Branaplam

Branaplam (development codes LMI070 and NVS-SM1) is a pyridazine derivative that is being studied as an experimental drug. It was originally developed by Novartis to treat spinal muscular atrophy (SMA); since 2020 it was being developed to treat Huntington's disease but the trial ended in 2023 due to toxicity concerns.

As a treatment for SMA, branaplam increases the amount of functional survival of motor neuron protein produced by the SMN2 gene through modifying its splicing pattern. It was studied since 2014 in a clinical trial in children with SMA type 1  until the study was discontinued in 2021.

In October 2020, Novartis announced that branaplam reduces the amount of huntingtin protein, which is one of the major therapeutic approaches in Huntington's disease. In 2021, U.S. Food and Drug Administration (FDA) granted an orphan drug status to branaplam for treatment of Huntington’s disease, and Novartis announced that they would start clinical trials in 2021. In August 2022, Novartis temporarily halted the dosing with branaplam in its clinical studies, and in December 2022 the company discontinued the study due to negative safety signals.