剥离字符串末尾的（）中的任何内容[关闭]

I have a text string:

$str = "This is my string (something else)";

The string may or may not have something in ( ), but if it does, I need to strip it entirely. I tried this:

$new = str_replace('/\\(.*/', '', $str); 

But it does not seem to work... What am I missing?

$new = preg_replace('/\(.*\)/', '', $str);