CK-2127107 (CK-107) is an experimental therapy being developed by Cytokinetics in collaboration with Astellas. The treatment is intended to improve muscle function and physical performance in people with diseases associated with muscle weakness and/or muscle fatigue, such as amyotrophic lateral sclerosis (ALS) and spinal muscular atrophy (SMA).

How CK-2127107 works

CK-2127107 is a fast skeletal muscle troponin activator (FSTA). It is designed to slow the rate of calcium release from the regulatory troponin complex, a protein that plays an essential role in the contraction of fast skeletal muscle fibers. By doing that, the treatment sensitizes the sarcomere (the basic mechanical unit that makes muscles work) to calcium, ultimately leading to an increase in the skeletal muscles’ ability to contract.

CK-2127107 in clinical trials

The safety, tolerability, bioavailability (the proportion of the drug entering the circulation when introduced into the body), pharmacokinetics (movement in the body), and pharmacodynamics (effect on the body) of CK-2127107 were evaluated in five Phase 1 trials.

Results from one study, performed in healthy volunteers, showed CK-2127107 was well-tolerated with no adverse events and led to increases in the force of muscle contraction measured by nerve stimulation in the participants.

The effectiveness, safety, and tolerability of CK-2127107 in ALS patients are being tested in a Phase 2 clinical trial (NCT03160898). Researchers will assess the change from baseline in the percent predicted slow vital capacity (SVC), a measure of the strength of respiratory muscles as a predictor of disease progression and survival, and other measures of skeletal muscle function after treatment with CK-2127107.

The study, FORTITUDE-ALS, is recruiting up to 450 eligible ALS patients at centers in the U.S. and Canada.

In addition to ALS, CK-2127107 also is being evaluated in an ongoing Phase 2 trial in people with SMA (NCT02644668), a Phase 2a trial (NCT02662582) in patients with chronic obstructive pulmonary disease (COPD), and a Phase 1 trial (NCT03065959) in elderly participants with limited mobility.

Other details

The U.S. Food and Drug Administration (FDA) granted CK-2127107 orphan drug status for the treatment of SMA.

Orphan drug designation helps companies develop products for rare diseases (those that affect fewer than 200,00 people in the U.S.) by giving them incentives such as tax credits or exemption from FDA user fees, assistance in clinical trial design, and potential market exclusivity for up to seven years if the drug is approved.


ALS News Today is strictly a news and information website about the disease. It does not provide medical advice, diagnosis or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.