Open-label Extension Study to Evaluate the Long-term Safety and Tolerability of Aficamten in Adults With HCM

To join this study, you must be an adult between 18 and 85 years old. A key requirement is that you must have already participated in an earlier study that investigated aficamten, the same medicine being looked at here. Also, your heart's main pumping chamber (left ventricle) must be working well enough, specifically with a measurement called LVEF at or above 55% at the start of this study.

There are also some reasons why you might not be able to join. For example, if you have recently taken another similar medicine called mavacamten, or if you've been part of another medical study involving a new drug or device in the last month (or longer for certain medications). We also can't include you if you've had certain heart procedures or developed specific heart rhythm problems since your last aficamten study, unless enough time has passed and your condition is stable.

Also, if during your previous aficamten study your heart's pumping ability dropped significantly below 40% and caused your medicine dose to be stopped, you wouldn't be able to join this study. If you've had a special heart device (ICD) fitted very recently, within 30 days before the start of this study, you also wouldn't be eligible.

If you decide to take part, you will continue to receive the study medicine, aficamten, at a dose between 5 and 20 mg. Throughout your participation, you will have regular check-ups with the study team. These visits will involve various tests to monitor your health and how you are responding to the medicine, including checks of your heart function. The study is designed to follow you for a long time, so you'll continue taking the medication and attending appointments for an extended period, which will be discussed fully with you before you join. The total duration of your participation will depend on the overall study plan and your individual progress.