Cytokinetics has suspended development of tirasemtiv after it failed to differentiate itself from placebo in a statistically significant manner.
Cytokinetics will scrap its late-stage drug to treat amyotrophic lateral sclerosis (ALS) after its key Phase III trial failed to meet primary endpoints. Shares of the stock plunged more than 33 percent following the Tuesday morning announcement.
Cytokinetics said it has suspended development of tirasemtiv after it failed to differentiate itself from placebo in a statistically significant manner. Cytokinetics said it will focus its ALS efforts on its next generation treatment as a potential therapy for patients.
Cytokinetics Chief Executive Officer Robert Blum said he was deeply disappointed that the Phase III trial failed. He said in a statement that the company remains committed to people with ALS who are “fighting this devastating disease and who need new therapies to slow the decline of respiratory function and muscle strength” that are key hallmarks of disease progression.
“While we believe that VITALITY-ALS demonstrated pharmacologic activity for the mechanism of action, we also believe that limitations of tirasemtiv may be addressed with our next-generation fast skeletal muscle activator, CK-2127107. Based on previous Phase I clinical studies, we believe CK-2127107 will be better tolerated and potentially more effective than tirasemtiv in patients with ALS and look forward to Phase 2 trial results in 2018. We are grateful to the trial investigators, site personnel, patients and caregivers who participated in VITALITY-ALS,” Blum said.
Also called Lou Gehrig’s disease, ALS is a rare disease that attacks and kills the nerve cells that control voluntary muscles. The Centers for Disease Control and Prevention estimates that approximately 12,000 to 15,000 Americans have ALS, with about 5,000 to 6,000 diagnosed annually. The average life expectancy of an ALS patient is approximately three to five years after diagnosis and only 10 percent of patients survive for more than 10 years. Death usually is a result of respiratory failure.
In May, Mitsubishi Tanabe won regulatory approval for Radicava, the first new ALS treatment in 22 years. Radicava was approved based on Phase III clinical trials that demonstrated patients taking the drug had a slower decline in physical function than those taking placebo.
Tirasemtiv, an experimental fast skeletal muscle troponin activator (FSTA), failed to meet the primary endpoint of slow vital capacity, a measure of lung function at 24 weeks, or any of the other secondary endpoints at 48 weeks. The measure of expelling air from the lungs was not consistently significant when compared to placebo, the company said. Full trial results are expected to be presented in December at the 27th Annual International ALS/MND Symposium in Boston.
There were some tolerability concerns with tirasemtiv, particularly in double-blind treatment, Cytokinetics said.
Cytokinetics’ next ALS hope is CK-2127107, a next-generation FSTA. The company said CK-2127107 appears to be more potent than tirasemtiv and also appears to be better tolerated by patients. In July, Cytokinetics initiated a Phase II trial to study CK-2127107. The trial will assess how CK-2127107 benefits patients in slow vital capacity and other measures of skeletal muscle function after 12 weeks of treatment. Cytokinetics is developing CK-2127107 with Astellas Pharma Inc.
Shares of Cytokinetics closed Monday at $11.10 but fell to a low of $7.25 in early trading.
