The California-based biotechnology company Cytokinetics on Friday announced plans to discontinue a late-stage clinical trial evaluating one of its experimental drugs as a treatment for ALS.
Cytokinetics said its decision follows the recommendation of an outside group of advisers who got an early look at some of the trial data. This group was tasked with conducting an “interim futility analysis” to determine whether the drug, called reldesemtiv, was unlikely to meet the study’s goals. According to Cytokinetics, the advisers concluded the drug had “no evidence of effect” across the study’s main and key secondary objectives.
“We are extremely disappointed with this outcome and would like to thank the people with ALS, caregivers, investigators and clinical trial staff for their participation,” Cytokinetics’ CEO Robert Blum said in a statement, adding that the company will “assess next steps relating to our neuromuscular development programs” in the coming months.
ALS, or amyotrophic lateral sclerosis, is an often rapid, always fatal disease characterized by the progressive erosion of nerve cells. To date, the Food and Drug Administration has approved three medicines specifically for ALS. But each has limited effects on function and survival, and, even with treatment, patients still live an average of just two to five years once symptoms arise.
Cytokinetics’ ALS research has revolved around “troponin,” a protein involved in muscle movement, with the idea being that activating this protein may help treat the disease. The company’s first attempt at this resulted in an experimental medicine called tirasemtiv, but it was shelved after missing the primary goal of a late-stage study that enrolled around 750 ALS patients.
Reldesemtiv is newer, and designed a bit differently than its predecessor. Yet Cytokinetics has still had trouble proving the drug’s merits in ALS. It failed a mid-stage study in 2019. And, according to Mizuho Securities analyst Salim Syed, Wall Street has ascribed nearly no value to the drug.
Instead, investors have been focused on aficamten, a drug Cytokinetics is developing for hypertrophic cardiomyopathy, and, until recently, another medication for heart failure that the FDA rejected last month in a closely watched decision.
For its latest ALS treatment, Cytokinetics set up its Phase 3 trial to have two interim futility analyses, with the first one taking place last year. At the time, the unblinded data available to the external advisers were from three months after at least one-third of the intended number of participants — which is set at 555 — had been enrolled and randomized.
The advisers ultimately concluded the trial should continue, which was “not a surprise,” according to Syed, as Cytokinetics’ chief medical officer had previously told investors the bar for moving forward was “fairly low.”
The second interim analysis, meanwhile, was scheduled to occur six months after at least one-third of the intended number of participants were randomized. Cytokinetics said this evaluation was conducted after approximately 460 patients had been assigned to an arm in the study and more than 200 had been assessed for 24 weeks.
The trial’s main objective was to look for how scores on a widely used scale for measuring ALS symptoms changed over a 24-week treatment period.