After rival fails, Cytokinetics could broaden Myqorzo label

Cytokinetics' cardiac myosin inhibitor Myqorzo has succeeded where first-to-market Camzyos from Bristol Myers Squibb failed, hitting the mark in a phase 3 trial in non-obstructive hypertrophic cardiomyopathy (HCM).

Myqorzo (aficamten) was approved by the FDA for obstructive HCM last December, more than three years after Camzyos (mavacamten) reached the market for that form of the disease, which is characterised by thickening of cardiac muscle and stiffness in the left ventricle that interferes with the function of the heart.

BMS's efforts to expand the label of its drug into the non-obstructive setting – a milder form of the disease in which there is no obstruction in blood flow from the heart to the body – suffered a major setback a year ago, however, when the ODYSSEY-HCM trial failed to show a statistically significant benefit.

That led to some speculation that obstructive and non-obstructive HCM might actually be two distinct diseases, requiring different treatment strategies. Now, however, the results of the ACACIA-HCM study of Myqorzo could set those fears aside.

In a statement, Cytokinetics said the trial met both its primary endpoints – the Kansas City Cardiomyopathy Questionnaire Clinical Summary Score (KCCQ-CSS) and maximal exercise performance based on the pVO2 biomarker – compared to placebo after 36 weeks.

In what appears to be a home run for Myqorzo, there were also statistically significant improvements compared to placebo in a range of secondary endpoints, including the proportion of participants with improvements in New York Heart Association (NYHA) Functional Class, the composite z-score of ventilatory efficiency and pVO2, and NT-proBNP, a biomarker for heart damage.

The readout puts Cytokinetics in pole position to bring the first treatment for non-obstructive HCM to market, which could double the number of patients eligible for its drug.

"We believe that the totality and consistency of evidence favouring aficamten across multiple patient-reported and physician-assessed endpoints of symptom improvement and physical function are clinically meaningful for patients with non-obstructive HCM," said the company's head of R&D, Fady Malik.

Myqorzo launched in the US in January and has also been approved in Europe and China, with a launch in Germany due in the next three months, so there will be great interest in the initial sales data for the drug when Cytokinetics reports its first-quarter results, due later today.

The potential market is witnessed by the stellar growth recorded by BMS for Camzyos, which broke the blockbuster barrier last year with a 77% rise in annual sales to reach almost $1.1 billion.

Analyst Srikripa Devarakonda of Truist said Myqorzo's approval for non-obstructive HCM could " solidify its ⁠status as the preferred HCM therapy over Camzyos," according to a Reuters report.

Image by Markus Kammermann from Pixabay