After yesterday’s expanded FDA approval of its Impella line of heart pumps Abiomed (NASDAQ:ABMD) is heading for an even more significant event. In a year or so a US study, Shield II, comparing Impella with St. Jude Medical’s HeartMate PHP pump during high-risk percutaneous coronary intervention (PCI) procedures will report data.
The approval for cardiogenic shock formalises Impella's use in this indication. Off-label use for cardiogenic shock already accounts for 40% of Impella sales, and with the company now free to market it actively sales could rise sharply. Approval for shock was the latest in a string of coups for Abiomed, but if the Shield II data favour HeartMate PHP at least some of its recent stock gains could be reversed.
The Impella devices are threaded into a patient’s heart on a catheter and left in place for a few hours to aid the heart in pumping blood during procedures such as stenting, before being removed. They may now also be used in patients in cardiogenic shock, a rare and often fatal condition where the heart cannot pump enough blood. It is most often precipitated by a severe heart attack; if treated immediately, about half of patients survive.
For this use they may be left in place longer – up to four days for the Impella 2.5 and CP models and up to six days for the Impella 5.0 and LD devices. This may be extended at the doctor’s discretion.
Analysts at Leerink wrote that though two-fifths of Impella sales are in cardiogenic shock, it is used in only around 5% of the 100,000 or so patients hospitalised for the disorder. On top of the approximately 120,000 patients in whom the devices may also be used to aid PCI, a market also around 5% penetrated, this ought to allow Abiomed to grow at more than 30% annually, the analysts wrote.
Current consensus sales forecasts compiled by EvaluateMedTech have the company growing at 24% annually to 2020.
But that growth could be forestalled by St. Jude. Last year the company bought Thoratec, which makes the HeartMate suite of left ventricular assist devices (St. Jude pumps up heart failure offering with $3.4bn Thoratec buy, July 22, 2015). These are larger, more heavy-duty heart pumps designed to treat heart failure. They are surgically implanted and left in place for months or years.
It is also developing the HeartMate PHP, a pump similar to, but larger and more powerful than, the Impella devices.
The Shield II study is an effort on St. Jude’s part to get FDA approval for the HeartMate PHP as a temporary support device for use during high-risk PCI. It is comparing the device head-to-head with the Impella 2.5 in 425 patients with the aim of proving noninferiority.
The pumps will be used for less than six hours – enough time to allow PCI to be performed and for the patient to stabilise afterwards. Endpoints concern rates of death, heart attack, stroke and bleeding as well as aortic regurgitation and hypotension.
The Impella 2.5 allows a maximum blood flow of 2.5 litres per minute, hence the name. The HeartMate PHP can pump up to four litres of blood per minute. This should allow HeartMate PHP recipients to achieve blood flow closer to normal rates than the Impella patients. Being larger, however, will likely mean the HeartMate PHP is harder to deliver than the Impella 2.5.
Shield II data are due at the beginning of next year. If the HeartMate PHP does prove noninferiority and gains FDA approval, St. Jude will have an edge when it comes to sales force. A much larger company than Abiomed and more diversified though still a cardiovascular specialist, St. Jude has the heft to outmarket its rival.
Abiomed will still be in the lead in the cardiogenic shock indication. It might be well advised to make the most of it.