RegEx mistakenly removes first paragraph in IE9

RegEx mistakenly removes first paragraph in IE9

I have a RegEx in my JavaScript which is supposed to remove empty
paragraphs from an HTML string (that is, <p> </p> and <p>&nbsp;</p>). It
works fine in FF, Chrome, IE8 but fails in IE9. In IE9 the first paragraph
is always deleted.
var parsedData = '<p>this first paragraph is deleted in IE9</p>';
parsedData += '<p>can contain any number of paragraphs</p><p>&nbsp;</p>';
parsedData += '<p>&nbsp;</p><p>also contains some empty
paragraphs</p><p></p>';
parsedData.replace(/(<p\s+.*>&nbsp;<\/p>|<p\s+.*>\s*<\/p>)*/gm, "");