Data from a pair of clinical trials released last week at the European Society of Cardiology annual meeting revealed conflicting results for Boston Scientific (NYSE:BSX) and Cyberonics (NSDQ:CYBX) and their respective vagus nerve stimulation devices for treating heart failure patients.
Boston Scientific’s Nectar-HF trial failed to meet its 6-month efficacy endpoint, while the Cyberonics Anthem-HF trial results showed the vagus nerve stim to be safe and reduce the symptoms of heart failure. But the picture is clouded by the more rigorous structure of Boston Scientific’s study, in which a cohort of patients received a sham procedure.
Nectar-HF principal investigator Dr. Faiez Zannad of the University of Lorraine in France said he was surprised by the results of his study, given the promising pre-clinical research behind the technology, Reuters reported. Zannad said the results might be partially explained by the possible need for a stronger electrical pulse, according to the news service, noting that it might take longer than 6 months for the treatment to show any benefits.
"The careful design and execution of Nectar-HF has resulted in high quality data that will improve the understanding of the role of VNS in the treatment of patients with heart failure," Zannad said in prepared remarks. "Although patients receiving therapy reported feeling better as assessed by quality of life questionnaires, the application of VNS failed to reveal clear benefit when compared to sham, because the effect of therapy was no better than sham on echocardiography derived measurements. Inclusion of an appropriate control group is crucial, and a randomized study like Nectar-HF should be the benchmark for future studies of novel device therapies for the treatment of heart failure."
Dr. Inder Anand of the University of Minnesota, who led the Cyberonics trial, said the 4.5% improvement shown in left ventricular ejection fraction in Anthem-HF is "a very impressive achievement," Reuters reported.
"Despite decades of research targeting the pathophysiology of chronic heart failure and development of pharmacological treatments that impart significant benefits, heart failure remains a leading cause of disability and death. We are encouraged by the significant beneficial effects of Autonomic Regulation Therapy in heart failure patients with reduced ejection fraction represented by the Anthem-HF study cohort. Presentation of the results and simultaneous publication in the Journal of Cardiac Failure provide important details that should permit selection of many patients that may benefit from this therapy, which appears to work synergistically with drugs commonly prescribed in connection with published guidelines," Anand said in a statement.
