What does the drug do?

Tirasemtiv is a muscle activator that increases force (contraction) and power of skeletal muscles and therefore delays muscle fatigue. Instead of aiming to slow down progression of MND, the aim of this drug treatment is to increase quality of life by increasing muscular strength.

A newer version of drug was made and called Reldesemtiv.

Phase 3 (VITALITY-ALS) - Tirasemtiv

Phase 3 clinical trial (known as VITALITY-ALS) recruited 600 people with MND in the USA, Canada and Europe. The trial tested the effectiveness of different doses of Tirasemtiv on breathing function over a period of 48 weeks. The trial was designed to try and reduce the side effects of the drug experienced in previous studies. Tirasemtiv failed to meet its primary and secondary endpoints in their Phase 3 clinical trial. You can read more about these results here. The development of Tirasemtiv was suspended.

Phase 2 (FORTITUDE-ALS) - Reldesemtiv

A new version of the drug, called Reldesemtiv, was tested in a Phase 2 trial which recruited 458 people with MND worldwide. Treatment with oral reldesemtiv appears to slow the deterioration of function, including breathing capacity and muscle strength in people with MND – regardless of whether they are taking riluzole or edaravone. You can read more about the trial here and the trial results here.

Phase 3 (COURAGE-ALS) - Reldesemtiv

The Phase 3 trial will enroll more than 500 people with early MND, to test its investigational therapy reldesemtiv in slowing progressive muscle weakness.The trial design builds upon the results of the recently completed FORTITUDE-ALS Phase 2 trial. The primary goal of COURAGE-ALS is to measure changes in the participants’ ALSFRS-R scores over the first 24 weeks. You can find out more about the trial here.

This trial is recruiting at the following sites in the UK:

Latest News

June 2022 - An Open-Label Extension (OLE) was announced. You can read more here.

Dec 2021 - Most of the patients enrolled are moderate to fast progressors - as discussed at the 32nd International Symposium on ALS/MND. You can read the abstract for the poster here.

Aug 2021 - COURAGE-ALS opened for enrollment. You can read more here.


Want to find out more about Reldesemtiv? Check out the resources below:


Update on clinical trials - part 2

Clinical Trials (Part 2) - Posters: Highlights from Perth

Last updated: 24/10/2022