kidney transplant, didn’t increase the number of regulatory T-cells in adults with amyotrophic lateral sclerosis (ALS) who are taking part in a Phase 2 clinical trial.

Along with not meeting its primary goal, RAP-ALS (NCT03359538) also failed to meet a number of secondary measures. The findings may have been impacted by the COVID-19 pandemic, which prevented many blood samples from being collected, and more trials may be needed to support the effectiveness of rapamycin, which was deemed generally safe and well tolerated.

“Rapamycin treatment is well tolerated and provides reassuring safety findings in ALS patients, but further trials are necessary to understand the biological and clinical effects of this drug in ALS,” the researchers wrote in “Randomized, double-blind, placebo-controlled trial of rapamycin in amyotrophic lateral sclerosis,” which was published in Nature Communications. The study was funded in part by Pfizer, which markets an approved version of rapamycin called Rapamune (sirolimus).

While the exact causes behind ALS are not clear, several disease processes are common to most patients. For example, most have an abnormal accumulation of proteins such as TDP-43 or SOD1 that form clumps outside the nucleus of nerve cells, triggering inflammation and damage.